Guangzhou Fullriver Battery New Technology Co., Ltd.

Guangzhou Fullriver Battery New Tochnology Co., Ltd.

Dingbo Cheng

Shihua Zeng

Shengcheng Tang

Xiaoping Zeng

Changyong Zhang

A method for grouping lithium secondary battery packs comprises the following steps: charging and discharging a battery for 1-3 cycles, recording the last discharge capacity C, setting a capacity lower limit, and determining the battery with the Cthereof not less than the capacity lower limit to be an eligible battery; discharging the battery to a discharge cut-off voltage Vso the battery is discharged to a power empty state; charging the empty battery to a capacity C; storing the battery for time tin an environment with a temperature ranging between 20-50&#xb0; C., recording the battery voltage V, storing the battery again for time tin the environment with the temperature ranging between 20-50&#xb0; C., recording the battery voltage V, calculating a voltage difference &#x394;V=V&#x2212;Vand setting the range of &#x394;V; and grouping eligible batteries in a previous step according to a certain capacity grouping standard.

Method for grouping lithium secondary battery packs

A method includes providing battery cells for secondary batteries. The battery cells are charged to a fixed voltage (Vc). The battery cells are laid aside in an open circuit for a preset self-discharge time period (t). A voltage (Vt) is measured after the period t for each battery cell. A voltage difference (&#x394;V) is determined for each battery cell, wherein &#x394;V=Vc&#x2212;Vt. A self-discharge rate (&#x3c1;) is measured for each &#x394;V. A self-discharge current (Ic) is calculated during the period t, wherein Ic is a function of &#x3c1;. The Ic is curve-fitted to the &#x394;V for each battery cell to obtain an Ic&#x2212;&#x394;V equation. The Ic is divided into h number of grades. The Ic&#x2212;&#x394;V equation is utilized to determine h number of grades of &#x394;V associated with each grade of Ic. Battery cells are selected having a same grade of Ic and &#x394;V for matching.

Method and system for equalizing and matching lithium secondary batteries

In the present invention, a method and system for equalizing and matching lithium secondary batteries belong to the field of secondary batteries. A lithium secondary battery is divided into more than one grade according to the magnitude of a consumable current Ic, the number of grades is h, the lithium secondary battery is divided into grades corresponding to the consumable current according to the magnitude of a voltage difference &#x394;V, a battery cell at a grade same as that of the consumable current and the voltage difference is selected for matching, so the range of the consumable current of the battery group can be controlled. The battery system configured in the method of the present invention converts consumable current grading into voltage difference grading after laying, so as to be convenient and swift; the range of the consumable current of the battery cell, the laying time, the equalization charging period, the equalization current, and the charger cutoff current are all under control, and are matched with each other, the equalization cost is low, and the charging equalization time is short; the laying service life and the maintenance period of the battery group can be designed or predicted during matching, and how many times of charging/discharging is required to charge the battery group to be balanced after the battery group is laid for an extremely long time is estimated in advance; the battery group reject rate is reduced, and the battery group reliability is improved.

The present invention provides a quick charge method belonging to the field of the battery and particularly relates to a quick charge method for lithium ion battery and polymer lithium ion battery. During a battery is being charged, the battery stops charging when the battery is charged to a charge limit voltage, and the charge limit voltage between two poles of the battery is set to be U=2U&#x2212;U, and Uis a stabilized voltage which the voltage of the battery falls back to after the voltage of the battery is charged to Uat a constant current, Uis a standard charge cutoff voltage used by a low rate constant current-constant voltage charging mode which is normally accepted by the industries, and the stabilized voltage Uis selected as follows: timing begins when the battery stops charging at the constant current, and from a certain time segment, when the drop of an open-circuit voltage of the battery is less than a certain value within the certain time segment, which means that the voltage of the battery is stable, and a voltage corresponding to the first time point of this time segment is selected as the stabilized voltage Uof the battery.

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Guangzhou, China

Dingbo Cheng