JP2005347077A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack capable of flexibly coping with variations of swelling of each element battery. <P>SOLUTION: The battery pack comprises a plurality of element batteries 1 which generate power by electrochemical reaction of hydrogen in the fuel gas and oxygen in the oxidizer gas by being supplied with the fuel gas and oxidizer gas and which are packaged outside in lamination, and spacers 2 which are arranged between the plurality of element batteries 1 laminated in a first direction 5 and are capable of extension and shrinkage in the first direction 5. The plurality of element batteries 1 are also arranged in a row in a second direction 6 perpendicular to the first direction 5, and the main surface of the spacers 2 contacting the element batteries 1 has irregular shape extended in a third direction 7 which is nearly perpendicular to the first direction 5 and the second direction 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an assembled battery, and in particular, to an assembled battery formed by combining a plurality of unit cells that are laminated.

  Conventionally, an assembled battery formed by stacking a plurality of unit cells is known (see, for example, Patent Document 1). In the assembled battery of Patent Document 1, a spacer formed as a plate having a triangular wave cross section is laminated together with the unit cell, and the space between the unit cell and the spacer is used as a flow path for the cooling medium. By restricting the deformation of the battery module by the support portion of the spacer, sufficient strength is secured and at the same time the cooling performance is improved.

Further, an assembled battery using a thin laminated battery (LB cell) with a laminated exterior as a unit battery is known (see, for example, Patent Document 2). In the assembled battery of Patent Document 2, a plurality of LB cells connected to each other are resin-sealed in one support body.
JP 2001-23702 A (refer to FIG. 1 and paragraph [0007] in particular) JP 2003-162989 A (refer to FIG. 1 and paragraph [0010] in particular)

  However, when the spacer of Patent Document 1 is applied to the assembled battery of Patent Document 2, the following problems arise unless the relationship between the direction in which the uneven shape of the spacer extends and the direction in which a plurality of LB cells are arranged is considered. Occur.

  That is, the LB cell is swollen by repeating charge and discharge, and this swollenness varies among the LB cells. Accordingly, if the direction in which the concave and convex shape of the spacer extends and the direction in which the plurality of LB cells are arranged are substantially parallel, a gap is formed where the bulge of the LB cell is small, and all the LB cells are I can't support it enough.

  A feature of the present invention is that a plurality of unit cells covered with a laminate, which are supplied with a fuel gas and an oxidant gas and generate power by an electrochemical reaction between hydrogen in the fuel gas and oxygen in the oxidant gas, An assembled battery including a spacer that is disposed between a plurality of unit cells that are stacked in a direction and that is expandable and contractable in a first direction, the plurality of unit cells being a second perpendicular to the first direction. The gist is that the main surfaces of the spacers arranged side by side and in contact with the unit cells have a concavo-convex shape extending in a third direction substantially perpendicular to the first and second directions.

  ADVANTAGE OF THE INVENTION According to this invention, the assembled battery which can respond flexibly to the variation in the swelling of each unit cell can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  As shown in FIG. 1, an assembled battery (hereinafter referred to as “battery module”) according to an embodiment of the present invention includes a plurality of unit cells 1 (hereinafter referred to as “LB cells”) covered with a laminate, Spacers 2 arranged between the plurality of LB cells 1 stacked in the direction 5, the end plate 4 sandwiching the upper and lower surfaces of the plurality of LB cells 1 stacked in the first direction 5, and the end plate 4 And a bolt 3 for fixing the plurality of LB cells 1 in a sandwiched state.

  The LB cell 1 is a fuel cell that is supplied with a fuel gas and an oxidant gas and generates power by an electrochemical reaction between hydrogen in the fuel gas and oxygen in the oxidant gas. A plurality (eight in FIG. 1) of LB cells 1 are stacked in the first direction 5, and a plurality (five in FIG. 1) of LB cells 1 are arranged in a second direction 6 perpendicular to the first direction 5. Has been placed. The number of LB cells 1 stacked in the first direction 5 and the number of LB cells 1 arranged in the second direction 6 are examples, and are not limited thereto.

  The spacer 2 is provided between the lower surface of the plurality of LB cells 1 and the end plate 4, between the LB cell 1 at the third stage from the bottom and the LB cell 1 at the fourth stage, and from the LB cells 1 and 6 at the fifth stage from the bottom. The LB cells 1 are inserted between the upper surfaces of the plurality of LB cells 1 and the end plate 4. The main surface of the spacer 2 in contact with the LB cell 1 has an uneven shape extending in a third direction 7 substantially perpendicular to the first direction 5 and the second direction 6. Further, the spacer 2 can be expanded and contracted in the first direction 5.

  The uneven shape of the spacer 2 is preferably a shape without a vertex (for example, a sine wave shape). It is possible to prevent the LB cell 1 from being damaged when the spacer 2 spreads in the second direction 6. That is, by forming a sine wave shape having no apex in the waveform, the surface pressure received from the LB cell 1 is not concentrated locally, and the balance between the reaction force of the spacer 2 and the surface pressure of the LB cell 1 is maintained. The material of the surface of the LB cell 1 that is in contact with the spacer 2 is not damaged or incised.

  Further, the spacer 2 can also function as a heat sink by flowing a cooling medium through the gap between the LB cell 1 and the spacer 2.

  Since the bolts 3 at the four corners of the end plate 4 fasten the end plate 4 with a predetermined pressing force, the length of the battery module in the first direction 5 is within a predetermined dimension. The LB cell 1 has a characteristic of expanding from the inside of the LB cell 1 by repeating charging and discharging. As the use continues, the characteristics of the LB cells 1 vary. That is, a difference occurs in the degree of expansion between the LB cells 1. Due to the structure of the LB cell 1, the change in the thickness of the LB cell due to expansion is mainly in the stacking direction (first direction 5). In order for the length of the battery module in the first direction 5 to maintain a predetermined dimension, the sum of the thicknesses of the LB cells 1 stacked in the first direction 5 and the sum of the thicknesses of the spacers 2 are made constant. There is a need to. Therefore, in order to change the thickness of the spacer 2 more flexibly, the spacer shape is a wave shape.

  FIG. 2A shows an enlarged part of the LB cell 1 shown in FIG. The spacer 2 is deformed until the balance between the surface pressure increased by expansion of the plurality of LB cells in contact with the upper and lower sides of the spacer 2 and the reaction force of the spacer 2 settles to a steady state. As a result, the thickness of the spacer 2 is reduced. If the surface pressures of the LB cell 1 and the LB cell 2 in the steady state are F1 and F2, and the reaction force of the spacer 2 is F3, the thickness of the spacer 2 satisfies F1 + F2 = F3.

  Further, as shown in FIG. 2A, only the LB cell 2 among the plurality of LB cells expands more than other LB cells. In this case, since the reaction force F3 of the spacer 2 in the LB cell 2 portion is larger than the reaction force F3 of the spacer 2 in the LB cell 3 portion, the thickness of the spacer 2 in the LB cell 2 portion is It becomes thinner than the thickness of the spacer 2 in the LB cell 3 part. As described above, the uneven shape of the spacer 2 extends in the third direction 7 substantially perpendicular to the second direction 6 in which the plurality of LB cells 1 are arranged, and therefore the first direction 5 between the LB cells 1. All the LB cells 1 can be fully supported in a flexible manner with respect to the thickness variation.

  As shown in FIG. 3A, the spacer 2 before the LB cell 1 expands is within a predetermined length in the second direction 6. On the other hand, as shown in FIG. 3B, when the LB cell 1 expands in the first direction 5 from the state of FIG. 3A, the reaction force of the spacer 2 increases and the thickness of the spacer 2 becomes the first. Shrink in direction 5 of 1. The contracted spacer 2 extends in the second direction. In the assembled battery according to the embodiment, it is desirable that a relief region 8 for the spacer 2 to extend in the second direction is provided. In order to maintain the balance between the surface pressure of the LB cell 1 and the stress of the spacer 2 due to the change in the thickness of the LB cell 1, the length of the spacer 2 is perpendicular to the stacking direction (first direction 5) ( Stretch in the second direction 6). The maximum length of the spacer 2 is when the spacer 2 becomes a plane by the LB cell 1. If the arrangement of the LB cell 1 and the spacer 2 is designed while securing the escape region 8 at this time, it is possible to avoid non-uniformly applying to any LB cell 1 with the reaction force of the spacer 2, and other LB cells 1 No unnecessary pressure is applied.

  As shown in FIG. 4A, in the assembled battery according to the comparative example, the spacer 2 is inserted between the LB cells 1 so that the direction in which the LB cells are arranged and the direction in which the uneven shape of the spacer extends are substantially parallel. . As shown in FIG. 4B, when expansion variation occurs between the LB cells 1, a gap is generated between the LB cell and the spacer 2, and it becomes difficult to support and fix the LB cells 1 to 3. Further, it becomes difficult to maintain the parallel stack of the spacer 2 and the LB cell. Further, when cooling air is passed through the gap between the spacers 2, the cooling air passing through the spacer 2 leaks from the gap and the cooling effect becomes non-uniform between the LB cells.

  As described above, according to the embodiment of the present invention, as shown in FIGS. 2A and 2B, the uneven shape of the spacer 2 is the second in which a plurality of LB cells 1 are arranged. The LB cells 1 extend in a third direction 7 substantially perpendicular to the first direction 6, so that all the LB cells 1 can be flexibly accommodated to variations in thickness in the first direction 5 between the LB cells 1. It can be fully supported.

  As described above, the present invention has been described by way of one embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. That is, it should be understood that the present invention includes various embodiments not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

It is a perspective view which shows the assembled battery (battery module) concerning embodiment of this invention. FIG. 2A is a cross-sectional view showing a change in the thickness of the spacer when the LB cell expands. FIG. 2B is a cross-sectional view showing a state in which the thickness of the LB cell shown in FIG. FIG. 3A is a cross-sectional view showing the state of the spacer before the LB cell expands. FIG. 3B is a cross-sectional view showing a state in which the LB cell has expanded from the state of FIG. 3A and the spacer has spread in the second direction. FIG. 4A is a perspective view showing a relationship between the direction in which the LB cells are arranged in the assembled battery according to the comparative example and the direction in which the uneven shape of the spacer extends. FIG. 4B is a cross-sectional view showing the state of the spacer when there is variation in expansion between LB cells.

Explanation of symbols

1. Unit cell (LB cell)
2 ... Spacer 3 ... Bolt 4 ... End plate 5 ... First direction 6 ... Second direction 7 ... Third direction 8 ... Escape area

Claims (3)

A plurality of unit cells covered with a laminate, which are supplied with a fuel gas and an oxidant gas, and generate electricity by an electrochemical reaction between hydrogen in the fuel gas and oxygen in the oxidant gas;
A spacer that is disposed between the plurality of unit cells stacked in a first direction and that can expand and contract in the first direction;
The plurality of unit cells are also arranged side by side in a second direction perpendicular to the first direction, and a main surface of the spacer in contact with the unit cells is a first layer substantially perpendicular to the first and second directions. 3. An assembled battery having an uneven shape extending in the direction of 3.   The assembled battery according to claim 1, wherein the uneven shape is a sinusoidal shape.   When the unit cell expands in the first direction, the spacer contracts in the first direction, and a clearance area is provided for the contracted portion of the spacer to extend in the second direction. The assembled battery according to claim 1 or 2, characterized in that:

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