US-12620650-B2 - Power storage device

US12620650B2US 12620650 B2US12620650 B2US 12620650B2US-12620650-B2

Abstract

A power storage device includes: a power storage stack including a first cell group, a second cell group, and a middle plate; a lower case having a bottom wall portion; a first heat conduction member disposed between the first cell group and the bottom wall portion; and a second heat conduction member disposed between the second cell group and the bottom wall portion. The lower case includes a pedestal portion supporting the middle plate, and the first heat conduction member and the second heat conduction member are provided to contact the pedestal portion.

Inventors

Kotaro Horiguchi
Ryota Aoki
Shinichiro Mori
Kazunari Hiromori

Assignees

TOYOTA JIDOSHA KABUSHIKI KAISHA

Dates

Publication Date: 20260505
Application Date: 20220921
Priority Date: 20210924

Claims (15)

1 . A power storage device comprising: a power storage stack that includes a first cell group and a second cell group each including a plurality of power storage cells, and a middle plate disposed between the first cell group and the second cell group; a lower case that has a bottom wall portion and on which the power storage stack is disposed, the bottom wall portion having an inner main surface facing toward the power storage stack and an outer main surface facing opposite to a side on which the power storage stack is located; a first heat conduction member disposed between the first cell group and the bottom wall portion; a second heat conduction member disposed between the second cell group and the bottom wall portion; and a cooler configured to transfer heat away from the power storage stack, the cooler disposed outside the lower case to thermally couple with the outer main surface; wherein the lower case includes a pedestal portion that is provided to rise from the bottom wall portion and supports the middle plate, the first heat conduction member and the second heat conduction member being provided to contact the pedestal portion, wherein the first heat conduction member abuts the first cell group and the bottom wall portion.
2 . The power storage device according to claim 1 , wherein the middle plate has a first protruding portion protruding from the pedestal portion toward the first cell group, and a second protruding portion protruding from the pedestal portion toward the second cell group, in an arrangement direction in which the first cell group and the second cell group are arranged, and when seen from a direction perpendicular to the arrangement direction, the first heat conduction member is provided to fill a gap between the first protruding portion and the pedestal portion, and the second heat conduction member is provided to fill a gap between the second protruding portion and the pedestal portion.
3 . The power storage device according to claim 1 , wherein the pedestal portion includes a first pedestal portion and a second pedestal portion disposed to be spaced from each other in a direction perpendicular to an arrangement direction in which the first cell group and the second cell group are arranged.
4 . The power storage device according to claim 1 , further comprising a pressing member that presses the power storage stack toward the bottom wall portion, wherein the power storage stack has one end and another end in an arrangement direction in which the first cell group and the second cell group are arranged, and the pressing member has a first pressing portion for pressing the one end toward the bottom wall portion, and a second pressing portion for pressing the other end toward the bottom wall portion.
5 . The power storage device according to claim 2 , wherein the pedestal portion includes a first pedestal portion and a second pedestal portion disposed to be spaced from each other in a direction perpendicular to an arrangement direction in which the first cell group and the second cell group are arranged.
6 . The power storage device according to claim 2 , further comprising a pressing member that presses the power storage stack toward the bottom wall portion, wherein the power storage stack has one end and another end in an arrangement direction in which the first cell group and the second cell group are arranged, and the pressing member has a first pressing portion for pressing the one end toward the bottom wall portion, and a second pressing portion for pressing the other end toward the bottom wall portion.
7 . The power storage device according to claim 3 , further comprising a pressing member that presses the power storage stack toward the bottom wall portion, wherein the power storage stack has one end and another end in an arrangement direction in which the first cell group and the second cell group are arranged, and the pressing member has a first pressing portion for pressing the one end toward the bottom wall portion, and a second pressing portion for pressing the other end toward the bottom wall portion.
8 . The power storage device according to claim 5 , further comprising a pressing member that presses the power storage stack toward the bottom wall portion, wherein the power storage stack has one end and another end in an arrangement direction in which the first cell group and the second cell group are arranged, and the pressing member has a first pressing portion for pressing the one end toward the bottom wall portion, and a second pressing portion for pressing the other end toward the bottom wall portion.
9 . The power storage device according to claim 1 , wherein the cooler includes a refrigerant flow path.
10 . The power storage device according to claim 1 , further comprising an outer heat conduction layer disposed between the cooler and the outer main surface of the bottom wall portion of the lower case.
11 . The power storage device according to claim 1 , wherein the pedestal portion extends upward from the bottom wall portion.
12 . The power storage device according to claim 1 , wherein the second heat conduction member abuts the second cell group and the bottom wall portion.
13 . The power storage device according to claim 1 , wherein the first heat conduction member fixes the first cell group to the bottom wall portion.
14 . The power storage device according to claim 12 , wherein the first heat conduction member fixes the first cell group to the bottom wall portion and the second heat conduction member fixes the second cell group to the bottom wall portion.
15 . The power storage device according to claim 10 , wherein the outer heat conduction layer abuts the cooler and the outer main surface of the bottom wall portion of the lower case.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This nonprovisional application claims priority to Japanese Patent Application No. 2021-155478 filed on Sep. 24, 2021 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference. BACKGROUND Field The present disclosure relates to a power storage device mounted on a vehicle. Description of the Background Art As a conventional power storage device, Japanese Patent Laying-Open No. 2020-053148 discloses a power storage device which includes a power storage stack and a cooler having a plurality of main cooling surfaces and recesses each provided between the plurality of main cooling surfaces, and in which a gel heat conduction member is disposed between the power storage stack and the plurality of main cooling surfaces, in a configuration in which the power storage stack and the cooler are disposed within a housing case. SUMMARY However, in the power storage device described in Japanese Patent Laying-Open No. 2020-053148, since the recesses are each provided between the plurality of main cooling surfaces, it is difficult to ensure that the heat conduction member has a large area, and heat conductivity may be reduced. Furthermore, a configuration in which a cooler is disposed outside a housing case has been considered. In such a case, it is conceivable to bring a bottom surface of a power storage stack into thermally close contact with a bottom wall portion of a lower case using a heat conduction member. In adhering the bottom surface of the power storage stack to the bottom wall portion via the heat conduction member, air between the bottom surface of the power storage stack and the bottom wall portion may fail to escape therefrom and remain therein. In such a case, adhesiveness of the power storage stack with respect to the lower case is reduced. Furthermore, when the heat conduction member has a small area, heat conductivity is reduced. The present disclosure has been made in view of the aforementioned problem, and an object of the present disclosure is to provide a power storage device that can improve adhesiveness of a power storage stack with respect to a lower case via a heat conduction member, and can ensure good heat conductivity. A power storage device based on the present disclosure includes: a power storage stack that includes a first cell group and a second cell group each including a plurality of power storage cells, and a middle plate disposed between the first cell group and the second cell group; a lower case that has a bottom wall portion and on which the power storage stack is disposed; a first heat conduction member disposed between the first cell group and the bottom wall portion; and a second heat conduction member disposed between the second cell group and the bottom wall portion. The lower case includes a pedestal portion that is provided to rise from the bottom wall portion and supports the middle plate. The first heat conduction member and the second heat conduction member are provided to contact the pedestal portion. By pressing and enlarging the first heat conduction member and the second heat conduction member by the power storage stack and the bottom wall portion of the lower case such that the middle plate is supported by the pedestal portion and the first heat conduction member and the second heat conduction member contact the pedestal portion as in the configuration described above, the first heat conduction member and the second heat conduction member can be pressed to be enlarged while letting air escape from the periphery of the pedestal portion surrounded by the first heat conduction member and the second heat conduction member, a bottom surface of the power storage stack, and the bottom wall portion. Thereby, the first heat conduction member and the second heat conduction member can have large areas. As a result, it is possible to maintain good heat conductivity, while improving adhesiveness between the power storage stack (the first cell group and the second cell group) and the bottom wall portion of the lower case via the first heat conduction member and the second heat conduction member. In the power storage device based on the present disclosure, the middle plate may have a first protruding portion protruding from the pedestal portion toward the first cell group, and a second protruding portion protruding from the pedestal portion toward the second cell group, in an arrangement direction in which the first cell group and the second cell group are arranged. In this case, when seen from a direction perpendicular to the arrangement direction, the first heat conduction member may be provided to fill a gap between the first protruding portion and the pedestal portion, and the second heat conduction member may be provided to fill a gap between the second protruding portion and the pedestal portion. According to the configuration described above, the first heat conduction member and the second heat condu