Battery

Abstract

To provide a battery in which a laminate film is efficiently welded to a current collecting terminal even without preheating.SOLUTION: A battery discussed herein includes an electrode laminate, a current collecting foil extending from a side portion of the electrode laminate, a current collecting terminal electrically connected to the current collecting foil, and a laminate film that winds the electrode laminate and the current collecting terminal and seals the electrode laminate together with the current collecting terminal. In addition, the current collecting terminal that constitutes the battery disclosed herein has a bonding region that is bonded to the current collecting foil, and the bonding region has a contact portion that is in contact with the current collecting foil and a non-contact portion that is not in contact with the current collecting foil.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] There is known a battery that includes an electrode laminate, a current collector terminal, and a laminate film that is formed by winding the electrode laminate and the current collector terminal and sealing the electrode laminate together with the current collector terminal. In such a battery, the laminate film is usually heat-sealed to the current collector terminal before the above-mentioned sealing is performed. In this regard, a technique for shortening the welding time during heat welding has been developed.

[0003] For example, Patent Document 1 discloses a method for producing a secondary battery in which, when a laminate film is thermally welded to a current collector terminal, the current collector terminal is preheated by pressing it with a heating element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-056815 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a battery in which a laminate film is efficiently welded to a current collecting terminal even without preheating. [Means for solving the problem]

[0006] The present inventors have found that the above problems can be solved by the following means. <Aspect 1> An electrode stack, a current collecting foil extending from a side portion of the electrode stack; A current collecting terminal electrically connected to the current collecting foil; and a laminate film that wraps the electrode stack and the current collector terminal and seals the electrode stack together with the current collector terminal; A battery having The current collecting terminal has a joining area joined to the current collecting foil, and The joining region has a contact portion that is in contact with the current collecting foil and a non-contact portion that is not in contact with the current collecting foil. battery. <Aspect 2> The current collecting terminal has an uneven shape in the joining region, the contact portion is formed by joining a convex portion of the current collecting terminal and the current collecting foil, and The non-contact portion is formed by not joining the concave portion of the current collecting terminal and the current collecting foil. 2. The battery of embodiment 1. <Aspect 3> The current collecting terminal has a roughened surface treatment portion in the bonding region, The non-contact portion is formed by not joining the roughened surface treatment portion and the current collecting foil. 2. The battery of embodiment 1. <Aspect 4> The battery of any one of aspects 1 to 3, wherein the ratio of the area of ​​the contact portion to the area of ​​the bonding region is greater than 0.0 and less than 1.0. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a battery in which a laminate film is efficiently welded to a current collecting terminal even without preheating. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic plan view illustrating a portion of a battery of the present disclosure. [Diagram 2] FIG. 2 is a schematic side view illustrating a portion of a battery of the present disclosure. [Diagram 3] FIG. 3 is a schematic side view illustrating a portion of a battery of the present disclosure. [Figure 4] FIG. 4 is a schematic side view illustrating a portion of a battery of the present disclosure. [Diagram 5] FIG. 5 is (a) a schematic side view illustrating a portion of a battery of the prior art, and (b) a diagram showing how heat applied to a laminate film transfers from the current collecting terminal to the electrode laminate through the current collecting foil when the laminate film is heat-welded to the current collecting terminal in a battery of the prior art. [Figure 6] FIG. 6 is a graph showing the time required to reach the welding temperature when a laminate film is thermally welded to a collector terminal when using the collector terminal of the battery of the present disclosure shown in FIG. 2 (A in the figure) and the collector terminal of the battery of the prior art shown in FIG. 5 (B in the figure). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure.

[0010] "battery" The battery of the present disclosure includes an electrode laminate, a current collecting foil extending from a side portion of the electrode laminate, a current collecting terminal electrically connected to the current collecting foil, and a laminate film that wraps the electrode laminate and the current collecting terminal and seals the electrode laminate together with the current collecting terminal. The current collecting terminal constituting the battery of the present disclosure has a bonding region that is bonded to the current collecting foil, and the bonding region has a contact portion that is in contact with the current collecting foil and a non-contact portion that is not in contact with the current collecting foil.

[0011] In a battery including an electrode laminate, a current collecting terminal, and a laminate film formed by winding the electrode laminate and the current collecting terminal and sealing the electrode laminate together with the current collecting terminal, there is a problem that the welding of the laminate film to the current collecting terminal does not proceed efficiently. The present inventors believed that one of the causes of the above problem is that heat applied to the laminate film for welding is transferred from the current collecting terminal to the electrode laminate through the portion where the current collecting terminal and the current collecting foil are in contact with each other.

[0012] That is, when the current collecting terminal 30 does not have a non-contact portion 120 as shown in FIG. 5(a), it is believed that when the laminate film 40 is welded to the current collecting terminal 30, the heat applied to the laminate film 40 by the heating element 200 moves as shown by the arrow, i.e., moves from the current collecting terminal 30 to the electrode laminate 10 through the current collecting foil 20, as shown in FIG. 5(b).

[0013] In this regard, the present inventors have found that, by having a current collecting terminal with a contact portion that is in contact with the current collecting foil and a non-contact portion that is not in contact with the current collecting foil, the laminate film can be efficiently welded to the current collecting terminal even without preheating. Without intending to be bound by any theory, this is thought to be because, by having the contact portion, the current collecting terminal ensures electrical conduction from the electrode laminate to the current collecting terminal, while, by having the non-contact portion, the transfer of heat from the current collecting terminal to the electrode laminate can be suppressed.

[0014] The battery of the present disclosure will be described below with reference to Fig. 1. Fig. 1 is a schematic plan view illustrating a part of the battery of the present disclosure when the battery is viewed in plan from the stacking direction of the electrode laminate. Note that the dimensional relationships (length, width, thickness, etc.) in Fig. 1 and other drawings do not reflect the actual dimensional relationships.

[0015] As shown in FIG. 1 , a battery 1 of the present disclosure includes an electrode laminate 10, a current collecting foil 20 extending from a side portion of the electrode laminate 10, a current collecting terminal 30 electrically connected to the current collecting foil, and a laminate film 40 that winds the electrode laminate 10 and the current collecting terminal 30 and seals the electrode laminate 10 together with the current collecting terminal.

[0016] <Electrode laminate> The electrode laminate 10 functions as a power generating element of the battery 1. The shape of the electrode laminate 10 is not particularly limited, but for example, it has a top surface portion, a bottom surface portion facing the top surface portion, and four side surface portions connecting the top surface portion and the bottom surface portion. The electrode laminate 10 may have a positive electrode current collector, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode current collector in this order.

[0017] Current collecting foil The current collecting foil 20 extends from a side portion of the electrode laminate 10. The current collecting foil 20 may be a bundle of positive current collectors in the electrode laminate 10 that are not laminated with other layers, and a bundle of negative current collectors in the electrode laminate 10 that are not laminated with other layers.

[0018] <Collector terminal> The current collecting terminal 30 is electrically connected to the current collecting foil 20. The material of the current collecting terminal 30 is not particularly limited as long as it has a current collecting function, and may be, for example, the same metal material as the positive electrode current collector and the negative electrode current collector.

[0019] The current collecting terminal 30 has a joining region 100 joined to the current collecting foil 20. The joining region 100 has contact portions 110 that are in contact with the current collecting foil 20, and non-contact portions 120 that are not in contact with the current collecting foil 20. The joining region 100 in the current collecting terminal 30 is an area formed by connecting the contact portions 110 with straight lines so as to be the smallest area that includes all of the contact portions 110.

[0020] <Lamination film> The laminate film 40 is formed by winding the electrode laminate 10 and the current collecting terminal 30, and seals the electrode laminate 10 together with the current collecting terminal 30. The laminate film 40 may have a welding layer and a metal layer, and can weld the welding layer to the current collecting terminal 30. The material of the welding layer is not particularly limited as long as it is a material that can be welded to the current collecting terminal, and may be, for example, a resin that can be thermally welded to the current collecting terminal.

[0021] Fig. 2 is a schematic side view illustrating a part of the battery 1 of the present disclosure. Fig. 2 is a view showing the configuration of the current collector foil 20 and the current collector terminal 30 in the AA cross section of Fig. 1. As shown in Fig. 2, the current collector terminal 30 constituting the battery 1 of the present disclosure has an uneven shape in the joining region, and the contact portion 110 may be formed by joining the convex portion 111 of the current collector terminal 30 and the current collector foil 20, and the non-contact portion 120 may be formed by not joining the concave portion 121 of the current collector terminal 30 and the current collector foil 20.

[0022] An example of a method for forming the uneven shape in the bonding area of ​​the current collector terminal 30 is press molding of the current collector terminal 30.

[0023] Fig. 3 is a schematic side view illustrating a part of the battery 1 of the present disclosure. As shown in Fig. 3(a), the current collecting terminal 30 constituting the battery 1 of the present disclosure has a roughened surface treatment portion 130 in a joining region, and the non-contact portion 120 may be formed by not joining the roughened surface treatment portion 130 and the current collecting foil 20.

[0024] Moreover, as shown in FIG. 3(b), the current collecting terminal 30 constituting the battery 1 of the present disclosure may have a roughened surface treatment portion 130 in the bonding area, and the contact portion 110 may be formed by bonding the roughened surface treatment portion 130 and the current collecting foil 20.

[0025] That is, in an embodiment having the surface-roughening treatment 130, the portion corresponding to the contact portion 110 of the current collecting terminal 30 may or may not be surface-roughened.

[0026] The method for forming the roughened surface treatment portion 130 in the bonding region of the current collecting terminal 30 is not particularly limited, and any method generally known as a method for roughening a metal surface can be used. Examples of such methods include mechanical treatments such as polishing, physical treatments such as laser irradiation, electrochemical treatments such as anodizing, and chemical treatments such as wet etching.

[0027] Fig. 4 is a schematic side view illustrating a part of the battery 1 of the present disclosure. As shown in Fig. 4, even when using a current collecting terminal 30 whose surface has not been processed or treated, the current collecting foil 20 is prevented from contacting parts other than the joint part with the current collecting terminal 30, so that the current collecting terminal 30 has a contact part 110 and a non-contact part 120.

[0028] For example, resin can be placed in the joining area of ​​the current collecting terminal 30, and after joining the part where this resin is not placed to the current collecting foil 20, the resin can be pulled out or melted and eliminated to form the non-contact portion 120 in the current collecting terminal 30.

[0029] Although the above describes an embodiment in which the non-contact portion is formed by a space provided between the current collecting terminal and the current collecting foil, the non-contact portion may be formed by a low thermal conductive member arranged between the current collecting foil and the current collecting terminal. That is, although not particularly shown, the current collecting terminal may have a low thermal conductive member arranged in a joining region, the contact portion may be formed by joining a portion where the low thermal conductive member is not arranged to the current collecting foil, and the non-contact portion may be formed by the low thermal conductive member.

[0030] The low thermal conductive member is not particularly limited as long as it is a material that has lower thermal conductivity than the materials constituting the current collecting terminals and the current collecting foil, and examples thereof include resins.

[0031] The ratio of the area of ​​the contact portion to the area of ​​the bonding region (area of ​​the contact portion / area of ​​the bonding region) may be more than 0.0 and less than 1.0. This ratio may be 0.1 or more, 0.2 or more, 0.3 or more, or 0.4 or more, and may be 0.9 or less, 0.8 or less, 0.7 or less, or 0.6 or less. This ratio may be 0.5. A small ratio is preferable from the viewpoint that heat applied to the laminate film when fusing the laminate film to the current collecting terminal is less likely to transfer from the current collecting terminal to the electrode laminate through the current collecting foil. A large ratio is preferable from the viewpoint of facilitating bonding between the current collecting foil and the current collecting terminal.

[0032] The ratio of the area of ​​the contact portion to the area of ​​the bonding region can be adjusted, for example, by controlling the area of ​​the above-mentioned concave portion and the area of ​​the roughened surface treatment portion.

[0033] The method for joining the current collecting terminal and the current collecting foil is not particularly limited, but may be, for example, a method of joining them by ultrasonic waves.

[0034] The method of welding the laminate film to the current collector terminal is not particularly limited, but a heat welding method is an example. When using this method, the welding temperature can be determined by the melting point of the material used as the welding layer of the laminate film. The time required to reach the welding temperature may be more than 0 seconds, less than 80 seconds, 70 seconds or less, or 60 seconds or less.

[0035] The battery in the present disclosure may be a lithium ion secondary battery. Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline automobiles, and diesel automobiles. In particular, the battery is preferably used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery in the present disclosure may also be used as a power source for moving objects other than vehicles (e.g., railways, ships, and aircraft), and may also be used as a power source for electrical products such as information processing devices. EXAMPLES

[0036] <Joining current collecting terminal and current collecting foil> Example 1 A current collecting terminal having the shape shown in FIG. 2 was produced by press molding. The thickness from the bottom surface of this current collecting terminal to the tip of the convex portion was 2 mm. A current collecting foil was prepared by laminating 30 sheets of 12 μm aluminum foil (A1050). The aluminum foil laminate was placed on the current collecting terminal, and the current collecting terminal and the current collecting foil were joined by ultrasonic bonding using a horn with a tip size of 1 mm. The distance between the joined parts was 2 mm. The ratio of the area of ​​the contact part to the area of ​​the joint region (area of ​​the contact part / area of ​​the joint region) was 0.5.

[0037] Comparative Example 1 5(a) was used, the current collecting terminal and the current collecting foil were joined in the same manner as in Example 1. The ratio of the area of ​​the contact portion to the area of ​​the joining region (area of ​​the contact portion / area of ​​the joining region) was 1.

[0038] "evaluation" The current collector terminal of each example was covered with a laminate film, and heat was applied to this laminate film to measure the time until the current collector terminal reached the welding temperature of 160° C. The material of the welding layer of the laminate film was polypropylene.

[0039] "result" The results of the above evaluation are shown in Table 1 and FIG.

[0040] [Table 1]

[0041] As shown in Table 1 and FIG. 6, in Example 1, which used a current collecting terminal in which the ratio of the area of ​​the contact portion to the area of ​​the bonded area (area of ​​the contact portion / area of ​​the bonded area) was 0.5, i.e., an article in which a current collecting terminal having a contact portion and a non-contact portion and a current collecting foil were bonded, the time it took for the current collecting terminal to reach the welding temperature was short. [Explanation of symbols]

[0042] 1 battery 10 Electrode laminate 20 Current collecting foil 30 Current collector terminal 40 Laminating Film 100 joint area 110 Contact part 111 Convex part 120 Non-contact part 121 Concave part 130 Roughening treatment section

Claims

1. An electrode stack, a current collecting foil extending from a side portion of the electrode stack; A current collecting terminal electrically connected to the current collecting foil; and a laminate film that wraps the electrode stack and the current collector terminal and seals the electrode stack together with the current collector terminal; A battery having The current collecting terminal has a joining area joined to the current collecting foil, and The joining region has a contact portion that is in contact with the current collecting foil and a non-contact portion that is not in contact with the current collecting foil. battery.

2. The current collecting terminal has an uneven shape in the joining region, the contact portion is formed by joining a convex portion of the current collecting terminal and the current collecting foil, and The non-contact portion is formed by not joining the concave portion of the current collecting terminal and the current collecting foil.

10. The battery of claim 1.

3. The current collecting terminal has a roughened surface treatment portion in the bonding region, The non-contact portion is formed by not joining the roughened surface treatment portion and the current collecting foil.

10. The battery of claim 1.

4. The battery according to any one of claims 1 to 3, wherein a ratio of an area of ​​the contact portion to an area of ​​the bonding region is greater than 0.0 and less than 1.0.

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