Battery and method for manufacturing a battery

Abstract

This disclosure provides a battery that can improve the ease of assembly between the outer casing and the lid, and a method for manufacturing the battery. [Solution] The battery of the present disclosure has a rectangular flat bottom wall and a pair of main body walls that are integrally erected on the long side of the bottom wall, and an outer casing having protruding portions that extend toward each other at the ends of the pair of main body walls opposite to the bottom wall, an electrode body housed in the outer casing, and a lid that is formed in a "convex" shape having a narrow portion and a wide portion in a cross-sectional view taken from a direction along the long side of the bottom wall, and is provided such that the narrow portion is sandwiched between the protruding portions, the protruding portions of the outer casing and the lid are welded to each other, and the ratio of the stiffness modulus of the outer casing to the Young's modulus of the electrode body (Young's modulus of the electrode body: stiffness modulus of the outer casing) is 1:1 to 1:2 in the direction from the side of the protruding portions toward the side of the bottom wall.

Description

Technical Field

[0001] The present disclosure relates to a battery and a method for manufacturing the battery.

Background Art

[0002] Patent Document 1 discloses a sealed battery in which a lid is welded to seal an opening at an upper portion of a battery can, wherein at least one of a long side and a short side of an opening end portion of the battery can has a portion where a tip end thereof extends beyond an upper portion of the lid when the lid is fitted to the opening end portion, and the portion extending beyond the upper portion of the lid is bent inward and then welded for sealing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] From the viewpoint of improving the productivity of batteries, batteries that can be assembled efficiently are demanded.

[0005] An object of the present disclosure is to provide a battery that can improve the assemblability of an exterior body and a lid, and a method for manufacturing the battery.

Means for Solving the Problems

[0006] The present inventors have found that the above problems can be solved by the following means: <<Aspect 1>> An exterior body having a rectangular flat plate-shaped bottom wall, a pair of main body walls integrally erected on respective long side portions of the bottom wall, and projecting portions projecting in directions approaching each other at respective end portions of the pair of main body walls on a side opposite to the bottom wall, An electrode body housed in the exterior body, A lid is provided such that, when viewed in cross-section from a direction along the long side of the bottom wall, it is formed in a "convex" shape having a narrow portion and a wide portion, and the narrow portion is sandwiched in the protruding portion. It is equipped with, The protruding portion of the exterior body and the cover body are welded to each other. In the direction from the protruding portion towards the bottom wall, the ratio of the stiffness modulus of the outer casing to the Young's modulus of the electrode (Young's modulus of the electrode: stiffness modulus of the outer casing) is 1:1 to 1:2. battery.

[0007] 《Aspect 2》 The electrode body has a heat conductive sheet on the bottom wall side and / or the lid side. The Young's modulus of the electrode body is the Young's modulus including the electrode body and the thermal conductive sheet. The battery described in Embodiment 1.

[0008] 《Aspect 3》 The battery according to embodiment 1, wherein the electrode body has a terminal portion that can close the opening of the outer casing on the short side of the bottom wall.

[0009] Appearance 4 A method for manufacturing a battery according to any one of the three embodiments, An opening step of moving the protruding portions of the exterior body in a direction that separates them from each other to widen the ends, An electrode insertion step involves inserting the electrode into the outer casing whose end has been widened, A cover insertion step involves inserting the cover into the end of the outer casing into which the electrode body is inserted, A clamping step, in which the protruding portions are moved in a direction toward each other so that the narrow portion of the lid is clamped by the protruding portions, A pressurizing step in which the outer casing and the electrode body are pressed in a direction perpendicular to the bottom wall, A sealing step of welding the narrow portion of the cover and the end of the outer casing to each other to seal the end of the outer casing, A method for manufacturing a battery having [a certain characteristic].

[0010] Aspect 5 The production method according to Aspect 4, wherein the pressurizing step and the sealing step are performed simultaneously. Effects of the Invention

[0011] According to the present disclosure, it is possible to provide a battery that can improve the assembling performance of the exterior body and the lid body, and a method for producing the battery. Brief Description of the Drawings

[0012] [Figure 1] Figure 1 is a schematic perspective view showing the battery according to the present embodiment. [Figure 2] Figure 2 is a schematic perspective view showing the electrode body of the battery according to the present embodiment. [Figure 3] Figure 3 is a schematic perspective view showing the exterior body of the battery according to the present embodiment. [Figure 4] Figure 4 is a schematic perspective view showing the lid body of the battery according to the present embodiment. [Figure 5] Figure 5 is a schematic cross-sectional view showing the internal structure of the battery according to the present embodiment. [Figure 6] Figure 6 is a schematic cross-sectional view showing the internal structure of the battery according to the present embodiment. [Figure 7] Figure 7 is a schematic cross-sectional view showing the method for producing the battery according to the present embodiment. Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist of the disclosure.

[0014] 1. Battery The battery of this disclosure comprises an outer casing having a rectangular flat bottom wall and a pair of main body walls integrally erected on the long sides of the bottom wall, and each of the pair of main body walls having protruding portions that extend toward each other at the ends opposite to the bottom wall, an electrode body housed in the outer casing, and a lid body formed in a "convex" shape with a narrow portion and a wide portion when viewed in cross-section from a direction along the long side of the bottom wall, with the narrow portion being sandwiched between the protruding portions, the protruding portions of the outer casing and the lid body being welded to each other, and the ratio of the stiffness modulus of the outer casing to the Young's modulus of the electrode body (Young's modulus of the electrode body: stiffness modulus of the outer casing) is 1:1 to 1:2 in the direction from the side of the protruding portions toward the side of the bottom wall.

[0015] The embodiments of the present invention will be described in detail below with reference to the drawings. For the sake of explanation, in each figure, the arrow UP will indicate the upward direction of the battery, the arrow FR will indicate the forward direction of the battery, and the arrow LH will indicate the left direction of the battery. Therefore, in the following description, when the directions of up and down, front and back, and left and right are mentioned without further specification, they refer to the up and down, front and back, and left and right directions of the battery, but the invention is not particularly limited to these directions.

[0016] As shown in Figure 1, the battery 10 according to this embodiment is an all-solid-state battery and comprises an electrode body 12 shown in Figure 2, an outer casing 20 shown in Figure 3 that houses the electrode body 12, and a lid 30 shown in Figure 4 that closes the upper end of the outer casing 20 that houses the electrode body 12 (the end opposite to the bottom wall 22, which will be described later). The outer casing 20 and the lid 30 are made of a metal such as an aluminum alloy.

[0017] 1-1. Electrode body As shown in Figure 2, the electrode body 12 is formed in the shape of a rectangular flat plate with the front-to-back direction as the thickness direction. Metal terminal portions 14 are pre-attached to both the left and right sides of the electrode body 12 by welding or the like. The terminal portions 14 are formed to be slightly larger than the left and right sides of the electrode body 12 and are sized to be able to close the opening 18 of the outer casing 20, which will be described later. On the outer surface of the terminal portion 14, a pair of electrode terminals 16 with a predetermined protruding height that form a roughly square shape when viewed from the left-to-right direction are integrally formed at a predetermined interval in the vertical direction.

[0018] 1-2. Exterior As shown in Figure 3, the exterior body 20 has a rectangular, flat bottom wall 22 with the left-right direction as its longitudinal direction, and a pair of main body walls 24 that are integrally erected on the long sides of the bottom wall 22. The short sides of the bottom wall 22 of the exterior body 20 are open 18. The upper ends of the pair of main body walls 24 (the ends opposite to the bottom wall 22) each have an integrally formed overhang 26 that extends toward each other.

[0019] Here, the overhang length L (see Figure 5) of the overhanging portions 26 in the direction toward each other is the same. In other words, the narrow portion 32 of the lid 30 that seals the upper end of the outer casing 20, which will be described later, is positioned in the center of its upper end in the front-rear direction. Also, as shown in Figure 5, a heat conductive sheet 28 made of a silicone-based resin material to a predetermined thickness is attached to almost the entire inner surface (upper surface) of the bottom wall 22 of the outer casing 20.

[0020] 1-3. Lid As shown in Figure 4, the lid 30 is formed in a "convex" shape with a narrow section 32 and a wide section 34 at the top and bottom when viewed in cross-section from a direction along the long side of the bottom wall 22 of the outer casing 20. As shown in Figure 5, the width of the wide section 34 that constitutes the lower part of the lid 30 in the front-to-back direction is the same as the distance between the pair of main body walls 24, and the narrow section 32 that constitutes the upper part of the lid 30 is formed in the center of the wide section 34 in the width direction (front-to-back direction).

[0021] In other words, half the difference between the width of the wide section 34 and the width of the narrow section 32 is the same as the overhang length L of the overhang section 26, and when the lid 30 is installed on the upper end of the outer casing 20 (between the upper ends of the pair of main body walls 24), its narrow section 32 is sandwiched from the front and rear by the overhang section 26 (see Figure 5).

[0022] In other words, the opposing end faces 26A (see Figure 3) of each protruding portion 26 abut against the front-to-back oriented side surface 32A (see Figure 4) of the narrow portion 32, and the protruding portions 26 fit into the stepped portion 36 formed by the narrow portion 32 and the wide portion 34. In this state, the lid 30 is joined to the upper end of the outer casing 20 by welding, thereby sealing the upper end.

[0023] Furthermore, the upper surface (outer surface) of the narrow section 32 and the upper surface (outer surface) of the protruding section 26 are flush with each other (see Figure 5). That is, the thickness (height) H1 of the narrow section 32 is the same as the plate thickness of the protruding section 26 (exterior body 20). Also, the thickness (height) H2 of the wide section 34 is formed to be thicker than the thickness H1 of the narrow section 32 (H2 > H1). In addition, as shown in Figure 5, a heat conductive sheet 38 made of a silicone-based resin material and formed to a predetermined thickness is attached to almost the entire surface of the lower surface (inner surface of the lid 30) of the wide section 34.

[0024] The battery of this disclosure, in the above configuration, further comprises a configuration in which the protruding portion of the outer casing and the lid are welded to each other, as shown in Figure 6, and the ratio of the stiffness modulus of the outer casing to the Young's modulus of the electrode (Young's modulus of the electrode: stiffness modulus of the outer casing) is 1:1 to 1:2 in the direction from the protruding portion to the bottom wall. Here, the direction from the protruding portion to the bottom wall can also be described as the direction perpendicular to the bottom wall of the outer casing.

[0025] In the battery of this disclosure, the protruding portion of the outer casing and the lid are welded to each other, from the viewpoint of sealing the electrode body inside the outer casing. Depending on the physical properties of the materials of the electrode body and the outer casing and the manufacturing method, such welding may cause the outer casing to bend or deform because the electrode body is less deformable than the outer casing. This deformation of the outer casing may result in insufficient contact between the protruding portion of the outer casing and the lid, making welding difficult.

[0026] In the battery of this disclosure, the ratio of the stiffness modulus of the outer casing to the Young's modulus of the electrode body (Young's modulus of the electrode body: stiffness modulus of the outer casing) is 1:1 to 1:2 in the direction from the protruding portion to the bottom wall. As a result, the outer casing is less prone to deformation such as bending after the battery is housed inside the outer casing, which leads to good contact between the protruding portion of the outer casing and the lid, and facilitates welding of these components.

[0027] Furthermore, in this disclosure, from the viewpoint of ensuring the heat dissipation of the battery, the electrode body may have a thermal conductive sheet on the bottom wall side and / or the lid side. Also, since the thermal conductive sheet made of resin is relatively flexible, the rigidity of the electrode body can be mitigated by the thermal conductive sheet made of resin, and the Young's modulus can be reduced when the electrode body and thermal conductive sheet are considered as a single unit. In this case, the Young's modulus of the electrode body is defined as the Young's modulus including the electrode body and the thermal conductive sheet.

[0028] The Young's modulus can be determined from the longitudinal strain stress when a force k0 acts to press the electrode body 10 toward the bottom wall 22, as shown in Figure 6. The stiffness modulus can be determined from the stress when a force k1 acts to bend the protruding portion 26 of the outer casing 20 from the protruding portion toward the bottom wall. Here, the stress can be calculated based on the following formula for calculating the stiffness modulus: Stress σ = Deflection due to load δ1 + Deflection due to the self-weight of the protruding part δ2 Here, Deflection due to load δ1 = (F × L 3 ) / (3×E×I) Deflection due to its own weight δ² = (w × L 4 ) / (8×E×I) Here, F is the load, L is the length of the overhang, and E is Young's modulus. Also, I (second moment of area) = b × h 3 The equation is / 12, and w = ρ × g × A. Note that b is the width of the overhang, h is the height of the overhang, A is the cross-sectional area of ​​the section perpendicular to the longitudinal direction of the overhang, ρ is the density of the overhang, and g is the acceleration due to gravity. Here, stress σ = (F × L) / Z, and Z (section modulus) = b × h 2 Since it is / 6, the stiffness (Young's modulus) can be calculated by combining it with the above formula.

[0029] 2. Battery manufacturing method First, as shown in Figure 6(A), a heat conductive sheet 28 is attached to the inner surface of the bottom wall 22 of the outer casing 20. Then, as shown in Figure 6(B), the protruding portions 26 of the outer casing 20 are moved in a direction that separates them from each other to widen the upper end of the outer casing 20 (opening process), and the electrode body 12 is inserted into the widened upper end of the outer casing 20 from above (electrode body insertion process). Figure 6(C) shows the state in which the electrode body 12 has been inserted (housed) in the outer casing 20.

[0030] Next, as shown in Figure 6(D), the lid 30 is inserted into the upper end of the outer casing 20 in which the electrode body 12 is inserted (housed) (lid insertion step). A heat conductive sheet 38 is attached to the lower surface of the wide portion 34 of the lid 30 in advance. Although not shown in the illustration, at this time as well, as shown in Figure 6(B), the protruding portions 26 of the outer casing 20 are moved in a direction that separates them from each other to widen the upper end of the outer casing 20 and insert the lid 30.

[0031] Once the lid 30 is inserted onto the upper end of the outer casing 20 (above the electrode body 12), the protruding portions 26 are moved toward each other, as shown in Figure 6(E), to clamp the narrow portion 32 of the lid 30 with the protruding portions 26, thereby sealing the upper end of the outer casing 20 (sealing process). That is, with the end faces 26A (see Figure 3) of each protruding portion 26 in contact with each side surface 32A (see Figure 4) of the narrow portion 32, the lid 30 is joined (sealed) to the upper end of the outer casing 20 by welding.

[0032] The manufacturing method of this disclosure includes a pressurizing step in which the outer casing 20 and the electrode body 10 are pressed in a direction perpendicular to the bottom wall 22, either before or simultaneously with the sealing step. The pressurizing is performed with enough force to bring the lid 30 and the upper end of the outer casing 20 into contact. In the welding (sealing step) after insertion of the electrode body 10, if the electrode body 10 is hard, the outer casing 20 may bend and open up without being able to maintain its shape. Therefore, by suppressing the deformation of the outer casing 20 with the pressurizing step, the sealing step can be performed more easily, in conjunction with the fact that the ratio of the stiffness modulus of the outer casing to the Young's modulus of the electrode body is 1:1 to 1:2.

[0033] Although the battery 10 according to this embodiment has been described above based on the drawings, the battery 10 according to this embodiment is not limited to the illustrated version, and can be appropriately modified in design without departing from the spirit of the present invention. [Examples]

[0034] 3. Examples 1-11 and Comparative Examples 1-14 3-1. Fabrication of electrode body and casing Electrode bodies A1-A5, outer casings B1-B5, and a cover were formed as shown in Figures 2-4. The Young's modulus and stiffness modulus of the electrode bodies are as shown in Table 1 below.

[0035] 3-2. Battery assembly The battery was assembled by combining electrode bodies A1-A5 and casing bodies B1-B5 as shown in Table 2, using the method shown in Figure 6. The welding of the casing body to the cover was performed by applying pressure perpendicular to the bottom wall of the casing body so that the casing body and the electrode body were in contact with the upper end of the cover.

[0036] 3-3.Results The results are shown in Tables 1 and 2.

[0037] [Table 1]

[0038] [Table 2]

[0039] As shown in Table 1, welding was successful in combinations where the ratio of the Young's modulus of the electrode to the stiffness modulus of the casing (Young's modulus of the electrode: stiffness modulus of the casing) was 1:1 to 1:2 (each example). In other combinations (each comparative example), welding was not performed sufficiently, and leakage was observed. [Explanation of Symbols]

[0040] 10 batteries 12 Electrode body 20 Exterior 22 Bottom wall 24 Main wall 26 Overhang 30 Lid 32 Narrow part 34 Wide section

Claims

1. An exterior body having a rectangular, flat bottom wall and a pair of main walls integrally erected on the long sides of the bottom wall, and each of the pair of main walls having an overhang that extends toward each other at the end opposite to the bottom wall, The electrode body housed in the aforementioned outer casing, A lid is provided such that, when viewed in cross-section from a direction along the long side of the bottom wall, it is formed in a "convex" shape having a narrow portion and a wide portion, and the narrow portion is sandwiched in the protruding portion. It is equipped with, The protruding portion of the exterior body and the cover body are welded to each other. In the direction from the protruding portion towards the bottom wall, the ratio of the stiffness modulus of the outer casing to the Young's modulus of the electrode (Young's modulus of the electrode: stiffness modulus of the outer casing) is 1:1 to 1:

2. battery.

2. The electrode body has a heat conductive sheet on the bottom wall side and / or the lid side. The Young's modulus of the electrode body is the Young's modulus including the electrode body and the thermal conductive sheet. The battery according to claim 1.

3. The battery according to claim 1, wherein the electrode body has a terminal portion that can close the opening of the outer casing on the short side of the bottom wall.

4. A method for manufacturing a battery according to any one of claims 1 to 3, An opening step of moving the protruding portions of the exterior body in a direction that separates them from each other to widen the ends, An electrode insertion step involves inserting the electrode into the outer casing whose end has been widened, A cover insertion step involves inserting the cover into the end of the outer casing into which the electrode body is inserted, A clamping step, in which the protruding portions are moved in a direction toward each other so that the narrow portion of the lid is clamped by the protruding portions, A pressurizing step in which the outer casing and the electrode body are pressed in a direction perpendicular to the bottom wall, A sealing step of welding the narrow portion of the cover and the end of the outer casing to each other to seal the end of the outer casing, A method for manufacturing a battery having [a certain characteristic].

5. The manufacturing method according to claim 4, wherein the pressurizing step and the sealing step are performed simultaneously.

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