The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 09, 2021
Filed:
Aug. 22, 2017
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Yusuke Onoda, Toyota, JP;
Nobuaki Koiwa, Gamagori, JP;
TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota, JP;
Abstract
The present teaching provides a highly durable lithium ion secondary battery including a flat shape wound electrode body, with which a high capacity retention ratio and suppression of resistance rise are realized, and also provides a battery pack constructed by using the secondary battery as a unit battery. The lithium ion secondary battery (unit battery) provided in accordance with the present teaching has a flat-shaped wound electrode body, and in a state in which a constraint pressure is applied in the direction toward the flat surface of the wound electrode body under the same conditions as the conditions when the battery pack is constructed, the condition of a D/B ratio being 1.01 or more and 1.07 or less is satisfied, where, in the lateral cross section of the wound electrode body, a thickness from an inner curve apex V to an outer curve apex P is taken as a center thickness D of a curved R portion, and a thickness from the inner curve apex V to an outer surface S of the wound electrode body along an R portion/F portion boundary line W is taken as a boundary thickness B of the curved R portion.