ELECTRODE FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

• Main Authors: TATEISHI KAZUYUKI, KURATSU MASATO, TAKAOKA AYUMI, NIWA YUKIMASA
• Format: Patent
• Language: English; Japanese
• Published: 03.12.2015
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

PROBLEM TO BE SOLVED: To enhance the dispersibility of a conductive assistant in an electrode mixture, thereby making possible to develop a high capacity with a small amount of a conductive assistant.SOLUTION: An electrode for nonaqueous electrolyte secondary batteries comprises a current collector; and an electrode mixture including an electrode active material including Spinel-type lithium manganate as a primary component, a conductive assistant and a binder, and applied to the current collector. The electrode satisfies the following requirements: (1)when N images of a predetermined area are extracted, as division unit images, from a carbon element map image obtained by the microscope analysis on a cross section of the electrode mixture applied to the electrode to determine a total area of the conductive assistant in each division unit image, a value obtained by dividing the difference between the maximum and minimum values of the total area by an average total area of the conductive assistant of the division unit images is 100% or less in percentage; (2)the maximum area of aggregates of the conductive assistant in the carbon element map image is 400-1000 μm; and (3)the electrode has a sheet resistance of 40 or less immediately after the application and drying of the electrode mixture. 【課題】電極合剤内の導電助剤の分散性を高め、少ない導電助剤量で高容量を発現する。【解決手段】スピネル型マンガン酸リチウムを主成分とする電極活物質、導電助剤及びバインダーを含む電極合剤を集電体上に塗工した非水電解質二次電池用電極であって、（１）電極に塗工された電極合剤の断面に対し、顕微鏡分析を実施して得られた炭素元素マップ画像から所定の面積の画像をＮ個抽出し、この分割単位画像一つあたりの導電助剤の総面積をそれぞれ求め、この総面積の最大値と最小値の差を、一分割単位画像における平均の導電助剤総面積で割ったパーセント値が１００％以下である。（２）炭素元素マップ画像における導電助剤の凝集体の最大面積が４００μｍ2以上、１０００μｍ2以下である。（３）塗工乾燥直後の電極のシート抵抗が４０ 以下である。【選択図】図３