Search

EP-3780138-B1 - POWER SUPPLY DEVICE AND ELECTRIC VEHICLE PROVIDED WITH POWER SUPPLY DEVICE

EP3780138B1EP 3780138 B1EP3780138 B1EP 3780138B1EP-3780138-B1

Inventors

  • NAKAHARA, CHIHARU
  • NAITO, MASAKAZU
  • OKII, Yuusuke

Dates

Publication Date
20260506
Application Date
20181116

Claims (11)

  1. A power supply device comprising: a battery stack (2) including a plurality of battery cells (1) that are stacked; a pair of end plates (3) that are disposed at both end portions of the battery stack (2); and a bind bar (4) that extends in a stacking direction of the plurality of battery cells (1) of the battery stack (2) and has both end portions coupled to the pair of end plates (3), wherein the battery stack (2) is a quadrangular prism extending in the stacking direction of the plurality of battery cells (1), and has four surrounding surfaces including an electrode surface (2A) where electrodes of the plurality of battery cells (1) are disposed, a bottom surface (2B) on an opposite side of the electrode surface (2A), and facing side surfaces (2C) on one of which the bind bar (4) is disposed, an elastic sheet (6) that is elastically deformable in a thickness direction is disposed in a compressed state between the bind bar (4) and the one of the facing side surfaces (2C) of the battery stack (2), and the elastic sheet (6) in the compressed state elastically holds the one of the facing side surfaces (2C) of the battery stack (2) and an inner surface of the bind bar (4) in a pressurized state, characterized in that the bind bar (4) includes at least one ridge (44) extending in the stacking direction of the plurality of battery cells (1) and comprising a curved shape in cross-section, with a predetermined radius of curvature, projecting outwards from the battery stack (2) and provided in a middle part of the battery stack (2) in a width direction, the at least one ridge extending a gap between the battery stack (2) and the bind bar (44).
  2. The power supply device according to claim 1, wherein the elastic sheet sandwiched in a compressed state is thicker than 30% of the gap or thicker than 50% of the gap or thicker than 80% of the gap.
  3. The power supply device according to claims 1 or 2, wherein the gap between the battery stack (2) and bind bar (4) is greater than 0.3mm or greater than 0.5mm.
  4. The power supply device according to claims 1 to 3, wherein the elastic sheet (6) is a rubbery elastic sheet.
  5. The power supply device according to claim 4, wherein the elastic sheet (6) is foamed rubber.
  6. The power supply device according to any one of claims 1 to 5, wherein the elastic sheet (6) is a closed-cell foam.
  7. The power supply device according to any one of claims 1 to 6, comprising a cooling plate (7X) that is disposed on the bottom surface (2B) of the battery stack (2) and cools each of the plurality of battery cells (1), wherein the cooling plate (7X) is disposed in a thermally coupled state over an entire width of the bottom surface (2B) of the battery stack (2).
  8. The power supply device according to claim 1, wherein the bind bar (4) is a metal plate, and is pressed to provide the ridge (44).
  9. The power supply device according to claim 1 to 8, wherein the bind bar (4) includes a main body (40) that is disposed on the one of the facing side surfaces (2C) of the battery stack (2), and fixing pieces that are coupled to both ends of the main body (40) and fixed to the pair of end plates (3), and the ridge (44) is provided extending from the main body (40) of the bind bar (4) to the fixing pieces.
  10. The power supply device according to any one of claims 1 to 9, wherein the bind bar (4) is a metal plate, and includes a main body (40) that is disposed on the one of the facing side surfaces (2C) of the battery stack (2), fixing pieces (41) that are coupled to both ends of the main body (40) and fixed to the pair of end plates (3), and corner plates (42) that are coupled to end edges of the main body (40) and end edges of the fixing pieces (41), each of the corner plates (42) includes a main body corner plate (42A) of a metal plate continuous to a side edge of the main body (40), and a fixing corner plate (42B) of a metal plate continuous to an end edge of corresponding one of the fixing pieces (41), the main body corner plate (42A) is bent at a boundary with the main body (40) at right angle, the fixing corner plate is bent at a boundary with the corresponding one of the fixing pieces (41) at right angle, and the main body corner plate (42A) and the fixing corner plate (42B) are fixed and attached to each other in a stacked state, to be disposed in a position facing the electrode surface (2A) of the battery stack (2).
  11. An electric vehicle (HV, EV) including the power supply device according to any one of claims 1 to 10, the electric vehicle (HV, EV) comprising: the power supply device; a running motor (93) that is supplied with electric power from the power supply device; a vehicle body (90) including the power supply device and the running motor (93); and wheels (97) that are driven by the running motor (93) to run the vehicle body (90).

Description

TECHNICAL FIELD The present invention relates to a power supply device in which a plurality of battery cells are stacked, and an electric vehicle including the power supply device, such as a hybrid automobile, a fuel cell automobile, an electric automobile, and an electric motorcycle. BACKGROUND ART In a power supply device in which a plurality of battery cells are stacked to form a battery stack, end plates are disposed on both end surfaces of the battery stack, and the pair of end plates disposed on both ends are coupled by a bind bar. In this power supply device, the battery stack is fixed in a pressurized state by the pair of end plates, and the battery cells are stacked so as not to be displaced. Both end portions of the bind bar are coupled to the end plates so that the end plates press the battery stack from both the end surfaces. The bind bar is provided with bent pieces by bending both end portions of the battery stack inward, and the bent pieces are fixed to surfaces of the end plates by screwing. In the power supply device having this structure, the end plates are disposed on both side surfaces of the battery stack, and the bind bar is coupled to both sides of the end plates (see PTL 1). In this power supply device, in order to fasten the prismatic battery cells in a stacked state, the prismatic battery cells are fixed by the bind bar that is an angle member. The bind bar has both ends fixed to the end plates disposed on both end surfaces of the prismatic battery cells in the stacked state. In particular, in order to prevent the prismatic battery cells from expanding due to repeated charging and discharging, it is necessary to firmly fasten the prismatic battery cells with the bind bar. A power supply device in which a large number of battery cells are stacked needs to be forcibly cooled because the battery cells generate heat due to charging and discharging and a temperature rises. A power supply device has been developed in which a cooling plate is disposed on a lower surface of the battery stack to cool the battery stack (see PTL 2). Citation List Patent Literature PTL1: Unexamined Japanese Patent Publication No. 2010-86887PTL2: Unexamined Japanese Patent Publication No. 2012-94456PTL 3: US 2011/200862PTL 4: US 2014/023906PTL 5: US 2015/144409 PTL 3 discloses a power supply device reflecting the preamble of present claim 1. PTL 4 and PTL 5 show further art. SUMMARY OF THE INVENTION Technical problem In the power supply device in which the cooling plate is disposed on the lower surface, it is important to thermally couple the cooling plate and the battery cells in a preferable state to efficiently cool each battery cell. In order to achieve this state, it is necessary to thermally couple the cooling plate to an entire width of a bottom surface of the battery stack without disposing the bind bar on the lower surface of the battery stack. Furthermore, not only in the power supply device in which the cooling plate is disposed, but also in the power supply device in which the battery stack is placed and held on a flat base plate, preferably, it is important that the bottom surface of the battery stack of the battery stack is exposed over the entire width. This is because if the bind bar locally holds both sides of the bottom surface of the battery stack, adverse effects such as deformation due to a pressure locally acting on bottom surfaces of the battery cells occur. The present invention has been made in view of such conventional problems, and an object thereof is to provide a technique capable of reliably preventing displacement of battery cells while a bottom surface of a stacked battery stack is exposed over an entire width. Solutions to problem A power supply device according to an aspect of the present invention includes a battery stack where a plurality of battery cells are stacked, a pair of end plates that are disposed at both end portions of the battery stack, and a bind bar that extends in a stacking direction of the battery cells of the battery stack and has both end portions coupled to the end plates. The battery stack is a quadrangular prism extending in the stacking direction of the battery cells, and has four surrounding surfaces including an electrode surface where electrodes of the battery cells are disposed, a bottom surface on an opposite side of the electrode surface, and facing side surfaces where the bind bar is disposed. In the power supply device, an elastic sheet that is elastically deformable in a thickness direction is disposed in a compressed state between the bind bar and each of the facing side surfaces of the battery stack, and the elastic sheet in the compressed state elastically holds each of the facing side surfaces of the battery stack and an inner surface of the bind bar in a pressurized state. The bind bar includes at least one ridge extending in the stacking direction of the plurality of battery cells and comprising a curved shape in cross-section, with a pre