High energy density safe lithium-ion battery

Abstract

The invention discloses a high-energy-density safe lithium-ion battery, which includes a positive electrode sheet, a negative electrode sheet, a diaphragm and an electrolyte; the composition of the positive electrode sheet slurry is, by mass ratio: LiNixMnyCo1-x-yO2: oxygen absorber: carbon Black: PVDF=92-96%: 0.1-3%: 1-3.5%: 2-3.5%, wherein 1≤x≤9, 9≥y≥1; the slurry composition of the negative plate is, by mass ratio: Graphite: carbon black: CMC: SBR = 91-95%: 1-3.5%: 1.2-2.5%: 1-3%; the diaphragm of the battery is made of polyolefin porous membrane and aromatic polyamide fiber hot-pressed composite. In the lithium ion battery of the present invention, the positive electrode material combines the advantages of LiCoO2, LiMnO2 and LiNiO2, and has the characteristics of high electrochemical capacity and good cycle performance. When the charging upper limit voltage is greater than 4.3-4.5V, the material structure remains stable and can be used Higher gram capacity; the actual gram capacity of the negative electrode is close to the theoretical gram capacity by modifying artificial graphite and natural graphite; by using polyolefin-aromatic polyamide as the diaphragm material, the lithium-ion battery is effectively improved. safety performance.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries. Background technique [0002] Lithium cobalt oxide (LiCoO 2 ) materials have been adopted by the majority of lithium-ion battery factories due to their advantages such as high gram capacity, high compaction density, high voltage platform, and good cycle performance. At present, lithium cobalt oxide is mostly used as the positive electrode material of lithium-ion batteries for emerging electronic devices such as smartphones and netbooks. [0003] The charging upper limit voltage of traditional lithium-ion batteries is 4.2V, and this standard is LiCoO 2 The battery is charged until the macroscopic molecular weight of the positive electrode material is Li x CoO 2 The potential difference between the positive and negative electrodes of the battery when x is 0.5. The reaction formula of the charging process is as follows: [0004] [0005] When the charging upper limit voltage o...

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Problems solved by technology

However, the closed cell temperature is about 130°C, and the membrane rupture temperature is about 150°C. The temperature range between closed cell and membrane rupture is too small, which will cause the separator to melt rapidly when the battery is thermally out of control, and the positive and negative electrodes are directly short-circuited. , battery explosion, fire

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