JP3948449B2 - Battery pack and manufacturing method thereof - Google Patents

Description

  The present invention relates to a battery pack having a plurality of unit cells and a method for manufacturing the battery pack.

  In recent years, in response to growing environmental awareness, there is a movement to shift the power source of automobiles from an engine using fossil fuel to a motor using electric energy. Therefore, the technology of the battery that serves as the power source of the motor is also rapidly developing.

In a conventional assembled battery, flat cells connected in series and / or in parallel are stacked at a predetermined interval, and the whole is pressed through the cells located in the outermost layer and fixed by an exterior member. As a result, the heat dissipation characteristics of the unit cells are improved, and an assembled battery having good cycle characteristics and rate characteristics is obtained (for example, see Patent Document 1).
JP 2000-195480 A

  However, since a large number of flat unit cells are incorporated in the assembled battery, handling of the electrode tab (electrode terminal) of the unit cell requires a great deal of labor. For example, in order to prevent short-circuiting of electrode tabs of adjacent unit cells, it is necessary to separately arrange spacers, which increases the work man-hours and lowers productivity.

  The present invention has been made to solve the problems associated with the above-described prior art, and an object thereof is to provide an assembled battery having good productivity and a method for manufacturing the battery.

In order to achieve the above object, the invention described in claim 1
A battery pack in which plate-like first and second frames for holding flat unit cells are stacked, the unit cells are stacked, and electrode tabs of the stacked unit cells are joined together ,
The second frame is an assembled battery having insulating means made of an insulating member capable of exposing and shielding the electrode tab of the unit cell.

In order to achieve the above object, the invention according to claim 5 provides:
Laminating a second frame having an insulating means made of an insulating member that holds the unit cell and can expose and shield the electrode tab of the unit cell on the first frame that holds the unit cell;
Exposing the electrode tab of the unit cell that is shielded by the insulating means;
The exposed electrode tab is joined to the electrode tab of the unit cell held by the first frame,
The assembled electrode tab is shielded by the insulating means.

  The present invention configured as described above has the following effects.

According to the first aspect of the present invention, since it is possible to ensure the insulation of the electrode tab and the prevention of short circuit by the insulating means arranged in advance on the second frame, a member such as a spacer is arranged separately. There is no need to do. Further, since the insulating means does not hinder the joining of the electrode tabs, it is possible to maintain the workability of joining the electrode tabs. That is, an assembled battery with good productivity can be provided.

According to the fifth aspect of the present invention, the insulating property of the electrode tab and the prevention of short circuit are ensured by the insulating means arranged in advance on the second frame before and after the joining of the electrode tabs of the unit cells. It is not necessary to separately arrange such members. Further, since the insulating means does not hinder the joining of the electrode tab, the workability of joining the electrode tab is maintained. That is, it is possible to provide a method for manufacturing an assembled battery having good productivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view for explaining the assembled battery according to Embodiment 1. FIG.

  The assembled battery 10 according to the first embodiment includes a stacked unit 30 in which frames 40 that hold flat cells are stacked, and is disposed on both sides of the stacked unit 30 to press the stacked unit 30 from both sides in the stacking direction. A pressing plate 70 and a supporting plate 80 to be fixed, and a fixing means 90 for fixing the stacked portion 30 via the supporting plate 80 and the pressing plate 70. Reference numerals 15A and 15B are power terminals connected to, for example, a charging device or a power source (motor). Moreover, the code | symbol 23 is a nut for fixing the connection bolt mentioned later.

  The stacked unit 30 includes an intermediate plate 35 that is arranged for each predetermined number of frames 40. The fixing means 90 includes a nut 92 and a fastening bolt 94 that is screwed into the nut 92.

  FIG. 2 is a perspective view for explaining the cell according to the first embodiment.

  The unit cell 60 is a secondary battery such as a lithium ion battery, a solid electrolyte battery, or a gel electrolyte battery, and includes an outer case 62 made of a laminate film whose peripheral portions are joined by thermal welding, and an electrode tab drawn from the outer case 62 66 (66A, 66B). For heat welding, for example, ultrasonic welding can be applied. Note that in this embodiment, such a flat cell is simply referred to as a cell.

  The electrode tabs 66 </ b> A and 66 </ b> B have different polarities, extend from opposing end surfaces, and have through holes 67. The through-hole 67 is penetrated by a connecting bolt whose periphery is insulated. For example, the electrode tab 66A is a negative electrode tab formed from, for example, a thin plate-like copper having a plate thickness of about 0.2 mm, and the electrode tab 66B is a positive electrode formed from, for example, a thin plate-like aluminum having a plate thickness of about 0.2 mm. It is a tab.

The unit cell 60 is rectangular and flat, and has a convex portion 63 for accommodating the power generation element and a heat welding portion 64 for sealing the inside. The power generation element includes, for example, a positive electrode plate, a positive electrode current collector, a separator, a negative electrode plate, a negative electrode current collector, and an electrolytic solution (electrolyte). The positive electrode current collector is a member for connecting the positive electrode plate and one end of the electrode tab 66 </ b> B inside the single battery 60. The negative electrode current collector is a member for connecting the negative electrode plate and one end of the electrode tab 66 </ b> A inside the outer case 62. The outer surface of the unit cell 60 is formed of a laminate film.

  The material of the laminate film is not particularly limited, and examples thereof include a polymer-metal composite material formed by integrating an exterior protective layer made of a polymer film, a metal film layer, and a heat welding layer made of a polymer film. .

  3 is a perspective view for explaining the first frame according to the first embodiment, FIG. 4 is a perspective view for explaining the second frame according to the first embodiment, and FIG. FIG. 6 is a partially enlarged view for explaining the insulating means according to the first embodiment, and FIG. 7 relates to the line VII-VII in FIG. 6. It is sectional drawing.

  The frame 40 is made of, for example, polypropylene, and has a plurality of openings 42 for holding the unit cells 60 in parallel. A washer 44 that is aligned with the through hole 67 of the unit cell 60 through which the connecting bolt passes is embedded in the vicinity of the opening 42.

  As the washer 44, two kinds of a conductive washer of a conductive member and an insulating washer of an insulating member are applied. A frame 40 (first frame 40A) to which the conductive washer is applied and a frame 40 (second frame 40B) to which the insulating washer is applied are stacked in pairs. On the other hand, the other electrode tab 66 located on the opposite side of the washer 44 is joined by welding. Since welding in the first embodiment is a superposition joining of dissimilar metals of aluminum and copper, ultrasonic welding (ultrasonic pressure welding) is preferable.

  Therefore, by laminating the first frame 40A and the second frame 40B as a pair, the electrode tabs 66 of the single cells 60 arranged at the same position on the frame 40 are serially arranged in the laminating direction by welding and washers 44. It is connected.

  The frame 40 has through holes 46 and 48. The locating pin used for positioning the frame 40 passes through the through hole 46. The through bolt 48 of the fixing means 90 passes through the through hole 48.

  Furthermore, the second frame 40 </ b> B has a window part 50 for a tool for welding the electrode tab 66 to approach, and insulating means 55 arranged in advance in the window part 50.

  As shown in FIGS. 6 and 7, the insulating means 55 has an apron-like thin film 56. The thin film 56 is an insulating member, and extends into the window portion from the side 51 (see FIG. 6) of the window portion 50 facing the end surface of the electrode tab 66 to be welded (located on the opposite side of the washer 44). The electrode tab 66 is covered so as to be electrically shielded. The thin film 56 is able to expose the electrode tab 66 by rolling up with one end fixed to the side 51 as a fulcrum. In addition, when the plate | board thickness of the thin film 56 is thick and it is difficult to roll up, the groove part along the edge | side 51 may be formed and what is called a resin hinge may be provided.

  Therefore, the insulating means 55 can electrically shield the electrode tab 66 before and after the electrode tab 66 is joined, and can expose the electrode tab when the electrode tab 66 is joined.

  That is, in the first embodiment, it is possible to ensure the prevention of short-circuits with the electrode tabs of other unit cells adjacent in the stacking direction of the electrode tabs 66 by the insulating means 55 arranged in advance in the frame frame 40B. Therefore, there is no need to separately arrange a member such as a spacer. Further, the insulating means 55 can be lifted up with the side 51 as a fulcrum, and does not hinder the joining of the electrode tab 66, so that the workability of joining the electrode tab 66 can be maintained. .

  The thin film 56 is preferably formed integrally with the frame 40B, but is not particularly limited. For example, the thin film 56 can be separately fixed to the frame 40B by adhesion or welding. Further, the thin film 56 is not limited to being disposed in the window portion 50.

  Further, the insulating means 55 can freely expose and shield the electrode tab, that is, shield the electrode tab before and after joining the electrode tab, and expose the electrode tab when the electrode tab is joined. If possible, the structure is not limited to the structure having the thin film 56.

  FIG. 8 is a perspective view for explaining the support plate according to the first embodiment.

  The support plate 80 has a heat sink function on which the frame 40 is placed and absorbs heat generated from the unit cells 60 held by the frame 40 and dissipates to the outside. The support plate 80 has insertion holes 81 and 82, grooves 84 and 85, and a vent hole 88.

  One end of the locate pin 96 is fixed to the insertion hole 81. The locate pin 96 is inserted into the through hole 46 of the frame 40 and is used for positioning the frame 40.

  One end of the fastening bolt 94 is screwed into the insertion hole 82 and is directly fixed. Therefore, it is not necessary to arrange a nut for fixing the fastening bolt 94 on the support plate 80, and the assembled battery 10 can be reduced in size and weight.

  The grooves 84 and 85 have insertion holes for erecting the connecting bolts 22 </ b> A to 22 </ b> D, and bus bars 24 and 27 insulated from the support plate 80 are embedded therein. The bus bar is a connection conductor, which is made of, for example, copper, and is used for connecting in series a stack of unit cells formed in parallel. The bus bars 24 and 27 have through holes 25 and 28 that are aligned with insertion holes for erecting connection bolts provided in the grooves 84 and 85.

  That is, the connecting bolts 22 </ b> A to 22 </ b> D extend from the support plate 80 through the bus bars 24 and 27.

  The vent 88 extends through the support plate 80 in the longitudinal direction and improves the heat dissipation efficiency. Note that the vent 88 can be omitted as appropriate in consideration of the amount of heat generated by the unit cell 60 held by the frame 40.

  The constituent material of the support plate 80 is preferably copper, aluminum, magnesium or the like, and aluminum is particularly preferable in consideration of heat dissipation and weight reduction.

  FIG. 9 is a perspective view for explaining the intermediate plate according to the first embodiment.

  The intermediate plate 35 is provided at an appropriate interval, for example, every time six frames 40 are stacked, and has a heat sink function for absorbing the heat generated from the unit cells 60 held by the frame 40 and dissipating it to the outside. Have. The intermediate plate 35 has through holes 36 and 37 and an opening 38.

  The locate hole 96 penetrates the through hole 36, and the fastening bolt 94 penetrates the through hole 37. The opening 38 is provided with a conductive conductive member (not shown) that is electrically insulated from the intermediate plate 35, and the connecting bolts 22 </ b> A to 22 </ b> D pass through the conductive member. The conduction member is used to electrically connect the electrode tabs of the unit cells held by the frame 40 arranged with the intermediate plate 35 interposed therebetween.

  The constituent material of the intermediate plate 35 may be the same as that of the support plate 80, but it is also possible to apply resin in consideration of weight reduction. Moreover, it is preferable to improve heat dissipation efficiency by providing a vent hole.

  FIG. 10 is a perspective view for explaining the pressing plate according to the first embodiment. FIG. 11 is a perspective view for explaining a bus bar arranged on the back surface of the pressing plate in FIG. 10 (lower side of the pressing plate in FIG. 10).

  The pressing plate 70 has through holes 72, 73, 74, an opening 76, and a vent hole 78. The locate pin 96 passes through the through hole 72. One end of the fastening bolt 94 is inserted into the through hole 73. The threaded portion of the fastening bolt 94 protruding from the pressing plate 70 is screwed with the nut 92 to generate a pressing force in a direction in which the supporting plate 80 and the pressing plate 70 are close to each other, thereby pressing and fixing the stacked portion 30. To do.

  The connecting bolts 22 </ b> B and 22 </ b> C pass through the through hole 74. The opening 76 is power terminals 15A and 15B fixed to the upper ends of the connecting bolts 22A and 22D. The power terminals 15A and 15B are connected to the electrode tab of the uppermost unit cell among the stacked unit cells, and are used as output terminals when taking out the power of the assembled battery.

  The vent 78 extends through the support plate 80 in the longitudinal direction and improves the heat dissipation efficiency. The air vent 78 can be omitted as appropriate in consideration of the heat generation amount of the unit cell 60.

  The constituent material of the pressing plate 70 is preferably copper, aluminum, magnesium or the like, and aluminum is particularly preferable in consideration of heat dissipation and weight reduction.

  The pressing plate 70 has a groove (not shown) for embedding the bus bar 26 insulated from the pressing plate 70 on the surface facing the support plate 80 (that is, the back surface). The bus bar 26 has a through hole aligned with the through hole 74, and the connecting bolts 22B and 22C pass through.

  FIG. 12 is a wiring diagram for explaining a connection state of the unit cells according to the first embodiment.

As described above, the electrode tabs 66 of the single cells 60 arranged at the same position of the frame 40 are connected in series in the stacking direction by joining (welding) and a conductive washer, and an electrically independent stacked body is formed. Form. Since the frame 40 holds four unit cells 60, four stacked bodies are formed. That is, the stacked unit 30 in the first embodiment includes the four stacked bodies 20A to 20D.

The stacked bodies 20 </ b> A to 20 </ b> D are connected in series by bus bars 24, 26, and 27 disposed on the pressing plate 70 and the support plate 80.

  Specifically, the unit cell 60 located in the lowermost layer of the laminate 20A and the unit cell 60 located in the lowermost layer of the laminate 20B adjacent to the laminate 20A are connected by the bus bar 24 arranged on the support plate 80. Is done. The unit cell 60 positioned in the uppermost layer of the stacked body 20B and the unit cell 60 positioned in the uppermost layer of the stacked body 20C adjacent to the stacked body 20B are connected by the bus bar 26 disposed on the back surface of the pressing plate 70. .

  The unit cell 60 positioned in the lowermost layer of the stacked body 20C and the unit cell 60 positioned in the lowermost layer of the stacked body 20D adjacent to the stacked body 20C are connected by the bus bar 27 disposed on the support plate 80. The unit cell 60 positioned at the uppermost layer of the stacked body 20A and the unit cell 60 positioned at the uppermost layer of the stacked body 20D are connected to the power terminals 15A and 15B, respectively.

  As described above, all the unit cells 60 are connected in series, and the assembled battery 10 can supply a large amount of power.

  FIG. 13 is a cross-sectional view for explaining the electrode tab joining step in manufacturing the assembled battery.

  First, the second frame 40B to which the insulating washer is applied is stacked and placed on the first frame 40A to which the conductive washer stacked on the support plate 80 is applied. At this time, the locating pins 96 extending from the support plate 80 are inserted into the through holes 46 of the second frame 40B, thereby positioning the first frame 40A and the second frame 40B in the stacking direction.

  At this point, as shown in FIG. 7, the thin film 56 extending into the window from the side 51 of the window 50 of the second frame 40 </ b> B covers the electrode tab 66.

  Then, as shown in FIG. 13, the thin film 56 of the second frame 40 </ b> B is lifted with one end fixed to the side 51 as a fulcrum, thereby exposing the electrode tab 66 and welding the electrode tab 66. Tool 58 approaches through window 50. Therefore, since the thin film 56 does not hinder the bonding of the electrode tabs, the electrode tab bonding workability is maintained.

  For example, in ultrasonic welding, the tool 58 is a vibration transmission mechanism (solid horn) having a tip to which a welding tip for clamping the electrode tab 66 of the second frame 40B is attached, and the electrode of the first frame 40A. Tab 66 is supported by the lower platform.

  When the joining of the electrode tabs 66 is completed, the rolled up thin film 56 is returned and covers the joined electrode tabs 66, so that the first frame 40A and the second frame 40B are stacked as a pair in the stacking direction. It is possible to prevent a short circuit between adjacent electrode tabs without using a special member only for preventing a short circuit such as a spacer.

  And the lamination | stacking part 30 is formed by arrange | positioning the intermediate | middle plate 35 suitably, repeating lamination | stacking and joining of 1st frame 40A and 2nd frame 40B. In addition, the electrode tab 66 located on the opposite side of the joined electrode tab 66 is appropriately connected by a conductive washer and an insulating washer.

  As described above, in the first embodiment, it is possible to provide an assembled battery having good productivity and a manufacturing method thereof.

  FIG. 14 is a plan view for explaining a modification of the insulating means according to the first embodiment, and FIG. 15 is a sectional view taken along line XV-XV in FIG.

  The thin film 56 of the insulating means 55 is not limited to the structure extended from the side 51 of the window part 50 facing the end surface of the electrode tab 66. As shown in FIGS. 14 and 15, one end of the thin film 56 is fixed to the side 52 of the window 50 located in a direction intersecting the end surface of the electrode tab 66, and the other end of the thin film 56 is opposed to the side 52. It is also possible to extend the side 53 to cover the electrode tab 66. In this case, the electrode tab 66 is exposed by rolling up one end of the thin film 56 fixed to the side 52 as a fulcrum.

  16 is a plan view for explaining the insulating means according to the second embodiment, and FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG.

  Insulating means 55A according to the second embodiment includes an insulating plate member 56A that is disposed so as to protrude from the side 51 of the window 50 toward the inside (inside the window). Therefore, the insulating means 55A shields the electrode tab 66 by projecting the plate member 56A inward before and after the joining of the electrode tab 66, and the plate member when the electrode tab 66 is joined. The electrode tab can be exposed by retracting 56A toward the outside (outside the window).

  In other words, the plate member 56A previously disposed on the frame ensures the insulation of the electrode tab 66 and the prevention of a short circuit, so that a member such as a spacer need not be separately disposed. In addition, since the plate member 56A does not hinder the joining of the electrode tab 66, the workability of joining the electrode tab 66 can be maintained.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

3 is a perspective view for explaining the assembled battery according to Embodiment 1. FIG. FIG. 3 is a perspective view for explaining a single battery according to the first embodiment. 4 is a perspective view for explaining a first frame according to Embodiment 1. FIG. 4 is a perspective view for explaining a second frame according to Embodiment 1. FIG. It is a perspective view which shows the state holding the cell of the 1st frame and the 2nd frame. FIG. 3 is a partially enlarged view for explaining an insulating unit according to the first embodiment. It is sectional drawing regarding the line VII-VII of FIG. 3 is a perspective view for explaining a support plate according to Embodiment 1. FIG. 4 is a perspective view for explaining an intermediate plate according to Embodiment 1. FIG. 3 is a perspective view for explaining a pressing plate according to Embodiment 1. FIG. It is a perspective view for demonstrating the bus-bar arrange | positioned at the back surface of the press plate of FIG. FIG. 3 is a wiring diagram for explaining a connection state of unit cells according to the first embodiment. It is sectional drawing for demonstrating the joining process of the electrode tab in manufacture of an assembled battery. FIG. 6 is a plan view for explaining a modification of the insulating means according to the first embodiment. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14. 6 is a plan view for explaining an insulating means according to Embodiment 2. FIG. It is sectional drawing regarding line XVII-XVII of FIG.

Explanation of symbols

10 .... Battery,
15A, 15B ... Power terminal,
20A to 20D..Laminated body,
22 (22A-22D) .. Connection bolt,
24, 26, 27 ... busbar,
25, 28 ... through holes,
30. ・ Laminated part,
35 ... Intermediate plate,
36, 37 ... through holes,
38 .. opening,
40 (40A, 40B) .. frame,
40 ・ ・ Frame
42 .. opening,
44. Washer,
46,48 ... through holes,
50 ・ ・ Window part,
51,52..side,
55, 55A .. Insulation means,
56..Thin film,
56A..Plate member,
58 ・ ・ Tool,
60 ・ ・ Single cell,
62 .. Exterior case,
63 .. convex part,
64 .. heat welding part,
66 (66A, 66B) .. Electrode tab,
67 .. Through hole,
70 ..Pressing plate,
72, 73, 74 .. through hole,
76 .. Opening,
78. ・ Vents,
80 .. Support plate,
81, 82 .. insertion hole,
84, 85 .. groove,
88 ・ ・ Vents,
90 .. Fixing means,
92.Nut,
94 .. Fastening bolt,
96. Locate pin.

Claims (8)

A battery pack in which plate-like first and second frames for holding flat unit cells are stacked, the unit cells are stacked, and electrode tabs of the stacked unit cells are joined together ,
The assembled battery according to claim 2, wherein the second frame includes an insulating unit made of an insulating member capable of exposing and shielding the electrode tab of the unit cell. The electrode tabs of the stacked unit cells are joined by welding ,
The second frame is provided with a window for a tool for welding the electrode tabs of the stacked unit cells to approach , and the insulating means exposes the electrode tabs of the unit cells in the window unit. The assembled battery according to claim 1, wherein the battery pack is provided so as to be shieldable. The insulating means is an insulating thin film provided integrally with the second frame, extending from one side of the window portion into the window portion, and the thin film is rolled up so that the electrode tab is The assembled battery according to claim 2, wherein the battery pack can be exposed.   The insulating means is an insulating plate member disposed so as to protrude from one side of the window part into the window part, and the plate member shields the electrode tab by protruding into the window part. The assembled battery according to claim 2, wherein the electrode tab is exposed by retracting out of the window. Laminating a second frame having an insulating means made of an insulating member that holds the unit cell and can expose and shield the electrode tab of the unit cell on the first frame that holds the unit cell;
Exposing the electrode tab of the unit cell that is shielded by the insulating means;
The exposed electrode tab is joined to the electrode tab of the unit cell held by the first frame,
The assembled electrode tab is shielded by the insulating means. The method for manufacturing an assembled battery according to claim 5, wherein the joining is performed by welding. The insulating means is an insulating thin film that extends from one side of a window part to which a tool for welding the electrode tabs of the stacked unit cells approaches, and can shield the electrode tabs in the window part. The method of manufacturing an assembled battery according to claim 6, wherein the electrode tab is exposed by rolling up the thin film, and the electrode tabs are welded together. The insulating means is an insulative plate member disposed so as to protrude freely from one side of the window part to which a tool for welding the electrode tabs of the stacked unit cells approaches. The electrode tab is shielded by projecting a plate member inside the window, and the electrode tab is exposed by retreating out of the window, and the electrode tabs are welded and joined. A method for producing an assembled battery according to claim 6.

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