Battery

Abstract

To obtain a battery tab lead structure capable of preventing communication between the inside and outside of a battery, and a battery.SOLUTION: A battery 10 includes a plate-shaped positive electrode side current collecting terminal 14 including a contact portion 14A that is capable of contacting an object to be supplied with power and that is arranged at one end side of the battery 10 in the first direction, and a base portion 14B that is arranged contiguous to the contact portion 14A on the central side of the battery 10 in the first direction of the contact portion 14A, and a positive electrode side tab film 18 that has a protrusion portion 18C protruding from a corner portion 14B1 that is arranged at the end portion of the base portion 14B in the second direction and is arranged around the base portion 14B in a welded state to the base portion 14B.SELECTED DRAWING: Figure 1

Description

Technical Field

[0015] , , pond ,

[0006]

[0001] The present invention relates to electricity In the pond related.

Background Art

[0002] In the following Patent Document 1, an invention related to a secondary battery is disclosed. In this secondary battery, its electrode assembly and electrolyte are covered by a sealing portion including an exterior material and a pair of covers.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the prior art according to the above Patent Document 1, the exterior material is bent to cover the side surface of the electrode assembly, and the pair of covers cover the end portions of the electrode assembly. And at the boundary portion between the exterior material and the cover, the exterior material covers the cover from the outside of the cover.

[0005] However, when adopting the above - mentioned configuration, a gap may occur between the corner portion of the bent exterior material and the cover, and it is conceivable that the inside and outside of the battery are communicated.

[0006] In consideration of the above facts, an object of the present invention is to obtain an electricity pond that can suppress the communication between the inside and outside of the battery.

Means for Solving the Problems

[0015] Claim 1The battery according to the present invention, as described above, comprises an electrode body, a current collector terminal in contact with one side surface of the electrode body in the first direction, and a covering that covers the other side of the electrode body and the current collector terminal in the first direction. 1 sheet Laminate sheet, welding layer and said welding layer The resin that makes up the structure and types A tab film comprising a surface layer composed of different resins, The laminate sheet has a welded portion where opposing parts are welded together, The tab film is interposed between the current collection terminal and the laminate sheet, and extends from the corners provided at the ends of the current collection terminal in the first direction and the second direction perpendicular to the thickness direction of the current collection terminal. It protrudes in the second direction and is thinned out in the second direction toward the opposite side of the corner. Equipped with a protrusion, The aforementioned tab film is Around the current collection terminal, the current collection terminal and the laminate sheet The protrusion is welded to the welded portion, and a part of the protrusion is embedded in the welded portion.

[0016] Claim 1 According to the present invention as described above, a current collector terminal is in contact with one side surface of the electrode body in the first direction, and the other side of the electrode body and the current collector terminal in the first direction is covered with a laminate sheet. A tab film is interposed between the current collector terminal and the laminate sheet, and this tab film is welded to the current collector terminal and the laminate sheet around the current collector terminal.

[0017] In this invention, ,Ta The tab film has a projection that extends from the corner located at the second end of the current collection terminal. As a result, the projection of the tab film fits into the corner of the folded laminate sheet from the current collection terminal side, preventing a gap from forming between the corner of the folded laminate sheet and the tab film. The battery according to claim 2 is the invention according to claim 1, wherein the welded portion is formed by welding the portion of the laminate sheet that is bent so that it overlaps in the thickness direction. The battery according to claim 3 is the invention according to claim 1 or claim 2, wherein at least one of the surfaces on one side in the thickness direction and the other side in the thickness direction of the welded portion is a flat surface. [Effects of the Invention]

[0018] As explained above, the electric The pond It has the excellent effect of preventing communication between the inside and outside of the battery. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic enlarged cross-sectional view showing the configuration of the main parts of the battery according to this embodiment (an enlarged view of the area enclosed by the dashed line in Figure 2). [Figure 2] This is a schematic cross-sectional view showing the configuration around the tab leads of the battery according to this embodiment (a cross-sectional view showing the state when cut along line 2-2 in Figure 3). [Figure 3] This is a schematic plan view showing the configuration of the battery according to this embodiment. [Figure 4] This diagram schematically illustrates the tab film attachment process in the battery according to this embodiment, where (A) shows the first step, (B) shows the second step, (C) shows the third step, and (D) shows the fourth step. [Figure 5] This is an enlarged cross-sectional view showing the configuration of a jig used in the tab film attachment process for the battery according to this embodiment. [Figure 6] This diagram schematically illustrates the process of attaching the laminate sheet in the battery according to this embodiment, where (A) shows the first step, (B) shows the second step, (C) shows the third step, and (D) shows the fourth step. [Modes for carrying out the invention]

[0020] Hereinafter, an example of an embodiment of a "battery 10" to which the tab-lead structure of the battery according to the present invention is applied will be described using Figures 1 to 6. As shown in Figure 3, the battery 10 is, for example, a laminate-type lithium-ion secondary battery. Hereafter, the longitudinal direction of the battery 10 will be referred to as the first direction, the short direction of the battery 10 as the second direction, and the thickness direction of the battery 10 as the third direction. In each figure, the first direction is indicated by arrow X, the second direction by arrow Y, and the third direction by arrow Z.

[0021] The battery 10 includes an electrode body 12, an electrolyte layer (not shown), a "positive electrode current collector terminal 14", a "negative electrode current collector terminal 16", a "positive electrode tab film 18", a "negative electrode tab film 20", and an exterior portion 22.

[0022] Specifically, the electrode body 12 is a laminated electrode body formed by laminating a plurality of sheet-shaped positive electrode bodies (not shown) and a plurality of sheet-shaped negative electrode bodies (not shown) in a third direction. The positive electrode bodies and the negative electrode bodies are alternately laminated in a state of being insulated from each other. Also, each of the positive electrode body and the negative electrode body may be one sheet.

[0023] The positive electrode body includes a positive electrode current collector and a positive electrode active material layer provided on its surface. As an example, aluminum is adopted as the material of the positive electrode current collector. The positive electrode active material layer contains a positive electrode active material (for example, a lithium transition metal composite oxide such as lithium nickel cobalt manganese composite oxide).

[0024] On the other hand, the negative electrode body includes a negative electrode current collector and a negative electrode active material layer provided on its surface. As an example, copper is adopted as the material of the negative electrode current collector. The negative electrode active material layer contains a negative electrode active material (for example, a carbon material such as graphite).

[0025] Furthermore, the electrode body 12 is provided with a positive electrode current collecting tab and a negative electrode current collecting tab (not shown). Specifically, the positive electrode current collecting tab is formed by a part of the positive electrode current collector extending to one side in the first direction, and the end face on one side in the first direction of the positive electrode current collecting tab is in contact with the positive electrode current collector terminal 14. That is, the end face on one side in the first direction of the positive electrode current collecting tab can be regarded as constituting the side face on one side in the first direction of the electrode body 12. Note that the positive electrode active material layer is not provided on the positive electrode current collecting tab.

[0026] On the other hand, the negative electrode current collector tab is constructed by having a portion of the negative electrode current collector body extend to 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 surface of the electrode body 12 on the other side in the first direction. Note that the negative electrode current collector tab is not provided with a negative electrode active material layer.

[0027] The electrolyte layer can be a liquid electrolyte layer, a gel-type electrolyte layer, or a solid electrolyte layer. In this embodiment, as an example, the electrolyte layer is a solid electrolyte layer containing a solid electrolyte, and the main part of the electrolyte layer is located between the positive electrode active material layer and the negative electrode active material layer. The type of solid electrolyte is not particularly limited as long as it has ionic conductivity.

[0028] Furthermore, when a liquid electrolyte layer is used, a separator may be placed between the positive electrode and the negative electrode to insulate the positive electrode active material layer from the negative electrode active material layer. 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.

[0029] The positive electrode current collector terminal 14 is made of aluminum and is a thin plate with its thickness direction as the third direction. This positive electrode current collector terminal 14 is composed of 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 side of the central part of the battery 10 in the first direction.

[0030] The contact portion 14A is capable of contacting a powered object (not shown), and power is supplied from the battery 10 to the powered object via the contact portion 14A.

[0031] On the other hand, the base portion 14B is joined to the positive electrode current collector tab by a joint (not shown) such as resistance welding, with the other end face of the base portion 14B in contact with the end face of the positive electrode current collector tab on one side in the first direction.

[0032] The negative electrode current collector terminal 16 is made of copper and is a thin plate with its thickness direction as the third direction. This negative electrode current collector terminal 16 is composed of a pair of "contact portions 16A" arranged on the other end side in the first direction of the battery 10, and a "base portion 16B" provided continuously with the contact portions 16A on the central side of the contact portions 16A in the first direction of the battery 10.

[0033] The contact portion 16A is capable of contacting a powered object (not shown), and power is supplied from the battery 10 to the powered object via the contact portion 16A.

[0034] On the other hand, the base portion 16B is joined to the negative electrode current collector tab by a joint (not shown) such as resistance welding, with one end face on the first direction in contact with the other end face on the first direction of the negative electrode current collector tab.

[0035] As shown in Figures 1 and 2, the positive electrode tab film 18 is positioned in close contact with the base portion 14B of the positive electrode current collector terminal 14. The positive electrode tab film 18 as a whole is shaped like a rectangular tube with its axial direction as the first direction, and is composed of a surface layer 18A that constitutes the surface side and a welded layer 18B that constitutes the base portion 14B side and is welded to the base portion 14B.

[0036] The surface layer 18A is made of a resin with excellent water resistance, moisture resistance, and gas barrier properties, such as polyethylene terephthalate (hereinafter referred to as PET), and the welded layer 18B is made of a resin such as PP with excellent heat weldability.

[0037] In this embodiment, four "projections 18C" are formed on the positive electrode tab film 18 in a cross-section viewed from the first direction. Specifically, the projections 18C are provided for each "corner portion 14B1" at one end of the base portion 14B of the positive electrode current collector terminal 14 in the second direction and the other end in the second direction.

[0038] Furthermore, the projection 18C provided on the corner 14B1 on one side in the second direction protrudes from the corner 14B1 in the direction of the second direction and is made thinner as it approaches that direction.

[0039] On the other hand, the projection 18C provided on the corner 14B1 on the other side in the second direction protrudes from the corner 14B1 on the other side in the second direction and is made thinner as it extends toward the other side in the second direction.

[0040] The negative electrode tab film 20 has the same configuration as the positive electrode tab film 18 and is positioned in close contact with the base portion 16B of the negative electrode current collection terminal 16. Although not shown in detail in the diagram, the negative electrode tab film 20 is also provided with four "projections 20A" similar to the positive electrode tab film 18.

[0041] The outer casing 22 is mainly composed of a single laminate sheet 24 that is folded into a rectangular tube shape with the axial direction as the first direction. Although not shown in detail, it is composed of a protective layer, a metal layer, and a welded layer stacked in order from the outside of the battery 10.

[0042] The protective layer is made of resins such as nylon and PET, the metal layer is made of aluminum and stainless steel, and the welding layer is made of resins such as PP and PE.

[0043] Furthermore, in this embodiment, when the laminate sheet 24 is folded, four corners 24A are formed on the laminate sheet 24 in a cross-section viewed from the first direction. The projections 18C of the positive electrode tab film 18 or the projections 20A of the negative electrode tab film 20 are inserted into these corners 24A, respectively.

[0044] (Operation and effects of this embodiment) Next, the operation and effects of this embodiment will be described.

[0045] In this embodiment, as shown in Figure 3, a plate-shaped positive electrode side current collector terminal 14 is provided, which includes a contact portion 14A and a base portion 14B. The contact portion 14A is positioned on one end side in the first direction of the battery 10 and is capable of contacting the power supply object.

[0046] On the other hand, the base portion 14B is provided continuously with the contact portion 14A on the first-direction central side of the battery 10 at the contact portion 14A. The positive electrode tab film 18 is arranged around the base portion 14B, welded to the base portion 14B.

[0047] By the way, when attaching an outer covering material such as a laminate sheet to the base portion 14B from the outside of the positive electrode tab film 18, depending on how the outer covering material is folded, a gap may occur between the corner of the folded outer covering material and the positive electrode tab film 18.

[0048] In this embodiment, as shown in Figure 1, a projection 18C is formed on the positive electrode tab film 18, and this projection 18C protrudes from a corner portion 14B1 provided at the end of the base portion 14B in the second direction.

[0049] Therefore, in this embodiment, the projection 18C of the positive electrode tab film 18 enters the corner 24A of the folded laminate sheet 24 from the positive electrode side current collection terminal 14 side, thereby preventing a gap from forming between the corner 24A of the folded laminate sheet 24 and the positive electrode side tab film 18.

[0050] Furthermore, in this embodiment, the projection 18C of the positive electrode tab film 18 protrudes in the second direction from the 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 overlap and the direction in which the corner 24A of the laminate sheet 24 into which the projection 18C of the positive electrode tab film 18 is inserted protrude are made different, thereby suppressing interference between the corner 24A of the laminate sheet 24 of one battery 10 and the other battery 10.

[0051] Furthermore, the same effects and behaviors described above also apply between the negative electrode tab film 20 and the laminate sheet 24.

[0052] Next, the mounting process for the positive electrode tab film 18 and the negative electrode tab film 20, and the mounting process for the laminate sheet 24 will be explained, mainly using Figures 4 to 6. Since the mounting process for the positive electrode tab film 18 and the mounting process for the negative electrode tab film 20 are the same, only the mounting process for the positive electrode tab film 18 will be explained.

[0053] In the installation process for the positive electrode tab film 18, in the first step shown in Figure 4(A), the "first film 26" is placed on the upper side of the base portion 14B of the positive electrode current collector terminal 14 in the third direction, such that the PET layer is on the opposite side of the positive electrode current collector terminal 14. Then, a plate-shaped "upper jig 28" is placed on the upper side of the first film 26 in the third direction so as to cover the base portion 14B when viewed from the third direction.

[0054] Furthermore, the "second film 30" is placed on the lower side of the base portion 14B in the third direction, such that the PET layer is on the opposite side of the positive electrode current collection terminal 14. Then, a plate-shaped "lower jig 32" is placed on the lower side of the second film 30 in the third direction so as to cover the base portion 14B when viewed from the third direction.

[0055] Furthermore, a plate-shaped "first lateral 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 placed on one side of the base portion 14B in the second direction.

[0056] As also shown in Figure 5, the end of the first horizontal jig 34 on the other side in the second direction is provided with a pair of first projections, or "projections 34A", that protrude in the third direction. Specifically, the corners 34A1 on one side in the second direction and the other side in the second direction are rounded or chamfered.

[0057] Then, the "third film 36" is temporarily fixed to the other side of the first horizontal jig 34 in the second direction, in a state where it is curved or bent so as to be convex toward the positive electrode current collection terminal 14, and the PET layer is on the opposite side of the positive electrode current collection terminal 14.

[0058] Furthermore, a "second horizontal jig 38," which has the same configuration as the first horizontal jig 34, is positioned on the other side of the base portion 14B in the second direction. In this case, the pair of "projections 38A" provided on the second horizontal jig 38, which serve as second projections, are located on the positive electrode side current collection terminal 14 side.

[0059] Then, the "fourth film 40" is temporarily fixed to one side of the second direction of the second lateral jig 38 in a curved or bent state so as to be convex toward the positive electrode current collection terminal 14, and with the PET layer on the opposite side of the positive electrode current collection terminal 14.

[0060] Next, in the second step shown in Figure 4(B), the upper jig 28, the lower jig 32, the first horizontal jig 34, and the second horizontal jig 38 are positioned in predetermined locations. 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.

[0061] Next, in the third step shown in Figure 4(C), the upper jig 28 is pressed from the upper side in the third direction and the lower jig 32 is pressed from the lower side in the third direction using a "hot press 42". As a result, the first film 26, the second film 30, the third film 36, and the fourth film 40 are integrated, and the positive electrode tab film 18 is formed around the base portion 14B.

[0062] At this time, the first film 26 and the third film 36 are sandwiched between the upper jig 28 and the projection 34A on the upper jig 28 side, so that a projection 18C is formed on the positive electrode tab film 18 that becomes thinner as it moves toward one side in the second direction. The boundary between this projection 18C and the excess portion of the first film 26 and the third film 36 toward one side in the second direction from the projection 18C is melted by the heat of the hot press 42 and cut or thinned.

[0063] Similarly, the first film 26 and the fourth film 40 are sandwiched between the upper jig 28 and the projection 38A on the upper jig 28 side, forming a projection 18C on the positive electrode tab film 18 that becomes thinner as it extends toward the other side in the second direction. The boundary between this projection 18C and the excess portion of the first film 26 and the fourth film 40 beyond the projection 18C in the second direction is melted and cut or thinned by the heat of the hot press 42.

[0064] Furthermore, at this time, the second film 30 and the third film 36 are sandwiched between the lower jig 32 and the projection 34A on the lower jig 32 side, so that a projection 18C is formed on the positive electrode tab film 18 that becomes thinner as it moves toward one side in the second direction. The boundary between this projection 18C and the excess portion of the second film 30 and the third film 36 toward one side in the second direction from the projection 18C is melted by the heat of the hot press 42, resulting in a cut or thinned state.

[0065] Similarly, the second film 30 and the fourth film 40 are sandwiched between the lower jig 32 and the projection 38A on the lower jig 32 side, forming a projection 18C on the positive electrode tab film 18 that becomes thinner as it extends toward the other side in the second direction. The boundary between this projection 18C and the excess portion of the second film 30 and the fourth film 40 on the other side of the projection 18C in the second direction is melted and cut or thinned by the heat of the hot press 42.

[0066] Next, in the fourth step shown in Figure 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 tab film 18.

[0067] On the other hand, in the process of attaching the laminate sheet 24, in the first step shown in Figure 6(A), the laminate sheet 24 is placed on the lower jig 44. Specifically, with one end 24B of the laminate sheet 24 placed on the upper surface of the lower jig 44, about half of the laminate sheet 24 is pushed into the recess 44A provided in the lower jig 44.

[0068] Next, in the second step shown in Figure 6(B), the composite 46, which integrates the electrode body 12, electrolyte layer, positive electrode current collector terminal 14, negative electrode current collector terminal 16, positive electrode tab film 18, and negative electrode tab film 20, is placed in the recess 44A such that the composite 46 is on the upper side of the laminate sheet 24. Then, with about half of the laminate sheet 24 covering the upper side of the composite 46 and the other end 24C of the laminate sheet 24 being on the upper side of the one end 24B, the upper jig 47 is placed on top of the lower jig 44.

[0069] Next, in the third step shown in Figure 6(C), the laminate sheet 24 is pressed against the composite 46 in the second direction using the clamp 48.

[0070] Next, in the fourth step shown in Figure 6(D), the laminate sheet 24 is pressed towards the composite 46 from the upper and lower sides in the third direction using the heat bar 50 at both ends of the composite 46 in the first direction, thereby welding the laminate sheet 24 to the composite 46.

[0071] At this time, at one end of the composite 46 in the first direction, as shown in Figure 1, the projection 18C of the positive electrode tab film 18 enters the corner 24A of the laminate sheet 24 from the positive electrode current collector terminal 14 side. The same applies between the negative electrode tab film 20 and the laminate sheet 24. Therefore, in this embodiment, it is possible to suppress the formation of a gap between the corner 24A of the folded laminate sheet 24 and the positive electrode tab film 18 and the negative electrode tab film 20.

[0072] As described above, in this embodiment, it is possible to suppress communication between the inside and outside of the battery 10.

[0073] <Supplementary explanation of the above embodiment> (1) In the above-described embodiment, the projection of the tab film protruded in a second direction from a corner provided at the second end of the base portion of the current collection terminal. However, depending on the specifications of the battery 10, the tab film may be configured to protrude in a third direction.

[0074] (2) In the embodiments described above, four protrusions were provided on 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 point where the corners on the second-direction end of the base portion of the current collection terminal are rounded, a configuration can be adopted in which no protrusions are provided on the corners of the tab film corresponding to this point. [Explanation of Symbols]

[0075] 10 batteries 14. Positive side current collection terminal (current collection terminal) 14A contact part 14B Base section 14B1 Corner 16. Negative side current collection terminal (current collection terminal) 16A contact part 16B Base section 18. Positive side tab film (tab film) 18C protrusion 20. Negative electrode tab film (tab film) 24 Laminating Sheets 26 Film 1 28 Upper jig 30. Film No. 2 32 Lower jig 34 1st horizontal jig 34A Protrusion 36 Third Film 38 2nd horizontal jig 38A Protrusion 40. Film No. 4 42 Hot Press

Claims

1. Electrode body and A current collector terminal in contact with one side surface in the first direction of the electrode body, A single laminate sheet covering the electrode body and the portion of the current collection terminal on the other side in the first direction, A tab film comprising a welding layer and a surface layer composed of a resin of a different type from the resin constituting the welding layer, Equipped with, The laminate sheet has a welded portion where opposing parts are welded together, The tab film is interposed between the current collection terminal and the laminate sheet, and has projections that protrude in the second direction from corners provided at the ends of the current collection terminal in the first direction and in a second direction perpendicular to the thickness direction of the current collection terminal, and that become thinner in the second direction toward the opposite side of the corner. The tab film is welded to the current collection terminal and the laminate sheet around the current collection terminal, A portion of the aforementioned protrusion is inserted into the welded portion. battery.

2. The welded portion is formed by welding the portion of the laminate sheet that is bent so that it overlaps in the thickness direction. The battery according to claim 1.

3. At least one of the surfaces on one side in the thickness direction and the other side in the thickness direction of the welded portion is a flat surface, The battery according to claim 1 or claim 2.

Images