JP7187433B2 - Constraining plate and battery stack - Google Patents

Description

TECHNICAL FIELD The present invention relates to a constraining plate and a battery stack, and more particularly to a constraining plate used to constrain a battery and a battery stack including the constraining plate.

Currently, electric vehicles, hybrid vehicles, plug-in hybrid vehicles, and the like are equipped with secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries. Such secondary batteries have problems of heat generation and expansion.

Patent Literature 1 describes a battery pack intended to improve efficiency of heat dissipation from a battery module to a heat capacity member. The battery pack described in Patent Document 1 contains a battery module in a housing, and the housing has a side plate having an inner wall surface to which the battery module is fixed and an outer wall surface to which a weight member is fixed. ing. A plurality of outward protrusions that protrude outward from the housing are provided on the outer wall surface side of the side plate in correspondence with the areas where the weight members are fixed. Moreover, Patent Document 1 also describes that heat transfer is improved by filling a heat transfer member between adjacent outward convex portions.

JP 2017-103158 A

However, with the technique of improving heat transfer as described in Patent Document 1, a difference in thermal resistance occurs between cells in the battery during natural heat dissipation, and variations in temperature between the cells tend to occur.

The present invention has been made to solve such problems, and provides a constraining plate capable of suppressing temperature variations between cells in a battery, and a battery stack including the constraining plate. Its purpose is to provide

A constraining plate according to an aspect of the present invention is brought into contact with a resin plate disposed on the end face side of a battery in which a plurality of cells are arranged, and on the side of the resin plate opposite to the side on which the batteries are disposed. a steel plate, wherein the resin plate has a plurality of protrusions arranged in the same direction as the cell arrangement direction, which is the arrangement direction of the cells, on the side that is brought into contact with the steel plate, and the steel plate includes the plurality of a plurality of recesses abutting on the projections, the recesses having a shape in which an internal space is formed in a state of being in contact with the projections, and the projections positioned on the outermost side in the cell arrangement direction The volume of the internal space formed by the recess and the recess is larger than the volume of the internal space formed by the projection located on the central side and the recess.

Moreover, it is preferable that the volume of the internal space decreases from the outside toward the center in the cell arrangement direction.
Furthermore, it is preferable that each of the plurality of protrusions is formed so that its outer shape increases from the outside toward the center in the cell arrangement direction.
Moreover, it is preferable that each of the plurality of protrusions is formed so that the contact area with the steel plate increases from the outside toward the center in the cell arrangement direction.

Moreover, it is preferable that the protrusion has a plurality of cross-sectional shapes in the cell arrangement direction.

Moreover, it is preferable that each of the plurality of protrusions is arranged so as to be symmetrical with respect to the center of the electrode group included in the battery and to overlap with the center of the outer shape of the battery.

Moreover, it is preferable that the internal space is evenly formed with respect to the center of the protrusion in the cell arrangement direction.

In addition, the steel plate can be attached with a plurality of bridging members for bridging the restraining plate and the other member in a state in which the battery group including the batteries is sandwiched between the restraining plate and the other member. preferably. Here, the cell arrangement direction is the same direction as the arrangement direction of the plurality of bridging members, and the plurality of protrusions include two outer protrusions located on the outermost side in the cell arrangement direction and the two outer protrusions. It can be configured with other protrusions located between the protrusions. Further, it is preferable that the width of the outer protrusion in the cell arrangement direction is larger than the width of the other protrusion in the cell arrangement direction.
Here, it is preferable that the volume of the outer protrusion is smaller than the volume of the other protrusion.

A battery stack according to another aspect of the present invention includes the constraining plate and a battery group including the batteries, the constraining plate is brought into contact with one end of the battery group, and the battery group is It is something that binds.

According to the present invention, it is possible to provide a constraining plate capable of suppressing temperature variations among cells in a battery, and a battery stack including the constraining plate.

FIG. 2 is a cross-sectional view showing one configuration example of a restraining plate according to Embodiment 1; FIG. 3 is a cross-sectional view for explaining transmission of battery internal pressure by projections in the constraining plate of FIG. 1 ; FIG. 5 is a cross-sectional view showing the configuration of a restraining plate according to a comparative example; FIG. 11 is an exploded perspective view schematically showing one configuration example of a restraining plate according to Embodiment 2; FIG. 5 is a cross-sectional view for explaining heat conduction by projections in the restraining plate of FIG. 4 ; FIG. 2 is a cross-sectional view for explaining heat conduction by projections in the restraining plate of FIG. 1; FIG. 11 is a perspective view showing one configuration example of a resin plate used in a restraining plate according to Embodiment 3; FIG. 8 is a cross-sectional view of one configuration example of a constraining plate according to Embodiment 3, viewed from the VIII-VIII direction in FIG. 7; 9 is a side view of the restraining plate of FIG. 8; FIG.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate. Also, in the embodiments, the same or equivalent elements may be denoted by the same reference numerals, and overlapping descriptions will be omitted as appropriate.

(Embodiment 1)
Embodiment 1 will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a cross-sectional view showing a configuration example of a restraining plate according to Embodiment 1. FIG. FIG. 2 is a cross-sectional view for explaining the transmission of the battery internal pressure by the protrusions in the restraining plate of FIG.

As shown in FIG. 1 , the restraining plate 1 according to this embodiment can include a resin plate 13 and a steel plate 15 . The restraint plates 1 are arranged at both ends of the battery 11 and can be used to restrain the battery 11 from deformation by restraining it from both sides. However, one side can be substituted with another type of constraining plate or another member.

A battery 11 to be held by the restraining plate 1 is a secondary battery, and six cells 11a, 11b, 11c, 11d, 11e, and 11f are arranged inside. In this example, the number of cells is six and all the cells 11a to 11f have the same width. However, the number of built-in cells is not limited to this, and the width of each cell may not be the same. Each cell can contain one or a plurality of sets (electrode groups) each including a positive electrode sheet, a negative electrode sheet, and a separator, and the cells can be separated by walls. Moreover, although omitted in FIG. 1, the object to be restrained by the restraining plate 1 can be a plurality of stacked batteries 11, and this structure is generally adopted.

The resin plate 13 is a plate-shaped member arranged on the end face side of the battery 11 in which the six cells 11a to 11f are arranged, and forms an air layer 18 between the resin plate 13 and the battery 11 as illustrated in FIG. A pedestal 12 can be provided for. The air layer 18 is a channel for flowing cooled air, and in the example of FIG. 1, is formed so as to communicate in the direction perpendicular to the paper surface. Cooled air can flow through the air layer 18 from, for example, a blowing mechanism such as a blower (not shown). The air layer 18 can also be formed by another member provided between the resin plate 13 and the battery 11 .

The steel plate 15 is a plate-like member that is brought into contact with the side of the resin plate 13 opposite to the side on which the batteries 11 are arranged. The material of the steel plate 15 does not matter.

The resin plates 13 are arranged in the same direction as the arrangement direction of the cells 11a to 11f (hereinafter referred to as the cell arrangement direction) on the side that contacts the steel plate 15 (the side opposite to the side that contacts the battery 11). projections 14a to 14f. Hereinafter, when each of the plurality of protrusions is described as a representative without distinction, the description will be made as "projection 14", and other parts and other examples will be described using the same expression method. .

The steel plate 15 has a plurality of recesses 16 that contact the plurality of projections 14 . By bringing the protrusion 14 into contact with the recess 16 and supporting the recess 16 with the protrusion 14 , the internal pressure from the battery 11 side can be transmitted from the resin plate 13 to the steel plate 15 , thereby suppressing the expansion of the battery 11 . can be done.

Furthermore, as illustrated in FIG. 1, the steel plate 15 is preferably formed by forming a convex portion on the opposite surface (outward surface) of each of the concave portions 16 .

The concave portion 16 has a shape in which an internal space (internal cavity) 17 is formed in a state of contact with the projection portion 14 . The internal space 17 has a function of suppressing the natural radiation of heat from the battery 11 .

FIG. 1 shows an example in which one protrusion 14 corresponds to one cell, that is, six protrusions 14a to 14f corresponding to six cells 11a to 11f, respectively. Further, an example in which one recess 16 is associated with one protrusion 14 to form one internal space 17 will be given. That is, the illustrated steel plate 15 has recesses 16a to 16f corresponding to the projections 14a to 14f, respectively, and internal spaces 17a to 16f are formed by the gaps between the recesses 16 and the projections 14 that are in contact with each other.

It should be noted that one internal space 17 can be formed by associating two or more projections 14 with one recess 16 . It is also possible to suppress the expansion of each cell of the battery 11 by providing two or more internal spaces 17 for each cell.

Moreover, all of the protrusions 14a to 14f can be formed so as to extend from the main body of the resin plate 13, and are basically resin-molded integrally with the main body. It can also be fixed by The pedestal portion 12 is similarly resin-molded integrally with the main body of the resin plate 13, but it is also possible to fix them by bonding them after performing resin-molding separately. In this case, the adhesive preferably has a lower heat resistance than the resin.

FIG. 2 shows an enlarged view of a set of cells 11c, protrusions 14c, and recesses 16c in FIG. The internal pressure from the cell 11c is dispersed in the concave portion 16c of the steel plate 15 (the outward convex portion corresponding to the concave portion 16c) as indicated by the white arrow in FIG. Therefore, each internal space 17 is arranged evenly with respect to the center of each protrusion 14 in the cell arrangement direction (in FIG. 2, symmetrically with respect to the dashed line in FIG. 2) so that such internal pressure can be dispersed. It can be said that it is preferable to be formed.

In FIG. 1, all of the concave portions 16a to 16f may have substantially the same shape in the direction perpendicular to the paper surface (excluding both ends in the direction perpendicular to the paper surface), that is, may have a vertically elongated groove-like shape. Correspondingly, each of the protrusions 14a to 14f can also have the same shape in the direction perpendicular to the paper surface.

In the constraining plate 1, the volume of the internal space 17a and the internal space 17f formed by the projections 14a and 14f and the recesses 16a and 16f located on the outermost sides in the cell arrangement direction both satisfy the following conditions. and

In other words, both the volume of the internal space 17a and the volume of the internal space 17f are larger than the volume of the internal space 17b formed by the projection 14b and the recess 16b located on the central side. The same applies to the internal spaces 17c, 17d, and 17e located on the central side, and the volume of the internal space 17a and the volume of the internal space 17f are both larger than the individual volumes of the internal spaces 17c, 17d, and 17e. and

Thereby, temperature variations between the central cell and the outermost cell of the battery 11 can be suppressed. In particular, when a blower mechanism is not provided, or when the blower mechanism is stopped even when a blower mechanism is provided, that is, when natural heat dissipation is performed, the difference in thermal resistance between the internal cells There is a concern that variations in temperature may occur. However, in this embodiment, even in such a case, it is possible to reduce variations in temperature between cells.

In order to explain such an effect of the present embodiment and accompanying effects, the configuration of a constraining plate according to a comparative example shown in FIG. 3 will be described. FIG. 3 is a cross-sectional view showing the configuration of a restraining plate according to a comparative example.

A constraining plate 100 according to a comparative example has the same internal space volume as the constraining plate 1 of FIG. The constituent elements of the constraining plate 100 are illustrated using numerals with 100 counted from the numerals of the constituent elements in the constraining plate 1 of FIG. 1, although the description thereof is omitted. The resin plate 113 of the restraining plate 100 is provided with a pedestal portion 119 for abutting on the steel plate 115 other than the concave portions 116 (116a to 116f).

In the constraining plate 100, the air layer in the internal space 117 has only the same heat insulation effect between the outer cells 111a and 111f, which generate less heat, and the central cells 111b to 111e, which generate more heat. It is not possible to equalize the degree of cooling by the mechanism. Therefore, in order to at least improve the heat insulation effect, the pedestal portion 119 is provided to increase the distance D2 from the end surface of the battery 111 to the outward convex portion corresponding to the concave portion 116 .

On the other hand, in the constraining plate 1 according to the present embodiment, the air layer in the internal space 17 inside the recess 16 serves as a heat insulating layer, and the air layers in the internal spaces 17a to 17f have different volumes as described above. It is That is, the air layers in the internal spaces 17a to 17f are configured so that the outer cells 11a and 11f, which generate less heat, have a greater heat insulation effect than the central cells 11b to 11e, which generate more heat. Therefore, in this embodiment, uniform cooling is achieved among the cells.

Furthermore, by adopting such a configuration that enables the equalization of the constraining plate 1, the distance D1 from the end surface of the battery 11 in the constraining plate 1 to the outward protrusion corresponding to the recess 16 is equal to the distance of the comparative example. It can be shorter than D2.

Further, the cooling performance can be improved as the size of the internal space 17 (the size of the air layer) increases. Further, as the contact area between the concave portion 16 and the projection portion 14 is increased, the heat conductivity of the contact portion is improved, and the cooling performance can be improved.

Therefore, as illustrated in FIG. 1, it is preferable that the volume of the internal space 17 decreases from the outside (end) toward the center in the cell arrangement direction. FIG. 1 shows an example in which the protrusions 14 are formed so that the outer shape (size of the outer shape) increases from the outside toward the center in the cell arrangement direction. The example of FIG. 1 is also an example in which the contact area with the steel plate 15 increases as the projection 14 goes from the outside toward the center in the cell arrangement direction. In this way, the protrusions 14 can be formed so that the outer shape increases from the outside toward the center in the cell arrangement direction, or the protrusions 14 are formed so that the contact area with the steel plate 15 increases. or can be configured to satisfy both.

(Embodiment 2)
The second embodiment will be described with a focus on differences from the first embodiment with reference to FIGS. 4 to 6, but various examples described in the first embodiment can be applied. FIG. 4 is an exploded perspective view schematically showing one configuration example of a restraining plate according to the second embodiment. FIG. 5 is a cross-sectional view for explaining heat conduction by the protrusions in the constraining plate of FIG. 4, and is a cross-sectional view seen from the VV direction of FIG. FIG. 6 is a cross-sectional view for explaining heat conduction by projections in the constraint plate of FIG.

As illustrated in FIG. 4 , the restraining plate 2 according to this embodiment includes a resin plate 23 and steel plates 25 . The resin plate 23 and the steel plate 25 are modified examples of the resin plate 13 and the steel plate 15, respectively. The resin plate 23 has ladder-shaped projections 24 (24a to 24f), and the steel plate 25 has outward projections 26 (26a to 26f) like rectangular grooves.

The outward convex portion 26 has a corresponding concave portion on the opposite side (the side in contact with the resin plate 23). Here, for convenience of explanation from the outside, the concave portion will be explained with the corresponding outward convex portion. is doing. As illustrated in FIG. 5, the internal space 27c formed by the protrusion 24c and the recess corresponding to the outward protrusion 26c also includes a ladder-shaped recess. The same is true for other internal spaces 27 .

The constraining plate 2 has protrusions 24 of a common size, but the recesses located on the outermost side (outward protrusions 26a and 26f on both ends of corresponding sizes) are replaced with recesses on the central side (sizes corresponding to them). are larger than the outward projections 26b to 26e). In this embodiment, this satisfies the condition described in the first embodiment regarding the volume of the internal space.

Moreover, the constraining plate 2 is arranged at one end of a battery group in which a plurality of batteries 21 are stacked. The battery stack 3 can include a constraining plate 2 and its battery group. One end of the battery group is brought into contact with the constraining plate 2, and the other end of the battery group is brought into contact with another member to provide a space between them. A plurality of bridging members may be used for bridging, and the battery group may be sandwiched and restrained from both ends thereof. As the other member, the constraining plate 2 is generally used, but it is not limited to this. The constraining plate 1 described with reference to FIG. 1 can also constrain the battery group with the configuration shown in FIG.

When the battery group is constrained by the constraining plate 2, the deformation of the steel plate 25 and the resin plate 23 depends on the constraining position. area), and the latter area is more susceptible to deformation. However, in this embodiment, the width of the outward protrusions 26a and 26f of the outermost cell of the battery is made larger than the width of the outward protrusions 26b to 26e on the central side to increase the strength. Two bridging members (not shown) are attached to each of the upper and lower ends at the holding positions 29 between the outward protrusions 26a and 26b and between the outward protrusions 26f and 26e to Groups can be detained. Here, the arrangement direction of the two bridging members can be the same direction as the cell arrangement direction, but a plurality of separate bridging members can be provided in a direction perpendicular to the cell arrangement direction.

Due to such an improvement in strength, even when a battery group is held by attaching a bridge member to the holding position 29, the cantilever region undergoes a greater amount of deformation than the corresponding both-support region between the bridge members. deformation can be suppressed.

Moreover, as shown in FIGS. 4 and 5, it is preferable to form the protrusion 24c so that the cross-sectional shape in the cell arrangement direction is divided into a plurality of sections. In other words, this cross section includes space. In FIG. 5, the ladder-shaped protrusion 24c is illustrated, but the other protrusions 24 are the same. Note that the pedestal portion 22 in FIG. 5 is an example in which the pedestal portions 12 in FIG. 1 are provided more densely.

Effects of such a configuration will be described. First, as the arrows in FIG. 6 indicate the state of heat conduction, in the constraining plate 1, heat is conducted from the heat source 11ca of the electrode group of the cell 11c to the single projecting portion 14c. On the other hand, as shown by the arrows in FIG. 5 showing the state of heat conduction, by configuring the protrusions 24c with a plurality of (two in this example), the heat from the heat source 21ca of the electrode group of the cell 21c to the protrusions 24c Heat is easily conducted, and heat transfer can be made uniform from any position of the electrode group.

(Embodiment 3)
Embodiment 3 will be described with reference to FIGS. 7 to 9, focusing on differences from Embodiments 1 and 2, but various examples described in Embodiments 1 and 2 can be applied. FIG. 7 is a perspective view showing one configuration example of a resin plate used in a constraining plate according to Embodiment 3, and FIG. It is sectional drawing seen from the direction. 9 is a side view of the restraining plate of FIG. 8; FIG.

As shown in FIGS. 7 to 9, the restraining plate 4 according to this embodiment includes a resin plate 43 and a steel plate 45. As shown in FIGS. The resin plate 43 and the steel plate 45 are modified examples of the resin plate 23 and the steel plate 25, respectively. The resin plate 43 has ladder-shaped projections 44 (44a, 44b, 44c, . ···)have. The outward projection 46 has a correspondingly shaped recess on the opposite side (the side that contacts the resin plate 43). The internal space 47a formed by the protrusion 44a and the recess corresponding to the outward protrusion 46a also includes a ladder-shaped recess. The same is true for other internal spaces 47 .

In the constraining plate 4, the width Wa of the outermost protrusion 44a is formed larger than the width Wb of the central protrusion 44b and the width of the protrusion 44c. Furthermore, in the constraining plate 4, as shown in FIG. 9, the width W1 of the outermost concave portion (outward convex portions 46a and 46f at both ends of corresponding size) is equal to the width W1 of the central concave portion (corresponding size). It is formed larger than the widths W2 and W3 of the outward projections 46b to 46e). Here, W2≧W3 can be established.

Furthermore, only with these conditions, the volume of the internal space 47 is the same as the condition described in the first embodiment (the volume of the internal space corresponding to the protrusion 44a on the outer side is the volume of the internal space corresponding to the protrusion 44b on the central side, etc.). greater than) may not be satisfied. Therefore, in order to satisfy this condition, the vertical length La of the outermost protrusion 44a is formed to be smaller than the length Lb of the central protrusion 44b and the length of the protrusion 44c. In FIG. 7, the protrusion 44a and the protrusions 44b and 44c have the same height, and the depth of the recess corresponding to the outward protrusion 46a and the depth of the recess corresponding to the outward protrusions 46b and 46c are the same. gives an example.

However, if the volume of the projections 44a on the outside is smaller than the volume of the projections 44b and 44c on the central side, even if the width Wa is larger than the width Wb and the width W1 is larger than the width W2, the first embodiment is applicable. The described conditions can be met. If the projection 44a on the outside has a smaller volume than the projections 44b and 44c on the central side, even when W1>W2, the corresponding internal space 47 can be enlarged and/or the corresponding steel plate It is possible to reduce the contact area of 45 with the recess.

As a result, the width W1 of the outward protrusions 46a and 46f is made larger than the widths W2 and W3 of the outward protrusions 46b to 46e on the central side to achieve both the effect of increasing the strength and the effect of improving the cooling performance. be able to.

In addition, as described in the second embodiment, the restraining plate 4 has a plurality of bridges (in FIG. 9, two for each of the upper end and the lower end) at the holding position 49 corresponding to the holding position 29. A member 50 can be attached. As can be seen from the examples of FIGS. 8 and 9, the bridge member 50 can be installed so as to hold the resin plate 43 and the battery group at the holding position 49 of the steel plate 45 . The bridging member 50 is composed of, for example, a rod-shaped or long plate-shaped member and a fastening member such as a nut that is tightened so as to shorten the length corresponding to the stacking length of the battery group near the holding position 49. can do. Here, too, the arranging direction of the plurality of bridging members 50 (the plurality of bridging members 50 at each end) can be the same as the cell arranging direction as shown in FIG. It is also possible to separately provide a plurality of bridging members in the direction.

Further, as illustrated in FIG. 8 for one cell 41a, the cell 41a can incorporate an electrode group 41ae and can be provided with a space 41as and the like. In this case, the center indicated by the center line C1 of the constraining plate 4 (that is, the height of the battery) deviates from the center indicated by the center line C2 of the electrode group 41ae.

When adopting such a configuration, the protrusions 44a are preferably arranged symmetrically with respect to the center (center line C2) of the electrode group 41ae of the cell 41a. Further, the protrusion 44a can be arranged so as to overlap the center of the battery's outer shape, that is, so that the protrusion overlaps the center of the battery's outer shape standard.

In this way, by arranging the projections 44a symmetrically with respect to the center of the electrode group 41ae, the amount of heat radiation from the electrode group 41ae of the cell 41a by the projections 44a can be equalized. Further, by setting the protrusion of the protrusion 44a so as to overlap with the central portion of the battery outer shape standard, expansion due to the internal pressure of the battery can be suppressed. Such an arrangement is the same for the projections 44 other than the projections 44a, and can be applied to the first and second embodiments as well. Moreover, even when the center line C1 and the center line C2 match, the same effect can be obtained by applying the same arrangement.

(other embodiments, etc.)
It should be noted that the present invention is not limited to the first to third embodiments, and can be modified as appropriate without departing from the scope of the invention. Moreover, the present invention may be carried out by appropriately combining each embodiment. For example, the shape of each member in Embodiments 1 to 3 is not limited to those illustrated. Further, for example, in the constraining plate 4 shown in FIG. 9, it is also possible to configure the protrusions to have the same size, thereby achieving at least the purpose of strengthening.

1, 2, 4 restraining plate 3 battery stacks 11, 21 batteries 11a, 11b, 11c, 11d, 11e, 11f, 21c, 41a cells 11ca, 21ca heat source 12 pedestals 13, 23, 43 resin plate 14 (14a, 14b , 14c, 14d, 14e, 14f), 24 (24a, 24b, 24c, 24d, 24e, 24f), 44 (44a, 44b, 44c) Projections 15, 25, 45 Steel plates 16 (16a, 16b, 16c, 16d) , 16e, 16f), 26 (26a, 26b, 26c, 26d, 26e, 26f), 46 (46a, 46b, 46c, 46d, 46e, 46f) concave portion (outward convex portion)
17 (17a, 17b, 17c, 17d, 17e, 17f), 27 (27c), 47 (47a) Internal space 18 Air layer 29, 49 Holding position 41ae Electrode group 41as Space 50 Bridge member

Claims (10)

a resin plate disposed on the end face side of a battery in which a plurality of cells are arranged;
a steel plate that is brought into contact with the side of the resin plate opposite to the side on which the battery is arranged;
with
The resin plate has a plurality of protrusions arranged in the same direction as the cell arrangement direction, which is the arrangement direction of the cells, on the side that contacts the steel plate,
The steel plate has a plurality of recesses that contact the plurality of protrusions,
The recess has a shape in which an internal space is formed in a state of contact with the projection,
The volume of the internal space formed by the protrusions and the recesses located on the outermost side in the cell arrangement direction is larger than the volume of the internal space formed by the protrusions and the recesses located on the center side. ,
restraining plate. The volume of the internal space decreases from the outside toward the center in the cell arrangement direction,
The constraining plate of claim 1. Each of the plurality of protrusions is formed so that an outer shape thereof increases from the outside toward the center in the cell arrangement direction.
3. The constraining plate of claim 2. Each of the plurality of protrusions is formed such that the contact area with the steel plate increases from the outside toward the center in the cell arrangement direction.
A constraining plate according to claim 2 or 3. The projection has a plurality of cross-sectional shapes in the cell arrangement direction,
Constraining plate according to any one of claims 1-4. Each of the plurality of protrusions is disposed so as to be symmetrical with respect to the center of the electrode group included in the battery and to overlap the center of the outer shape of the battery,
Constraining plate according to any one of claims 1-4. The internal space is evenly formed with respect to the center of the protrusion in the cell arrangement direction,
Constraining plate according to any one of claims 1-6. The steel plate can be attached with a plurality of bridging members for bridging the restraining plate and the other member in a state in which the battery group including the batteries is sandwiched between the restraining plate and the other member. ,
The cell arrangement direction is the same direction as the arrangement direction of the plurality of bridging members,
the plurality of protrusions are composed of two outer protrusions positioned on the outermost side in the cell arrangement direction and another protrusion positioned between the two outer protrusions;
the width of the outer protrusion in the cell arrangement direction is greater than the width of the other protrusion in the cell arrangement direction;
Constraining plate according to any one of claims 1-7. The volume of the outer projection is smaller than the volume of the other projection,
The constraining plate of claim 8. 10. A battery pack comprising the constraining plate according to any one of claims 1 to 9 and a battery group including the batteries, wherein the constraining plate is brought into contact with one end of the battery group to constrain the battery group from both ends. , battery stack.

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