SECONDARY BATTERY

• Main Author: KIKUCHI KYOKO
• Format: Patent
• Language: English; Japanese
• Published: 26.07.2018
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

PROBLEM TO BE SOLVED: To provide a secondary battery capable of inhibiting increase in battery resistance caused by reaction unevenness, by preventing electrolytic solution in a wound electrode body from flowing out to the outside during charging/discharging.SOLUTION: A secondary battery disclosed herein comprises a wound electrode body 20 including a positive electrode 21 and a negative electrode 25 that are wound. Such secondary battery includes: a flat and tabular winding core 30, around which the positive electrode 21 and negative electrode 25 are wound, arranged inside the wound electrode body 20; and a wound core part 20A, at which a positive electrode mixture layer 23 and a negative electrode mixture layer 27 are opposite to each other, formed at the wound electrode body 20's center part in a winding axis direction X. The secondary battery disclosed herein includes projections 34 formed on each of both side edge parts of the winding core 30, the projections projecting from a flat surface 30a of the winding core 30 and extending along both side edges of the winding core 30. The positive electrode 21 and the negative electrode 25 are wound around the winding core 30 so that both side edge parts of the wound core part 20A are opposite to the projections 34 of the winding core 30.SELECTED DRAWING: Figure 5 【課題】捲回電極体内の電解液が充放電中に外部へ流出することを防止し、反応ムラによる電池抵抗の上昇を抑制することができる二次電池を提供する。【解決手段】ここで開示される二次電池は、正極２１と負極２５とが捲回された捲回電極体２０を備えている。かかる二次電池では、捲回電極体２０の内側に正極２１と負極２５とが捲回される扁平な板状の巻き芯３０が配置されているとともに、捲回軸方向Ｘにおける捲回電極体２０の中央部に正極合材層２３と負極合材層２７とが対向する捲回コア部２０Ａが形成されている。そして、ここで開示される二次電池では、巻き芯３０の両側縁部の各々に当該巻き芯３０の扁平面３０ａから突出し、巻き芯３０の両側縁に沿って延びる凸条３４が形成されており、捲回コア部２０Ａの両側縁部と、巻き芯３０の凸条３４とが対向するように正極２１と負極２５とが巻き芯３０に捲回されている。【選択図】図５