Battery

Abstract

The invention relates to a battery. A battery according to the present disclosure includes an electrode laminate, a collector foil extending from a side surface portion of the electrode laminate, a collector terminal electrically connected to the collector foil, and a laminate film that winds the electrode laminate and the collector terminal and seals the electrode laminate and the collector terminal together. In addition, a current collector terminal constituting the battery of the present disclosure has a bonding region bonded to the current collector foil, and the bonding region has a contact portion that is in contact with the current collector foil and a non-contact portion that is not in contact with the current collector foil.

Description

Technical Field

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

[0002] A battery is known, which includes an electrode stack, a current collecting terminal, and a laminate film that winds the electrode stack and the current collecting terminal and seals the electrode stack and the current collecting terminal together. In such a battery, the above-mentioned sealing is usually performed after the laminate film is heat-welded to the current collecting terminal. In response to this, a technology for shortening the welding time during heat welding has been developed.

[0003] For example, Japanese Patent Application Laid-Open No. 2005-056815 discloses a method for manufacturing a secondary battery in which, when a laminate film is thermally welded to a collector terminal, the collector terminal is preheated by pressing the collector terminal with a heating element. Summary of the invention

[0004] An object of the present disclosure is to provide a battery in which a laminate film can be efficiently welded to a current collector terminal even without preheating.

[0005] The inventors of the present application have found that the above-mentioned problems can be solved by the following means.

[0006] Method 1

[0007] A battery, comprising:

[0008] An electrode stack;

[0009] A collector foil extending from a side surface of the electrode stack;

[0010] a current collecting terminal electrically connected to the current collecting foil; and

[0011] a laminate film that winds the electrode stack and the current collector terminal to seal the electrode stack and the current collector terminal together,

[0012] in,

[0013] The current collector terminal has a bonding region bonded to the current collector foil, and

[0014] The bonding region has a contact portion that is in contact with the collector foil and a non-contact portion that is not in contact with the collector foil.

[0015] Method 2

[0016] In the battery according to embodiment 1,

[0017] The collector terminal has a concavo-convex shape in the bonding area,

[0018] The contact portion is formed by joining the convex portion of the collector terminal to the collector foil, and,

[0019] The non-contact portion is formed by the concave portion of the collector terminal not being joined to the collector foil.

[0020] Method 3

[0021] In the battery according to embodiment 1,

[0022] The collector terminal has a roughened portion in the bonding region,

[0023] The non-contact portion is formed by the roughened portion and the collector foil not being bonded to each other.

[0024] Method 4

[0025] In the battery according to any one of aspects 1 to 3,

[0026] A 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.

[0027] According to the present disclosure, it is possible to provide a battery in which a laminate film can be efficiently welded to a current collector terminal even without preheating. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like symbols represent like elements, and in which:

[0029] Figure 1 is a schematic top view illustrating a portion of a battery of the present disclosure;

[0030] Figure 2 is a schematic side view illustrating a portion of a battery of the present disclosure;

[0031] Figure 3A is a schematic side view illustrating a portion of a battery of the present disclosure;

[0032] Figure 3B is a schematic side view illustrating a portion of a battery of the present disclosure;

[0033] Figure 4 is a schematic side view illustrating a portion of a battery of the present disclosure;

[0034] Figure 5A is a schematic side view of a portion of a battery illustrating the prior art;

[0035] Figure 5Bis a diagram showing a state in which, when a laminate film is heat-welded to a collector terminal in a conventional battery, heat applied to the laminate film is transferred from the collector terminal to the electrode stack through the collector foil; and

[0036] Figure 6 This refers to the use of heat-welding the laminate film to the collector terminal. Figure 2 The collector terminal (A in the figure) of the battery of the present disclosure is shown, and Figure 5A , Figure 5B The graph of time until the welding temperature is reached in the case of the collector terminal (B in the figure) of a battery in the prior art is shown. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present disclosure will be described in detail. It should be noted that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present disclosure.

[0038] Battery

[0039] The battery disclosed in the present invention comprises: an electrode stack, a collector foil extending from a side surface of the electrode stack, a collector terminal electrically connected to the collector foil, and a laminate film that winds the electrode stack and the collector terminal and seals the electrode stack and the collector terminal together. In addition, the collector terminal constituting the battery disclosed in the present invention has a bonding area bonded to the collector foil, and the bonding area has a contact portion that contacts the collector foil and a non-contact portion that does not contact the collector foil.

[0040] In a battery having an electrode stack, a collector terminal, and a laminate film that winds the electrode stack and the collector terminal and seals the electrode stack and the collector terminal together, there is a problem that the laminate film cannot be effectively welded to the collector terminal. The inventors of the present application believe that one of the reasons for the above problem is that the heat applied to the laminate film for welding is transferred from the collector terminal to the electrode stack through the portion where the collector terminal contacts the collector foil.

[0041] like Figure 5A As shown, in the case where the collector terminal 30 does not have the non-contact portion 120, as shown in FIG. Figure 5B As shown, the laminate film 40 may be welded to the collector terminal 30. In this case, it is considered that the heat applied to the laminate film 40 by the heating element 200 moves as shown by the arrow, that is, moves from the collector terminal 30 to the electrode stack 10 through the collector foil 20.

[0042] In this regard, the inventors of the present application have found that by providing the collector terminal with a contact portion that contacts the collector foil and a non-contact portion that does not contact the collector foil, the laminate film can be effectively welded to the collector terminal even without preheating. It is believed that this is because the collector terminal can ensure electrical conduction from the electrode stack to the collector terminal by having the above-mentioned contact portion, and can suppress the movement of heat from the collector terminal to the electrode stack by having the above-mentioned non-contact portion. However, it is not intended to be bound by any theory.

[0043] Below, refer to Figure 1 , the battery of the present disclosure is described. Figure 1 1 is a schematic top view of a portion of a battery in the present disclosure when viewed from the stacking direction of the electrode stack. Figure 1 The dimensional relationships (length, width, thickness, etc.) in other drawings do not reflect actual dimensional relationships.

[0044] like Figure 1 As shown, the battery 1 of the present disclosure includes an electrode stack 10, a collector foil 20, a collector terminal 30, and a laminate film 40 that winds the electrode stack 10 and the collector terminal 30 and seals the electrode stack 10 and the collector terminal together. The collector foil 20 extends from a side surface of the electrode stack 10. The collector terminal 30 is electrically connected to the collector foil.

[0045] Electrode stack

[0046] The electrode stack 10 functions as a power generation element of the battery 1. The shape of the electrode stack 10 is not particularly limited. However, the electrode stack 10 has, for example, a top portion, a bottom portion facing the top portion, and four side portions connecting the top portion and the bottom portion. In addition, the electrode stack 10 may have a positive electrode collector, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode collector in this order.

[0047] Collector Foil

[0048] The collector foil 20 extends from the side surface of the electrode stack 10. The collector foil 20 may be a bundle of the positive electrode collectors in the electrode stack 10 where other layers are not stacked, or a bundle of the negative electrode collectors in the electrode stack 10 where other layers are not stacked.

[0049] Collector terminal

[0050] The collector terminal 30 is electrically connected to the collector foil 20. The material of the collector terminal 30 is not particularly limited as long as it has a current collecting function. For example, the material of the collector terminal 30 may be the same metal material as the positive electrode collector and the negative electrode collector.

[0051] The collector terminal 30 has a bonding region 100 bonded to the collector foil 20. The bonding region 100 has a contact portion 110 in contact with the collector foil 20 and a non-contact portion 120 that is not in contact with the collector foil 20. It should be noted that the bonding region 100 in the collector terminal 30 is a region formed by connecting the contact portions 110 with straight lines in a manner that becomes the minimum region including all the contact portions 110.

[0052] Laminating film

[0053] The laminate film 40 winds the electrode stack 10 and the collector terminal 30 and seals the electrode stack 10 and the collector terminal 30 together. The laminate film 40 may have a welding layer and a metal layer. The laminate film 40 can weld the welding layer to the collector 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 collector terminal. The material of the welding layer can be, for example, a resin that can be thermally welded to the collector terminal.

[0054] Figure 2 It is a schematic side view illustrating a part of the battery 1 of the present disclosure. Figure 2 is Figure 1 The structure of the collector foil 20 and the collector terminal 30 is shown in the II-II cross section of FIG. Figure 2 As shown, the collector terminal 30 constituting the battery 1 of the present disclosure has a concave-convex shape in the joint region. The contact portion 110 can be formed by joining the convex portion 111 of the collector terminal 30 with the collector foil 20. Also, the non-contact portion 120 can be formed by not joining the concave portion 121 of the collector terminal 30 with the collector foil 20.

[0055] As a method of forming the concavo-convex shape in the bonding region of the current collector terminal 30 , for example, there is a method of press-forming the current collector terminal 30 .

[0056] Figure 3A , Figure 3B 1 is a schematic side view illustrating a portion of the battery 1 of the present disclosure. Figure 3A As shown, the collector terminal 30 constituting the battery 1 of the present disclosure has a roughened portion 130 in the bonding region. The non-contact portion 120 may be formed by the roughened portion 130 not being bonded to the collector foil 20 .

[0057] In addition, if Figure 3B As shown, the collector terminal 30 constituting the battery 1 of the present disclosure has a roughened portion 130 in a bonding region. The contact portion 110 can be formed by bonding the roughened portion 130 to the collector foil 20 .

[0058] That is, in the embodiment having the roughened portion 130 , the portion of the collector terminal 30 corresponding to the contact portion 110 may or may not be roughened.

[0059] There is no particular limitation on the method for forming the roughened portion 130 in the bonding region of the collector terminal 30, and a method generally known as a method for roughening a metal can be used. Examples of such methods include mechanical treatment such as grinding, physical treatment such as laser irradiation, electrochemical treatment such as aluminum oxide film treatment, and chemical treatment such as wet etching.

[0060] Figure 4 It is a schematic side view illustrating a part of the battery 1 of the present disclosure. Figure 4 2 shows a battery using a collector terminal 30 whose surface has not been processed or treated. Even when using a collector terminal 30 whose surface has not been processed or treated, by setting the collector foil 20 not to contact a portion other than the joint portion with the collector terminal 30, a battery in which the collector terminal 30 has a contact portion 110 and a non-contact portion 120 can be manufactured.

[0061] For example, resin is placed in the bonding region of the collector terminal 30 , and the portion not provided with the resin is bonded to the collector foil 20 . Thereafter, the resin is pulled out or melted to disappear, thereby forming the non-contact portion 120 in the collector terminal 30 .

[0062] In the above description, the non-contact portion is formed by the space provided between the collector terminal and the collector foil. However, the non-contact portion may also be formed by a low thermal conductivity component disposed between the collector foil and the collector terminal. That is, although not specifically shown, the collector terminal has a low thermal conductivity component disposed in the bonding area. The contact portion may be formed by bonding the portion not provided with the low thermal conductivity component to the collector foil. Furthermore, the non-contact portion may be formed by a low thermal conductivity component.

[0063] The low thermal conductive member is not particularly limited as long as it is a material having a thermal conductivity lower than that of the material constituting the current collecting terminal and the current collecting foil, and examples thereof include resins and the like.

[0064] The ratio of the area of ​​the contact portion to the area of ​​the bonding region (the area of ​​the contact portion / the area of ​​the bonding region) may be greater than 0.0 and less than 1.0. The ratio may be greater than 0.1, greater than 0.2, greater than 0.3, or greater than 0.4, or less than 0.9, less than 0.8, less than 0.7, or less than 0.6. In addition, the ratio may be 0.5. From the viewpoint that it is difficult for the heat applied to the laminated film to move from the collector terminal to the electrode stack through the collector foil when the laminated film is welded to the collector terminal, the ratio is preferably small. In addition, from the viewpoint that it is easy to join the collector foil to the collector terminal, the ratio is preferably large.

[0065] The ratio of the area of ​​the contact portion to the area of ​​the bonding region can be adjusted by controlling the area of ​​the concave portion and the area of ​​the roughened portion, for example.

[0066] The method of joining the current collector terminal and the current collector foil is not particularly limited, and an example thereof is a method of joining by ultrasonic waves.

[0067] The method of welding the laminated film to the collector terminal is not particularly limited, and a heat welding method can be exemplified. When this method is adopted, the welding temperature can be determined by the melting point of the material used as the welding layer of the laminated film. In addition, the time until the welding temperature is reached can be greater than 0 seconds, or less than 80 seconds, 70 seconds or less, or 60 seconds or less.

[0068] The battery in the present disclosure may be a lithium-ion secondary battery. As the use of the battery, for example, power sources for vehicles such as hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), electric vehicles (BEV), gasoline vehicles, and diesel vehicles can be cited. In particular, it is preferably used as a driving power source for hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), or electric vehicles (BEV). In addition, the battery in the present disclosure can be used as a power source for mobile bodies other than vehicles (for example, railways, ships, and airplanes), and can also be used as a power source for electrical products such as information processing devices.

[0069] Bonding of collector terminal and collector foil

[0070] Example 1

[0071] By stamping, Figure 2 The collector terminal has the shape shown. The thickness from the bottom surface of the collector terminal to the front end of the convex portion is 2 mm. In addition, as the collector foil, a collector foil made by stacking 30 sheets of 12 μm aluminum foil (A1050) was prepared. The stack of aluminum foils is arranged on the collector terminal, and the collector terminal and the collector foil are joined by ultrasonic bonding using a welding head with a front end size of 1 mm. The distance between the joined parts is 2 mm. In addition, the ratio of the area of ​​the contact portion to the area of ​​the joining area (area of ​​the contact portion / area of ​​the joining area) is 0.5.

[0072] Comparative Example 1

[0073] In addition to using Figure 5AExcept for the collector terminal having the shape shown, the collector terminal was joined to the collector foil 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.

[0074] evaluate

[0075] The current collector terminal of each example was covered with a laminate film, the laminate film was heated, and the time until the current collector terminal reached the welding temperature of 160° C. was measured. The material of the welding layer of the laminate film was polypropylene.

[0076] result

[0077] The results of the above evaluation are shown in Table 1 and Figure 6 Shown in.

[0078] Table 1

[0079]

[0080] In Example 1, which uses a collector terminal and a collector foil bonded together with a ratio of the area of ​​the contact portion to the area of ​​the bonding region (the area of ​​the contact portion / the area of ​​the bonding region) of 0.5, the time until the collector terminal reaches the welding temperature is short. This is shown in Table 1 and Figure 6 The current collector terminal having a contact portion and a non-contact portion has a ratio of the area of ​​the contact portion to the area of ​​the bonding region (the area of ​​the contact portion / the area of ​​the bonding region) of 0.5.

Claims

1. A battery, comprising: An electrode stack; A collector foil extending from a side surface of the electrode stack; A collector terminal, the collector terminal being electrically connected to the collector foil; as well as a laminate film that winds the electrode stack and the current collector terminal to seal the electrode stack and the current collector terminal together, in, The collector terminal has a bonding region bonded to the collector foil, and The bonding region has a contact portion that is in contact with the collector foil and a non-contact portion that is not in contact with the collector foil.

2. The battery according to claim 1, wherein The collector terminal has a concave-convex shape in the bonding area, The contact portion is formed by joining the convex portion of the collector terminal to the collector foil, and, The non-contact portion is formed by the concave portion of the collector terminal not being joined to the collector foil.

3. The battery according to claim 1, wherein The collector terminal has a roughened portion in the bonding region, The non-contact portion is formed by the roughened portion and the collector foil not being bonded to each other.

4. The battery according to any one of claims 1 to 3, wherein A 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.

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