CPC H01M 10/6557 (2015.04) [H01M 10/625 (2015.04); H01M 10/651 (2015.04); H01M 10/658 (2015.04); H01M 10/6567 (2015.04); H01M 50/204 (2021.01); H01M 50/291 (2021.01); H01M 10/6555 (2015.04); Y02E 60/10 (2013.01)] | 12 Claims |
1. A partition member which partitions between a pair of unit batteries or a partition member which partitions between a unit battery and a member other than the unit battery, comprising:
a first surface; and
a second surface opposite to the first surface,
wherein θd1, θd2, θp1, and θp2 defined as follows satisfy:
(θp1/θp2)/(θd1/θd2)≤1.0×10−4
θd1: when a first point existing on the first surface of the partition member reaches 150° C., thermal resistance per unit area in a thickness direction defined by a difference in temperature between the first point and a second point at a plane-symmetrical position to the first point with respect to a division plane that bisects the partition member in the thickness direction on the second surface;
θp1: when the first point existing on the first surface of the partition member reaches 150° C., thermal resistance per unit area in a plane direction defined by a difference between a temperature at a first intersection point where a straight line connecting the first point and the second point and the division plane intersect each other and a temperature at a point on the division plane at a position at a distance that is ½ of a length of the partition member in a long axis direction from the first point in the long axis direction;
θd2: when the entire first surface is set to 40° C., thermal resistance per unit area in the thickness direction of the partition member which is defined by a difference in temperature between a third point at a same position as the first point and a fourth point at a same position as the second point; and
θp2: when the entire first surface is set to 40° C., thermal resistance per unit area in the plane direction of the partition member which is defined by a difference between a temperature at an intersection point where a straight line connecting the third point and the fourth point and the division plane intersect each other and a temperature at a point on the division plane at a position at a distance that is ½ of the length of the partition member in the long axis direction from the intersection point in the long axis direction,
wherein the partition member comprises a packaging material including a fluid having a boiling point at ordinary pressure of 80° C. to 250° C., a fluid holding portion that includes a porous body and a flow path, and
wherein the porous body includes a fibrous layer and a particle layer.
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