The present disclosure relates to a lithium-replenishing material, a preparation method thereof, and a lithium-ion battery. The lithium-replenishing material comprises metal lithium particles and conductive material, and the conductive material includes a built-in segment embedded in metal lithium particles and an exposed segment external to metal lithium particles; the electrical conductivity of the conductive material is greater than 100 s/cm. The lithium-replenishing material of the present disclosure can accomplish the electron conduction between the metal lithium particles and the anode active material through the conductive material, which increases the channel of electron conduction, and at the same time facilitates the transport of lithium ions, and improves the efficiency of lithium-replenishing significantly by rapid intercalation process of lithium ions, thereby resulting in inhibiting the formation of isolated lithium effectively and avoiding the formation of dendrites piercing the battery separator and causing potential safety hazards.

A secondary battery according to an embodiment of the present disclosure is a secondary battery including a cathode in which a cathode material is applied onto a cathode current collector, wherein the cathode material includes an irreversible additive and a cathode active material, and the irreversible additive includes lithium nickel oxide (LNO) having a trigonal crystal structure within an operating range from 3.0 V or more to 4.0 V or less in the secondary battery.

The present disclosure relates to a method for optimizing the formation protocol of a battery. The method can include the steps of: (a) providing a battery cell structure comprising an anode, an electrolyte, and a cathode including cations that move from the cathode to the anode during charging; (b) performing a first charge of the battery cell structure using a predetermined formation protocol to create a formed battery cell; and (c) determining a cell internal resistance of the formed battery cell. Therefore, one can compare the cell internal resistances of two battery cells formed by using identical battery cell structures and different formation protocols, and select a formation protocol if the first cell internal resistance of a first formed battery is greater than or less than the second cell internal resistance of a second formed battery.

The embodiments of the present application relate to the technical field of battery production, and disclose a formation system, comprising a clamp, a suction nozzle, and a negative pressure source, the clamp being used to clamp a battery, the suction nozzle being disposed corresponding to a liquid injection hole of the battery to collect formation exhaust gas from the battery, and the negative pressure source being connected to the suction nozzle to provide negative pressure environment for the suction nozzle, wherein there is a preset distance between the suction nozzle and the liquid injection hole of the battery to prevent electrolyte in the battery from being drawn out. The formation system according to the embodiments of the present application can prevent the loss of electrolyte caused by the electrolyte inside the battery being drawn out of a housing.

A negative electrode material that is used for a negative electrode of a lithium secondary battery containing a non-aqueous electrolyte solution, includes: a first layer that contains lithium metal as a negative electrode active material; and a second layer that is arranged on at least one surface of the first layer. The second layer consists of a compound represented by a general formula M.sub.xA.sub.y (M is an element selected from a group consisting of Al, In, Mg, Ag, Si, and Sn, and A is an element selected from a group consisting of O, N, P, and F, and 0.3<x/y<3). The second layer has a thickness of 100 nm or less.

A battery unit may comprise a first cell type and a second cell type electrically connected at least in series, wherein the first cell type may include N first cells, the second cell type may include M second cells, and N and M are positive integers; the first cell may have a discharge cell balance rate of CB1, the second cell may have a discharge cell balance rate of CB2, with 0.5≤CB1≤CB2≤1.4, and when the battery unit is charged to 95%-100% of the state of charge, the first cell may have a corresponding open-circuit voltage change rate of not greater than 0.005 V/% SOC, and the second cell type may have a corresponding open-circuit voltage change rate greater than that of the first cell.

A method for operating a battery having at least two battery cells includes a symmetrization process, in which states of charge of the battery cells are symmetrized continuously or repeatedly; a first measurement process that runs across a first predefined duration during symmetrization and in which measurements are performed repeatedly. In each of the measurements, the battery cell that has the lowest quiescent voltage out of the battery cells in the measurement is determined. It is determined whether the same battery cell was always determined as the battery cell having the lowest quiescent voltage during the first measurement process; and when this is the case a checking process is performed in which symmetrization is interrupted or terminated and it is checked whether the battery cell for which the lowest quiescent voltage was always determined during the first preceding measurement process exhibits increased charge loss that indicates a possible defect.

Manufacturing a lithium-ion battery includes assembling the lithium-ion battery; and performing an initial charging on the lithium-ion battery. The lithium-ion battery includes a positive electrode, a negative electrode, and an electrolyte; the negative electrode contains a negative electrode active material containing a precursor of a silicon material, the precursor having a composition represented by SiO.sub.x where a relationship of 0<x<2 is satisfied. The initial charging includes a first step where the charging is performed to an intermediate voltage at a first current rate, and a second step where the charging is performed from the intermediate voltage to a maximum voltage at a second current rate. The first current rate is lower than 0.5 C; the second current rate is higher than the first current rate; and the intermediate voltage is 3.75 V or higher.

An activation method for a lithium secondary battery, and a lithium secondary battery manufactured using the same are disclosed herein. In some embodiments, the method comprises charging a secondary battery, wherein the secondary battery includes a positive electrode having a sacrificial positive electrode material represented by Formula 1 and having an orthorhombic structure, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte solution, and then holding the secondary battery for a predetermined period of time at a voltage of 3.2 V or greater.

A method for charging and discharging a battery, includes, operations of: manufacturing a battery by coupling a battery case and battery electrodes and injecting an electrolyte into the battery case; and activating a battery by inputting a current pulse having a predetermined period to the battery electrodes, wherein the period includes a first time and a second time, equal to or less than the first time, wherein the battery is charged by the current pulse during any one of the first time and the second time, and the battery is discharged by the current pulse during the other one of the first time the second time.