JP2018098082A - Spacer in pressing device of battery cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need to join a flexible sheet 32 and a connector 51, in a spacer 1 that expands and contracts due to introduction and ejection of pressurized air.SOLUTION: A spacer 1 disposed between battery cells comprises: a frame 31 made of hard rigid resin; and two flexible sheets 32 arranged on both faces of the frame 31. The frame 31 has a sheet joining face 45 continuous in a rectangular shape, to which the sheet 32 is joined. An area inside the sheet joining face 45 has a plurality of holes 50, as a sheet support wall 46 receding further backward than the sheet joining face 45. A connector 51 is molded integrally with the frame 31, and a communication passage 52 passing through the center of the connector 51 communicates with one hole 50A. Since the sheet 32 is joined to a sheet joining face 45 including a flat face, joining strength and sealability are easily ensured.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an improvement of a spacer that is arranged between individual battery cells and expands by fluid pressure in a pressurizing device for a battery cell that pressurizes a flat battery cell in its thickness direction.

  A battery cell used in an electric vehicle or a hybrid vehicle has, for example, a power generation element enclosed with an electrolyte inside an exterior body made of a laminate film, and has a thin flat shape in the thickness direction. Positive and negative terminals are derived from part of the section. When manufacturing this type of battery cell, a step of pressurizing the battery cell in a predetermined thickness direction is performed so that the electrolyte is satisfactorily permeated while discharging the gas inside the exterior body.

  Patent Document 1 previously filed by the present applicant discloses a pressurizing device using an air bag type spacer. This pressurizing device uses a bag-like spacer that expands in the thickness direction of a battery cell by supplying pressurized air as a spacer between battery cells of a magazine that houses a plurality of battery cells. After the battery cells are inserted and arranged in a state where the spacers are contracted, a large number of battery cells can be pressurized simultaneously by expanding each spacer.

International Publication No. 2015/141631

  The spacer of Patent Document 1 has a configuration in which, for example, two rubber sheets are joined to each other at a peripheral portion to form a bag shape, and the peripheral portion is bonded to a frame-shaped frame. Therefore, it is necessary to bond a pipe-shaped connector for connecting to the pressurized air piping between the two rubber sheets and bond it to the rubber sheet. The adhesive strength at the boundary between the connector and the rubber sheet There has been a problem that it is relatively difficult to ensure sealing performance.

  In order to solve the above problem, the spacer of the present invention is provided with a communication path with one end exposed to the outside as a connector on a frame having sheet bonding surfaces on both sides, and two flexible sheets are attached to the frame. They are joined on both sides.

  Therefore, the flexible sheet is simply joined to the sheet joining surface of the spacer, and there is no need to sandwich the connector.

  According to the present invention, there is no bonding portion between the flexible sheet and the connector, and therefore, problems of bonding strength and sealing performance at the boundary between the two as in the conventional case can be avoided.

The top view of the pressurization apparatus provided with the spacer which concerns on this invention. The front view of a pressurizing device. The front view which shows 1st Example of a spacer. The perspective view of a spacer similarly. The expanded sectional view along the AA line of FIG. The front view of the flame | frame in 1st Example. Sectional drawing of a frame similarly. The front view which shows 2nd Example of a spacer. Sectional drawing of the flame | frame in 2nd Example.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 and FIG. 2 show the configuration of the entire pressure device 10 using the spacer 1 of the present invention. The pressurizing device 10 is fixed to the housing 11 at predetermined equal intervals with respect to the thickness direction of the battery cell 2 (in the direction of arrow P in the figure) and the housing 11 that accommodates the plurality of battery cells 2, and enclosed inside And a plurality of spacers 1 that expand in the thickness direction of the battery cell 2 according to the air pressure (fluid pressure) of air as the working fluid. An air device 13 is provided outside the housing 11 as a fluid pressure source capable of adjusting the air pressure in the plurality of spacers 1.

  Although not shown in detail, the battery cell 2 is, for example, a lithium ion secondary battery, has a flat rectangular external shape, and is formed of a conductive metal foil at one end edge in the longitudinal direction. A pair of thin plate-like terminals are provided. The battery cell 2 is a so-called film-clad battery in which a rectangular electrode laminate is accommodated in an exterior body made of a laminate film together with an electrolyte. Said electrode laminated body which is an electric power generation element is comprised from the some positive electrode plate and negative electrode plate which were laminated | stacked alternately via the separator.

  The housing 11 includes a base plate 14 having a flat rectangular plate shape to be conveyed by a conveyor, and a pair of fixed plates 15 erected at both ends in the longitudinal direction of the base plate 14. A plurality of spacers 1 are arranged at predetermined equal intervals between the fixed plates 15. 1 and 2, the spacer 1 is schematically shown.

  The fixed plate 15 receives the entire load when the plurality of battery cells 2 are pressurized, is relatively thick, and is firmly fixed to the base plate 14.

  Guide shafts 16 spanned between the two fixing plates 15 are fixed to the four corners of the fixing plate 15, and the spacers 1 are slidably supported in the thickness direction P by these four guide shafts 16. Has been. A cylindrical bush 17 is inserted between the spacers 1 in the guide shaft 16 so that the pitch between the adjacent spacers 1 is constant. That is, the bushes 17 and the spacers 1 are alternately arranged on the guide shaft 16 so as to be in contact with each other, and the whole is sandwiched between the fixing plates 15 on both sides. Thus, the plurality of spacers 1 are arranged at regular intervals between the pair of fixed plates 15.

  In addition, an air pipe 22 extending in parallel with the guide shaft 16 is disposed as a pressure supply passage on the side portion of the housing 11, and air is supplied from the air device 13 to each spacer 1 through the air pipe 22. It has become so. A check valve 29 for preventing a backflow of air introduced into the spacer 1 is provided at the base end of the air pipe 22, and the air is connected to the check valve 29 through a joint 30 that is detachably connected. The pipe 22 is connected to the air device 13. The check valve 29 is opened by engagement of an unillustrated opening jig or supply of pilot pressure, and air can be released from the spacer 1. In order to increase the contraction speed of the spacer 1 during air bleeding, the air device 13 preferably includes a pressure reducing mechanism including an ejector pump in addition to the pressure pump.

  The pressurizing device 10 as described above is used, for example, for pressurization of the battery cell 2 during initial charging of the battery cell 2 and subsequent aging. The battery cell 2 is inserted into the housing 11 while the individual spacers 1 are contracted. As illustrated, battery cells 2 are inserted between two adjacent spacers 1, whereby each spacer 1 is positioned between the individual battery cells 2. Since the spacer 1 contracts, a sufficiently large gap is ensured between the two spacers 1, so that the battery cell 2 can be easily inserted by a robot hand or the like.

  After the insertion, the housing 11 is transferred to the pressurizing process and connected to the air device 13. By supplying pressurized air to each spacer 1 by the air device 13, each spacer 1 expands. Thereby, the battery cell 2 arrange | positioned between the two adjacent spacers 1 is pressurized in the thickness direction. When the battery cell 2 is in a pressurized state, the air device 13 can be stopped and the joint 30 can be removed from the check valve 29. Even after the joint 30 is removed, the pressurized state is maintained by the check valve 29.

  When the aging is completed and the battery cell 2 is taken out from the housing 11, the check valve 29 is opened to discharge air, and the spacer 1 is contracted again. As a result, the gap between the adjacent spacers 1 becomes larger than the thickness of the battery cell 2, so that the battery cell 2 can be easily extracted from the pressure device 10 by a robot hand or the like.

  FIG. 3 is a front view showing the spacer 1 of the first embodiment alone, and FIG. 4 is a perspective view. FIG. 5 is an enlarged view of a main part along the line AA in FIG. The spacer 1 includes a rectangular frame 31 that is integrally formed of hard synthetic resin, and two flexible sheets 32 that are respectively joined to both surfaces of the frame 31. The sheet 32 is made of a cloth having an appropriate strength as a base material, and a soft synthetic resin or rubber is provided on one or both sides thereof to provide a soft synthetic resin layer or a rubber layer. Here, the hard synthetic resin is preferably selected from acrylonitrile-styrene-butadiene resin, polycarbonate resin, hard polyurethane resin, hard polyvinyl chloride resin, polyamide resin, etc., and the soft synthetic resin or rubber is soft It is desirable to select from among polyvinyl chloride resin, soft polyurethane, natural rubber, chloroprene rubber and the like.

  6 and 7 are a front view and a sectional view of the frame 31 alone before the sheet 32 is joined. In the first embodiment, the frame 31 has a rectangular plate shape as a whole, and includes projecting pieces 34 projecting sideways at the four corners, and the guide shafts 16 described above are respectively provided on the projecting pieces 34. A notch 35 to be fitted is provided. In addition, a bottom wall 36 is provided along the lower edge, side walls 37 and 38 are provided along the left and right side edges, and a guide wall 39 is provided in parallel with one side wall 38. . The bottom wall 36, the side walls 37, 38 and the guide wall 39 protrude from the front and back surfaces of the frame 31 in the thickness direction P, respectively, and basically have a symmetrical shape on the front and back surfaces of the frame 31. Further, the side walls 37 and 38 and the guide wall 39 have substantially the same outer shape, so that the battery cell 2 inserted between the two adjacent spacers 1 is smoothly guided at the upper part. Tapered portions 37a, 38a, 39a are provided. In addition, as shown in FIG. 4, on one surface of the frame 31 (assuming this is the front side), the cell is divided into three parts so as to receive the inserted battery cell 2 from below. Support pieces 40 (40A, 40B, 40C) are provided so as to protrude further from the bottom wall 36 in the thickness direction P.

  Of the four protruding pieces 34, a pin 41 protruding in the thickness direction P is provided on the front side of the two protruding pieces 34 positioned on the upper side of the frame 31 in the same manner as the cell support piece 40. . The cell support piece 40 and the pair of pins 41 protruding to the front side of the frame 31 abut against the surface of the back side of the frame 31 of the adjacent spacer 1 when assembled to the housing 11 as shown in FIGS. , And functions to ensure an interval between two adjacent spacers 1. Therefore, the bush 17 described above can be omitted.

  In the illustrated example, one end edge of the battery cell 2 from which a terminal (not shown) is drawn is in a posture in which the end of the battery cell 2 is on the guide wall 39 side (in other words, a posture in which the terminal is sideways) It is inserted between each spacer 1. Accordingly, the spacer 1 is asymmetrical, and the pair of terminals of the battery cell 2 are guided by the side wall 38 and the guide wall 39 of the two adjacent spacers 1.

  On both the front and back surfaces of the frame 31, there are provided sheet joining surfaces 45 that are continuous in a rectangular shape. The sheet joining surface 45 has a substantially constant width and along a plane along the periphery of a rectangular region surrounded by the upper edge and bottom wall 36 of the frame 31 and the side wall 37 and the guide wall 39. Is formed. Each of the two sheets 32 has a size corresponding to the outer dimension of the sheet bonding surface 45, and a peripheral edge portion is bonded to the sheet bonding surface 45 via an adhesive. The sizes of the sheet 32 and the sheet bonding surface 45 are set in consideration of the size of the battery cell 2 to be pressurized.

  On the other hand, the area inside the sheet bonding surface 45 of the frame 31, that is, the area of the central portion surrounded by the sheet bonding surface 45 is the plate thickness of the frame 31 on the sheet bonding surface 45 (that is, along the thickness direction P described above). The flat sheet support wall 46 is slightly thinner than (thickness). In other words, the sheet support wall 46 is interposed between the two sheets 32 attached to both surfaces of the frame 31 in a partition shape. As shown in FIG. 5, there is a slight step at the boundary 48 between the sheet support wall 46 and the surrounding sheet bonding surface 45, and the surface of the sheet support wall 46 recedes from the sheet bonding surface 45. . Therefore, a slight gap 47 exists between the sheet 32 adhered to the sheet bonding surface 45 and the surface of the sheet support wall 46.

  The sheet bonding surface 45 can be configured on the same plane without a step with the surface (the portion not covered by the sheet 32) at the peripheral edge of the frame 31, but as in the illustrated example, the positioning of the sheet 32 is performed. Therefore, the sheet joining surface 45 may be provided in a shape retreated from the surface at the peripheral edge of the frame 31 (see FIG. 5).

  As shown in FIGS. 6 and 7, a plurality of circular holes 50 are formed through the sheet support wall 46. In one example, about 100 holes 50 having a diameter of several millimeters are evenly arranged. The shape of the hole 50 is not limited to a circle, and the size and number of the holes 50 are not limited to the above embodiment.

  A connector 51 for connecting the air pipe 22 described above is integrally formed on the side wall 37 of the frame 31. The connector 51 is formed in a tubular shape protruding on the outer surface of the side wall 37 along the direction orthogonal to the thickness direction P (more specifically, the direction orthogonal to the side wall 37). As shown in the drawing, an annular concavo-convex portion 51a for preventing the air pipe 22 from coming off is provided at the tip portion. A communication passage 52 through which pressurized air flows is provided at the center of the connector 51. The communication path 52 linearly extends inside the frame 31 along the central axis of the connector 51, and the tip reaches one hole 50 (denoted by reference numeral 50A). Specifically, it communicates with a hole 50 </ b> A that is closest to the side wall 37 and located on the extension line of the connector 51. The communication path 52 may be secondarily machined after the frame 31 is molded, or may be formed using a pin-shaped slide core when the frame 31 is molded. A configuration in which the communication path 52 is further extended from the illustrated example and communicated with the plurality of holes 50 is also possible. As described above, the communication path 52 formed through the inside of the frame 31 communicates with the internal space of the spacer 1 defined by the two sheets 32 through the hole 50A, and one end thereof is connected to the connector 51. As exposed to the outside.

  In the spacer 1 of the first embodiment configured as described above, the connector 51 for connecting the air pipe 22 is provided on the frame 31, and the flexible sheet 32 is a sheet having a flat surface. Since it adheres to the joint surface 45, it becomes easy to ensure the adhesive strength and the sealing property. That is, it is not necessary to sandwich the tubular connector and join the two sheets as in the prior art. Since the sheet joining surface 45 is a simple flat surface, the sheet 32 can be joined by ultrasonic welding or high-frequency welding without using an adhesive. In addition, since there is no unevenness on the sheet bonding surface 45, it is easy to stick the flexible sheet 32 without wrinkles or slack, and transfer of wrinkles to the exterior body when the battery cell 2 is pressurized. Can be avoided.

  Further, since the two flexible sheets 32 are bonded and fixed at the periphery to a rectangular sheet-bonding surface 45, the sheet-bonding surface of each sheet 32 is introduced with the introduction and discharge of pressurized air. Although the region inside 45 expands and contracts, in the first embodiment, the sheet support wall 46 exists on the back side of the central portion of the sheet 32 that is displaced in this way. Therefore, when the sheet 32 is contracted, particularly when forced air bleeding is performed by the decompression mechanism of the air device 13, the sheet 32 pressed from the outside due to the pressure difference from the atmospheric pressure is supported by the sheet support wall 46, It is kept almost flat. Therefore, the phenomenon that wrinkles occur in the sheet 32 when contracted can be suppressed, and transfer of wrinkles to the exterior body when the battery cell 2 is pressurized in the next process cycle can be avoided.

  Further, the seat support wall 46 contributes to the improvement of the rigidity of the entire frame 31 and the entire spacer 1.

  Further, the sheet support wall 46 is retracted through a step with respect to the surrounding sheet bonding surface 45, and a slight gap 47 exists between the surface of the sheet support wall 46 and the sheet 32. Therefore, the pressurized air introduced from the communication path 52 through the hole 50 </ b> A spreads evenly throughout the internal space between the two sheets 32 through the gap 47 and the plurality of holes 50. Conversely, even when air is released, air is quickly released from the entire surface of the sheet 32 through the plurality of holes 50 and the gaps 47. Since the sheet 32 has flexibility, the gaps 47 are not actually uniformly formed. However, since the hole 50A through which the communication path 52 communicates is adjacent to the boundary 48 having a step, the vicinity of the hole 50A. The gap 47 is easily secured. That is, the opening surfaces at both ends of the hole 50A are not easily blocked by the sheet 32, and the introduction / discharge of the pressurized air is smooth.

  In the illustrated example, the connector 51 is formed so as to protrude in a tubular shape. However, the connector may be formed in the frame 31 in a screw hole shape, for example, and the air pipe 22 may be connected to the connector through another member, for example. Good.

  In the above embodiment, the sheet support wall 46 is relatively thin to form the gap 47, and a step is provided between the sheet bonding surface 45, but the peripheral edge of the sheet 32 (that is, on the sheet bonding surface 45). The gap 47 may be secured by partially forming a thick region) and joining the thick portion to the sheet joining surface 45. In this case, the sheet bonding surface 45 and the surface of the sheet support wall 46 can be flush with each other.

  Next, a second embodiment of the spacer 1 will be described with reference to FIGS. FIG. 8 is a front view of the spacer 1 according to the second embodiment, and FIG. 9 is a cross-sectional view of the frame 31 according to the second embodiment.

  In the second embodiment, a region surrounded by the sheet joining surface 45 of the frame 31 is formed as one rectangular opening 61. The side wall 37 of the frame 31 is provided with a connector 51 protruding in a tubular shape as in the first embodiment described above. The tip of the communication path 52 along the center of the connector 51 communicates with the opening 61. ing.

  Note that the sheet bonding surface 45 can also be configured on the same plane with no level difference from the surface at the periphery of the frame 31 (the portion not covered by the sheet 32).

  According to such a configuration, the weight of the frame 31 and the weight of the spacer 1 can be reduced as compared with the first embodiment.

DESCRIPTION OF SYMBOLS 1 ... Spacer 2 ... Battery cell 11 ... Housing 13 ... Air equipment 22 ... Air piping 31 ... Frame 32 ... Flexible sheet 45 ... Sheet joint surface 46 ... Sheet support wall 50 ... Hole 51 ... Connector 52 ... Communication path 61 ... Opening Part

Claims (7)

In a pressurizing device for a battery cell in which a power generation element is enclosed with an electrolytic solution inside an exterior body made of a laminate film and pressurizes a plurality of battery cells having a thin flat shape in the thickness direction in the thickness direction. A spacer that is disposed between the battery cells and expands in the thickness direction in response to the fluid pressure of the working fluid sealed inside;
A frame provided with a rectangular sheet-bonding surface on both sides;
Two flexible sheets respectively disposed on both sides of the frame and having a peripheral edge bonded to the sheet bonding surface;
A communication path formed through the inside of the frame so as to communicate with the internal space of the spacer defined by the two flexible sheets, and having one end exposed to the outside as a connector;
The spacer in the pressurizing device of the battery cell characterized by having. The frame has a plate-like portion having a plurality of holes in a region surrounded by the sheet joining surface,
The communication path communicates with at least one of the plurality of holes.
The spacer in the pressurization apparatus of the battery cell of Claim 1 characterized by the above-mentioned.   3. The pressurization of the battery cell according to claim 2, wherein there is a step at a boundary between the plate-like portion and the sheet joining surface, and the surface of the plate-like portion is positioned so as to recede from the sheet joining surface. Spacer in the device. In the frame, a region surrounded by the sheet joining surface is formed as one opening, and the communication path communicates with the opening.
The spacer in the pressurization apparatus of the battery cell of Claim 1 characterized by the above-mentioned.   The said frame is integrally molded with the hard synthetic resin, The spacer in the pressurization device of the battery cell in any one of Claims 1-4 characterized by the above-mentioned.   The said flexible sheet | seat consists of a cloth provided with the application layer which consists of soft synthetic resins, The spacer in the pressurization apparatus of the battery cell in any one of Claims 1-5 characterized by the above-mentioned.   The battery according to any one of claims 1 to 6, wherein the connector is formed in a tubular shape protruding along a direction orthogonal to the thickness direction on an outer surface of the side wall of the frame. Spacer in cell pressurizer.

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