JP6488700B2 - Battery module and battery module manufacturing method - Google Patents

Description

  The present invention relates to a battery module and a battery module manufacturing method.

  For example, the battery module described in Patent Document 1 connects an array body in which a plurality of battery cells are held in a cell holder, a pair of end plates sandwiching the array body, and a pair of end plates. A restraining bolt. The restraint bolt is made of metal and is inserted through each of the insertion holes provided in the cell holder.

JP 2011-222490 A

  In the battery module of Patent Document 1, when battery cells expand in the arrangement direction due to deterioration or overcharge, it is conceivable that the distance between adjacent cell holders increases and the restraint bolts are exposed between the cell holders. In this case, there is a possibility that the exposed restraint bolt and the battery cell come into contact with each other, and there is a possibility that the insulation between the battery cell and the restraint bolt cannot be maintained.

  It is an object of the present invention to provide a battery module that can maintain insulation between the battery cell and the restraint bolt even when the battery cell expands, and a battery module manufacturing method that can manufacture such a battery module. .

  A battery module according to an aspect of the present invention is provided with an array body configured to include a plurality of battery cells that are held along a predetermined array direction while being held by a cell holder having electrical insulation properties. An elastic member disposed on at least one side in the arrangement direction, a pair of end plates that sandwich the array body and the elastic member from the arrangement direction, and a metal restraining bolt that connects the pair of end plates, The cell holder has an insertion hole through which the restraint bolt is inserted, and one of the adjacent cell holders protrudes from the edge of the insertion hole on the surface facing the other cell holder so as to cover at least the battery cell side of the restraint bolt. The insertion hole of the other cell holder has a recess into which the restraining bolt and the protrusion are inserted, and the insertion length of the protrusion in the arrangement direction with respect to the recess , Is equal to or greater than the allowable amount of compression per battery cell of the elastic member with respect to the expansion of the battery cell.

  In this battery module, when the battery cell expands, the elastic member is compressed and deformed to allow the battery cell to expand. At this time, the distance between the adjacent cell holders increases by the amount of expansion of the battery cell. In this battery module, one protrusion of the adjacent cell holder is inserted into the recess of the other cell holder, and the protrusion The insertion length in the arrangement direction with respect to the elastic member is greater than or equal to the allowable compression amount per battery cell for the elastic member against the expansion of the battery cell. Therefore, even when the expansion amount of the battery cell reaches the allowable compression amount per battery cell and the distance between the cell holders is increased by the allowable compression amount per battery cell, the state where the protruding portion is inserted into the recess is maintained. The protrusion can be positioned between adjacent cell holders. Therefore, even when the battery cell is expanded, the battery cell between the cell holders and the restraint bolt are separated by the projecting portion having insulation properties, and the insulation between the battery cell and the restraint bolt is maintained.

  The protruding portion may be a cylindrical portion that communicates with the insertion hole and through which the restraining bolt is inserted. In this case, since the restraint bolt is covered over the entire circumference by the cylindrical portion, the insulation of the restraint bolt is improved.

  Moreover, at least one of the cell holders may have protrusions on both sides in the arrangement direction. In this case, since the shape of the cell holder can be made different between the cell holder having the protruding portions on both sides and the cell holder that receives the protruding portions adjacent to the cell holder, it is possible to suppress the erroneous assembly of these. .

  The battery module manufacturing method according to one aspect of the present invention includes an array formed by arranging a plurality of battery cells held by a cell holder having electrical insulation along a predetermined array direction, and an array direction with respect to the array And an elastic member disposed on at least one side of the metal plate between the pair of end plates from the arrangement direction and connecting the pair of end plates with a metal restraint bolt, and having an insertion hole through which the restraint bolt is inserted. The cell holder is used, and one of the adjacent cell holders is provided with a protruding portion that protrudes from the edge of the insertion hole in the surface facing the other cell holder so as to cover at least the battery cell side of the restraint bolt. The insertion hole is provided with a concave portion into which the restraining bolt and the protruding portion are inserted. In the assembly process, the insertion direction of the protruding portion with respect to the concave portion is inserted. Length, so that the above permissible amount of compression per battery cell of the elastic member with respect to the expansion of the battery cells, inserting the protrusion into the recess.

  In the battery module manufactured by this battery module manufacturing method, the insertion length in the arrangement direction with respect to the concave portion of the protruding portion is equal to or larger than the allowable compression amount per battery cell of the elastic member against the expansion of the battery cell. Therefore, even when the expansion amount of the battery cell reaches the allowable compression amount per battery cell and the distance between the cell holders is increased by the allowable compression amount per battery cell, the state where the protruding portion is inserted into the recess is maintained. The protrusion can be positioned between adjacent cell holders. Therefore, even when the battery cell is expanded, the battery cell between the cell holders and the restraint bolt are separated by the projecting portion having insulation properties, and the insulation between the battery cell and the restraint bolt is maintained.

  ADVANTAGE OF THE INVENTION According to this invention, even when a battery cell expand | swells, the manufacturing method of the battery module which can maintain the insulation between a battery cell and a restraint volt | bolt, and such a battery module can be provided.

It is a perspective view of the battery module which concerns on one Embodiment of this invention. It is a schematic sectional drawing in the II-II line of FIG. (A) is the perspective view which looked at the cell holder from the one side of the arrangement direction, (b) is the perspective view seen from the other side. (A) is a schematic sectional drawing of the battery module before expansion of a battery cell, (b) is a schematic sectional drawing of the battery module after expansion of a battery cell. It is a schematic sectional drawing of the battery module which concerns on a modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a perspective view of a battery module 1 according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view taken along the line II-II in FIG. The battery module 1 is used in a state in which, for example, a plurality of battery modules 1 are accommodated in a casing to form a battery pack.

  As shown in FIGS. 1 and 2, the battery module 1 includes an array body 17 in which a plurality of battery cells 11 are arrayed along a predetermined array direction D, and one side in the array direction D with respect to the array body 17. An elastic member 21 disposed on the right side in FIG. 2, a pair of end plates 31 that sandwich the array 17 and the elastic member 21, and a restraining bolt 35 that connects the pair of end plates 31 to each other. .

  The battery cell 11 is a battery in which an electrode assembly is accommodated in a rectangular box-like case. The battery cell 11 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. In this example, seven battery cells 11 are arranged along the arrangement direction D. The battery cell 11 is held by a cell holder 41. The electrode terminals of adjacent battery cells 11 are electrically connected to each other by a bus bar 13 (FIG. 1). Thereby, the adjacent battery cells 11 are electrically connected in series.

  As shown in FIG. 2, a metal-made rectangular plate-shaped heat transfer plate 15 is interposed between adjacent battery cells 11. The heat transfer plate 15 is a member for adjusting the temperature of the battery cell 11 and is provided to reduce the temperature difference between the adjacent battery cells 11. The array 17 includes the battery cell 11, the cell holder 41, the bus bar 13, and the heat transfer plate 15. The configuration of the cell holder 41 will be described later.

  The elastic member 21 is formed in a flat plate shape by rubber, for example. As shown in FIG. 2, the elastic member 21 is disposed between the array body 17 and the end plate 31. In the present embodiment, the middle plate 25 is disposed between the array body 17 and the elastic member 21. The middle plate 25 is formed in a flat plate shape with resin, for example. Since the middle plate 25 is interposed between the array body 17 and the elastic member 21, variations in the load acting on the array body 17 from the elastic member 21 are suppressed. The middle plate 25 is provided with an insertion hole 27 through which the restraining bolt 35 is inserted. In this example, a cylindrical portion 50 of a cell holder 41 described later is inserted into the insertion hole 27 together with the restraining bolt 35.

  The end plate 31 is formed in a flat plate shape from metal, for example. The pair of end plates 31 sandwich the array body 17, the elastic member 21, and the middle plate 25 from both sides in the array direction D. The pair of end plates 31 are connected by a plurality of (four in this example) restraining bolts 35 extending in the arrangement direction D.

  The restraint bolt 35 is made of a metal such as iron. Each end plate 31 is provided with a plurality of insertion holes 33 through which the restraint bolts 35 are inserted. Each constraining bolt 35 is sequentially inserted into an insertion hole 33 of one end plate 31, insertion holes 49 and 57 of each cell holder 41 described later, an insertion hole 27 of the middle plate 25, and an insertion hole 33 of the other end plate 31. The nut 37 is fastened outside the other end plate 31. By this fastening, a restraining load is applied to the array body 17, the elastic member 21, and the middle plate 25.

  FIG. 3A is a perspective view of the cell holder 41 as viewed from one side in the arrangement direction D, and FIG. 3B is a perspective view as viewed from the other side. The cell holder 41 is made of, for example, resin and has electrical insulation. As shown in FIG. 3, the cell holder 41 includes a frame body portion 42 and a partition portion 43. Hereinafter, one surface in the arrangement direction D of the cell holder 41 is referred to as a first facing surface 44, and the other surface is referred to as a second facing surface 45. In the assembled state, the first facing surface 44 is a facing surface with the cell holder 41 adjacent on one side in the arrangement direction D, and the second facing surface 45 is a facing surface with the cell holder 41 adjacent on the other side.

  The frame body portion 42 includes a bottom plate 46 and a pair of side plates 47 that stand from both ends of the bottom plate 46. Legs 48 projecting in the thickness direction of the bottom plate 46 are provided at both ends of the bottom plate 46. Each leg portion 48 is provided with a circular insertion hole 49 penetrating in the arrangement direction D. The restraint bolt 35 is inserted into each of the insertion holes 49.

  Each leg portion 48 is provided with a cylindrical portion 50 (protruding portion) that protrudes from the edge portion of the insertion hole 49 in the first facing surface 44. The cylindrical portion 50 is formed in a cylindrical shape and communicates with the insertion hole 49. The inner diameter of the cylindrical portion 50 is the same as the diameter of the insertion hole 49, for example. The restraint bolt 35 is inserted into each tubular portion 50, and the tubular portion 50 covers the entire circumference of the restraint bolt 35.

  As shown in FIG. 2 and FIG. 4 described later, the insertion hole 49 includes a constraining bolt 35 and a recess 51 into which the cylindrical portion 50 of the adjacent cell holder 41 is inserted. The recess 51 is provided so as to be recessed from the second facing surface 45 in the arrangement direction D, and has, for example, a cylindrical shape. The diameter of the recess 51 is larger than the diameter of the other part in the insertion hole 49. More specifically, the diameter of the portion other than the recess 51 in the insertion hole 49 is the same as the diameter of the restraining bolt 35 or slightly larger than the diameter of the restraining bolt 35. On the other hand, the diameter of the recess 51 is at least larger than the diameter of the other part by at least the thickness of the cylindrical part 50 in the radial direction. Thereby, the restraint bolt 35 and the cylindrical part 50 can be inserted into the recess 51.

  As shown in FIG. 4A, the length L1 of the recesses 51 in the arrangement direction D, that is, the distance in the arrangement direction D from the second facing surface 45 to the bottom surface of the recesses 51 is relative to the recesses 51 of the cylindrical part 50. It is larger than the insertion length L2 in the arrangement direction D. Therefore, in the assembled state, the tip surface of the cylindrical portion 50 and the bottom surface of the recess 51 do not contact each other, and a gap 53 is formed between the tip surface of the cylindrical portion 50 and the bottom surface of the recess 51. . In the present embodiment, the protruding length of the cylindrical portion 50 in the arrangement direction D from the first facing surface 44 is larger than the insertion length L2. In the assembled state, a gap 54 is formed between the first facing surface 44 and the second facing surface 45 of the adjacent cell holders 41.

  As shown in FIG. 3, the partition portion 43 connects a pair of side plates 47. A pair of terminal accommodating portions 55 is provided on the partition portion 43. Each terminal accommodating part 55 has a circular inner wall surrounding the electrode terminal. Further, a pair of square pillars 56 connected to the terminal accommodating part 55 are provided on the partition part 43.

  Each column part 56 is provided with an insertion hole 57 penetrating in the arrangement direction D. The insertion hole 57 has, for example, the same shape as the insertion hole 49 and has a recess 51. The constraining bolts 35 are also inserted into the respective insertion holes 57. Each column portion 56 is provided with a cylindrical portion 50 so as to protrude from the edge portion of the insertion hole 57. The restraint bolt 35 is also inserted into the tubular portion 50, and the restraint bolt 35 and the tubular portion 50 are inserted into the recess 51 of the insertion hole 57.

  In the cell holder 41, an accommodation space S is formed by the frame body part 42 and the partition part 43. When the battery cell 11 is accommodated in the accommodation space S, the battery cell 11 is held by the cell holder 41. Further, in the cell holder 41, a rectangular opening 59 is formed by the frame body portion 42 and the lower end surface of the partition portion 43 in FIG. In the assembled state, the heat transfer plate 15 is disposed in the opening 59. As a result, as shown in FIGS. 2 and 4, the partition portion 43 is disposed in the gap formed between the adjacent battery cells 11 by the heat transfer plate 15.

  In this assembled state, no restraint load is applied to the cell holder 41, and the cell holder 41 slides along the arrangement direction D (along the restraint bolt 35) with respect to the battery cell 11 and the heat transfer plate 15. It is movable. Specifically, the cell holder 41 is slidable by the shorter one of the length of the gap 53 in the arrangement direction D and the length of the gap 54 in the arrangement direction D. In this example, these lengths are the same. 2 and 4, a state in which the cell holder 41 is disposed at a position where the partition portion 43 abuts on one surface of the battery cell 11 in the arrangement direction D is shown.

  Next, the case where the battery cell 11 expands in the arrangement direction D will be described with reference to FIG. 4A is a schematic cross-sectional view of the battery module 1 before the battery cell 11 is expanded, and FIG. 4B is a schematic cross-sectional view of the battery module 1 after the battery cell 11 is expanded. FIG. 4B shows a state where the compression amount of the elastic member 21 has reached the allowable compression amount A1. In addition, as an aspect of expansion | swelling of the battery cell 11, the case where any one of the some battery cells 11 expands and the case where two or more or all the battery cells 11 expand simultaneously are included. Below, the case where all the battery cells 11 expand | swell uniformly is mentioned as an example, and is demonstrated. For convenience of explanation, the dimensions of the elastic member 21 shown in FIG. 4 may be different from the actual ones.

  In the battery module 1, when each battery cell 11 expands, the elastic member 21 is compressed and deformed, so that the expansion of each battery cell 11 is allowed. More specifically, first, the expanded battery cell 11 is displaced toward the elastic member 21 side. The displaced battery cell 11 presses the adjacent battery cell 11 to the elastic member 21 side via the heat transfer plate 15 and displaces it to the elastic member 21 side. Accordingly, the battery cell 11 arranged closest to the elastic member 21 in the arrangement direction D is displaced toward the elastic member 21 by an amount obtained by adding the expansion amounts of all the battery cells 11. The battery cell 11 presses the middle plate 25 toward the elastic member 21 side. Thereby, the middle plate 25 moves to the elastic member 21 side. The elastic member 21 is compressed and deformed by being pressed by the middle plate 25. As a result of the operation described above, when each battery cell 11 expands, the elastic member 21 is compressed and deformed by the amount of expansion of the battery cell 11 as a whole, and the expansion of each battery cell 11 is allowed. At this time, the distance between the adjacent cell holders 41 increases by the amount of expansion of each battery cell 11.

  As shown in FIG. 4, the elastic member 21 can be compressed and deformed until the compression amount reaches the allowable compression amount A1. That is, in the battery module 1, the expansion of each battery cell 11 is allowed by the amount obtained by dividing the allowable compression amount A1 by the number of battery cells 11. Hereinafter, this amount is defined as an allowable compression amount A2 per battery cell of the elastic member 21 with respect to the expansion of the battery cell 11.

  In the battery module 1, the insertion length L2 of the cylindrical portion 50 with respect to the recess 51 is equal to or greater than the allowable compression amount A2 per battery cell. For this reason, as shown in FIG. 4B, the expansion amount of each battery cell 11 reaches the allowable compression amount A2 per battery cell (the compression amount of the elastic member 21 reaches the allowable compression amount A1), and the cell holder Even when the distance between the terminals 41 increases by the allowable compression amount A2 per battery cell, the state in which the cylindrical portion 50 is inserted into the recess 51 is maintained, and the cylindrical portion 50 extends between the cell holders 41. Become. Therefore, even when the battery cell 11 expands, the battery cell 11 and the restraint bolt 35 between the cell holders 41 are separated by the insulating cylindrical portion 50, and the insulation between the battery cell 11 and the restraint bolt 35 is achieved. Sex is maintained.

  Moreover, in the battery module 1, since the restraint bolt 35 is covered over the perimeter by the cylindrical part 50, the insulation of the restraint bolt 35 is improved.

  The insertion length L2 is determined as follows, for example. First, for the elastic member 21, the allowable compression amount A1 is calculated from the compression characteristics. By dividing the allowable compression amount A1 by the number of battery cells 11, the allowable compression amount A2 per battery cell is calculated. The insertion length L2 is set to a predetermined length that is greater than or equal to the allowable compression amount A2. Here, in the present embodiment, since the cell holder 41 is slidable by a predetermined amount as described above, the predetermined amount may be further added to the insertion length L2. Further, an amount corresponding to the dimensional tolerance may be further added to the insertion length L2.

  The assembly process of the battery module 1 will be described. In the assembly process, an array 17 formed by arranging a plurality of battery cells 11 held by the cell holder 41 along the array direction D, and an elastic member 21 disposed on one side of the array direction D with respect to the array 17 are provided. A pair of end plates 31 are sandwiched from the arrangement direction D, and the pair of end plates 31 are connected to each other by restraining bolts 35. At this time, the cylindrical portion 50 is inserted into the recess 51 so that the insertion length L2 is equal to or greater than the allowable compression amount A2 per battery cell. Thereby, the battery module 1 is manufactured. For example, the following method can be considered as a method for adjusting the insertion length L2. For example, a marker or the like serving as a mark is provided in advance at a position away from the tip of the tubular part 50 by the insertion length L2, and the tubular part 50 is inserted into the recess 51 so that the mark cannot be seen in the assembly process. May be.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. The present invention can be modified without departing from the scope described in the claims or applied to other embodiments. May be.

  In the battery module of the present invention, one of the adjacent cell holders has a cylindrical portion 50 (protruding portion) on the surface facing the other cell holder, and the other cell holder has a recess 51 on the surface facing the one cell holder. It only has to be. For example, in the above embodiment, the concave portion 51 may be provided on the first facing surface 44, and the cylindrical portion 50 may be provided on the second facing surface 45. Moreover, both the cylindrical part 50 and the recessed part 51 may be provided in the 1st opposing surface 44 and the 2nd opposing surface 45, respectively. For example, the cylindrical portion 50 is provided on the first opposing surface 44 of each leg portion 48, the concave portion 51 is provided on the first opposing surface 44 of each column portion 56, and the concave portion is provided on the second opposing surface 45 of each leg portion 48. 51 and the cylindrical portion 50 may be provided on the second facing surface 45 of each column portion 56.

  Moreover, in the said embodiment, although all the cell holders were made into the same shape, the cell holder from which a shape differs mutually may be included. For example, the battery module according to the modification shown in FIG. 5 includes a cell holder 41A and a cell holder 41B having different shapes. The cell holder 41 </ b> A has a cylindrical portion 50 on both surfaces in the arrangement direction D, that is, on the first facing surface 44 and the second facing surface 45. The cell holder 41B adjacent to the cell holder 41A has recesses 51 on both surfaces in the arrangement direction D. The cell holder 41A and the cell holder 41B are alternately arranged. According to this battery module, since the shape of the cell holder 41A and the shape of the cell holder 41B can be made different, incorrect assembly is suppressed. Note that at least one of the plurality of cell holders only needs to have a different shape from the other cell holders such as the cell holder 41A or the cell holder 41B, and the battery module may be configured by appropriately combining the cell holders described above.

  In the said embodiment, although the cylindrical part 50 was provided as a protrusion part which protrudes from the 1st opposing surface 44, the protrusion part should just cover the battery cell 11 side of the restraint bolt 35, for example, a bowl shape, It is good also as arbitrary shapes, such as flat form and rod shape. In this case, the concave portion has a shape corresponding to the shape of the protruding portion (the protruding portion can be inserted).

  The elastic member 21 only needs to be arranged on at least one side in the arrangement direction D with respect to the arrangement body 17 and may be arranged on both sides. The arrangement on both sides is preferable in that the battery cell 11 can be further allowed to expand. The cell holder 41 only needs to have an insulating property at least in contact with the battery cell 11, the heat transfer plate 15, and the restraint bolt 35, and a part thereof may be made of metal. The whole is preferably made of resin from the viewpoint of ease of molding, and the one containing a metal is preferable in terms of improving the rigidity. The middle plate 25 may be omitted.

DESCRIPTION OF SYMBOLS 1 ... Battery module, 11 ... Battery cell, 17 ... Array, 21 ... Elastic member, 25 ... Middle plate, 31 ... End plate, 35 ... Restraint bolt, 41, 41A, 41B ... Cell holder, 44 ... 1st opposing surface, 45 ... second opposing surface, 49, 57 ... insertion hole, 50 ... cylindrical part (protruding part), 51 ... concave part, D ... array direction.

Claims (4)

An array configured to include a plurality of battery cells that are held by a cell holder having electrical insulation and arranged in a predetermined array direction;
An elastic member disposed on at least one side in the arrangement direction with respect to the array;
A pair of end plates sandwiching the array body and the elastic member from the array direction;
A metal restraint bolt that connects the pair of end plates, and
The cell holder has an insertion hole through which the restraint bolt is inserted,
One of the adjacent cell holders has a protruding portion that protrudes from the edge of the insertion hole on the surface facing the other cell holder so as to cover at least the battery cell side of the restraining bolt,
The insertion hole of the other cell holder has a recess into which the restraint bolt and the protrusion are inserted,
The insertion length of the protrusion in the arrangement direction with respect to the recess is equal to or greater than an allowable compression amount per battery cell of the elastic member with respect to expansion of the battery cell .
Even when the expansion amount of the battery cell reaches the allowable compression amount per battery cell and the distance between the adjacent cell holders increases by the allowable compression amount per battery cell, the protrusion is inserted into the recess. A battery module that is maintained in a sealed state .   The battery module according to claim 1, wherein the protruding portion is a cylindrical portion that communicates with the insertion hole and through which the restraint bolt is inserted.   The battery module according to claim 1, wherein at least one of the cell holders has the protrusions on both surfaces in the arrangement direction. An array formed by arranging a plurality of battery cells held by a cell holder having electrical insulation along a predetermined arrangement direction, and an elastic member arranged on at least one side in the arrangement direction with respect to the arrangement It is sandwiched between a pair of end plates from the arrangement direction, and comprises an assembly step of connecting the pair of end plates with a metal restraining bolt,
Using the cell holder having an insertion hole through which the restraint bolt is inserted,
One of the adjacent cell holders is provided with a protruding portion that protrudes from an edge of the insertion hole on the surface facing the other cell holder so as to cover at least the battery cell side of the restraining bolt,
The insertion hole of the other cell holder is provided with a recess into which the restraint bolt and the protrusion are inserted,
In the assembly process,
The insertion length of the array direction with respect to the concave portion of the protrusion, Ri Do a more tolerable amount of compression per battery cell of said elastic member relative to the expansion of the battery cells, and,
Even when the expansion amount of the battery cell reaches the allowable compression amount per battery cell and the distance between the adjacent cell holders increases by the allowable compression amount per battery cell, the protrusion is inserted into the recess. A method for manufacturing a battery module, wherein the protruding portion is inserted into the concave portion so that the maintained state is maintained .

Images