Ultrathin metal shell lithium ion battery and preparation method thereof

Abstract

The present invention discloses an ultrathin metal shell lithium ion battery and a preparation method thereof. The battery comprises an ultrathin metal shell and an internal battery cell, the internalbattery cell is composed of a positive pole piece, a negative pole piece, an isolating membrane and an electrolyte, and a lithium metal layer is embedded in the inner wall of the ultrathin metal shell to form a lithium electrode; a lithium electrode terminal capable of being connected with an external power supply is arranged on the outer wall of the ultrathin metal shell, the terminal of the negative pole piece is set as a battery cell negative pole, the battery cell negative pole is provided with a negative lead, and the terminal of the positive pole piece is set as a battery cell positivepole which is provided with a positive lead; and the lithium electrode terminal is connected with the negative lead or the positive lead through direct conductive connection or an external power supply, so that lithium metal lost electrons on the inner wall of the metal shell are changed into lithium ions, migrated through electrolyte and pre-embedded into the negative pole piece. The metal shellis arranged to be the lithium electrode, the lithium pre-embedding process of the negative electrode is accelerated under the auxiliary effect of external voltage, the first charging and discharging efficiency of the battery is further improved, and the cycle life of the battery is further prolonged.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to an ultra-thin metal shell lithium ion battery and a preparation method thereof. Background technique [0002] In recent years, with the increasing environmental pollution, the new energy industry has attracted more and more attention. Lithium-ion power battery is an important part of electric vehicles, and its safety performance, energy density and cycle life will directly affect the popularization and use of electric vehicles, thus arousing widespread concern. [0003] Under the condition that the material system of lithium-ion batteries remains unchanged, increasing the energy density of batteries by continuously reducing the volume or weight occupied by inactive materials in the batteries has always been a direction of efforts in the commercialization of lithium-ion batteries. Various components such as current collectors, separators, outer casings, and heat-conduct...

AI Technical Summary

Problems solved by technology

And in patent CN200410052213, just the metal lithium that is encapsulated in the non-breathable cellulose packaging material is placed in different positions of the battery (in the positive electrode sheet, the negative electrode sheet or the metal shell), relying on the spontaneous primary cell reaction to release the metal lithium Converting to lithium ions to supplement the lithium ions consumed during the charging and discharging process of the battery. This method does not consider the speed of pre-intercalation of lithium. The actual test results show that the speed of pre-intercalation of lithium is very slow and random.

Because metal lithium has extremely high chemical reactivity and has high requirements on the environment, some of the above-mentioned methods of pre-intercalation of lithium cannot guarantee the safety of actual operation, and some of them are too complicated in the specific operation process. It cannot be produced industrially, and some are too inefficient to restrict the capacity of large-scale production or the processing cost is too high to affect the overall cost of the battery

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