collector terminals

Abstract

This disclosure provides a current collector terminal with improved adhesion to a laminated exterior. [Solution] The current collector terminal of the present disclosure is a current collector terminal for a laminated battery, wherein the laminated battery comprises a laminated casing, an electrode stack housed within the laminated casing, and the current collector terminal, wherein the current collector terminal comprises a current collector connection portion for electrically connecting to the current collector of the electrode stack, an external terminal connection portion for electrically connecting to an external terminal, and an intermediate portion between the current collector connection portion and the external terminal connection portion, wherein recesses and protrusions are alternately arranged in the width direction in the intermediate portion.

Description

Technical Field

[0001] This disclosure relates to current collector terminals.

Background Art

[0002] Patent Document 1 discloses a battery having an electrode body, a plurality of current collector tabs extending from a side surface portion of the electrode body, a current collector terminal connected to the plurality of current collector tabs, and a laminate film housing the electrode body and the plurality of current collector tabs. The current collector tab has a root portion which is an end portion on the electrode body side, a connection portion for connecting to the current collector terminal, and an intermediate portion connecting the root portion and the connection portion. The plurality of current collector tabs each have a laminated connection portion in which their respective connection portions are laminated in the thickness direction. The current collector terminal has an inner surface facing the side surface portion of the electrode body and a side surface disposed along an outer edge of the inner surface. The laminate film is disposed on the side surface of the current collector terminal, and a main surface of the laminated connection portion is joined to the inner surface. In a plan view in the lamination direction of the electrode body, the current collector terminal has a base portion including a first end portion corresponding to the position of the inner surface and a second end portion facing the first end portion, and a protruding portion protruding from the base portion to the side opposite to the electrode body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A laminated battery may have a laminated casing, an electrode stack housed within the laminated casing, and a current collector terminal. The current collector terminal may have a current collector connection portion, an external terminal connection portion, and an intermediate portion between the current collector connection portion and the external terminal connection portion. The current collector connection portion is the part for electrically connecting to the current collector of the electrode stack. The external terminal connection portion is the part for electrically connecting to the external terminal. The intermediate portion is the part that is bonded to the laminated casing in whole or in part, sealing the electrode stack within the laminated casing.

[0005] In the above configuration, if the adhesion between the laminated casing and the current collector terminal is insufficient, there is a risk that the laminated casing and the current collector terminal will delaminate from each other. Delamination between the laminated casing and the current collector terminal can lead to incomplete sealing of the electrode laminate.

[0006] This disclosure provides a current collector terminal with improved adhesion to a laminated exterior. [Means for solving the problem]

[0007] The Disclosing Party has found that the above problem can be achieved by the following means: 《Aspect 1》 A current collection terminal for laminated batteries, The laminated battery comprises a laminated outer casing, an electrode stack housed within the laminated outer casing, and the current collector terminal. The aforementioned current collection terminal, A current collector connection part for electrically connecting the electrode stack to the current collector, External terminal connection section for electrically connecting to external terminals, and The intermediate portion between the current collector connection part and the external terminal connection part, It has and In the aforementioned intermediate portion, recesses and protrusions are arranged alternately across the width direction. Current collector terminal. 《Aspect 2》 The current collector terminal according to embodiment 1, wherein the recess and the protrusion are arranged alternately in the width direction in a region including the longitudinal center line of the intermediate portion. 《Aspect 3》 The current collector terminal according to embodiment 1 or 2, wherein recesses and protrusions are alternately arranged in the width direction in at least a portion of the external terminal connection portion. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a current collector terminal with improved adhesion to a laminated exterior. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of a current collector terminal 1 according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic diagram of the current collection terminal 1 in the A-A' section of Figure 1. [Figure 3] Figure 3 is a schematic diagram of a laminated battery 20 having a current collector terminal 1 according to one embodiment of the present disclosure. [Figure 4(a)] Figure 4(a) is a schematic diagram of the sample of Comparative Example 1. [Figure 4(b)] Figure 4(b) shows the stress distribution obtained by CAE (Computer Aided Engineering) analysis of the sample of Comparative Example 1. [Figure 5(a)] Figure 5(a) is a schematic diagram of the sample from Example 1. [Figure 5(b)] Figure 5(b) shows the stress distribution obtained by CAE (Computer Aided Engineering) analysis of the sample from Example 1. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below. However, this disclosure is not limited to the embodiments described below, and can be implemented in various modified forms within the scope of the essence of the disclosure.

[0011] 1.Collector terminal For example, as shown in FIG. 1, the current collecting terminal 1 of the present disclosure is a current collecting terminal 1 for the laminated battery 20. Here, the laminated battery 20 has, for example, a laminated exterior body 3, an electrode laminate 2 housed in the laminated exterior body 3, and the current collecting terminal 1, as shown in FIG. 3. The current collecting terminal 1 has a current collector connection portion 12 for electrically connecting to the current collector of the electrode laminate 2, an external terminal connection portion 11 for electrically connecting to an external terminal, and an intermediate portion 13 between the current collector connection portion 12 and the external terminal connection portion 11. For example, as shown in FIG. 2, in the intermediate portion 13, recesses 13a and protrusions 13b are alternately arranged in the width direction. FIGS. 1 and 2 are not intended to limit the present disclosure.

[0012] In the present disclosure, the current collecting terminal has a length direction, a width direction, and a thickness direction. The thickness direction of the current collecting terminal can be a direction that coincides with the thickness direction of the battery laminate. The length direction of the current collecting terminal is perpendicular to the thickness direction of the current collecting terminal and is a direction along the arrangement of the external terminal connection portion, the intermediate portion, and the current collector connection portion. The width direction of the current collecting terminal is a direction perpendicular to the thickness direction and the length direction of the current collecting terminal.

[0013] The material of the current collecting terminal may be the same as that used in a current collecting terminal generally used in a laminated battery. The material of the current collecting terminal may be a material having conductivity. Specifically, it may be selected from the group consisting of metals such as aluminum, copper, stainless steel, nickel, zinc, tin, lead, iron, tungsten, gold, and silver.

[0014] In the current collecting terminal, the ratios occupied in the length direction of the external terminal connection portion, the current collector connection portion, and the intermediate portion are not particularly limited and may be appropriately set based on, for example, the ease of connection of the external terminal connection portion to the external terminal, the ease of connection of the current collector connection portion to the current collector of the battery laminate, and the ease of fusion of the intermediate portion with the laminated exterior body.

[0015] 1-1. Intermediate portion The middle part is located between the external terminal connection part and the current collector connection part. In the middle part, recesses and protrusions are alternately arranged in the width direction. When the current collecting terminal constitutes a laminated battery, all or part of the middle part is configured to be fused with the laminated exterior body.

[0016] Due to the above configuration of the middle part, the adhesion of the current collecting terminal of the present disclosure to the laminated exterior body is improved. Although not limited by the principle, in the middle part of the current collecting terminal of the present disclosure, since recesses and protrusions are alternately arranged in the width direction, peeling between the laminated exterior body and the middle part can be suppressed. More specifically, for example, peeling between the current collecting terminal and the laminated exterior body due to heat generation during charge and discharge of the electrode laminate can be suppressed. The heat generation of the electrode laminate can heat the current collecting terminal and the laminated exterior body. When the current collecting terminal and the laminated exterior body are heated, stress is generated on the adhesion surface between the current collecting terminal and the laminated exterior body due to the linear expansion difference, which reduces the adhesion between the two and may cause peeling. Since the recesses and protrusions are alternately arranged in the width direction in the middle part of the current collecting terminal of the present disclosure, the stress generated on the adhesion surface between the current collecting terminal and the laminated exterior body can be dispersed at the boundaries of the plurality of recesses and protrusions. That is, it is possible to suppress the stress generated on the adhesion surface from concentrating at a specific location. Thereby, peeling between the two can be suppressed.

[0017] The length and number of the recesses and protrusions in the width direction in the middle part are not particularly limited, but from the perspective of suppressing peeling due to the linear expansion difference, the larger the number, the better. For example, the length of one recess and one protrusion in the width direction may be 0.0001 times to 0.25 times the length of the middle part in the width direction, respectively. The length of one recess and one protrusion in the width direction may be 0.0001 times or more, 0.001 times or more, or 0.01 times or more the length of the middle part in the width direction, and may be 0.25 times or less, 0.1 times or less, 0.01 times or less, or 0.001 times or less.

[0018] The recesses and protrusions may be created, for example, by forming multiple grooves in the middle of the current collection terminal. In this case, the bottom of the grooves becomes the recess. The grooves may have an inclination of 0° to 45° with respect to the length direction. The grooves may also be parallel to the length direction.

[0019] In a current collector terminal according to one embodiment, it is preferable that recesses and protrusions are alternately arranged in the width direction in a region including the longitudinal center line of the intermediate portion. This is because stress due to the difference in linear expansion can be particularly distributed in the region including the center point of the intermediate portion.

[0020] 1-2. Current collector connection section The current collector connection section is the part used to electrically connect to the current collector of the electrode stack when constructing a laminated battery.

[0021] 1-3. External terminal connection section The external terminal connection section is the part used to electrically connect to external terminals when a laminated battery is assembled. Normally, the external terminal connection section protrudes from the laminated casing when the laminated battery is assembled.

[0022] In at least a portion of the external terminal connection section, it is preferable that recesses and protrusions are arranged alternately in the width direction.

[0023] The presence of recesses and protrusions in the external terminal connection area increases the surface area of ​​the current collection terminal in that area.

[0024] This improves heat dissipation at the external terminal connection point, allowing heat generated inside the laminated battery to be effectively expelled to the outside. Consequently, the difference in linear expansion between the current collection terminal and the laminated casing is also suppressed.

[0025] 2. Laminated batteries The laminated battery of this disclosure has a current collector terminal of this disclosure. The laminated battery of this disclosure has a laminated casing, an electrode stack housed within the laminated casing, and a current collector terminal.

[0026] Figure 3 is a schematic diagram of a laminated battery 20 having a current collector terminal 1 according to one embodiment of the present disclosure. The laminated battery 20 has a structure in which a battery stack 2 is housed in a laminated outer casing 3. The current collector terminal 1 has an external terminal connection portion 11, a current collector connection portion 12, and an intermediate portion 13. The intermediate portion 13 is located between the external terminal connection portion 11 and the current collector connection portion 12. Although not shown, the external terminal connection portion 11 is configured to electrically connect the laminated battery 20 to an external terminal of an external circuit. Although not shown, the current collector connection portion 12 is electrically connected to the positive electrode current collector or the negative electrode current collector of the battery stack 2.

[0027] 2-1. Laminated outer casing The laminated outer casing has at least a structure in which a heat-sealable layer and a metal layer are laminated. The laminated film may also have the heat-sealable layer, metal layer and resin layer in this order along the thickness direction. Examples of materials for the heat-sealable layer include olefin resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloy, and stainless steel. Examples of materials for the resin layer include polyethylene terephthalate (PET) and nylon. The thickness of the heat-sealable layer is, for example, 40 μm to 100 μm. The thickness of the metal layer is, for example, 30 μm to 60 μm. The thickness of the resin layer is, for example, 20 μm to 60 μm. The thickness of the laminated film is, for example, 80 μm to 250 μm.

[0028] 2-2. Electrode Laminate An electrode stack typically comprises a power generation unit having 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 in the thickness direction. An electrode stack typically has multiple power generation units stacked in the thickness direction. Adjacent power generation units can share a positive electrode current collector and / or a negative electrode current collector.

[0029] The positive electrode current collector, positive electrode active material layer, electrolyte layer, negative electrode active material layer, and negative electrode current collector may be those described in, for example, Patent Document 1. [Examples]

[0030] Comparative Example 1 and Example 1 1. Sample preparation As shown in Figure 4(a), the laminated outer casing and the intermediate portion 13 of the current collector terminal 1 of Comparative Example 1 were bonded together with adhesive layer 5. In Comparative Example 1, the current collector terminal did not have recesses or protrusions in the intermediate portion 13. On the other hand, as shown in Figure 5(a), in Example 1, recesses 13a and protrusions 13b were provided in the intermediate portion 13 of the current collector terminal 1. The stress distribution was investigated by CAE analysis (Computer Aided Engineering) at the measurement area 100 enclosed by the dotted line frame.

[0031] As shown in Figure 4(b), in Comparative Example 1, it was analyzed that a stress of 68 MPa was applied to the end portion of the intermediate part 13 between the laminated casing 3 and the current collector terminal 1. On the other hand, as shown in Figure 5(b), in Example 1, the stress was distributed not only to the end portion of the intermediate part 13 between the laminated casing 3 and the current collector terminal 1, but also to the boundary portion between the recess 13a and the protrusion 13b. The stress on the end portion of the intermediate part 13 of the current collector terminal 1 was 59 MPa, which is a lower value than in Comparative Example 1. [Explanation of symbols]

[0032] 1 Current collector terminal 11 External terminal connection section 12 Current collector connection part 13. Middle section 13a Recess 13b Convex part 2-electrode stack 3. Laminated outer casing 20 Laminated Batteries 5 Adhesive layer 100 measurement sites

Claims

1. A current collection terminal for laminated batteries, The laminated battery comprises a laminated outer casing, an electrode stack housed within the laminated outer casing, and the current collector terminal. The aforementioned current collection terminal, A current collector connection part for electrically connecting the electrode stack to the current collector, External terminal connection section for electrically connecting to external terminals, and The intermediate portion between the current collector connection part and the external terminal connection part, It has and In the aforementioned intermediate portion, recesses and protrusions are arranged alternately across the width direction. Current collector terminal.

2. The current collector terminal according to claim 1, wherein the recess and the protrusion are alternately arranged in the width direction in a region including the longitudinal center line of the intermediate portion.

3. The current collector terminal according to claim 1 or 2, wherein at least a portion of the external terminal connection portion is also arranged with alternating recesses and protrusions in the width direction.

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