ELECTRODE FOR SECONDARY BATTERY AND SECONDARY BATTERY INCLUDING THE SAME

• Main Authors: KITAYOSHI MASANORI, SHIONOYA HARUKA, ENOHARA KATSUSHI, MASHITA NAOHIRO
• Format: Patent
• Language: English; Japanese
• Published: 26.09.2022
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

To provide an electrode having an electrode active material layer with a reduced ion diffusion resistance.SOLUTION: Any electrode 5 of positive and negative electrodes of a secondary battery includes an electrode current collector 6 and an electrode active material layer 7 formed on the electrode current collector and containing active material particles as an electrode active material. A recess part 8 is formed on the surface of the electrode active material layer. When the electrode active material layer is uniformly divided into three layers, an upper layer, an intermediate layer and a lower layer, in the thickness direction from the surface of the recess part to the electrode current collector, and the electrode densities (g/cm3) of the upper layer, the intermediate layer, and the lower layer are d1, d2, d3, respectively, they have a relationship of 0.8<(d1/d3)<1.1. The porosity of the electrode active material layer is 10% or more and 50% or less. The area ratio of the recess part is 2% or more and 40% or less. The volume ratio of the recess part is 5% or more and 14% or less.SELECTED DRAWING: Figure 6 【課題】イオン拡散抵抗の低く抑えられた電極活物質層を有する電極を提供する。【解決手段】二次電池の正負極いずれかの電極５であって、電極集電体６と、電極集電体上に形成された、電極活物質としての活物質粒子を含んだ電極活物質層７と、を備えている。電極活物質層の表面には、凹部８が形成されている。電極活物質層は、凹部の表面から電極集電体に至る厚み方向を上層、中間層および下層の３つの層に均等に区分し、上層、中間層、下層の電極密度（ｇ／ｃｍ３）を、それぞれ、ｄ１、ｄ２、ｄ３としたときに、０．８＜（ｄ１／ｄ３）＜１．１の関係を具備する。電極活物質層の空隙率は、１０％以上５０％以下である。凹部の面積率は、２％以上４０％以下である。凹部の体積率は、５％以上１４％以下である。【選択図】図６