A power storage device includes an electricity storage element, a case having an opening and housing the electricity storage element, and a sealing member sealing the opening. The sealing member includes an elastic member fit in the opening. The elastic member contains an elastic polymer and a hindered phenol compound. The hindered phenol compound having a phenol skeleton includes a first hindered group and a second hindered group. The first hindered group is bonded to a first substitution site of the phenol skeleton, and the second hindered group is bonded to a second substitution site of the phenol skeleton. Each of the first substitution site and second substitution site is adjacent to a substitution site of the phenol skeleton to which a phenolic hydroxy group is bonded. The first hindered group and the second hindered group each include one or more tertiary carbon atoms. One of the one or more tertiary carbon atoms in the first hindered group and one of the one or more tertiary carbon atoms in the second hindered group are bonded to the first substitution site and the second substitution site, respectively.
蓄电装置包括一个蓄电元件、一个具有开口并容纳蓄电元件的外壳和一个密封开口的密封部件。密封部件包括一个与开口相配合的弹性部件。弹性部件包含弹性聚合物和受阻
苯酚化合物。具有
苯酚骨架的受阻
苯酚化合物包括第一受阻基团和第二受阻基团。第一受阻基团与
苯酚骨架的第一取代位点键合,第二受阻基团与
苯酚骨架的第二取代位点键合。每个第一取代位点和第二取代位点都与
苯酚骨架的一个取代位点相邻,
苯酚骨架的一个取代位点上键合有一个
酚羟基。第一受阻基团和第二受阻基团各自包括一个或多个叔碳原子。第一受阻基团中的一个或多个叔碳原子和第二受阻基团中的一个或多个叔碳原子分别与第一取代位点和第二取代位点键合。