JP2013069657A - Electrical storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device capable of improving the strength of an end plate and easily connecting a connecting member and the end plate.
A power storage device includes a plurality of power storage elements (10) arranged side by side in a predetermined direction (X direction), a pair of end plates (30) sandwiching the plurality of power storage elements in a predetermined direction, and a predetermined direction. And a plurality of connecting members (40) respectively connected to the pair of end plates and disposed at positions sandwiching the plurality of power storage elements. The end plate has a plate main body (31, 324) including a surface orthogonal to a predetermined direction, and ribs (321a, 322a, 323a) protruding in the predetermined direction from the plate main body. The protruding surface of the rib is connected to the plurality of connecting members at a position adjacent to the plurality of connecting members.
[Selection] Figure 1

Description

  The present invention relates to a power storage device including a structure that applies a restraining load in a predetermined direction to a plurality of power storage elements arranged side by side in a predetermined direction.

  When a battery pack is configured using so-called rectangular unit cells, there are some in which a plurality of unit cells are arranged in a predetermined direction. Here, the plurality of single cells are sandwiched between a pair of end plates, and a connection band extending in a predetermined direction is connected to the pair of end plates. By using the end plate and the connecting band, a binding force can be applied to the plurality of single cells. Thereby, expansion | swelling etc. of a cell can be suppressed.

JP 2001-068081 A JP-A-08-250151 JP 2000-149900 A Japanese Patent Laid-Open No. 06-029041 JP 2009-205820 A

  In a structure in which a binding force is applied to the single cell using the end plate and the connecting band, a load is applied to the end plate due to the expansion of the single cell, so it is necessary to ensure the strength of the end plate.

  A power storage device according to the present invention includes a plurality of power storage elements arranged side by side in a predetermined direction, a pair of end plates sandwiching the plurality of power storage elements in the predetermined direction, and a pair of end plates extending in a predetermined direction. And a plurality of connecting members respectively disposed at positions sandwiching the plurality of power storage elements. The end plate has a plate body including a surface orthogonal to the predetermined direction, and a rib protruding in the predetermined direction from the plate body. The protruding surface of the rib is connected to the plurality of connecting members at a position adjacent to the plurality of connecting members. By using the end plate and the connecting member, a load (restraint force) acting in a predetermined direction can be applied to the plurality of power storage elements.

  The ribs can be provided at positions sandwiching the connecting member. Thereby, a connection member will be connected with respect to two ribs which pinch | interpose a connection member, and can improve the intensity | strength in the part which connects a connection member and a rib. By using the fastening member arranged along the direction in which the connecting member and the rib are adjacent to each other, the connecting member and the rib can be connected. As the fastening member, a rivet inserted into a through hole formed in the rib or a rivet used in a joining method by SPR can be used. On the other hand, the connecting member and the rib can be connected without using a rivet. That is, the connecting member and the rib can be connected without forming a through hole in advance in the connecting member and the rib. Specifically, the connecting member and the rib can be connected to each other by a joining method using mechanical clinch. Moreover, a connection member and a rib can be connected by welding.

  If a joining method using SPR or mechanical clinch is used, there is no need to previously form through holes in the connecting members and ribs. Here, when the through hole is formed, it is necessary to make the through hole a long hole in consideration of individual differences of the storage element and the like. That is, as the through hole, it is necessary to use a hole extending in the longitudinal direction (predetermined direction) of the connecting member. When the through hole is a long hole, the rivet inserted into the through hole is displaced inside the through hole, and the load (restraint force) acting on the power storage element changes. If a joining method using SPR or mechanical clinching is used, it is not necessary to form a through hole, so that the displacement of rivets inside the through hole can be prevented, and the load (binding force) acting on the power storage element changes. Can be prevented.

  In a cross section when the connecting member is cut along a plane orthogonal to the predetermined direction, the maximum length in the direction in which the plurality of connecting members sandwich the plurality of power storage elements (referred to as the first direction) is orthogonal to the direction in which the plurality of power storage elements are sandwiched. It can be longer than the maximum length in the direction (referred to as the second direction). Since the connecting member extends in a predetermined direction along the plurality of power storage elements, it becomes easy to receive a load in the first direction. Here, by making the maximum length in the first direction longer than the maximum length in the second direction, even if a load in the first direction is applied to the connection member, deformation of the connection member can be suppressed. . As a cross-sectional shape of a connection member, it can form in rectangular shape and elliptical shape, for example.

  The end plate can be provided with legs that are formed integrally with the rib and are used to fix the end plate. By integrally forming the leg portion and the rib, the strength of the leg portion can be improved. The leg can be formed along a plane orthogonal to the rib. Since the rib extends in the first direction, it is easy to secure a space for providing the leg portion by using the region in the second direction of the end plate.

  The plurality of power storage elements can be accommodated in the case. When the electrode terminal protruding to the side where the connecting member is disposed is provided in the power storage element, the connecting member can be closer to the inner wall surface of the case than the electrode terminal. Thereby, when a load is applied to the case, the load can be released to the connecting member, and the load can be prevented from being applied to the electrode terminal.

  When using a bus bar module fixed to the electrode terminal to electrically connect a plurality of power storage elements, the connecting member can be closer to the inner wall surface of the case than the bus bar module. Thereby, when a load is applied to the case, the deformed case can be prevented from hitting the bus bar module.

  A flange portion protruding in a predetermined direction can be provided on the outer edge of the plate body. By providing the flange portion, the strength of the plate body can be improved. In addition, at least a part of the flange portion can be positioned inside the contact area between the end plate and the electricity storage element. The binding force of the power storage element is transmitted in the contact area between the end plate and the power storage element. For this reason, the intensity | strength of the plate main body with respect to a restraint force can be improved by positioning a flange part inside a contact area | region.

  A partition member can be disposed between two power storage elements adjacent in a predetermined direction. The partition member is used to form a movement space of a heat exchange medium used for adjusting the temperature of the power storage element on the surface of the power storage element. Specifically, if a protrusion is provided on the surface of the partition member facing the power storage element, a space for moving the heat exchange medium can be secured between the power storage element and the partition member.

  According to the present invention, the strength of the end plate can be improved by providing the end plate with ribs. Further, since the protruding surface of the rib is connected to the connecting member at a position adjacent to the connecting member, the connecting member and the rib can be connected using the connecting member that extends in the predetermined direction. By using the protruding surface of the rib, it is possible to secure a region used for connection with the connecting member.

It is a perspective view which shows the external appearance of a battery stack. It is a front view of a partition plate. It is a side view of a partition plate. It is sectional drawing of a restraint band. It is a disassembled perspective view of an end plate. FIG. 6 is an exploded perspective view of the end plate when viewed from a direction different from FIG. 5. It is sectional drawing which shows the structure of a metal plate among end plates. It is a figure explaining the connection structure of an end plate and a connection band. It is sectional drawing which shows the connection structure of the connection band and rib which used the joining method by SPR. It is sectional drawing which shows the connection structure of the connection band and rib which used the mechanical clinch. It is a figure which shows the through-hole of the connection band in which a rivet is inserted. It is a figure which shows the state which gave restraint force to the cell and the partition plate using the restraint machine. It is a figure which shows the structure which connected the connection band and the end plate in the state which gave the restraint force to the cell and the partition plate using the restraint machine. It is a figure explaining the position of the rivet in the through-hole of a connection band. It is a figure explaining the load which acts on an end plate when a cell expand | swells. It is explanatory drawing when a load acts on an end plate. It is explanatory drawing when a load acts on a connection band. It is explanatory drawing when a load acts on an upper case. It is a front view which shows the structure of the resin plate among end plates. It is a figure explaining the positional relationship between the area | region which gives a load (restraint force), and an end plate. It is an external view of the connection band which is a modification. It is B1-B1 sectional drawing of FIG. It is B2-B2 sectional drawing of FIG. It is a figure which shows the structure of the end plate which is a modification.

  Examples of the present invention will be described below.

  A battery stack that is Embodiment 1 of the present invention will be described.

  FIG. 1 is a perspective view showing an external appearance of a battery stack. In FIG. 1, an X axis, a Y axis, and a Z axis are orthogonal to each other. In this embodiment, an axis corresponding to the vertical direction is a Z axis. The relationship among the X axis, the Y axis, and the Z axis is the same in other drawings. The battery stack shown in FIG. 1 is accommodated in a pack case (not shown), and a battery pack (corresponding to a power storage device) is configured by the battery stack and the pack case.

  The battery pack of the present embodiment can be mounted on a vehicle, for example. The battery pack can output energy used for running the vehicle. Specifically, the electric energy output from the battery pack can be converted into kinetic energy by a motor / generator, and the vehicle can be driven using this kinetic energy. When the vehicle is braked, the regenerative electric power generated by the motor / generator can be stored in the battery pack.

  The battery stack 1 includes a plurality of single cells (corresponding to power storage elements) 10 arranged side by side in the X direction. As the unit cell 10, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. An electric double layer capacitor (capacitor) can be used instead of the secondary battery. The number of unit cells 10 constituting the battery stack 1 can be appropriately set in consideration of the required output of the battery stack 1 and the like.

  In the present embodiment, the plurality of single cells 10 are arranged in the X direction, but the present invention is not limited to this. Specifically, one battery module can be configured using a plurality of single cells, and the plurality of battery modules can be arranged in the X direction.

  A power generation element that charges and discharges is housed inside the unit cell 10. The power generation element includes a positive electrode element, a negative electrode element, and a separator disposed between the positive electrode element and the negative electrode element. The separator contains an electrolytic solution. The positive electrode element has a current collector plate and a positive electrode active material layer formed on the surface of the current collector plate. The negative electrode element has a current collector plate and a negative electrode active material layer formed on the surface of the current collector plate.

  The unit cell 10 includes a positive electrode terminal (also referred to as an electrode terminal) 11 and a negative electrode terminal (also referred to as an electrode terminal) 12, and the positive electrode terminal 11 and the negative electrode terminal 12 protrude upward from the upper surface of the unit cell 10. . The positive electrode terminal 11 is electrically connected to the positive electrode element of the power generation element, and the negative electrode terminal 12 is electrically connected to the negative electrode element of the power generation element.

  The plurality of single cells 10 are electrically connected in series by two bus bar modules 50. The bus bar module 50 includes a plurality of bus bars and a holder that holds the plurality of bus bars. The bus bar is formed of a conductive material, and is connected to the positive electrode terminal 11 of one unit cell 10 and the negative electrode terminal 12 of the other unit cell 10 in two unit cells 10 adjacent in the X direction. . The holder is made of an insulating material such as resin.

  A partition plate (corresponding to a partition member) 20 is disposed between two unit cells 10 adjacent in the X direction. The partition plate 20 can be formed of an insulating material such as resin. Thereby, the two cell 10 which pinches | interposes the partition plate 20 in a X direction can be made into an insulation state.

  FIG. 2 is a front view of the partition plate 20 when viewed from the X direction, and FIG. 3 is a side view of the partition plate 20 when viewed from the Y direction.

  The partition plate 20 has a plurality of ribs 21 on the surface facing the unit cell 10 in the X direction. As shown in FIG. 3, the plurality of ribs 21 are formed only on the surface of the two unit cells 10 facing one unit cell 10. Each rib 21 protrudes in the X direction, and extends in the Z direction as shown in FIG. The plurality of ribs 21 are arranged in the Y direction with a predetermined interval.

  The tips of the ribs 21 in the X direction are in contact with the unit cells 10. A space is formed between the partition plate 20 and the unit cell 10 by the rib 21 coming into contact with the unit cell 10. This space is a space where a heat exchange medium used for temperature adjustment of the unit cell 10 moves. The shape of the rib 21 is not limited to the shape shown in FIG. That is, the rib 21 may be anything that can form a space between the partition plate 20 and the unit cell 10.

  When the unit cell 10 is generating heat due to charging / discharging or the like, the temperature increase of the unit cell 10 can be suppressed by flowing a cooling heat exchange medium through the space described above to contact the unit cell 10. In addition, when the unit cell 10 is excessively cooled, the temperature decrease of the unit cell 10 can be suppressed by flowing a heat exchange medium for heating through the space described above to contact the unit cell 10. . A gas or a liquid can be used as the heat exchange medium.

  On the other hand, when the tips of the ribs 21 in the X direction come into contact with the cell 10, a load can be applied to the cell 10 as will be described later. Thereby, the expansion | swelling and shrinkage | contraction of the cell 10 accompanying charging / discharging can be suppressed. The plurality of ribs 21 are provided at positions facing the power generation elements arranged in the unit cell 10 in the X direction. Since the expansion and contraction of the unit cell 10 is due to the expansion and contraction of the power generation element, the expansion and contraction of the power generation element can be efficiently suppressed by providing the plurality of ribs 21 at positions facing the power generation element.

  Two accommodation portions 22 are provided on the upper portion of the partition plate 20, and the two accommodation portions 22 are arranged in the Y direction. A through-hole 22a for allowing a connecting band (corresponding to a connecting member) 40, which will be described later, to pass through is formed inside each accommodating portion 22. By inserting the connection band 40 into the through hole 22a, the accommodating portion 22 can cover the connection band 40.

  Since the some partition plate 20 is arrange | positioned along with the X direction, the accommodating part 22 in these partition plates 20 is also arrange | positioned along with the X direction. The two accommodating portions 22 adjacent in the X direction are in contact with each other, and the through holes 22a in the two accommodating portions 22 are connected to each other. By arranging the plurality of accommodating portions 22 in the X direction, the entire connection band 40 can be covered.

  The upper end of the accommodating portion 22 is in contact with the inner wall surface of the upper case 61. The upper case 61 is a member that constitutes a part of a pack case that houses the battery stack 1. In the present embodiment, the accommodating portion 22 is in direct contact with the upper case 61, but the present invention is not limited to this. That is, another member (for example, an elastic body) can be interposed between the accommodating portion 22 and the upper case 61.

  A space S1 surrounded by the two housing portions 22 and the upper case 61 arranged in the Y direction is a space in which a heat exchange medium used for temperature adjustment of the unit cell 10 moves. Here, the space S1 can be used as, for example, a passage (supply passage) for supplying the heat exchange medium to the unit cell 10.

  The upper end of the housing portion 22 is located above the upper ends of the electrode terminals 11 and 12, and the electrode terminals 11 and 12 are separated from the inner wall surface of the upper case 61. Further, the upper end of the accommodating portion 22 is located above the bus bar module 50, and the bus bar module 50 is separated from the inner wall surface of the upper case 61. In FIG. 2, the positions of the electrode terminals 11 and 12 and the bus bar module 50 are indicated by dotted lines. In the present embodiment, the upper end of the accommodating portion 22 is located at the uppermost position of the battery stack 1.

  Two accommodating portions 23 are provided in the lower part of the partition plate 20, and the two accommodating portions 23 are arranged in the Y direction. A through hole 23 a for penetrating the connecting band 40 is formed inside each housing portion 23. The housing part 23 can cover the connection band 40 by inserting the connection band 40 into the through hole 23a.

  Similar to the housing part 22, the plurality of housing parts 23 are arranged side by side in the X direction. The two accommodating portions 23 adjacent in the X direction are in contact with each other, and the through holes 23a in the two accommodating portions 23 are connected to each other. Thereby, the whole connection band 40 can be covered by the plurality of accommodating portions 23.

  The lower end of the accommodating portion 23 is in contact with the inner wall surface of the lower case 62. A space S2 surrounded by the two accommodating portions 23 and the lower case 62 arranged in the Y direction is a space in which a heat exchange medium used for temperature adjustment of the unit cell 10 moves. Here, the space S2 can be used as, for example, a passage (discharge passage) for discharging the heat exchange medium used for temperature adjustment of the unit cell 10. Here, one of the spaces S1 and S2 can be used as a heat exchange medium supply passage, and the other can be used as a heat exchange medium discharge passage.

  A pair of end plates 30 are disposed at both ends of the battery stack 1 in the X direction. The connection band 40 extends in the X direction, and both ends of the connection band 40 in the X direction (longitudinal direction) are fixed to the pair of end plates 30. The connection band 40 is formed in a flat plate shape.

  FIG. 4 is a cross-sectional view of the connection band 40 taken along the YZ plane. As illustrated in FIG. 4, the width W (length in the Z direction) of the connection band 40 is larger than the thickness T (length in the Y direction) of the connection band 40. In the present embodiment, the connecting band 40 is arranged so that the width direction of the connecting band 40 is the Z direction. The width direction of the connection band 40 corresponds to a direction in which the two connection bands 40 respectively disposed on the upper surface and the lower surface of the battery stack 1 sandwich the plurality of unit cells 10.

  In the present embodiment, as shown in FIG. 4, the cross-sectional shape of the connecting band 40 is formed in a rectangular shape, but the present invention is not limited to this. That is, the length in the Z direction should be longer than the length in the Y direction with respect to a cross section when the connection band 40 is cut along a plane (YZ plane) orthogonal to the longitudinal direction (X direction) of the connection band 40. Therefore, for example, the cross-sectional shape of the connection band 40 can be formed in an elliptical shape.

  Two connection bands 40 are disposed on the upper surface of the battery stack 1, and two connection bands 40 are disposed on the lower surface of the battery stack 1. That is, the connection band 40 is arrange | positioned in the position which pinches | interposes the battery stack 1 in a Z direction, respectively. By using the connection band 40 and the end plate 30, a binding force (load) can be applied to the plurality of single cells 10 sandwiched between the pair of end plates 30. The restraining force is a force for pressing each cell 10 from both sides in the X direction.

  In the present embodiment, the connection band 40 is disposed on the upper surface and the lower surface of the battery stack 1, but the present invention is not limited to this. For example, each of the connecting bands 40 can be disposed at a position sandwiching the battery stack 1 in the Y direction. In this case, the structure of the end plate 30 may be changed according to the position of the connecting band 40. In the present embodiment, the two connection bands 40 are arranged on the upper surface or the lower surface of the battery stack 1, but the number of the connection bands 40 can be set as appropriate. For example, only one connection band 40 may be disposed on each of the upper surface and the lower surface of the battery stack 1.

  Next, the structure of the end plate 30 will be described. 5 and 6 are perspective views showing the appearance of the end plate 30 when viewed from different directions.

  The end plate 30 includes a resin plate 31 and a metal plate 32. The resin plate 31 is in contact with the unit cell 10 disposed at the end of the battery stack 1 in the X direction. The resin plate 31 has an accommodating portion 311 that accommodates the connecting band 40, similarly to the accommodating portions 22 and 23 of the partition plate 20.

  The resin plate 31 has two claw portions 312 that protrude toward the metal plate 32 side. The claw portion 312 is used for fixing the resin plate 31 to the metal plate 32. Further, the resin plate 31 has two pins 313 protruding toward the metal plate 32 side. The pins 313 are used for positioning the resin plate 31 with respect to the metal plate 32.

  The metal plate 32 includes a first metal plate 321, a second metal plate 322, a third metal plate 323, and a fourth metal plate 324. FIG. 7 is a schematic view showing a cross section when the metal plate 32 is cut along the XY plane. As shown in FIG. 7, the first metal plate 321, the second metal plate 322, and the third metal plate 323 are fixed to the fourth metal plate 324 by welding or the like.

  The fourth metal plate 324 has a pair of legs 324a. Each leg 324a is formed with a through hole 324b. A bolt (not shown) for fixing the leg 324a to the lower case 62 (see FIG. 2) passes through the through hole 324b. The fourth metal plate 324 has a through hole 324c into which the claw portion 312 of the resin plate 31 is inserted. The claw portion 312 engages with the fourth plate 324 in a state of passing through the through hole 324c. Thereby, the resin plate 31 can be fixed to the fourth metal plate 324.

  The fourth metal plate 324 has a through hole 324d into which the pin 313 of the resin plate 31 is inserted. The resin plate 31 can be positioned with respect to the fourth metal plate 324 by inserting the pin 313 into the through hole 324d. On the outer edge of the fourth metal plate (corresponding to the plate main body) 324, a flange portion 324e protruding in the X direction is formed. The flange portion 324e protrudes toward the outside of the battery stack 1 in the X direction.

  The first metal plate 321 has a pair of ribs 321a protruding in the X direction at both ends in the Y direction. The rib 321a protrudes toward the outside of the battery stack 1 in the X direction. The rib 321a is located in a plane orthogonal to the Y direction (in the XZ plane). The width (length in the X direction) of the rib 321a is larger than the thickness (length in the Y direction) of the rib 321a. Each rib 321a has two through holes 321b.

  The second metal plate 322 and the third metal plate 323 are arranged at positions sandwiching the first metal plate 321 in the Y direction. The second metal plate 322 and the third metal plate 323 have a symmetrical shape with respect to the first metal plate 321.

  The second metal plate 322 has a rib 322a facing the rib 321a of the first metal plate 321 in the Y direction. The rib 322a protrudes in the X direction. In other words, the rib 322a protrudes toward the outside of the battery stack 1 in the X direction. The width (length in the X direction) of the rib 322a is larger than the thickness (length in the Y direction) of the rib 322a. Two through holes 322b are formed in the rib 322a. When the ribs 321a and 322a overlap, the through holes 321b and 322b are located on the same axis and face each other in the Y direction.

  The third metal plate 323 has a rib 323a facing the rib 321a of the first metal plate 321 in the Y direction. The rib 323a protrudes in the X direction. In other words, the rib 323a protrudes toward the outside of the battery stack 1 in the X direction. The width (length in the X direction) of the rib 323a is larger than the thickness (length in the Y direction) of the rib 323a. Two through holes 323b are formed in the rib 323a. When the rib 323a and the rib 321a overlap, the through holes 321b and 323b are located on the same axis and face each other in the Y direction.

  As shown in FIG. 8, the connection band 40 is disposed between one rib 321 a of the first metal plate 321 and the rib 322 a of the second metal plate 322. The connection band 40 has a through hole that faces the through hole 321b of the rib 321a and the through hole 322b of the rib 322a in the Y direction.

  When the through holes in the connection band 40 and the ribs 321a and 322a are positioned coaxially, a rivet (corresponding to a fastening member) 70 is inserted into these through holes. The rivet 70 is disposed along a direction (Y direction) orthogonal to the ribs 321a and 322a. By using the rivet 70, the connecting band 40 and the ribs 321a and 322a can be fixed to each other.

  Since the connection band 40 is disposed on the upper surface and the lower surface of the battery stack 1, the connection band 40 is fixed by the rivet 70 in a state where the two connection bands 40 are sandwiched between the ribs 321a and 322a. In this embodiment, the connecting band 40 is fixed to the end plate 30 (metal plate 32) using the rivet 70, but the present invention is not limited to this. That is, it is only necessary that the connecting band 40 can be fixed to the end plate 30. For example, a bolt can be used instead of the rivet 70.

  The connection band 40 is disposed between the other rib 321a of the first metal plate 321 and the rib 323a of the third metal plate 323. The connection band 40 has a through hole that faces the through hole 321b of the rib 321a and the through hole 323b of the rib 323a in the Y direction. When the through holes in the connecting band 40 and the ribs 321a and 323a are located on the same axis, the rivet 70 is inserted into these through holes. By using the rivet 70, the connecting band 40 and the ribs 321a and 323a can be fixed to each other.

  Since the connection band 40 is disposed on the upper and lower surfaces of the battery stack 1, the connection band 40 is fixed by the rivet 70 in a state where the two connection bands 40 are sandwiched between the ribs 321a and 323a.

  On the other hand, as a method for fixing the connecting band 40 and the end plate 30 (metal plate 32), there are a joining method using SPR (self-piercing rivet) and a joining method using mechanical clinch. Moreover, the connection band 40 and the end plate 30 can also be fixed by welding. As welding, a known technique can be used as appropriate, for example, spot welding or ultrasonic welding can be used.

  In the joining method using SPR, the connecting band 40 and the end plate 30 can be mechanically joined using an SPR rivet. That is, by using an SPR rivet, an interlock (hook) described later can be formed between the connection band 40 and the end plate 30, and the connection band 40 and the end plate 30 can be mechanically joined.

  Here, a method of joining the connecting band 40 and the ribs 321a and 322a (see FIG. 8) will be specifically described. The connecting band 40 and the ribs 321a and 323a (see FIG. 8) can be joined by the same method.

  First, after the coupling band 40 is sandwiched between the ribs 321a and 322a, the ribs 321a and 322a and the coupling band 40 are sandwiched by a die (not shown) and a receiver (not shown). Here, it is assumed that the rib 322a is in contact with the receiver and the rib 321a is in contact with the die. The rib 321a may be in contact with the receiver, and the rib 322a may be in contact with the die.

  The receiver is provided with a punch, and an SPR rivet 71 (see FIG. 9) is disposed at the tip of the punch. When the punch is moved toward the die, the tip 71a (see FIG. 9) of the SPR rivet 71 presses the rib 322a and the connecting band 40, and then penetrates the rib 322a and the connecting band 40. Grooves are formed in the die, and the ribs 321a are pushed into the SPR rivets 71 penetrating the ribs 322a and the connecting band 40 and deformed along the grooves of the die.

  Further, the tip 71a of the SPR rivet 71 is also deformed along the die groove. Specifically, the SPR rivet 71 has two tip portions 71a, and the two tip portions 71a are deformed in directions away from each other. The tip portion 71a of the SPR rivet 71 bites into the rib 321a without penetrating the rib 321a, and an interlock is formed as shown in FIG.

  FIG. 9 shows a state (cross section) in which the ribs 321 a and 322 a and the connection band 40 are joined by the SPR rivet 71. By adopting the joined state shown in FIG. 9, the ribs 321a and 322a and the connecting band 40 can be fixed. In other words, the connection band 40 and the end plate 30 can be fixed. Here, as shown in FIG. 9, in the SPR rivet 71, the ribs 321a and 322a and the connecting band 40 are sandwiched between the tip end portion 71a and the base end portion 71b.

  On the other hand, in the joining method using mechanical clinch, the connecting band 40 and the end plate 30 are deformed using a punch and a die, and an interlock (hook) is formed between the connecting band 40 and the end plate 30. The interlocking band 40 and the end plate 30 can be joined by the interlock.

  Here, a method of joining the connecting band 40 and the ribs 321a and 322a (see FIG. 8) will be specifically described. The connecting band 40 and the ribs 321a and 323a (see FIG. 8) can be joined by the same method.

  First, after the coupling band 40 is sandwiched between the ribs 321a and 322a, the ribs 321a and 322a and the coupling band 40 are sandwiched by a die (not shown) and a receiver (not shown). Here, it is assumed that the rib 322a is in contact with the receiver and the rib 321a is in contact with the die. The rib 321a may be in contact with the receiver, and the rib 322a may be in contact with the die.

  The receiver is provided with a punch, and when the punch is moved toward the die, the tip of the punch presses the ribs 322a and 321a and the connecting band 40. Grooves are formed in the die, and the ribs 322a and 321a and the connection band 40 (in particular, the ribs 321a and the connection band 40) are deformed along the groove of the die.

  Here, a part of the rib 322a bites into the connecting band 40, or a part of the connecting band 40 bites into the rib 321a, thereby forming an interlock. FIG. 10 shows an interlock formed between the connecting band 40 and the rib 321a.

  FIG. 10 shows a state (cross section) in which the ribs 321a and 322a and the connecting band 40 are joined by mechanical clinch. By setting it as the joining state shown in FIG. 10, the ribs 321a and 322a and the connection band 40 can be fixed. In other words, the connection band 40 and the end plate 30 can be fixed.

  If a joining method using SPR or mechanical clinching is used, there is no need to form a through hole for inserting the rivet 70 (see FIG. 8) into the connection band 40 or the metal plate 32 (ribs 321a and 322a). As shown in FIG. 11, when the through holes 41 and 42 are formed at both ends in the longitudinal direction of the connection band 40, at least one of the through holes 42 needs to be formed in a shape extending in the longitudinal direction of the connection band 40. is there. In other words, the through hole 42 needs to be a long hole.

  When manufacturing the battery stack 1, the plurality of single cells 10 and the partition plate 20 arranged in the X direction are sandwiched between the pair of end plates 30, and the connection band 40 is fixed to the end plates 30. . Since the unit cell 10 and the partition plate 20 have individual differences, in order to insert the rivet 70 into the through holes 41 and 42, it is necessary to make the through hole 42 a long hole in consideration of individual differences. . If the through hole 42 is not a long hole, the through holes 41 and 42 of the connecting band 40 and the through holes of the metal plate 32 (ribs 321a, 322a, and 323a) may be misaligned. 70 cannot be inserted.

  If the through hole 42 is a long hole, the rivet 70 may move within the range of the through hole 42. As shown in FIG. 12, when the restraining force L is applied to the single cell 10, the pair of end plates 30 are moved in a direction approaching each other using the restraining machine 80. In FIG. 12, the end plate 30 (ribs 321a, 322a, 323a of the metal plate 32) is formed with a through hole 30A for inserting the rivet 70 therein. The through hole 30A corresponds to the through holes 321b, 322b, and 323b described with reference to FIGS. The through hole 30A is formed in a shape along the outer shape of the rivet 70, and is not a long hole.

  The connection band 40 is fixed to the end plate 30 in a state where the binding force L is applied to the plurality of single cells 10 via the pair of end plates 30. Specifically, by inserting the rivet 70 into the through hole 30A of the end plate 30 (ribs 321a, 322a, 323a) and the through holes 41, 42 of the connection band 40, as shown in FIG. The end plate 30 is fixed. At this time, the rivet 70 may be located at a position P <b> 1 shown in FIG. 14 with respect to the through hole (long hole) 42 of the connection band 40. FIG. 14 is an enlarged view showing a region R in FIG. 13, and is a view showing a positional relationship between the through hole (long hole) 42 of the connection band 40 and the rivet 70.

  After the connection band 40 and the end plate 30 are fixed, the restraining machine 80 is separated from the pair of end plates 30. Since the connecting band 40 and the end plate 30 are fixed by the rivets 70, the binding force for the plurality of single cells 10 is maintained. Here, when the restraining machine 80 is separated from the end plate 30, the pair of end plates 30 tends to move away from each other due to the reaction force that the unit cell 10 and the partition plate 20 try to return to the original state.

  When the through hole 42 is a long hole, the rivet 70 may move along the through hole 42 as the pair of end plates 30 are displaced away from each other. Specifically, the rivet 70 may move from the position P1 shown in FIG. 14 to the position P2. In this case, the restraint force applied to the unit cell 10 is reduced by the amount of movement of the rivet 70.

  Even if a desired restraining force is given to the single cell 10 using the restraining machine 80, the desired restraining force cannot be given to the single cell 10 due to a decrease in the restraining force accompanying the movement of the rivet 70.

  If a joining method using SPR or mechanical clinching is used, it is not necessary to form a through hole in the connection band 40 or the end plate 30, so that it is possible to suppress a decrease in restraining force accompanying the movement of the rivet 70. That is, in the joining method using SPR or mechanical clinch, the position where the connecting band 40 and the end plate 30 are joined is not shifted, and therefore, the load applied to the unit cell 10 by the restraining device 80 is prevented from being greatly reduced. can do.

  Here, if the restraining force of the unit cell 10 is reduced, it is conceivable that the restraining force of the unit cell 10 using the restraining machine 80 is increased in advance by the amount of the restraining force. However, in this case, the structure of the unit cell 10 and the partition plate 20 must be made to withstand the restraining force as much as the restraining force is increased, and the cost increases.

  If the joining method by SPR or mechanical clinching is used, it is not necessary to unnecessarily increase the restraining force of the unit cell 10 using the restraint machine 80, and the structure of the unit cell 10 and the partition plate 20 has a structure stronger than necessary. There is no need to do. Therefore, it is possible to suppress an increase in cost due to the structure of the unit cell 10 or the partition plate 20 being a strong structure.

  As described above, by fixing the connecting band 40 to the pair of end plates 30 (metal plate 32), a binding force can be applied to the plurality of single cells 10 sandwiched between the pair of end plates 30. That is, if the distance between the pair of end plates 30 in the X direction is shorter than the total length in the X direction when the plurality of single cells 10 and the partition plate 20 are arranged in the X direction, the binding force is applied to the plurality of single cells 10. Can be given. By applying a binding force to the unit cell 10, the expansion of the unit cell 10 can be suppressed.

  When fixing the connection band 40 to the pair of end plates 30 (metal plate 32), first, one end of the connection band 40 is fixed to one end plate 30. Next, the other end of the connection band 40 is fixed to the other end plate 30 while applying a load in the X direction to the plurality of unit cells 10. Here, the connection band 40 only extends in the X direction, and the end of the connection band 40 is simply inserted between the ribs 321a and 322a or between the ribs 321a and 323a. The end can be easily fixed to the end plate 30.

  When the cell 10 expands, a load E1 in the direction indicated by the arrow in FIG. 15 is generated. FIG. 15 is a schematic view when the battery stack 1 is viewed from the Y direction.

  The load E1 acts on the end plate 30. Here, as described above, the end plate 30 (metal plate 32) has the ribs 321a, 322a, and 323a, and both ends of the ribs 321a, 322a, and 323a in the Z direction are fixed to the connecting band 40. ing.

  For this reason, even if the end plate 30 receives the load E1, the deformation of the end plate 30 can be suppressed by the ribs 321a, 322a, and 323a. Since the ribs 321a, 322a, and 323a extend in a direction orthogonal to the plane (YZ plane) that receives the load E1, the ribs 321a, 322a, and 323a are not easily deformed even when the load E1 is received. Yes.

  If the ribs 321a, 322a, and 323a are omitted, the end plate 30 is configured by a flat plate positioned in the YZ plane. In this case, the entire surface of the flat plate is subjected to the load E1, and the flat plate is easily bent as indicated by a dotted line F1 in FIG. In order to suppress deformation of the end plate 30 formed of a flat plate, the thickness of the end plate 30 (length in the X direction) must be increased.

  In the present embodiment, the deformation of the ribs 321a, 322a, 323a, in other words, the deformation of the end plate 30 can be suppressed only by securing the width (length in the X direction) of the ribs 321a, 322a, 323a. it can. In the present embodiment, the thickness (the length in the Y direction) of the ribs 321a, 322a, and 323a can be made smaller than the width (the length in the X direction) of the ribs 321a, 322a, and 323a. The thickness (length in the Y direction) of the ribs 321a, 322a, and 323a can be set to the minimum necessary value, and the material of the ribs 321a, 322a, and 323a can be reduced.

  On the other hand, the width of the connection band 40 (length in the Z direction) is larger than the thickness of the connection band 40 (length in the Y direction), and the width direction of the connection band 40 is in the Z direction. A connecting band 40 is arranged. By arranging the connection band 40 in this way, it is possible to make it difficult for the connection band 40 to be deformed by the dotted line F2 in FIG.

  Here, when the connection band 40 is arranged so that the width direction of the connection band 40 is in the Y direction, in other words, the thickness direction of the connection band 40 is in the Z direction, the connection band 40 receives the load E2. When received, it is likely to be deformed as indicated by the dotted line F2 in FIG. The deformation indicated by the dotted line F2 in FIG. 17 is a deformation when the load E2 is applied upward in FIG. When a load is applied downward in FIG. 17, the deformation is the reverse of the deformation indicated by the dotted line F2.

  When the battery pack of this embodiment is mounted on a vehicle, vibrations generated in the vehicle, in particular, vibrations in the Z direction (corresponding to the load E2) act on the battery pack (battery stack 1). Even when subjected to such vibration, the deformation of the connecting band 40 can be suppressed.

  As described above, by suppressing the deformation of the end plate 30 and the connecting band 40, it is possible to maintain a state in which a desired restraining force is applied to the plurality of unit cells 10.

  On the other hand, in the present embodiment, as described with reference to FIG. 2, the accommodating portion 22 of the partition plate 20 accommodates the connecting band 40, and the upper end of the accommodating portion 22 is in contact with the upper case 61. For this reason, when a load (external force) is applied to the upper case 61, not only the upper case 61 but also the battery stack 1 can receive the load. That is, according to the present embodiment, the strength of the battery pack can be improved.

  A method of transmitting a load when an external force (load) is applied to the upper case 61 will be described with reference to FIG. FIG. 18 is a view showing the internal structure of the battery pack, and is a view of the battery stack 1 as viewed from the X direction.

  When the load E <b> 3 is applied to the upper case 61, the load E <b> 3 is transmitted to the connection band 40 through the accommodating portion 22 of the partition plate 20. Here, as described with reference to FIG. 2, since the electrode terminals 11 and 12 and the bus bar module 50 are separated from the inner wall surface of the upper case 61, the load E <b> 3 applied to the upper case 61 is applied to the electrode terminals 11 and 12. And transmission to the bus bar module 50 can be suppressed.

  Since the connecting band 40 is connected to the end plate 30 at both ends in the X direction, the load E3 is transmitted to the end plate 30 via the connecting band 40. Since the end plate 30 is fixed to the lower case 62 via the leg portions 324a of the fourth metal plate 324, the load E3 transmitted to the end plate 30 is transmitted to the lower case 62.

  Thus, when the load E3 acts on the upper case 61, the load E3 can be received not only in the upper case 61 but also in a plurality of locations in the battery stack 1, and the load E3 can be dispersed. Thereby, the intensity | strength of a battery pack can be improved.

  In order to transmit the load E3 applied to the upper case 61 to the battery stack 1 (particularly, the connection band 40), the connection band 40 may be closer to the upper case 61 than the electrode terminals 11 and 12. In this embodiment, since the bus bar module 50 is connected to the electrode terminals 11 and 12, the connecting band 40 may be closer to the upper case 61 than the bus bar module 50.

  Here, since the connecting band 40 and the end plate 30 are fixed by the rivet 70, the load E3 also acts on the rivet 70. The connection band 40 is fixed by the rivet 70 in a state where it is sandwiched between the ribs 321a and 322a (or the ribs 321a and 323a), and the load acting on the rivet 70 from the connection band 40 is the ribs 321a and 322a. (Or dispersed in the ribs 321a and 323a). Thereby, the load which the rivet 70 receives can be reduced.

  It is also conceivable that only the upper case 61 is deformed to absorb the load E3. In this case, in order to prevent the deformed upper case 61 from coming into contact with the electrode terminals 11 and 12, it is necessary to widen the distance between the upper case 61 and the electrode terminals 11 and 12. However, if the distance between the upper case 61 and the electrode terminals 11 and 12 is increased, the battery pack is increased in size.

  On the other hand, since the flange portion 324e is formed on the fourth metal plate 324 of the end plate 30, the strength of the end plate 30 can be improved. In the present embodiment, a binding force is applied to the plurality of single cells 10, and a part of the flange portion 324e is located in a region where the binding force is transmitted. The region where the binding force is transmitted is a region where the end plate 30 and the unit cell 10 are in contact with each other. This will be specifically described below.

  FIG. 19 is a front view showing the configuration of the resin plate 31 in the end plate 30. FIG. 19 is a view of the resin plate 31 shown in FIGS. 5 and 6 when viewed from the opposite side. As shown in FIG. 19, a plurality of ribs 313 are formed on the resin plate 31. The resin plate 31 has the same structure as that of the partition plate 20, and the rib 313 corresponds to the rib 21 (see FIG. 2).

  The rib 313 of the resin plate 31 is in contact with the unit cell 10. Here, the region A is a region including a plurality of ribs 313 and is a region where the resin plate 31 and the unit cell 10 are in contact with each other. The metal plate 32 (321 to 324) is fixed to the surface of the resin plate 31 opposite to the surface on which the rib 313 is formed, as shown in FIG. As shown in FIG. 20, a part of the flange portion 324e in the metal plate 32 (fourth metal plate 324) is located inside the contact region A.

  By positioning the flange portion 324e inside the contact area A, deformation of the end plate 30 can be suppressed. That is, the load transmitted from the contact area A can be received by the flange portion 324e, and the deformation of the end plate 30 (metal plate 32) can be suppressed. Here, when the flange part 324e is located outside the contact area A, the load transmitted from the contact area A acts on the area inside the flange part 324e, and the area inside the flange part 324e. Will be easily deformed.

  In the present embodiment, the connecting band 40 is sandwiched between the two ribs 321a and 322a or sandwiched between the two ribs 321a and 323a, but is not limited thereto. Specifically, the connecting band 40 can be fixed to one rib. For example, only the rib 321a is provided, and the connecting band 40 can be connected to the rib 321a. Even if it is such a structure, the effect similar to a present Example can be acquired.

  In this embodiment, the connecting band 40 having the cross-sectional shape shown in FIG. 4 is used, but the present invention is not limited to this. Considering the ease of attachment of the connection band 40 to the ribs 321a, 322a, and 323a, for example, the connection band 40 may be shaped as shown in FIG. In FIG. 21, the connection band 40 is formed in a columnar shape, and only both end portions in the longitudinal direction (corresponding to the X direction) are formed in a flat plate shape. 22A is a cross-sectional view along B1-B1 in FIG. 21, and FIG. 22B is a cross-sectional view along B2-B2 in FIG. By forming both end portions of the connection band 40 in a flat plate shape, both end portions of the connection band 40 can be connected to the ribs 321a, 322a, 323a as in the present embodiment.

  In this embodiment, the end plate 30 (metal plate 32) is provided with ribs 321a, 322a and 323a, but this is not restrictive. For example, ribs disposed along a plane (XY plane) orthogonal to the ribs 321a, 322a, and 323a can be provided on the end plate 30 (metal plate 32). Thereby, the intensity | strength of the end plate 30 (metal plate 32) can be improved.

  In this embodiment, the connecting band 40 is sandwiched between the ribs 321a and 322a (or the ribs 321a and 323a), but the rib may be sandwiched between the connecting bands. Specifically, the end portion of the connecting band in the longitudinal direction is formed in a bifurcated manner, and a rib can be disposed between the bifurcated portions.

  FIG. 23 is a front view of an end plate 30 as a modification of the present embodiment when viewed from the X direction. In FIG. 23, members having the same functions as those described in the present embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, differences from the present embodiment will be mainly described.

  In this modification, the configuration of the metal plate 32 in the end plate 30 is different from the present embodiment. Also in this modification, the first metal plate 321, the second metal plate 322, and the third metal plate 323 are fixed to the fourth metal plate 324. The fourth metal plate 324 has a flange portion 324e at the outer edge, and the flange portion 324e is located inside the contact region A. Thereby, the intensity | strength of the end plate 30 can be improved similarly to a present Example.

  The second metal plate 322 has ribs 322a and leg portions 322c, and the ribs 322a and leg portions 322c are integrally formed. The third metal plate 323 has ribs 323a and leg portions 323c, and the ribs 323a and leg portions 323c are integrally formed. By integrally forming the ribs 322a and 323a and the leg portions 322c and 323c, the strength of the leg portions 322c and 323c can be improved.

  Here, since the ribs 322a and 323a are disposed in the XZ plane, it is easy to secure a space for providing the leg portions 322c and 323c in the Y direction. By securing the size of the leg portions 322c and 323c in the Y direction, the end plate 30 can be easily fixed to the lower case 62.

1: Battery stack 10: Single battery (storage element)
11: Positive terminal (electrode terminal) 12: Negative terminal (electrode terminal)
20: partition plate (partition member) 30: end plate 31: resin plate 32: metal plate 321: first metal plate 321a: rib 322: second metal plate 322a: rib 323: third metal plate 323a: rib 324: first 4 metal plate 324a: leg part 324e: flange part 40: connecting band (connecting member)
50: Busbar module 61: Upper case 62: Lower case 70: Rivet (fastening member)

Claims (12)

A plurality of power storage elements arranged side by side in a predetermined direction;
A pair of end plates sandwiching the plurality of power storage elements in the predetermined direction;
A plurality of connecting members extending in the predetermined direction and connected to the pair of end plates, and arranged at positions sandwiching the plurality of power storage elements, respectively.
The end plate is
A plate body including a surface orthogonal to the predetermined direction;
A rib that protrudes from the plate body in the predetermined direction, and is connected to the plurality of connecting members at a position adjacent to the plurality of connecting members among the protruding surfaces;
A power storage device comprising:   The power storage device according to claim 1, wherein the end plate includes the ribs at positions where the connection member is interposed.   The power storage device according to claim 1, wherein the connecting member and the rib are fastened to each other by a fastening member that is disposed along a direction in which the connecting member and the rib are adjacent to each other.   The power storage device according to claim 3, wherein the fastening member is a rivet used in a joining method by SPR.   The power storage device according to claim 1, wherein the connecting member and the rib are connected to each other without forming a through hole in advance in the connecting member and the rib.   The power storage device according to claim 5, wherein the connecting member and the rib are connected to each other by a joining method using mechanical clinch.   In a cross section when the connecting member is cut along a plane orthogonal to the predetermined direction, the maximum length in the direction in which the plurality of connecting members sandwich the plurality of power storage elements is orthogonal to the direction in which the plurality of power storage elements are sandwiched. The power storage device according to claim 1, wherein the power storage device is longer than a maximum length in the direction.   The power storage device according to any one of claims 1 to 7, wherein the end plate is formed integrally with the rib and includes a leg portion used for fixing the end plate. It has a case for accommodating the plurality of power storage elements,
The power storage element has an electrode terminal protruding to the side where the connecting member is disposed,
The power storage device according to claim 1, wherein the connecting member is closer to an inner wall surface of the case than the electrode terminal. It is used to electrically connect the plurality of power storage elements, and has a bus bar module fixed to the electrode terminal,
The power storage device according to claim 9, wherein the connecting member is closer to an inner wall surface of the case than the bus bar module. The plate body is formed along an outer edge of the plate body and has a flange portion protruding in the predetermined direction.
11. The power storage device according to claim 1, wherein at least a part of the flange portion is located inside a contact region between the end plate and the power storage element. The partition member is disposed between the two power storage elements adjacent to each other in the predetermined direction, and forms a moving space of a heat exchange medium used for temperature adjustment of the power storage element on the surface of the power storage element. The power storage device according to any one of claims 1 to 11.

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