JP6295849B2 - Constraining structure of stacked battery - Google Patents

Description

  The present invention relates to a constraining structure for a stacked battery in which flat batteries are stacked and constrained.

  In a conventional battery module, flat battery cells are stacked to form a stacked body. An intermediate plate is provided in the laminated body, and the laminated body is restrained by fastening bolts that penetrate the intermediate plate and the laminated body (see, for example, Patent Document 1).

JP 2004-303472 A

  In the technique described in Patent Document 1 described above, a cylindrical collar is used together with a fastening bolt. The collar functions as a support and supports the end plate and the intermediate plate in parallel.

  However, since most of the battery cells are electrodes, the spring constant is large, and the thickness of the laminate varies depending on the tolerance of the comma in the battery cell, the clearance, or the number of stacks. Color length is required. Moreover, it is necessary to keep the surface pressure of the constrained laminated body uniform.

  Therefore, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a constraining structure for a multilayer battery that can absorb tolerance variations of the multilayer battery while pressing the multilayer battery uniformly. And

  The present invention employs the following technical means in order to achieve the aforementioned object.

The present invention includes a fastening member (15, 16) that extends in the stacking direction and is inserted through an insertion hole (18) formed in each of the pair of end plates and connects the pair of end plates; And a support member (14, 141, 142) that is provided integrally with at least one of the end plates and supports a part of the outer peripheral surface of the fastening member that is inserted through the insertion hole. Are close to each other by fastening the fastening member, and the end plate presses the laminated battery inward by fastening , the support members are respectively provided inside the stacking direction of the pair of end plates, and one support member is , and supports a part of the outer peripheral surface of the insertion has been fastening member into the insertion hole, the other support member, laminated, characterized by supporting a part of the outer peripheral surface of one of the support members It is a restraint structure of the pond.

  According to such this invention, the support member extended in the lamination direction supports a part of outer peripheral surface of the fastening member extended in a lamination direction. Thus, the support member can suppress the deformation of the end plate without the support member interfering with the inward pressing by the fastening member. Accordingly, the parallelism of the pair of end plates can be maintained by the fastening member and the support member. In addition, since the support member does not interfere with the inward pressing of the fastening member, the fastening member can press the stacked battery uniformly by bringing the pair of end plates closer to each other. Therefore, the multilayer battery can be uniformly pressed by the pair of end plates while absorbing the tolerance variation of the multilayer battery.

  In addition, the code | symbol in the bracket | parenthesis of each above-mentioned means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a top view which shows the battery module 10 of 1st Embodiment. 2 is a plan view showing a state in which the battery module 10 is disassembled. FIG. 2 is an enlarged plan view showing a battery module 10. FIG. It is a figure for demonstrating a fastening state. It is a figure for demonstrating the fastening state of a comparative example. It is a graph which shows the relationship between a restraint load and internal resistance. It is a top view which shows 10 A of battery modules of 2nd Embodiment. It is a top view which shows the state which decomposed | disassembled battery module 10A. It is a top view which shows the state which decomposed | disassembled the battery module 10B of 3rd Embodiment. It is a top view which expands and shows the battery module 10B. It is a top view which shows the state which decomposed | disassembled the battery module 10C of 4th Embodiment. It is a top view which expands and shows battery module 10C.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. In some embodiments, portions corresponding to the matters described in the preceding embodiments may be given the same reference numerals, or one letter may be added to the preceding reference numerals, and overlapping descriptions may be omitted. In addition, when a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those of the embodiment described in advance. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination does not hinder the combination.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. The battery module 10 includes a stacked battery 11 inside. The stacked battery 11 is configured by stacking a plurality of flat batteries 12. The plurality of battery modules 10 are electrically connected to each other to form a battery module assembly. The battery module assembly is used in, for example, a hybrid vehicle using a traveling drive source by combining an internal combustion engine and a motor driven by electric power charged in a battery, an electric vehicle using a motor as a traveling drive source, and the like. The flat battery 12 is, for example, a nickel hydrogen secondary battery, a lithium ion secondary battery, or an organic radical battery.

  Hereinafter, the direction in which the battery cells are stacked is referred to as a stacking direction Y. A direction perpendicular to the stacking direction Y and along the long side of the rectangular battery cell is referred to as a length direction X. A direction perpendicular to the stacking direction Y and along the short side of the rectangular battery cell is referred to as a width direction Z.

  The battery module 10 is controlled by electronic components used for charging and discharging a plurality of flat batteries 12 or temperature adjustment. The battery module 10 houses a plurality of flat batteries 12 electrically connected in series and stacked. The electronic component is, for example, a DC / DC converter, a motor that drives a blower member, an electronic component that is controlled by an inverter, or various electronic control devices.

  The flat battery 12 has a flat plate shape with a thin outer case. The outer case is made of, for example, an insulating laminate sheet. The flat battery 12 has an internal space sealed by heat-sealing the outer edges of two laminate sheets. In this internal space, although not shown, an electrode laminate, an electrolyte, a terminal connection part, a part of the positive terminal part, and a part of the negative terminal part are incorporated.

  Remaining portions of the positive electrode terminal portion and the negative electrode terminal portion protrude from the outer case of the flat battery 12 (not shown). A terminal exposed from the outer case is connected to a terminal having a different polarity in the adjacent flat battery 12. Therefore, the laminated | stacked several flat battery 12 is connected in series. Of the terminals connected in series, the terminals at both ends, that is, the plus terminal and the minus terminal installed at both ends of the stacked battery 11 are supplied with electric power or discharged toward other electric devices. used.

  Next, the holding structure of the battery module 10 will be described. As shown in FIG. 1, the battery module 10 includes a pair of end plates 13, a collar 14, bolts 15, and nuts 16.

  The exterior of the battery module 10 is constituted by a pair of end plates 13. The pair of end plates 13 are respectively provided on the front surface and the back surface of the stacked battery 11 and presses the stacked battery 11 inward.

  The end plate 13 has four L-shaped leg portions 17 at four corners. An insertion hole 18 through which the bolt 15 is inserted is formed in the leg portion 17. Further, a collar 14 that functions as a support member is provided integrally with the end plate 13 in the insertion hole 18 of the end plate 13 that is located at the top of FIG. As shown in FIG. 3, the collar 14 extends in the stacking direction Y and supports a part of the outer peripheral surface of the bolt 15 inserted through the insertion hole 18. The collar 14 is shorter than the length of the bolt 15. Further, as shown in FIG. 3, the lower end of the collar 14 is located away from the inner surface of the lower end plate 13 with the pair of end plates 13 sandwiching the stacked battery 11. Therefore, even if the bolt 15 is tightened, the collar 14 does not interfere with the tightening of the bolt 15.

  The bolts 15 and the nuts 16 are fastening members, and at least two bolts 15 in this embodiment are used for connecting the end plates 13. The insertion holes 18 are provided at the four corners of the end plate 13 when viewed in the stacking direction Y. Therefore, as shown in FIG. 1, the insertion holes 18 are located at both ends in the length direction X when viewed in the width direction Z. The stacked battery 11 is arranged in the center in the length direction X when viewed in the width direction Z. Therefore, the bolts 15 and nuts 16 at the four corners are arranged so as to sandwich the stacked battery 11 when viewed in the stacking direction Y.

  A head 19 is fixed to the end plate 13 by welding or the like in a state in which the bolt 15 is inserted into the insertion hole 18 in the end plate 13 positioned below in FIG. As described above, the collar 14 is fixed to the insertion hole 18 of the upper end plate 13 by welding or the like.

  The collar 14 is cylindrical and has an inner diameter that is slightly larger than the outer diameter of the bolt 15. Therefore, as shown in FIG. 3, the bolt 15 can be inserted through the inside of the collar 14. In a state where the bolt 15 is inserted into the collar 14, at least a part of the outer peripheral surface inserted into the collar 14 of the bolt 15 is supported by the inner peripheral surface of the collar 14. The length of the collar 14 is shorter than the bolt 15 as described above, but is preferably set to be more than half of the interval in the stacking direction Y of the portion where the insertion holes 18 of the pair of end plates 13 are formed.

  Further, the portion of the end plate 13 in which the insertion hole 18 is formed is deformed so as to be located inside the pressing portion that presses the stacked battery 11. In the present embodiment, the insertion hole 18 is provided in the L-shaped leg portion 17 as described above. Thus, the insertion hole 18 is disposed at a position shifted from the surface of the pressing portion to the inner side (center side) in the stacking direction Y. As a result, the bolt 15 is inserted through the insertion hole 18, and the head portion 19, which is a portion positioned outside the stacking direction Y of the insertion hole 18, is positioned inside the stacking direction Y from the pressing portion. Further, as shown in FIG. 3, the nut 16 is also located on the inner side in the stacking direction Y from the pressing portion of the end plate 13.

  When the stacked battery 11 is constrained, first, the bolt 15 is inserted into the insertion hole 18 between the leg portions 17 of the pair of end plates 13 facing each other. As shown in FIG. 3, when the bolt 15 and the nut 16 are tightened in the connected state, the distance between the bolt 15 and the nut 16 is reduced, and the stacked battery 11 is sandwiched from both sides by the pair of end plates 13. It is. Further, the bolts 15 and the nuts 16 are tightened to approach each other, and the end plate 13 presses the stacked battery 11 inward by the tightening. As a result, the stacked flat battery 12 between the pair of opposite end plates 13 is pressed to restrain the expansion of the flat battery 12. The stacked battery 11 is constrained by the pair of end plates 13 to realize a constraining structure of the stacked battery 11.

  As described above, in the constraining structure of the stacked battery 11 of the present embodiment, the collar 14 extending in the stacking direction Y supports a part of the outer peripheral surface of the bolt 15 extending in the stacking direction Y. Thereby, the collar 14 can suppress the deformation of the end plate 13 without the collar 14 interfering with the inward pressing by the bolt 15. Further, by providing the collar 14, a restraining pressure can be applied in the vertical direction to the surface of the end plate 13, and the parallelism of the pair of end plates 13 can be maintained by the bolt 15 and the collar 14. Since the collar 14 does not interfere with the inner pressing of the bolt 15, the bolt 15 can press the stacked battery 11 uniformly by bringing the pair of end plates 13 close to each other. Therefore, the multilayer battery 11 can be uniformly pressed by the pair of end plates 13 while absorbing the tolerance variation of the multilayer battery 11.

  As shown in FIG. 4, since the deformation of the bolt 15 is suppressed by the collar 14, the pair of end plates 13 can be kept parallel. In the comparative example shown in FIG. 5, when only the bolt 15 is used without using the collar 14, the end plate 13 is deformed by tightening the bolt 15. Since there is no support on the axis of the bolt 15 that holds the stacked battery 11, the end plate 13 is inclined, and stress concentration occurs on the end plate 13 with the stacked battery 11 as a fulcrum. As a result, the end plate of the comparative example presses the four corners of the stacked battery 11 and cannot uniformly press the surface of the stacked battery 11.

  As shown in FIG. 6, the internal resistance of the stacked battery 11 is high in either the low load region where the constraint load is low or the high load region where the constraint load is high. In the high load (over-constrained) region, the electrolyte exudes from between the electrodes and the amount of Li ions decreases, so the internal resistance increases. In the low load region, the distance between the electrodes increases, and the generated gas accumulates between the electrodes, so that a portion that does not contribute to the reaction is generated and the internal resistance increases.

  However, the internal resistance is low when the load is appropriate. When the load is in the proper load range, the distance between the electrodes is appropriate, and the distance between the electrodes is not too far, so that there is no shortage of Li ions due to leakage of the electrolyte. And there is no occurrence of a portion that does not contribute to the reaction due to the generated gas. As a result, when the load is in the appropriate load range, the resistance value becomes small. In other words, if the constraining surface pressure is uneven, the above phenomenon may occur locally, so ideally, pressing the entire constraining surface uniformly with an appropriate load will improve battery performance. It is necessary to put out.

  Therefore, as in the present embodiment, the restraint load can be adjusted by the tightening amount of the bolt 15 while being uniformly pressed by the tightening of the bolt 15, so that the load can be adjusted to an appropriate load range. As a result, the capacity of the multilayer battery 11 can be maximized while the multilayer battery 11 is reliably restrained.

  In this way, the collar 14 fixed at a right angle to the end plate 13 and the bolt 15 to be fastened come into contact with each other, so that the end plate 13 is maintained in parallel and the stacked battery 11 is pressed uniformly. As a result, deformation of the end plate 13 can also be suppressed.

  In the present embodiment, four bolts 15 are used to connect the end plates 13, and the four bolts 15 are arranged so as to sandwich the stacked battery 11 when viewed in the stacking direction Y. In this way, the bolts 15 are arranged not on the position where the multilayer battery 11 is penetrated but on the outer side of the multilayer battery 11 so as to sandwich the multilayer battery 11. In the case of such an arrangement, the outer periphery of the stacked battery 11 is fastened with the bolts 15, so that the end plate 13 may be bent as shown in FIG. 5. However, in the present embodiment, since the collar 14 is fixed to the end plate 13, the curvature of the end plate 13 can be suppressed by the collar 14.

  In addition, when there is a reason that the bolt 15 cannot penetrate the laminated battery 11, the bolt 15 needs to be disposed on the outer periphery. Even in such a case, the bolt 15 can be suitably tightened. The case where the bolt 15 cannot penetrate the stacked battery 11 is a case where it is difficult to penetrate the bolt 15 through the battery, for example, because the battery is electrically and airtightly independent.

  Furthermore, in this embodiment, the part in which the insertion hole 18 is formed in the end plate 13 is deformed so as to be located inside the stacking direction Y from the pressing part. Further, the bolt 15 is inserted through the insertion hole 18 and the portion of the insertion hole 18 positioned outside the stacking direction Y is positioned inside the stacking direction Y of the pressing portion of the end plate 13. By attaching the bolt 15, it is possible to prevent the head 19 and the nut 16 of the bolt 15 from protruding outward from the surface of the end plate 13. In other words, the portion where the insertion hole 18 is formed can be used as a storage space for storing the head portion 19 of the bolt 15 and the nut 16. As a result, the battery module 10 can be prevented from increasing in size. Further, it is possible to prevent the battery module 10 from having a portion that partially protrudes from the surface.

  In other words, the end plate 13 has a concave or convex shape formed along the outer periphery of the multilayer battery 11, and holds the multilayer battery 11 at both ends. As a result, the fastening portion including the bolt 15 and the nut 16 can be downsized, and a small case shape along the stacked battery 11 can be obtained.

  In the present embodiment, the collar 14 is provided inside the end plate 13. As a result, the storage space for the collar 14 is not newly formed, so that the battery module 10 can be prevented from being enlarged. Further, by arranging the collar 14 on the inner side, the central portion where the bolt 15 is easily deformed can be supported, so that the deformation of the bolt 15 can be more reliably suppressed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is characterized in that the end plate 13A has a flat plate shape.

  As shown in FIGS. 7 and 8, the end plate 13A has a flat plate shape, and a portion where the insertion hole 18 is formed is also flat. The collar 14 and the bolt 15 are respectively fixed to the end plate 13A as in the first embodiment. The laminated battery 11 can be restrained by assembling in the same manner as in the first embodiment and fastening the bolt 15. Further, since the end plate 13A has a simple configuration, the manufacturing cost is reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. This embodiment is characterized in that the collars 141 and 142 are provided on both of the pair of end plates 13B.

  The collar 141 of the end plate 13B located in the upper part of FIG. 9 has the same configuration as that of the first embodiment. The collar 142 of the end plate 13B located in the lower part of FIG. 9 has a cylindrical shape, and the inner diameter is slightly larger than the outer diameter of the upper collar 141. Therefore, as shown in FIG. 10, the upper collar 141 can be inserted through the lower collar 142. In the state where the upper collar 141 is inserted into the lower collar 142, at least a part of the outer peripheral surface inserted into the lower collar 142 is the inner peripheral surface of the lower collar 142 and the upper collar 141. Is supported. The length of the lower collar 142 is shorter than the bolt 15 like the upper collar 141, but is preferably set to be more than half of the interval in the stacking direction Y of the portion where the insertion holes 18 of the pair of end plates 13B are formed. Is done.

  In the present embodiment, a detent 20 for the bolt 15 is provided between the head 19 of the bolt 15 and the end plate 13B. The rotation stopper 20 can prevent the bolt 15 from being loosened due to vibration or the like of the battery module 10.

  In this way, by increasing from one collar 14 to one collar 141 and the other collar 142, the deformation of the bolt 15 can be further prevented. Further, deformation of the two collars 141 and 142 can be suppressed. Accordingly, even when the tightening force is large, the end plate 13B can be kept parallel while suppressing the deformation of the end plate 13B.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described using FIG. 11 and FIG. The present embodiment is characterized in that the collar 14C is provided outside the end plate 13C.

  The collar 14C is fixed to the outside of the end plate 13C. As shown in FIG. 12, in the constrained state, the bolt 15 is inserted through the inside of the collar 14C, so that the length of the bolt 15 is longer than the total dimension between the pair of end plates 13C and the collar 14C. Is set as follows.

  As described above, in the present embodiment, the collar 14C is provided outside the end plate 13C. However, since the inner peripheral surface of the collar 14C supports the outer peripheral surface of the bolt 15, the parallelism of the pair of end plates 13C can be maintained. it can.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The structure of the said embodiment is an illustration to the last, Comprising: The scope of the present invention is not limited to the range of these description. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  In the first embodiment described above, the plurality of battery cells are arranged such that the side surfaces are stacked on each other in a row, but the arrangement is not limited to this. The arrangement of the battery cells may be a plurality of rows.

  In the first embodiment described above, the battery module 10 is mounted on the vehicle, but is not limited to the vehicle, and may be mounted on other moving means such as an aircraft and a ship. Moreover, you may mount in another apparatus instead of a moving means.

  In the first embodiment described above, four bolts 15 are used, but the number is not limited to four, and may be two or more.

  In the first embodiment described above, the fastening member is realized by the bolt 15 and the nut 16. However, the fastening member is not limited to such a configuration. For example, the fastening member is formed by forming a hole having an internal thread in one end plate 13. May be realized.

  In the first embodiment described above, the collar 14 is cylindrical. However, the collar 14 is not limited to the cylindrical shape, and may be any shape that supports the outer peripheral surface of the bolt 15. For example, as the support member, a plurality of solid pillars may be annularly arranged around the insertion hole 18.

DESCRIPTION OF SYMBOLS 10 ... Battery module 11 ... Stack type battery 12 ... Flat battery 13 ... End plate 14 ... Collar (support member) 15 ... Bolt (fastening member)
16 ... Nut (fastening member) 17 ... Leg portion 18 ... Through hole 19 ... Head 20 ... Non-rotation 141 ... Upper collar (supporting member)
142 ... lower collar (support member)

Claims (3)

A constraining structure of a stacked battery (11) in which a plurality of flat batteries (12) are stacked in the thickness direction,
A pair of end plates (13) provided on the front surface and the back surface of the stacked battery, respectively, for pressing the stacked battery inward;
Fastening members (15, 16) that extend in the stacking direction and are inserted through insertion holes (18) formed in each of the pair of end plates and connect the pair of end plates;
A support member (14, 141, 142) that extends in the stacking direction, is provided integrally with at least one of the end plates, and supports a part of the outer peripheral surface of the fastening member that is inserted into the insertion hole; Including
The pair of end plates approach each other by tightening the fastening member, and the end plates press the stacked battery inward by the tightening,
The support members are respectively provided inside the stacking direction of the pair of end plates,
One of the support members supports a part of the outer peripheral surface of the fastening member inserted through the insertion hole,
The other support member supports a part of the outer peripheral surface of one of the support members. At least two of the fastening members are used to connect the end plates;
2. The constraining structure for a stacked battery according to claim 1, wherein the two fastening members are arranged so as to sandwich the stacked battery as viewed in the stacking direction. The portion where the insertion hole is formed in the end plate is located on the inner side than the pressing portion pressing the stacked battery,
The portion of the fastening member that is inserted through the insertion hole and is located outside of the insertion hole in the stacking direction is positioned inside the stacking direction of the pressing portion. Or a constraining structure for a stacked battery as described in 2 above.

Images