Buffer member and power storage pack

Abstract

To provide a technique of suppressing melting of an elastic body when a single cell is generating heat.SOLUTION: A buffer member 30 is arranged between two single cells 10 adjacent to each other. The buffer member 30 includes: a tabular first heat resistance part 32; a tabular second heat resistance part 34 facing the first heat resistance part 32; and a resin elastic part 36 arranged between the first heat resistance part 32 and the second heat resistance part 34. In that configuration, the first heat resistance part 32 (or the second heat resistance part 34) can be placed between the single cells 10 and the elastic part 36. The elastic part 36 can be thus prevented from being heated directly when the single cells 10 are generating heat and melting of the elastic part 36 can be therefore suppressed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a buffer member and a power storage pack including the buffer member.

Background Art

[0002] Power storage devices such as lithium-ion secondary batteries are widely used as power sources for various electrical devices. Such power storage devices may be used in the form of a power storage pack in which a plurality of single cells (single power storage devices) are electrically connected. For example, a power storage pack is constructed by arranging a plurality of single cells along a predetermined arrangement direction and restraining the plurality of single cells. In this type of power storage pack, a buffer member may be disposed between two adjacent single cells. Since this buffer member has a predetermined elasticity, it can disperse the restraining pressure applied to each single cell. Further, the buffer member can also suppress the propagation of heat generated in a specific single cell to other single cells by preventing the single cells from directly contacting each other.

[0003] For example, the elastic member (buffer member) described in Japanese Unexamined Patent Application Publication No. 2023-35097 includes a heat insulating sheet, an elastic body formed on one side of the heat insulating sheet, and a flame retardant regulating body formed on one side of the heat insulating sheet. The elastic member having such a configuration can maintain the heat insulating effect because the regulating body can maintain the cell interval even if the elastic body melts due to the heat generation of the single cell.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, the buffer member is a member having a pressure dispersion function and a heat insulation function. On the other hand, the buffer member described in Japanese Patent Application Laid-Open No. 2023-35097 has a flame retardant control body, so that the heat insulation function can be maintained even if the elastic body melts. However, since such an invention does not suppress the melting of the elastic body, it is difficult to maintain the pressure dispersion function.

[0006] The technology disclosed herein has been made in view of such problems, and an object thereof is to provide a technology capable of suppressing the melting of an elastic body during single cell heat generation.

Means for Solving the Problems

[0007] The buffer member disclosed herein is disposed between two adjacent single cells. And this buffer member includes a plate-shaped first heat-resistant part, a plate-shaped second heat-resistant part facing the first heat-resistant part, and an elastic part made of resin disposed between the first heat-resistant part and the second heat-resistant part.

[0008] In the buffer member disclosed herein, the elastic part is sandwiched between the first heat-resistant part and the second heat-resistant part. As a result, the first heat-resistant part (or the second heat-resistant part) can be interposed between the single cell and the elastic part. As a result, it is possible to prevent the elastic part from being directly heated during single cell heat generation, and thus it is possible to suppress the melting of the elastic part.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings. In addition, matters other than those specifically mentioned in this specification and matters necessary for implementing the technology disclosed here (for example, detailed configurations of electrode bodies and electrolytes) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed here can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field. In addition, the notation "A to B" indicating a range in this specification shall include the meaning of "greater than A" and "less than B" in addition to the meaning of "A or more and B or less".

[0011] Note that the "power storage device" in this specification is a concept including a device in which a charge carrier moves between a pair of electrodes (a positive electrode and a negative electrode) to cause a charge and discharge reaction. That is, the power storage device in the technology disclosed here includes, in addition to secondary batteries such as lithium ion secondary batteries, nickel metal hydride batteries, and nickel cadmium batteries, capacitors such as lithium ion capacitors and electric double layer capacitors.

[0012] <First Embodiment> The first embodiment of the power storage pack disclosed herein will be described below. FIG. 1 is a perspective view schematically showing the power storage pack according to the first embodiment. FIG. 2 is a perspective view schematically showing the single cell shown in FIG. 1. FIG. 3 is a side view for explaining the positional relationship between the buffer member and the single cell in the power storage pack according to the first embodiment. In the drawings referred to in this specification, the reference signs L, R, F, Rr, U, and D represent left, right, front, rear, upper, and lower, respectively. Further, the reference signs X, Y, and Z represent the width direction, the depth direction, and the height direction, respectively. However, these directions are merely defined for convenience of explanation and do not limit the installation mode of the power storage pack disclosed herein.

[0013] As shown in FIGS. 1 to 3, the power storage pack 1 according to the present embodiment includes a plurality of single cells 10, a restraint member 20, and a buffer member 30. Each will be described below.

[0014] 1. Single cell 10 As shown in FIGS. 1 and 3, a plurality of single cells 10 are arranged along a predetermined arrangement direction (depth direction Y). The number of single cells 10 can be appropriately increased or decreased according to the specifications of the power storage pack 1 and the like, and does not limit the technology disclosed herein. As an example, the number of single cells 10 can be 12 to 24. Further, in FIG. 3, for convenience of explanation, only two single cells 10 and one buffer member 30 are enlarged and shown, but this FIG. 3 also does not limit the number of single cells 10 and buffer members 30.

[0015] The single cell 10 in the present embodiment is a power storage device having a power storage element. Specifically, the single cell 10 includes an electrode body, an electrolyte, and a battery case 12. Although not shown, the electrode body and the electrolyte are housed inside the battery case 12. These power storage elements (electrode body and electrolyte) can be used without particular limitation using conventionally known materials that can be used in general power storage devices. For this reason, in this specification, a detailed description of the power storage elements is omitted.

[0016] On the one hand, the battery case 12 is a flat rectangular container. This battery case 12 includes a case body 14 and a sealing plate 16. The case body 14 is a flat box-shaped body having an opening on the upper surface. Specifically, the case body 14 includes a bottom 14b which is a long rectangular plate-shaped member extending in the width direction X, a pair of first side walls 14c extending upward D from the long sides (sides along the width direction X) of the bottom 14b, and a pair of second side walls 14d extending upward D from the short sides (sides along the depth direction Y) of the bottom 14b. And an opening surrounded by the upper ends of each of the first side walls 14c and the second side walls 14d is formed on the upper surface of the case body 14. On the other hand, the sealing plate 16 is a long rectangular plate-shaped member extending in the width direction X. This sealing plate 16 is attached to the case body 14 so as to close the opening on the upper surface. Note that the battery case 12 (the case body 14, the sealing plate 16) is preferably made of a metal material (for example, aluminum, aluminum alloy, etc.) having a predetermined rigidity.

[0017] Also, a positive electrode terminal 17 and a negative electrode terminal 18 are provided on the sealing plate 16. The positive electrode terminal 17 is connected to the positive electrode of the electrode body in the battery case 12. The negative electrode terminal 18 is connected to the negative electrode of the electrode body in the battery case 12. And as shown in FIG. 3, each single cell 10 is arranged such that the first side walls 14c face each other between two adjacent single cells 10. In this arrangement of the single cells 10, the orientations of each single cell 10 are alternately reversed so that the positive electrode terminal 17 of one single cell 10 and the negative electrode terminal 18 of the other single cell 10 are close to each other (see FIG. 1). And the positive electrode terminal 17, the negative electrode terminal 18, and the bus bar 40 are all conductive members mainly composed of a metal material (such as aluminum, copper, etc.).

[0018] 2. Restraining member 20 The restraining member 20 is a member that restrains a plurality of single cells 10 along the arrangement direction (depth direction Y). The restraining member 20 shown in FIG. 1 includes an end plate 22 and a restraining band 24. The end plate 22 is a pair of plate-like members arranged at both ends in the depth direction Y. A plurality of single cells 10 are arranged between this pair of end plates 22. The restraining band 24 is a long member extending in the depth direction Y. The pair of end plates 22 are connected by this restraining band 24. As a result, a plurality of single cells 10 are restrained along the depth direction Y.

[0019] 3. Buffer member 30 The buffer member 30 is arranged between two adjacent single cells 10. As shown in FIG. 1, the buffer member 30 is a plate-like member having a rectangular flat surface extending in the width direction X and the height direction Z. The flat surface of this buffer member 30 faces the first side wall 14c of the single cell 10. Since this buffer member has a predetermined elasticity, the restraining pressure applied to the first side wall 14c of the single cell 10 can be dispersed. Further, the buffer member 30 can prevent the single cells 10 from directly contacting each other, and can also suppress the propagation of heat generated in a specific single cell 10 to other single cells 10.

[0020] Here, the buffer member 30 according to the present embodiment includes a first heat-resistant part 32, a second heat-resistant part 34, and an elastic part 36 (see FIG. 3). Hereinafter, each part constituting the buffer member 30 will be described.

[0021] (1) First heat-resistant part 32 The first heat-resistant part 32 is a heat-resistant plate-like member. As shown in FIG. 3, the first heat-resistant part 32 is arranged so as to contact the single cell 10A in the front F. Specifically, the first heat-resistant part 32 has a flat outer surface 32a. The outer surface 32a of this first heat-resistant part 32 is in contact with the first side wall 14c of the single cell 10A in the front F. On the other hand, the first heat-resistant part 32 in the present embodiment has a flat inner surface 32b. The inner surface 32b of this first heat-resistant part 32 is in contact with the elastic part 36 described later.

[0022] Note that the "heat resistance" in this specification refers to having a melting point such that the single cell does not melt even when it generates heat beyond the temperature rise during normal use. However, the melting point required for the heat-resistant part varies depending on the type of single cell. Therefore, the "heat-resistant part" in the technology disclosed herein is not limited to materials having a specific melting point. As an example, a lithium-ion secondary battery may heat up to about 85°C during charge and discharge, but may exceed 100°C when some abnormality occurs. Therefore, when the single cell 10 is a lithium-ion secondary battery, the melting point of the first heat-resistant part 32 is preferably 300°C or higher, more preferably 400°C or higher, and particularly preferably 500°C or higher. Examples of materials having such a melting point include ceramic materials such as alumina, ceria, and zirconia, metal materials such as iron and aluminum, and alloy materials such as stainless steel. Further, the first heat-resistant part 32 is more preferably a material having a low thermal conductivity. Thereby, melting of the elastic part 36 can be more suitably suppressed. Examples of materials having a high melting point and low thermal conductivity include porous ceramics and the like.

[0023] Note that the thickness t1 of the first heat-resistant part 32 in FIG. 3 is preferably 1 mm or more, more preferably 1.5 mm or more, further preferably 2 mm or more, and particularly preferably 3 mm or more. Thereby, heat transfer to the elastic part 36 can be more suitably suppressed. Note that the arrangement length (dimension in the depth direction Y) of the power storage pack 1 is determined according to the specifications of the device to be mounted. Therefore, if the total thickness of the buffer member 30 is reduced, the number of single cells 10 that can be mounted on the power storage pack 1 can be increased, contributing to an improvement in the performance of the power storage pack 1. From the viewpoint of this mounting efficiency, the upper limit of the thickness t1 of the first heat-resistant part 32 is preferably 7 mm or less, more preferably 6 mm or less, further preferably 5 mm or less, and particularly preferably 4 mm or less.

[0024] (2) Second heat-resistant part 34 The second heat-resistant part 34 is a plate-shaped member facing the first heat-resistant part 32. This second heat-resistant part 34 is arranged to contact the single cell 10B at the rear Rr. Specifically, the outer surface 34a of the second heat-resistant part 34 is a flat surface that contacts the first side wall 14c of the single cell 10B at the rear Rr. Also, the inner surface 34b of the second heat-resistant part 34 is a flat surface that faces the inner surface 32b of the first heat-resistant part 32 with the elastic part 36 interposed therebetween.

[0025] Note that various designs (melting point, material, thickness t2) regarding the second heat-resistant part 34 can be appropriately adjusted from the same perspective as the first heat-resistant part 32. However, the second heat-resistant part 34 does not necessarily have to have the same design as the first heat-resistant part 32. For example, different materials can be used for the first heat-resistant part 32 and the second heat-resistant part 34 as long as they have appropriate heat resistance (melting point) in relation to the heat generation temperature of the single cell 10. Also, the thickness t1 of the first heat-resistant part 32 and the t2 of the second heat-resistant part 34 may be the same or different.

[0026] (3) Elastic part 36 The elastic part 36 is a resin plate-shaped member interposed between the first heat-resistant part 32 and the second heat-resistant part 34. This elastic part 36 has substantially the same height and width as the first side wall 14c of each single cell 10. And the elastic part 36 is a resin member that elastically deforms with respect to the restraint pressure in the depth direction Y. According to such an elastic part 36, the restraint pressure in the depth direction Y can be dispersed in the width direction X and the height direction Z, so that the variation in the restraint pressure applied within the plane of the first side wall 14c of the single cell 10 can be suppressed. Note that examples of the material of the elastic part 36 include EPDM (ethylene propylene rubber), silicone rubber, fluorine rubber, soft resin, structural elastomer, etc. The elastic part 36 containing these resin materials can exhibit a particularly suitable pressure dispersion function.

[0027] Further, the thickness t3 of the elastic portion 36 is preferably 1 mm or more, more preferably 1.5 mm or more, still more preferably 2 mm or more, and particularly preferably 2.5 mm or more. By this, the restraint pressure applied to each single cell 10 can be more suitably dispersed. On the other hand, from the viewpoint of mounting efficiency, the upper limit of the thickness t3 of the elastic portion 36 is preferably 5 mm or less, more preferably 4.5 mm or less, still more preferably 4 mm or less, and particularly preferably 3 mm or less.

[0028] As described above, in the buffer member 30 according to the present embodiment, the elastic portion 36 is sandwiched between the first heat-resistant portion 32 and the second heat-resistant portion 34. As a result, the first heat-resistant portion 32 (or the second heat-resistant portion 34) can be interposed between the single cell 10 and the elastic portion 36. As a result, it is possible to prevent the elastic portion 36 from being directly heated when the single cell 10 generates heat, and thus it is possible to suppress the melting of the elastic portion 36. Therefore, according to the present embodiment, the pressure dispersion function of the elastic portion 36 can be suitably maintained. Further, since it is possible to prevent a decrease in the total thickness of the buffer member 30 due to the melting of the elastic portion 36, the heat insulation function, which is another function of the buffer member 30, can also be suitably maintained.

[0029] <Second Embodiment> Next, a second embodiment of the power storage pack disclosed herein will be described. FIG. 4 is a side view for explaining the positional relationship between the buffer member and the single cell in the power storage pack according to the second embodiment. FIG. 5 is a plan view of the inner surface of the first heat-resistant portion shown in FIG. 4. FIG. 6 is a side view for explaining the state in which the elastic portion in FIG. 4 has melted.

[0030] As shown in FIG. 3, in the first embodiment, the first heat-resistant part 32 with a flat inner surface 32b is used. On the other hand, the first heat-resistant part 32 in the second embodiment includes a plurality of first convex parts 32p protruding toward the second heat-resistant part 34 (see FIG. 4). This first convex part 32p protrudes rearward Rr from the inner surface 32b of the first heat-resistant part 32. A flat surface facing the inner surface 34b of the second heat-resistant part 34 is formed at the tip 32p1 of the first convex part 32p. The first heat-resistant part 32 in the present embodiment is in contact with the elastic part 36 at the tip 32p1 of this first convex part 32p. Further, as shown in FIG. 5, the first convex part 32p is a ridge (linear protrusion) extending along the first direction (width direction X) in a plan view. And a first concave part 32r, which is a groove extending in the width direction X, is formed between two adjacent first convex parts 32p in the height direction Z. In other words, in the second embodiment, the first convex part 32p extending in the width direction X and the first concave part 32r extending in the width direction X are alternately formed on the inner surface 32b of the first heat-resistant part 32 in the height direction Z.

[0031] As described above, according to the technology disclosed herein, since the elastic part can be prevented from being directly heated during single-cell heat generation, melting of the elastic part can be suppressed. In addition to this, according to the second embodiment, even after the elastic part 36 has melted due to excessive heat generation of the single cell 10, a suitable heat insulation function can be maintained. Specifically, when the elastic part 36 melts due to excessive heat generation of the single cell 10, as shown in FIG. 6, the first heat-resistant part 32 and the second heat-resistant part 34 may come into contact with each other. At this time, in the second embodiment, since a plurality of first convex parts 32p are formed on the first heat-resistant part 32, the contact area between the first heat-resistant part 32 and the second heat-resistant part 34 can be reduced. And since air or a resin material (the melted elastic part 36) exists in the space (the first concave part 32r) between the first convex parts 32p, the thermal conductivity becomes lower than that of the first heat-resistant part 32 and the second heat-resistant part 34. Thereby, even after the elastic part 36 has melted, a heat insulation function of a certain level or more is maintained, and heat propagation from one single cell 10 to the other single cell 10 can be suppressed.

[0032] Further, as described above, the first convex portion 32p in the present embodiment is a linear protrusion extending along the first direction (width direction X) in a plan view. When such a linear first convex portion 32p is provided, the contact between the first heat-resistant portion 32 and the second heat-resistant portion 34 when the elastic portion 36 melts is stabilized. As a result, the bias of the restraint pressure after the elastic portion 36 melts can be suppressed to a certain extent. Note that the "first direction" in which the first convex portion extends is not limited to the width direction X. For example, the linear first convex portion may extend in the height direction or in an oblique direction. Further, the linear first convex portion does not necessarily need to be continuously formed from one edge portion to the other edge portion of the first heat-resistant portion. For example, the first convex portion may be partially interrupted while extending along the first direction, or may be formed only at the central portion of the inner surface of the first heat-resistant portion.

[0033] Note that the protruding amount P1 (dimension in the depth direction Y) of the first convex portion 32p shown in FIG. 4 is preferably 2 mm or more, more preferably 2.5 mm or more, further preferably 3 mm or more, and particularly preferably 3.5 mm or more. Thereby, even when the elastic portion 36 melts, the inner surface 32b of the first heat-resistant portion 32 and the inner surface 34b of the second heat-resistant portion 34 can be sufficiently separated, so that the heat insulation function can be maintained more preferably. Further, from the viewpoint of mounting efficiency, the protruding amount P1 of the first convex portion 32p is preferably 5 mm or less, more preferably 4.5 mm or less, and particularly preferably 4 mm or less.

[0034] Further, the width W1 (see FIG. 5) of the first convex portion 32p is preferably 1 mm or more, more preferably 2 mm or more, further preferably 3 mm or more, and particularly preferably 5 mm or more. Thereby, the strength of the first convex portion 32p can be sufficiently ensured, so that it is possible to suppress the first convex portion 32p from being crushed by the restraint pressure. On the other hand, the upper limit of the width W1 of the first convex portion 32p is preferably 15 mm or less, more preferably 13 mm or less, further preferably 12 mm or less, and particularly preferably 10 mm or less. Thereby, the contact area between the first heat-resistant portion 32 and the second heat-resistant portion 34 when the elastic portion 36 melts can be further reduced.

[0035] Further, the width W2 of the first concave portion 32r is preferably 1 mm or more, more preferably 2 mm or more, still more preferably 3 mm or more, and particularly preferably 5 mm or more. This can further improve the heat insulation function during the melting of the elastic portion 36. On the other hand, the upper limit of the width W2 of the first concave portion 32r is preferably 15 mm or less, more preferably 13 mm or less, still more preferably 12 mm or less, and particularly preferably 10 mm or less. This can suppress the crushing of the first convex portion 32p by the restraint pressure.

[0036] <Third Embodiment> Next, a third embodiment of the power storage pack disclosed herein will be described. FIG. 7 is a side view for explaining the positional relationship between the buffer member and the single cell in the power storage pack according to the third embodiment. FIG. 8 is a plan view of the inner surface of the second heat-resistant portion shown in FIG. 7. FIG. 9 is a plan view for explaining the support region of the buffer member shown in FIG. 7. For convenience of explanation, in FIG. 9, the region where the first convex portion 32p is formed is shown by a solid line, and the region where the second convex portion 34p is formed is shown by a dotted line. And the support region S where the first convex portion 32p and the second convex portion 34p face each other is hatched.

[0037] As shown in FIG. 4, in the buffer member 30 according to the second embodiment, the first convex portion 32p is provided only on the first heat-resistant portion 32. In contrast, in the buffer member 30 according to the third embodiment, convex portions are provided on both the first heat-resistant portion 32 and the second heat-resistant portion 34 (see FIG. 7). Specifically, also in the third embodiment, the first heat-resistant portion 32 includes a plurality of first convex portions 32p protruding toward the second heat-resistant portion 34. In addition, the second heat-resistant portion 34 in the third embodiment includes a plurality of second convex portions 34p protruding toward the first heat-resistant portion 32. And as shown in FIG. 9, in this buffer member 30, a support region S where the first convex portion 32p and the second convex portion 34p face each other is formed. According to such a configuration, the heat insulation function during the melting of the elastic portion 36 can be further improved. Hereinafter, it will be specifically described.

[0038] First, the first convex portion 32p in the third embodiment protrudes rearward Rr from the inner surface 32b of the first heat-resistant portion 32. And the first convex portion 32p extends along the first direction (width direction X) (see FIG. 9). Since the structure of this first convex portion 32p is the same as the structure of the first convex portion 32p in the above-described second embodiment (see FIG. 5), a detailed description thereof is omitted.

[0039] On the other hand, the second heat-resistant portion 34 in the third embodiment has a second convex portion 34p that protrudes forward F from the inner surface 34b (see FIG. 7). The tip 34p1 of this second convex portion 34p has a flat surface that contacts the elastic portion 36. As shown in FIG. 8, the second convex portion 34p is a ridge that extends along the second direction (diagonal direction in FIG. 8) in a plan view. And a second concave portion 34r is formed between two adjacent second convex portions 34p. In other words, on the inner surface 34b of the second heat-resistant portion 34 in the third embodiment, the second convex portion 34p extending in the diagonal direction and the second concave portion 34r extending in the diagonal direction are alternately formed.

[0040] In the buffer member 30 according to this embodiment, a support region S is formed in the thickness direction, where the first convex portion 32p and the second convex portion 34p face each other. Specifically, in this embodiment, the first convex portion 32p extending in the first direction and the second convex portion 34p extending in the second direction intersect in a plan view. As shown by the hatched portion in FIG. 9, the portion where the first convex portion 32p and the second convex portion 34p intersect becomes the support region S. In this support region S, the tip 32p1 of the first convex portion 32p and the tip 34p1 of the second convex portion 34p face each other. And this support region S becomes the contact portion between the first heat-resistant portion 32 and the second heat-resistant portion 34 when the elastic portion 36 melts. That is, in the third embodiment, when the elastic portion 36 melts, the first heat-resistant portion 32 and the second heat-resistant portion 34 are in point contact. Thereby, the contact area between the first heat-resistant portion 32 and the second heat-resistant portion 34 can be further reduced. Thereby, the heat insulation function when the elastic portion 36 melts can be improved. Also, according to the third embodiment, since the first heat-resistant portion 32 and the second heat-resistant portion 34 can be supported at a large number of points, even though the contact area is reduced, it is possible to prevent the restraint pressure from concentrating on a specific portion. As described above, according to this embodiment, the heat insulation function and the pressure dispersion function when the elastic portion 36 melts can be achieved at a high level simultaneously.

[0041] Also, the area of the support region S in a plan view is preferably 1 / 10 or more (preferably 1 / 5 or more) of the total area of the opposing regions of the first heat-resistant portion 32 and the second heat-resistant portion 34 (typically, the area of the buffer member 30 in a plan view). Thereby, the contact between the first heat-resistant portion 32 and the second heat-resistant portion 34 when the elastic portion 36 melts can be more preferably stabilized. On the other hand, the area of the support region S is preferably 1 / 2 or less (preferably 1 / 3 or less) of the total area of the opposing regions. Thereby, the contact area between the first heat-resistant portion 32 and the second heat-resistant portion 34 can be further reduced, and the heat insulation function when the elastic portion 36 melts can be further improved.

[0042] <Other Embodiments> The first to third embodiments of the technology disclosed herein have been described above. However, the technology disclosed herein is not limited to the above-described embodiments. The technology disclosed herein includes various modifications and changes of the above-described embodiments.

[0043] For example, the convex portions (the first convex portion, the second convex portion) in the second to third embodiments are ridges extending in a predetermined direction in a plan view. However, the first convex portion and the second convex portion only need to be able to maintain the distance between the first heat-resistant portion and the second heat-resistant portion during melting of the elastic portion, and are not limited to a specific planar shape. For example, the first convex portion and the second convex portion may be columnar (circular columnar, rectangular columnar) protrusions scattered on the inner surface of the heat-resistant portion. Even when such columnar convex portions are provided, the contact area between the first heat-resistant portion and the second heat-resistant portion during melting of the elastic portion can be reduced.

[0044] Also, as shown in FIG. 9, in the third embodiment, the support region S is formed by intersecting the first convex portion 32p extending in the first direction (width direction X) and the second convex portion 34p extending in the second direction (diagonal direction). However, since the support region can be formed by opposing the first convex portion and the second convex portion in the thickness direction, it is not limited to the third embodiment. For example, a first heat-resistant portion having a linearly extending first convex portion and a second heat-resistant portion with a plurality of columnar second convex portions scattered thereon may be combined. Also in this case, a buffer member having a support region can be formed. However, as shown in FIG. 9, when the linear first convex portion 32p and the linear second convex portion 34p are combined, a plurality of support regions S can be regularly formed. Thereby, the pressure dispersion function during melting of the elastic portion 36 can be more preferably improved.

[0045] Also, a general power storage pack includes a plurality of buffer members (see FIG. 1). The buffer member disclosed herein may be used for all of the plurality of buffer members, or may be used only for a part of them. For example, when the total number of buffer members in the power storage pack is set to 100%, if the buffer member disclosed herein is used at 10% or more (more preferably 15% or more, particularly preferably 20% or more), a suitable pressure dispersion function and heat insulation function can be exhibited as the entire power storage pack.

[0046] In addition, for the single cell 10 in the above-described embodiment, a battery case 12 including a case body 14 having an opening on the upper surface and a sealing plate 16 closing the opening is used. However, the battery case of the single cell may have a shape that can be constrained by a constraining member (typically a rectangular shape), and is not limited to the shape in the above-described embodiment. For example, the battery case of the single cell may include a rectangular tube-shaped case body having openings on both side surfaces in the width direction and a pair of sealing plates closing each of the openings on both side surfaces. Even when such a configuration is adopted, a rectangular battery case can be constructed, and thus it can be constrained with a buffer member interposed therebetween.

[0047] Note that each member (the first heat-resistant part, the second heat-resistant part, the elastic part) constituting the buffer member may or may not be adhered to each other. As described above, in constructing the power storage pack, a buffer member is arranged between a plurality of single cells and constrained along the arrangement direction. At this time, the first heat-resistant part, the elastic part, and the second heat-resistant part may be arranged between the single cells in this order for constraint. Thereby, even when the members are not adhered to each other, a buffer member including the first heat-resistant part, the elastic part, and the second heat-resistant part can be formed between two single cells.

[0048] The embodiments of the technology disclosed herein have been described above. In addition, the technology disclosed herein includes the forms described in the following Items 1 to 7.

[0049] <Item 1> A buffer member disposed between two adjacent single cells, a plate-shaped first heat-resistant part, a plate-shaped second heat-resistant part facing the first heat-resistant part, and a resin-made elastic part interposed between the first heat-resistant part and the second heat-resistant part A buffer member comprising.

[0050] <Item 2> The buffer member according to Item 1, wherein the first heat-resistant part includes a plurality of first convex portions protruding toward the second heat-resistant part.

[0051] <Item 3> The buffer member according to Item 2, wherein the first convex portion is a protrusion extending along a first direction in a plan view.

[0052] <Item 4> The second heat-resistant portion includes a plurality of second convex portions protruding toward the first heat-resistant portion, The buffer member according to Item 2 or Item 3, wherein a support region is formed in which the first convex portion and the second convex portion face each other in the thickness direction.

[0053] <Item 5> The buffer member according to Item 4, wherein an area of the support region in a plan view is 1 / 5 or more and 1 / 3 or less of a total area of an opposing region between the first heat-resistant portion and the second heat-resistant portion.

[0054] <Item 6> The buffer member according to Item 4 or 5, wherein the first convex portion is a protrusion extending along a first direction in a plan view, and the second convex portion is a protrusion extending along a second direction intersecting the first direction.

[0055] <Item 7> A plurality of single cells arranged along a predetermined arrangement direction, A restraint member that restrains the plurality of single cells along the arrangement direction, A buffer member disposed between two adjacent single cells, Comprising The plurality of buffer members include the buffer member according to any one of claims 1 to 6, a power storage pack.

Explanation of Reference Numerals

[0056] 1: Power storage pack 10: Single cell 12: Battery case 14: Case body 16: Sealing plate 17: Positive terminal 18: Negative terminal 20: Restraint member 22: End plate 24: Restraining band 30: Buffer member 32: First heat-resistant part 32p: First convex part 32r: First concave part 34: Second heat-resistant part 34p: Second convex part 34r: Second concave part 36: Elastic part 40: Bus bar

Claims

1. A buffer member disposed between two adjacent single cells, a plate-shaped first heat-resistant part, a plate-shaped second heat-resistant part facing the first heat-resistant part, and an elastic part made of resin interposed between the first heat-resistant part and the second heat-resistant part The buffer member is provided with.

2. The buffer member according to claim 1, wherein the first heat-resistant part includes a plurality of first convex parts protruding toward the second heat-resistant part.

3. The buffer member according to claim 2, wherein the first convex part is a ridge extending along a first direction in a plan view.

4. The second heat-resistant part includes a plurality of second convex parts protruding toward the first heat-resistant part, and a support region is formed in which the first convex part and the second convex part face each other in the thickness direction. The buffer member according to claim 2.

5. The buffer member according to claim 4, wherein an area of the support region in a plan view is 1 / 5 or more and 1 / 3 or less of a total area of an opposing region between the first heat-resistant part and the second heat-resistant part.

6. The buffer member according to claim 4, wherein the first convex part is a ridge extending along a first direction in a plan view, and the second convex part is a ridge extending along a second direction intersecting the first direction.

7. A plurality of single cells arranged along a predetermined arrangement direction, a restraining member for restraining the plurality of single cells along the arrangement direction, a plurality of buffer members disposed between two adjacent single cells, and is provided with The plurality of buffer members include the buffer member according to any one of claims 1 to 6. A power storage pack.

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