Tab film cutting method

Abstract

To provide a tab lead structure for a battery capable of suppressing the communication of the inside and the outside of a battery, the battery and a tab film cut method.SOLUTION: A battery 10 comprises: a tabular cathode-side current collection terminal 14 including a contact part 14A which can be brought into contact with a power supplied object and is disposed at the side of one end of the battery 10 in a first direction, and a base part 14B which is provided continuously to the contact part 14A at the side of a center of the battery 10 in the contact part 14A in the first direction; and a cathode-side tab film 18 in which a projection 18C protruding from a corner 14B1 provided in an end of the base part 14B in a second direction is formed and which is disposed around the base part 14B while being welded with the base part 14B.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to Ta This relates to a film cutting method. [Background technology]

[0002] Patent Document 1 below discloses an invention related to a secondary battery. In this secondary battery, the electrode assembly and electrolyte are covered with a sealing part including an exterior material and a pair of covers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-108623 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the prior art disclosed in Patent Document 1, the exterior material is folded to cover the side surfaces of the electrode assembly, and a pair of covers cover the ends of the electrode assembly. At the boundary between the exterior material and the cover, the exterior material covers the cover from the outside.

[0005] However, when the above-described configuration is adopted, it is conceivable that a gap will be generated between the corners of the folded exterior material and the cover, resulting in communication between the inside and outside of the battery.

[0006] In consideration of the above, the present invention provides a method for preventing communication between the inside and outside of a battery. Ruta The objective is to obtain a film cutting method. [Means for solving the problem]

[0018] Claim 1The tab film cutting method according to the present invention described in the item (1) includes: arranging a first film above a plate-shaped collector terminal; arranging an upper jig above the first film; arranging a second film below the collector terminal; arranging a lower jig below the second film; arranging a first horizontal jig having first protrusions protruding upward and downward on one side of the collector terminal in a thickness direction of the collector terminal when viewed from a first direction and in a second direction perpendicular to the first direction; temporarily fixing a third film to a portion on the other side of the first horizontal jig in the second direction in a curved or bent state so as to be convex toward the collector terminal; arranging a second horizontal jig having second protrusions protruding upward and downward on the other side of the collector terminal in the second direction; and pressing from above the upper jig and below the lower jig with a hot press.

[0019] Claim 1 According to the present invention described in the above, a first film is placed above a plate-shaped current collecting terminal, and an upper jig is placed above the first film. Also, a second film is placed below the current collecting terminal, and a lower jig is placed below the second film.

[0020] A first horizontal jig having first protrusions protruding above and below the current collector terminal is disposed on one side of the current collector terminal in a second direction perpendicular to the thickness direction of the current collector terminal as viewed from the first direction, and a third film is temporarily fixed to a portion of the first horizontal jig on the other side in the second direction in a curved or bent state so as to be convex toward the current collector terminal.

[0021] A second horizontal jig having second protrusions protruding above and below the current collecting terminal is disposed on the other side in the second direction with respect to the current collecting terminal. Then, the fourth film is temporarily fixed to a portion on one side in the second direction of the second horizontal jig in a curved or bent state so as to be convex toward the current collecting terminal.

[0022] In the present invention, by pressing from above the upper jig and from below the lower jig using a hot press in the above-mentioned state, the first film, the second film, the third film, and the fourth film are integrated to form a tab film around the collector terminal.

[0023] In addition, when the first film and the third film are sandwiched between the upper jig and the first protrusion on the upper jig side during pressing by the hot press, a protrusion that is thinner toward one side in the second direction is formed on the tab film, and the excess parts of the first film and the third film on one side in the second direction from the protrusion are melted and cut off by the heat of the hot press.

[0024] Similarly, the first film and the fourth film are sandwiched between the upper jig and the second protrusion on the upper jig side, so that a protrusion that is thinner toward the other side in the second direction is formed on the tab film. Then, the excess portions of the first film and the fourth film on the other side in the second direction from the protrusion are melted and cut off by the heat of the hot press.

[0025] In addition, when the second film and the third film are sandwiched between the lower jig and the first protrusion on the lower jig side during pressing by the hot press, a protrusion that is thinner toward one side in the second direction is formed on the tab film, and the excess portions of the second film and the third film on one side in the second direction from the protrusion are melted and cut off by the heat of the hot press.

[0026] Similarly, the second film and the fourth film are sandwiched between the lower jig and the second protrusion on the lower jig side, so that a protrusion that is thinner toward the other side in the second direction is formed on the tab film. Then, the excess portions of the second film and the fourth film on the other side in the second direction from the protrusion are melted and cut off by the heat of the hot press.

[0027] Then, by forming the protrusions on the tab film as described above, the protrusions of the tab film enter from the collector terminal side into the corners of the exterior material, such as a laminate sheet, attached to the collector terminal from the outside of the tab film. Therefore, in the present invention, it is possible to suppress the occurrence of gaps between the corners of the folded exterior material and the tab film. Effect of the Invention

[0028] As described above, the present invention Ruta The film cutting method has the excellent effect of preventing communication between the inside and outside of the battery. [Brief description of the drawings]

[0029] [Figure 1] FIG. 3 is an enlarged cross-sectional view (enlarged view of a portion surrounded by a two-dot chain line in FIG. 2) that shows a schematic configuration of a main part of a battery according to the present embodiment. [Diagram 2] 2 is a cross-sectional view (a cross-sectional view showing a state cut along line 2-2 in FIG. 3) that shows a schematic configuration of the periphery of a tab lead of the battery according to the present embodiment. [Diagram 3] FIG. 1 is a plan view illustrating a schematic configuration of a battery according to an embodiment of the present invention. [Figure 4] FIG. 1 is an explanatory diagram showing a schematic diagram of the attachment process of a tab film in a battery according to this embodiment, where (A) shows the first process, (B) shows the second process, (C) shows the third process, and (D) shows the fourth process. [Diagram 5] 4 is an enlarged cross-sectional view showing the configuration of a jig used in the attachment process of the tab film in the battery according to the present embodiment. FIG. [Figure 6] FIG. 1 is an explanatory diagram showing a schematic diagram of the process of attaching a laminate sheet in a battery according to this embodiment, where (A) shows the first process, (B) shows the second process, (C) shows the third process, and (D) shows the fourth process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an example of an embodiment of a "battery 10" to which the battery tab lead structure according to the present invention is applied will be described with reference to Figs. 1 to 6. As shown in Fig. 3, the battery 10 is, as an example, a laminated lithium ion secondary battery. In the following, the longitudinal direction of the battery 10 is referred to as a first direction, the lateral direction of the battery 10 is referred to as a second direction, and the thickness direction of the battery 10 is referred to as a third direction. In each drawing, the first direction is indicated by an arrow X, the second direction is indicated by an arrow Y, and the third direction is indicated by an arrow Z.

[0031] The battery 10 includes an electrode body 12, an electrolyte layer (not shown), a positive electrode collector terminal 14, a negative electrode collector terminal 16, a positive electrode tab film 18, a negative electrode tab film 20, and an exterior part 22.

[0032] In detail, the electrode body 12 is a laminated electrode body configured by stacking a plurality of sheet-shaped positive electrode bodies (not shown) and a plurality of sheet-shaped negative electrode bodies (not shown) in the third direction. The positive electrode bodies and the negative electrode bodies are alternately stacked in a state insulated from each other. Also, the positive electrode body and the negative electrode body may each be one sheet.

[0033] The positive electrode body includes a positive electrode current collector and a positive electrode active material layer provided on the surface of the positive electrode current collector. The positive electrode current collector is made of aluminum, for example. The positive electrode active material layer contains a positive electrode active material (for example, a lithium transition metal composite oxide such as a lithium nickel cobalt manganese composite oxide).

[0034] On the other hand, the negative electrode body includes a negative electrode current collector and a negative electrode active material layer provided on the surface of the negative electrode current collector. The material of the negative electrode current collector is, for example, copper. The negative electrode active material layer contains a negative electrode active material (for example, a carbon material such as graphite).

[0035] Furthermore, the electrode body 12 is provided with a positive electrode current collector tab and a negative electrode current collector tab (not shown). In detail, the positive electrode current collector tab is configured by a part of the positive electrode current collector extending to one side in the first direction, and the end face of the positive electrode current collector tab on one side in the first direction is in contact with the positive electrode side current collector terminal 14. In other words, the end face of the positive electrode current collector tab on one side in the first direction can be considered to constitute the side face of the electrode body 12 on one side in the first direction. It should be noted that no positive electrode active material layer is provided on the positive electrode current collector tab.

[0036] On the other hand, the negative electrode current collector tab is configured by a part of the negative electrode current collector extending in the other side in the first direction, and the end face of the negative electrode current collector tab on the other side in the first direction is in contact with the negative electrode current collector terminal 1. In other words, the end face of the negative electrode current collector tab on the other side in the first direction can be considered to constitute the side face of the electrode body 12 on the other side in the first direction. Note that no negative electrode active material layer is provided on the negative electrode current collector tab.

[0037] The electrolyte layer may be a liquid electrolyte layer, a gel electrolyte layer, a solid electrolyte layer, or the like, but in the present embodiment, as an example, the electrolyte layer is a solid electrolyte layer containing a solid electrolyte, and a major portion of the electrolyte layer is disposed between the positive electrode active material layer and the negative electrode active material layer. Note that the type of solid electrolyte is not particularly limited as long as it has ion conductivity.

[0038] In addition, when a liquid electrolyte layer is used, a separator that insulates the positive electrode active material layer from the negative electrode active material layer may be disposed between the positive electrode body and the negative electrode body. As the separator, for example, a sheet material made of a resin such as polyethylene (hereinafter referred to as PE) or polypropylene (hereinafter referred to as PP) can be used.

[0039] The positive electrode side current collector terminal 14 is made of aluminum and has a thin plate shape with the plate thickness direction being the third direction. This positive electrode side current collector terminal 14 includes a pair of "contact portions 14A" arranged on one end side in the first direction of the battery 10, and a "base portion 14B" provided continuously with the contact portions 14A on the central side of the battery 10 in the first direction.

[0040] The contact portion 14A is capable of coming into contact with a power-receiving object (not shown), and power is supplied from the battery 10 to the power-receiving object via the contact portion 14A.

[0041] On the other hand, the base portion 14B is joined to the positive electrode current collecting tab at a joint not shown by resistance welding or the like, with its end face on the other side in the first direction in contact with the end face on one side in the first direction of the positive electrode current collecting tab.

[0042] The negative electrode side current collector terminal 16 is made of copper and has a thin plate shape with the plate thickness direction being the third direction. This negative electrode side current collector terminal 16 includes a pair of "contact portions 16A" arranged on the other end side of the battery 10 in the first direction, and a "base portion 16B" provided continuously with the contact portions 16A on the central side of the battery 10 in the first direction.

[0043] The contact portion 16A is capable of coming into contact with a power-receiving object (not shown), and power is supplied from the battery 10 to the power-receiving object via the contact portion 16A.

[0044] On the other hand, the base portion 16B is joined to the negative electrode collector tab at a joint not shown by resistance welding or the like, with its end face on one side in the first direction in contact with the end face on the other side in the first direction of the negative electrode collector tab.

[0045] 1 and 2, the positive electrode side tab film 18 is disposed in close contact with the periphery of the base portion 14B of the positive electrode side current collecting terminal 14. The positive electrode side tab film 18 as a whole has a rectangular tubular shape with the axial direction being the first direction, and is configured to include a surface layer 18A that constitutes the surface side portion, and a welding layer 18B that constitutes the base portion 14B side portion and is welded to the base portion 14B.

[0046] The surface layer 18A is made of a resin such as polyethylene terephthalate (hereinafter referred to as PET) that has excellent water resistance, moisture resistance, and gas barrier properties, and the welding layer 18B is made of a resin such as PP that has excellent thermal welding properties.

[0047] In this embodiment, in a cross section of the positive electrode side tab film 18 viewed from the first direction, four "protrusions 18C" are formed on the positive electrode side tab film 18. In detail, the protrusions 18C are provided for each of the "corners 14B1" at an end portion on one side in the second direction and an end portion on the other side in the second direction of the base portion 14B of the positive electrode side current collecting terminal 14.

[0048] Furthermore, the protrusion 18C provided at the corner 14B1 on one side in the second direction protrudes from the corner 14B1 towards one side in the second direction and becomes thinner towards the one side in the second direction.

[0049] On the other hand, the protrusion 18C provided at the corner 14B1 on the other side in the second direction protrudes from the corner 14B1 toward the other side in the second direction and becomes thinner toward the other side in the second direction.

[0050] The negative electrode side tab film 20 has a similar structure to the positive electrode side tab film 18, and is disposed in close contact with the periphery of the base portion 16B of the negative electrode side current collecting terminal 16. Although not shown in detail, the negative electrode side tab film 20 is also provided with four "projections 20A" like the positive electrode side tab film 18.

[0051] The exterior portion 22 is mainly constituted by folding a single "laminate sheet 24" into a rectangular tube shape with the axial direction as the first direction, and although not shown in detail, is constituted by laminating a protective layer, a metal layer, and a welding layer in that order from the outside of the battery 10.

[0052] The protective layer is made of a resin such as nylon or PET, the metal layer is made of aluminum or stainless steel, and the welding layer is made of a resin such as PP or PE.

[0053] In this embodiment, the laminate sheet 24 is folded, so that four corners 24A are formed in the laminate sheet 24 in a cross section of the laminate sheet 24 viewed from the first direction. The protrusions 18C of the positive electrode side tab film 18 or the protrusions 20A of the negative electrode side tab film 20 are inserted into these corners 24A, respectively.

[0054] (Actions and Effects of the Present Embodiment) Next, the operation and effects of this embodiment will be described.

[0055] 3, the present embodiment includes a plate-shaped positive electrode side current collecting terminal 14 including a contact portion 14A and a base portion 14B. The contact portion 14A is disposed on one end side in the first direction of the battery 10 and is capable of coming into contact with an object to be supplied with power.

[0056] On the other hand, the base portion 14B is provided contiguous with the contact portion 14A on the central side of the contact portion 14A in the first direction of the battery 10. A positive electrode side tab film 18 is disposed around the periphery of the base portion 14B in a state where it is welded to the base portion 14B.

[0057] Incidentally, when an exterior material such as a laminate sheet is attached to the outside of the positive electrode side tab film 18 on the base portion 14B, depending on how the exterior material is folded, a gap may occur between the corner of the folded exterior material and the positive electrode side tab film 18.

[0058] Here, in this embodiment, as shown in FIG. 1, a protrusion 18C is formed on the positive electrode side tab film 18, and this protrusion 18C protrudes from a corner 14B1 provided at the end of the base portion 14B in the second direction.

[0059] For this reason, in this embodiment, the protrusion 18C of the positive electrode side tab film 18 fits into the corner 24A of the folded laminate sheet 24 from the positive electrode side current collecting terminal 14 side, thereby preventing a gap from occurring between the corner 24A of the folded laminate sheet 24 and the positive electrode side tab film 18.

[0060] In this embodiment, the protrusion 18C of the positive electrode side tab film 18 protrudes in the second direction from a corner 14B1 provided at the end of the base portion 14B in the second direction. Therefore, when the batteries 10 are stacked in the third direction, the direction in which the batteries 10 are stacked is different from the direction in which the corner 24A of the laminate sheet 24 into which the protrusion 18C of the positive electrode side tab film 18 is inserted protrudes, thereby preventing the corner 24A of the laminate sheet 24 of one battery 10 from interfering with the other battery 10.

[0061] The above-mentioned functions and effects are similarly achieved between the negative electrode tab film 20 and the laminate sheet 24.

[0062] Next, the process of attaching the positive electrode side tab film 18 and the negative electrode side tab film 20 and the process of attaching the laminate sheet 24 will be described mainly with reference to Figures 4 to 6. Since the process of attaching the positive electrode side tab film 18 and the process of attaching the negative electrode side tab film 20 are similar processes, only the process of attaching the positive electrode side tab film 18 will be described with reference to the process of attaching the positive electrode side tab film 18 and the negative electrode side tab film 20.

[0063] 4(A), in the process of attaching the positive electrode tab film 18, a "first film 26" is arranged on the upper side in the third direction of the base portion 14B of the positive electrode collector terminal 14 so that the PET layer is on the opposite side of the positive electrode collector terminal 14. Then, a plate-shaped "upper jig 28" is arranged on the upper side in the third direction of this first film 26 so as to cover the base portion 14B when viewed from the third direction.

[0064] Furthermore, a "second film 30" is disposed below the base portion 14B in the third direction such that the PET layer is opposite the positive electrode-side current collecting terminal 14. A plate-shaped "lower jig 32" is disposed below the second film 30 in the third direction such that it covers the base portion 14B when viewed from the third direction.

[0065] Also, a plate-like "first horizontal jig 34" whose thickness in the third direction is approximately the same as the thickness of the base portion 14B in the third direction is disposed on one side in the second direction with respect to the base portion 14B.

[0066] 5, a pair of first protrusions, ie, "protrusions 34A" protruding in the third direction, are provided on the end of the first horizontal jig 34 on the other side in the second direction. In more detail, the protrusions 34A have rounded or squared corners 34A1 on one side in the second direction and the other side in the second direction.

[0067] Then, the "third film 36" is temporarily fixed to the other side of the first horizontal jig 34 in the second direction in a curved or bent state so as to be convex toward the positive electrode side collector terminal 14, and with the PET layer facing away from the positive electrode side collector terminal 14.

[0068] Further, a "second horizontal jig 38" having a similar configuration to the first horizontal jig 34 is disposed on the other side in the second direction with respect to the base portion 14B. Note that at this time, a pair of "projections 38A" as second projections provided on the second horizontal jig 38 are located on the positive electrode side current collecting terminal 14 side.

[0069] Then, the "fourth film 40" is temporarily fixed to one side of the second direction of the second horizontal jig 38 in a curved or bent state so as to be convex toward the positive electrode side collector terminal 14, and with the PET layer facing away from the positive electrode side collector terminal 14.

[0070] 4(B), the upper jig 28, the lower jig 32, the first horizontal jig 34, and the second horizontal jig 38 are arranged in predetermined positions. In this state, the first film 26 and the second film 30 are in contact with the third film 36 and the fourth film 40, respectively.

[0071] 4(C), a "hot press 42" is used to press from above in the third direction of the upper jig 28 and from below in the third direction of the lower jig 32. As a result, the first film 26, the second film 30, the third film 36, and the fourth film 40 are integrated together to form the positive electrode side tab film 18 around the base portion 14B.

[0072] At this time, the first film 26 and the third film 36 are sandwiched between the upper jig 28 and the protrusion 34A on the upper jig 28 side, so that a protrusion 18C that is thinner toward one side in the second direction is formed in the positive electrode side tab film 18. The boundary between this protrusion 18C and the excess parts of the first film 26 and the third film 36 on one side in the second direction from the protrusion 18C is melted by the heat of the hot press 42 and becomes cut or thinned.

[0073] Similarly, by sandwiching the first film 26 and the fourth film 40 between the upper jig 28 and the protrusion 38A on the upper jig 28 side, a protrusion 18C that is thinner toward the other side in the second direction is formed in the positive electrode side tab film 18. The boundary between this protrusion 18C and the excess parts of the first film 26 and the fourth film 40 on the other side in the second direction from the protrusion 18C is melted by the heat of the hot press 42 and becomes cut or thinned.

[0074] At this time, the second film 30 and the third film 36 are sandwiched between the lower jig 32 and the protrusion 34A on the lower jig 32 side, so that a protrusion 18C that is thinner toward one side in the second direction is formed in the positive electrode side tab film 18. The boundary between this protrusion 18C and the excess parts of the second film 30 and the third film 36 on one side in the second direction from the protrusion 18C is melted by the heat of the hot press 42 and becomes cut or thinned.

[0075] Similarly, by sandwiching the second film 30 and the fourth film 40 between the lower jig 32 and the protrusion 38A on the lower jig 32 side, a protrusion 18C that is thinner toward the other side in the second direction is formed in the positive electrode side tab film 18. The boundary between this protrusion 18C and the excess parts of the second film 30 and the fourth film 40 on the other side in the second direction from the protrusion 18C is melted by the heat of the hot press 42 and becomes cut or thinned.

[0076] Next, in the fourth step shown in FIG. 4(D), the upper jig 28, the lower jig 32, the first horizontal jig 34, and the second horizontal jig 38 are removed, and the excess portions of the first film 26, the second film 30, the third film 36, and the fourth film 40 are removed from the positive electrode side tab film 18.

[0077] 6(A), the laminate sheet 24 is placed on a lower jig 44. In detail, with one end 24B of the laminate sheet 24 placed on the upper surface of the lower jig 44, approximately half of the laminate sheet 24 is pressed into a recess 44A provided in the lower jig 44.

[0078] 6(B), a composite 46 in which the electrode body 12, electrolyte layer, positive electrode side current collector terminal 14, negative electrode side current collector terminal 16, positive electrode side tab film 18, and negative electrode side tab film 20 are integrated is placed in the recess 44A so that the composite 46 is on the upper side of the laminate sheet 24. Then, an upper jig 47 is placed on the upper side of the lower jig 44 in a state in which about half of the laminate sheet 24 covers the upper side of the composite 46 and the other end 24C of the laminate sheet 24 is on the upper side of one end 24B.

[0079] Next, in a third step shown in FIG. 6(C), the laminate sheet 24 is pressed against the composite body 46 in the second direction by a clamp 48.

[0080] Next, in the fourth step shown in Figure 6 (D), the laminate sheet 24 is pressed toward the composite 46 from the upper side in the third direction and the lower side in the third direction at both ends of the composite 46 in the first direction with a heat bar 50, thereby welding the laminate sheet 24 to the composite 46.

[0081] 1, at one end side in the first direction of the composite body 46, the protrusion 18C of the positive electrode side tab film 18 fits into the corner 24A of the laminate sheet 24 from the positive electrode side current collector terminal 14 side. This is also true between the negative electrode side tab film 20 and the laminate sheet 24. For this reason, in this embodiment, it is possible to suppress the occurrence of gaps between the corner 24A of the folded laminate sheet 24 and the positive electrode side tab film 18 and the negative electrode side tab film 20.

[0082] As described above, in this embodiment, communication between the inside and outside of the battery 10 can be prevented.

[0083] <Supplementary explanation of the above embodiment> (1) In the above-described embodiment, the protrusion of the tab film protrudes in the second direction from the corner provided at the end of the base portion of the current collecting terminal in the second direction. However, depending on the specifications of the battery 10, the protrusion of the tab film may be configured to protrude in a third direction.

[0084] (2) In the above embodiment, four protrusions are provided for one tab film, but the configuration of the tab film is not limited to this. For example, if the laminate sheet is curved at a portion where the corners provided at the end of the base portion of the current collecting terminal in the second direction are rounded, a configuration in which no protrusions are provided at the corners of the tab film corresponding to these portions may be adopted. [Explanation of symbols]

[0085] 10 batteries 14 Positive collector terminal (collector terminal) 14A contact part 14B Base 14B1 Corner 16 Negative collector terminal (collector terminal) 16A contact part 16B Base 18 Positive electrode tab film (tab film) 18C protrusion 20 Negative electrode tab film (tab film) 24 Laminate sheet 26 1st Film 28 Upper jig 30 2nd Film 32 Lower jig 34 1st horizontal jig 34A Protrusion 36 Third Film 38 2nd horizontal jig 38A Protrusion 40 Fourth Film 42 Hot Press

Claims

[Claim 1] A first film is disposed above a plate-shaped current collecting terminal; An upper jig is disposed above the first film; A second film is disposed below the current collecting terminal; A lower jig is disposed below the second film; a first horizontal jig provided with a first protrusion protruding upward and downward is disposed on one side of the current collector terminal in a thickness direction of the current collector terminal and in a second direction perpendicular to the first direction when viewed from a first direction; a third film is temporarily fixed to a portion of the first horizontal jig on the other side in the second direction in a curved or bent state so as to be convex toward the current collecting terminal; a second horizontal jig provided with second protrusions protruding upward and downward is disposed on the other side in the second direction with respect to the current collecting terminal; In a state where the fourth film is temporarily fixed to the portion on one side in the second direction of the second horizontal jig in a curved or bent state so as to be convex toward the current collecting terminal, Pressing the upper jig from above and the lower jig from below with a hot press; How to cut tab film.

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