Electricity storage device

Abstract

To improve productivity of a power storage device.SOLUTION: Power storage device 100 includes a cylindrical case body 12, an electrode assembly 20, an electrolyte solution 50, a positive electrode terminal 35, a negative electrode terminal 45, a positive electrode sealing plate 30, and a negative electrode sealing plate 40. Two opposite surfaces of the cylindrical case body 12 are open. A positive electrode attachment hole 32 to which the positive electrode terminal 35 is attached is formed in the positive electrode sealing plate 30. The positive electrode sealing plate 30 covers one of the two opposing surfaces. In the negative electrode sealing plate 40, a negative electrode attachment hole 42 to which the negative electrode terminal 45 is attached is formed. The negative electrode sealing plate 40 covers the other of the two opposing surfaces. In the positive electrode sealing plate 30, a first through hole 31 through which the electrolyte 50 can be injected is formed. A second through-hole 41 through which the electrolytic solution 50 can be injected is formed in the negative electrode sealing plate 40.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2019-57421 discloses a secondary battery including an outer case, an electrode assembly, and an upper surface member. The electrode assembly is housed inside the outer case. The upper surface member is provided on the top of the outer case. The upper surface member is provided with a liquid inlet and a lid. The lid closes the liquid inlet. The upper surface member is provided with a recess. The liquid inlet is formed in the bottom surface of the recess. The lid is movable between a first position that closes the liquid inlet and a second position that is distant from the liquid inlet. The first position is inclined so as to be lower than the second position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-57421 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors wish to improve the productivity of electricity storage devices that include a cylindrical case body with two opposing open sides. [Means for solving the problem]

[0005] The electricity storage device disclosed herein includes a cylindrical case body, an electrode assembly, an electrolyte, a positive electrode terminal, a negative electrode terminal, a positive electrode sealing plate, and a negative electrode sealing plate. The cylindrical case body has openings on two opposing sides. The electrode assembly is housed within the case body. The electrolyte is housed within the case body. The positive electrode terminal is connected to the electrode assembly. The negative electrode terminal is connected to the electrode assembly. The positive electrode sealing plate has a positive electrode mounting hole to which the positive electrode terminal is attached. The positive electrode sealing plate closes one of the two opposing sides. The negative electrode sealing plate has a negative electrode mounting hole to which the negative electrode terminal is attached. The negative electrode sealing plate closes the other of the two opposing sides. The positive electrode sealing plate has a first through hole through which the electrolyte can be poured. The negative electrode sealing plate has a second through hole through which the electrolyte can be poured. Such an electricity storage device has good productivity. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view of an electricity storage device 100. As shown in FIG. [Figure 2] FIG. 2 is a perspective view of the electricity storage device 100. As shown in FIG. [Figure 3] FIG. 3 is a schematic diagram of the electricity storage device 100. As shown in FIG. [Figure 4] FIG. 4 is a schematic diagram of the electrode body 20. [Figure 5] FIG. 5 is a schematic diagram showing how the electrolyte solution 50 is poured into the case 10. As shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view of the positive electrode sealing plate 30 of the electricity storage device 100A. [Figure 7] FIG. 7 is a cross-sectional view of the negative electrode sealing plate 40 of the electricity storage device 100A. [Figure 8] FIG. 8 is a schematic diagram showing a procedure for resin-molding second sealing member 62 integrally with negative electrode sealing plate 40 and negative electrode terminal 45. As shown in FIG. [Figure 9] FIG. 9 is a schematic diagram showing a procedure for resin-molding second sealing member 62 integrally with negative electrode sealing plate 40 and negative electrode terminal 45. As shown in FIG. [Figure 10]FIG. 10 is a schematic diagram showing a second sealing member 62 according to another embodiment. [Figure 11] FIG. 11 is a schematic diagram showing a second sealing member 62 according to another embodiment. [Figure 12] FIG. 12 is a schematic diagram showing a second sealing member 62 according to another embodiment. [Figure 13] FIG. 13 is a schematic diagram showing how the electrolyte solution 50 is poured into the case 10. As shown in FIG. [Figure 14] FIG. 14 is a schematic diagram of the power storage device 100B. DETAILED DESCRIPTION OF THE INVENTION

[0007] An embodiment of the technology disclosed herein will be described below with reference to the drawings. The embodiments described herein are, of course, not intended to limit the present invention. The drawings are schematic and do not necessarily reflect the actual product. Furthermore, components and parts performing the same function are appropriately designated by the same reference numerals, and redundant explanations will be omitted where appropriate. In the following description, the reference numerals L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom, and the reference numerals X, Y, and Z in the drawings represent the short-side direction, long-side direction, and height direction of the energy storage device, respectively. However, these directions are merely used for convenience of explanation and do not in any way limit the installation form of the energy storage device.

[0008] 1 and 2 are perspective views of the electricity storage device 100. FIG. 3 is a schematic diagram of the electricity storage device 100. FIG. 3 shows a schematic view of the internal configuration of the electricity storage device 100 when the case 10 is broken along the wide surface portions 12b and 12c. In FIG. 3, the sealing member inside the case 10 is not shown. FIG. 4 is a schematic view of the electrode body 20.

[0009] In this specification, the term "electricity storage device" refers to a device that can be repeatedly charged and discharged. Electricity storage devices include secondary batteries such as lithium ion secondary batteries and nickel-metal hydride batteries. Electricity storage devices also include capacitors such as lithium ion capacitors and electric double layer capacitors. Below, an electricity storage device 100 will be described together with a method for manufacturing the electricity storage device 100, using a lithium ion secondary battery as an example.

[0010] <Electricity storage device 100> 3, the electricity storage device 100 includes a case body 12, an electrode assembly 20, an electrolyte 50 (see FIG. 5), a positive electrode terminal 35, a negative electrode terminal 45, a positive electrode sealing plate 30, and a negative electrode sealing plate 40. The case body 12, the positive electrode sealing plate 30, and the negative electrode sealing plate 40 are collectively referred to as the case 10.

[0011] Case 10 The case 10 is a housing that houses the electrode assembly 20 and the electrolyte solution 50. As shown in FIGS. 1 and 2, the outer shape of the case 10 here is a flat, bottomed, and generally rectangular parallelepiped (rectangular). The material of the case 10 is not particularly limited. The case 10 can be made of a metal such as aluminum or an aluminum alloy.

[0012] <Case body 12> The case body 12 has at least one open surface. As shown in FIG. 3, the case body 12 is a cylindrical member with two opposing faces open. The case body 12 has a rectangular cylindrical shape with both ends in the long side direction Y open. In this embodiment, the case body 12 has two opposing faces (the left and right faces in the long side direction Y) with the smallest areas of the approximately rectangular parallelepiped case 10 open. The case body 12 has open ends 12e1 and 12e2 on a first end (right side) and a second end (left side). The long side (dimension in the long side direction Y) of the case body 12 is longer than the long sides (dimension in the height direction Z) and short sides (dimension in the short side direction X) of the openings 12h1 and 12h2 at both ends.

[0013] The case body 12 is formed from a single metal plate by bending the single metal plate into a rectangular tube shape and joining the seams (for example, by welding).

[0014] As shown in FIGS. 1 and 2, the case body 12 has a pair of opposing wide surface portions 12b and 12c and a pair of opposing narrow surface portions 12a and 12d. The pair of narrow surface portions 12a and 12d are continuous with the pair of wide surface portions 12b and 12c. The "wide surface portions" are portions of the case body 12 that form the surfaces with the largest area when the energy storage device 100 is assembled. The "narrow surface portions" are portions of the case body 12 that form surfaces with an area smaller than that of the wide surface portions when the energy storage device 100 is assembled. The wide surface portions have a larger area than the narrow surface portions. The narrow surface portions 12a and 12d and the wide surface portions 12b and 12c are substantially rectangular. The dimensions of the narrow surface portions 12a and 12d and the wide surface portions 12b and 12c along the long side direction Y are substantially the same. The narrow surface portions 12a and 12d have a longer dimension along the long side direction Y than along the short side direction X. The wide surface portions 12b and 12c have a longer dimension along the long side direction Y than along the height direction Z.

[0015] The narrow surface portion 12a constitutes the upper surface of the case body 12. The narrow surface portion 12a may be provided with a gas release valve 13 that breaks when the internal pressure in the case 10 reaches or exceeds a predetermined value. Wide surface portions 12b and 12c extend downward from the narrow surface portion 12a approximately perpendicularly. The wide surface portion 12b extends from one long side (the front in this embodiment) of the narrow surface portion 12a. The wide surface portion 12c extends from the other long side (the front in this embodiment) of the narrow surface portion 12a. The wide surface portion 12b and the wide surface portion 12c face each other in the short side direction X. The wide surface portions 12b and 12c constitute the side surfaces of the case body 12. The narrow surface portion 12d is connected to the lower ends of the wide surface portions 12b and 12c. The narrow surface portion 12d extends substantially perpendicularly from the wide surface portions 12b and 12c. The narrow surface portion 12d constitutes the bottom surface of the case body 12. The narrow surface portion 12a and the narrow surface portion 12d face each other in the height direction Z. In the above-described embodiment, the narrow surface portion 12a constitutes the top surface of the case body 12, and the narrow surface portion 12d constitutes the bottom surface of the case body 12, but this is not limited to this. When the electricity storage device 100 is in use, any of the narrow surface portions 12a and 12d or the wide surface portions 12b and 12c may be arranged to constitute the top and bottom surfaces of the case body 12.

[0016] One of the pair of narrow surface portions 12a, 12d has a continuous weld 12d1 formed along the long side direction Y (the direction connecting the openings 12h1, 12h2 at both ends). The narrow surface portion 12d can be welded by, for example, laser welding. The weld 12d1 may be formed on the narrow surface portion 12a of the case body 12, or on the wide surface portions 12b, 12c.

[0017] As shown in Fig. 3, openings 12h1 and 12h2 are formed at both ends (ends 12e1 and 12e2) of the case body 12 in the long side direction Y. The openings 12h1 and 12h2 are formed by the short sides of the narrow surface portions 12a and 12d and the wide surface portions 12b and 12c. The opening 12h1 is formed at the end 12e1 on the first side (right side) of the case body 12. The opening 12h2 is formed at the end 12e2 on the second side (left side) of the case body 12. The openings 12h1 and 12h2 are substantially rectangular. When manufacturing the electricity storage device, the electrode body 20 is inserted through the openings 12h1 and 12h2.

[0018] <Electrode body 20> The electrode assembly 20 is housed in the case main body 12 (case 10). As shown in FIG. 4, the electrode assembly 20 includes a positive electrode 22, a negative electrode 24, and a separator 26. In this embodiment, the electrode assembly 20 is a wound electrode assembly in which a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 are wound with the strip-shaped separator 26 interposed therebetween. In this embodiment, the winding axis of the electrode assembly 20 is set in the long side direction Y. Therefore, the surfaces where the positive electrode 22 and the negative electrode 24 are stacked with the separator 26 interposed therebetween are exposed on the right side surface 20a and the left side surface 20b of the electrode assembly 20. The structure of the electrode assembly 20 is not particularly limited, and may be any other conventionally known structure (such as a stacked electrode assembly).

[0019] The positive electrode 22 includes a positive electrode current collector foil 22a and a positive electrode active material layer 22b formed on at least one surface of the positive electrode current collector foil 22a. The positive electrode current collector foil 22a is made of a metal material having a predetermined conductivity. The positive electrode current collector foil 22a is made of a metal foil, such as aluminum or an aluminum alloy. The positive electrode active material layer 22b is a layer containing a positive electrode active material. The positive electrode active material is a material that can reversibly absorb and release charge carriers in relation to the negative electrode active material described below. The positive electrode active material is not particularly limited. Examples of the positive electrode active material that can be used include lithium transition metal composite oxides such as lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel manganese composite oxide, and lithium nickel cobalt composite oxide. The positive electrode active material layer may contain additives such as a binder and a conductive material.

[0020] The negative electrode 24 includes a negative electrode current collector foil 24a and a negative electrode active material layer 24b formed on at least one surface of the negative electrode current collector foil 24a. The negative electrode current collector foil 24a is made of a metal material having a predetermined conductivity. The negative electrode current collector foil 24a may be made of a metal foil, such as copper or a copper alloy. The negative electrode active material layer 24b is a layer containing a negative electrode active material. The negative electrode active material is a material that can reversibly absorb and release charge carriers in relation to the positive electrode active material. The negative electrode active material is not particularly limited. Examples of the negative electrode active material include carbon materials, silicon-based materials, and mixed oxides thereof. Examples of the carbon material include graphite, hard carbon, soft carbon, and amorphous carbon. Examples of the silicon-based material include silicon and silicon oxide. The negative electrode active material layer may include additives such as a binder, a conductive material, and a thickener.

[0021] The separator 26 has a plurality of fine through-holes formed therein that allow charge carriers to pass through. The separator may include a substrate and a heat-resistant layer (HRL) formed on the surface of the substrate. A resin porous film may be preferably used as the substrate. For example, a porous sheet (film) made of a resin such as a polyolefin (e.g., polyethylene (PE) or polypropylene (PP)) or a polyamide may be used as the substrate. The substrate may have a single-layer structure or a laminate structure of two or more layers. The heat-resistant layer may contain ceramic particles and a binder. The separator may include an adhesive layer. The adhesive layer is a layer that has excellent adhesiveness to the electrode plates (positive electrode and negative electrode). The adhesive layer may be formed on the surface of the separator. A resin material, such as a fluorine-based resin or an acrylic resin, may be used as the adhesive layer. The adhesive layer may contain an inorganic filler or the like.

[0022] The electrode assembly 20 includes a positive electrode tab 23 and a negative electrode tab 25 extending in opposite directions. The positive electrode tab 23 is a portion extending from the end of the first side (right side) of the electrode assembly 20 toward the first side. The positive electrode tab 23 is a portion where the positive electrode active material layer 22b is not formed and the positive electrode current collector foil 22a is exposed. The positive electrode tab 23 is configured by stacking multiple layers of positive electrode current collector foil 22a protruding toward the first side. A positive electrode current collector 23a (see FIG. 3) is connected to the positive electrode tab 23. The positive electrode current collector 23a is a metallic conductive member connected to the positive electrode terminal 35. The positive electrode current collector 23a can be made of the same type of metal as the positive electrode current collector foil 22a. The positive electrode current collector 23a is disposed at a position corresponding to the positive electrode tab 23.

[0023] The negative electrode tab 25 is a portion extending from the end of the electrode assembly 20 on the second side (left side) toward the second side. The negative electrode tab 25 is a portion on which the negative electrode active material layer 24b is not formed and where the negative electrode current collector foil 24a is exposed. The negative electrode tab 25 is configured by stacking multiple layers of negative electrode current collector foil 24a protruding toward the second side. A negative electrode current collector 25a (see FIG. 3) is connected to the negative electrode tab 25. The negative electrode current collector 25a is a metallic conductive member connected to the negative electrode terminal 45. The negative electrode current collector 25a may be made of the same type of metal as the negative electrode current collector foil 24a. The negative electrode current collector 25a is disposed at a position corresponding to the negative electrode tab 25. The electrode assembly 20 may be housed in the case 10 while covered with an insulating film 28.

[0024] <Insulating film 28> As shown in Fig. 3, the insulating film 28 is a film that covers the electrode body 20 along the inner surface of the case body 12. The insulating film 28 is formed in a cylindrical shape. The insulating film 28 is also called an electrode body holder, and is an insulating member that covers the electrode body 20 and insulates the electrode body 20 from the case 10 (case body 12). The material of the insulating film 28 is not particularly limited, but for example, a resin material such as polypropylene (PP) or polyethylene (PE) can be used.

[0025] After the electrode body 20 is housed in the case body 12, the opening 12h1 is closed by the positive electrode sealing plate 30, and the opening 12h2 is closed by the negative electrode sealing plate .

[0026] <Positive electrode sealing plate 30> The positive electrode sealing plate 30 (first sealing plate) is a member that seals one of the two opposing surfaces. The positive electrode sealing plate 30 is attached to the end 12e1 of the case body 12 and seals the opening on the first side. The positive electrode sealing plate 30 is a plate member having a shape corresponding to the shape of the opening 12h1. The positive electrode sealing plate 30 has a shape that follows the short sides of the wide surface portions 12b, 12c and the narrow surface portions 12a, 12d. In this embodiment, the positive electrode sealing plate 30 is approximately rectangular. The material of the positive electrode sealing plate 30 is not particularly limited. The same metal as that of the case body 12 can be used for the positive electrode sealing plate 30. The positive electrode sealing plate 30 can be made of a metal such as aluminum or an aluminum alloy. A first through hole 31 is formed in the positive electrode sealing plate 30. A positive electrode mounting hole 32 is formed in the positive electrode sealing plate 30.

[0027] <First through hole 31> The first through hole 31 penetrates the positive electrode sealing plate 30. In this embodiment, the first through hole 31 is located higher than the center of the positive electrode sealing plate 30. The first through hole 31 is a hole having a size that allows the electrolyte 50 (see FIG. 5) to be poured therein. The first through hole 31 is also referred to as a liquid pouring hole. In this embodiment, the first through hole 31 has a substantially circular shape. The size of the first through hole 31 is not particularly limited as long as the size allows the electrolyte 50 to be poured from the outside to the inside of the case 10. The diameter of the first through hole 31 can be set to approximately 1 mm to 5 mm or less (for example, approximately 2 mm to 4 mm).

[0028] <Positive electrode mounting hole 32> The positive electrode mounting hole 32 is a hole to which a positive electrode terminal 35 is attached. The positive electrode mounting hole 32 penetrates the positive electrode sealing plate 30. In this embodiment, the positive electrode mounting hole 32 is substantially circular. The positive electrode mounting hole 32 is provided below the first through-hole 31. The positive electrode mounting hole 32 is located in the center of the positive electrode sealing plate 30. The positive electrode mounting hole 32 may have a larger diameter than the first through-hole 31. The positive electrode terminal 35 is attached to the positive electrode mounting hole 32 via a sealing member 60. The sealing member 60 airtightly seals the positive electrode mounting hole 32. A material with excellent chemical resistance may be used as the sealing member 60. The sealing member 60 may be made of resin.

[0029] <Positive terminal 35> The positive electrode terminal 35 is a member connected to the electrode body 20 (see FIG. 3). The positive electrode terminal 35 may be made of the same metal as the positive electrode current collector foil 22a (see FIG. 4). The positive electrode terminal 35 may be made of, for example, aluminum or an aluminum alloy. In this embodiment, the positive electrode terminal 35 has a head 35a and a shaft 35b (see FIG. 6). The head 35a is a portion exposed to the outside of the case 10. The shaft 35b is a portion inserted into the inside of the case 10 and connected to the positive electrode current collector 23a. In this embodiment, the positive electrode current collector 23a is a plate-shaped member substantially parallel to the positive electrode sealing plate 30. The positive electrode current collector 23a has a through-hole 23a1 (see FIG. 6).

[0030] The shaft portion 35b is a generally cylindrical portion. The outer diameter of the shaft portion 35b is set to be smaller than the inner diameter of the positive electrode mounting hole 32. The shaft portion 35b is inserted into the positive electrode mounting hole 32. The shaft portion 35b is connected to the positive electrode current collector 23a inside the case 10. Although not particularly limited, the shaft portion 35b can be connected to the periphery of the through-hole 23a1 of the positive electrode current collector 23a by crimping, welding, or the like. The positive electrode terminal 35 is connected to the electrode assembly 20 via the positive electrode current collector 23a, which is connected to the positive electrode tab 23.

[0031] The head 35a is provided at one end (right side) of the shaft portion 35b. In this embodiment, the head 35a is housed in a recess 30a1 (see FIG. 6) provided in the outer surface 30a of the positive electrode sealing plate 30. The recess 30a1 does not necessarily have to be provided in the positive electrode sealing plate 30. The head 35a extends radially outward relative to the shaft portion 35b. The head 35a has a substantially rectangular shape in a plan view taken along the axial direction of the shaft portion 35b. The shape of the head 35a is not particularly limited. The length of each side of the head 35a is greater than the inner diameter of the positive electrode mounting hole 32. The head 35a is connected to an external connection member such as a bus bar outside the case 10.

[0032] A negative electrode sealing plate 40 is attached to an end 12e2 of the case body 12 opposite to the end 12e1 to which the positive electrode sealing plate 30 is attached.

[0033] <Negative electrode sealing plate 40> As shown in Fig. 3, the negative electrode sealing plate 40 (second sealing plate) is a member that seals the other of the two opposing faces. The negative electrode sealing plate 40 is attached to the end 12e2 of the case body 12 and seals the opening face on the second side. The negative electrode sealing plate 40 is a plate member having a shape corresponding to the shape of the opening 12h2.

[0034] The negative electrode sealing plate 40 can be made of a material having the same shape as the positive electrode sealing plate 30. In other words, the positive electrode sealing plate 30 and the negative electrode sealing plate 40 may be made of a material having the same shape. A second through-hole 41 is formed in the negative electrode sealing plate 40. A negative electrode mounting hole 42 is formed in the negative electrode sealing plate 40. In this embodiment, the negative electrode sealing plate 40 is made of a material having the same configuration as the positive electrode sealing plate 30. Hereinafter, descriptions of the negative electrode sealing plate 40 that overlap with those of the positive electrode sealing plate 30 will be omitted as appropriate. A negative electrode terminal 45 is attached to the negative electrode mounting hole 42 via a sealing member 60.

[0035] <Second through hole 41> The second through hole 41 penetrates the negative electrode sealing plate 40. In this embodiment, the second through hole 41 is located in the center of the negative electrode sealing plate 40, similar to the first through hole 31. The second through hole 41 is a hole set to a size that allows the electrolyte solution 50 to be poured therein. The second through hole 41 is also referred to as a liquid pouring hole. The shape, dimensions, etc. of the second through hole 41 are similar to those of the first through hole 31, and therefore detailed description thereof will be omitted.

[0036] As shown in FIGS. 1 and 2, the first through hole 31 and the second through hole 41 are arranged at positions rotationally symmetrical with respect to the central axis A of the case body 12. The central axis A is parallel to the positive electrode sealing plate 30 and the negative electrode sealing plate 40. The central axis A passes through a midpoint between the positive electrode sealing plate 30 and the negative electrode sealing plate 40 and a midpoint between the pair of wide surface portions 12b, 12c. The central axis A is along the height direction Z. In this embodiment, the central axis A passes through the centers of the narrow surface portions 12a, 12d.

[0037] In this embodiment, the first through hole 31 is provided in the center of the positive electrode sealing plate 30 in the short side direction X. The second through hole 41 is provided in the center of the negative electrode sealing plate 40 in the short side direction X. The first through hole 31 and the second through hole 41 are both arranged in approximately the center of the sealing plate where they are provided in the short side direction X. Therefore, the first through hole 31 and the second through hole 41 are arranged in positions that are rotationally symmetrical with respect to the central axis A. Note that the positions of the first through hole 31 and the second through hole 41 are not limited to these positions.

[0038] <Negative electrode mounting hole 42> The negative electrode mounting hole 42 is a hole to which a negative electrode terminal 45 is attached. The negative electrode mounting hole 42 penetrates the negative electrode sealing plate 40. The shape, position, dimensions, etc. of the negative electrode mounting hole 42 are similar to those of the positive electrode mounting hole 32, and therefore detailed description thereof will be omitted.

[0039] <Negative terminal 45> The negative electrode terminal 45 is a member connected to the electrode body 20 (see FIG. 3). The negative electrode terminal 45 may be made of the same metal as the negative electrode current collector 25a (see FIG. 4). For example, copper, a copper alloy, or the like may be used as the negative electrode terminal 45. In this embodiment, the negative electrode terminal 45 has a head 45a and a shaft 45b (see FIG. 7). The shaft 45b is inserted into the case 10 and is connected to the negative electrode current collector 25a. The head 45a is exposed to the outside of the case 10. The head 45a is connected to an external connection member, such as a bus bar, outside the case 10. The shape and dimensions of the negative electrode terminal 45 are similar to those of the positive electrode terminal 35, and therefore detailed description thereof will be omitted.

[0040] During manufacture of the electricity storage device, the positive electrode sealing plate 30 and the negative electrode sealing plate 40 are attached to the ends 12e1, 12e2 of the case body 12 after the electrode body 20 is inserted into the case body 12. The process from inserting the electrode body 20 into the case body 12 to sealing the case body 12 with the positive electrode sealing plate 30 and the negative electrode sealing plate 40 can be performed, for example, by the following procedure.

[0041] The negative electrode current collector 25a is connected to the negative electrode tab 25 of the electrode assembly 20. The negative electrode current collector 25a is connected to the negative electrode terminal 45 attached to the negative electrode sealing plate 40. The negative electrode tab 25 extending along the long side direction Y is bent. The electrode assembly 20 with the negative electrode sealing plate 40 attached is inserted into the case body 12 through the opening 12h2. The positive electrode current collector 23a is connected to the positive electrode tab 23 of the electrode assembly 20. The positive electrode current collector 23a is connected to the positive electrode terminal 35 attached to the positive electrode sealing plate 30. The positive electrode tab 23 extending along the long side direction Y is bent. The positive electrode sealing plate 30 and the negative electrode sealing plate 40 are joined to the ends 12e1 and 12e2 of the case body 12, respectively. The joining of the positive electrode sealing plate 30 and the negative electrode sealing plate 40 to the case body 12 can be performed, for example, by laser welding. In addition, insulating members may be provided between the positive electrode sealing plate 30 and the electrode body 20 and between the negative electrode sealing plate 40 and the electrode body 20 to prevent direct contact between the positive electrode sealing plate 30 and the electrode body 20 and between the negative electrode sealing plate 40 and the electrode body 20.

[0042] When the electrode body 20 is inserted into the case body 12 and the openings 12h1, 12h2 of the case body 12 are closed by the positive electrode sealing plate 30 and the negative electrode sealing plate 40, the electrolyte 50 is poured into the case .

[0043] <Electrolyte 50> The electrolyte solution 50 may be any solution used in general power storage devices without any particular limitations. One example is a non-aqueous electrolyte solution in which a supporting salt is dissolved in a non-aqueous solvent. In the non-aqueous electrolyte solution used in lithium ion secondary batteries, a carbonate-based solvent such as ethylene carbonate, dimethyl carbonate, or ethyl methyl carbonate may be used as the non-aqueous solvent. A fluorine-containing lithium salt such as LiPF6 may be used as the supporting salt. The electrolyte solution 50 may contain additives as needed.

[0044] FIG. 5 is a schematic diagram showing the injection of the electrolyte solution 50 into the case 10. FIG. 5 schematically shows a cross section of the electricity storage device 100 during injection. As shown in FIG. 5, when the electrolyte solution 50 is injected, the narrow surface portion 12a constituting the upper surface of the case body 12 can be directed upward so that the first through-hole 31 and the second through-hole 41 are located upward. The injected electrolyte solution 50 can permeate the electrode assembly 20 from both side surfaces 20a, 20b. A nozzle 70 is inserted into the first through-hole 31 and the second through-hole 41, and the electrolyte solution 50 is injected. The electrolyte solution 50 injected into the case 10 permeates from both side surfaces 20a, 20b of the electrode assembly 20 toward the center of the electrode assembly 20. When a predetermined amount of the electrolyte solution 50 has been injected, the injection of the electrolyte solution 50 is stopped. After the liquid is injected, the first through-hole 31 and the second through-hole 41 can be sealed with a sealing member 65 (see FIG. 3).

[0045] The sealing member 65 is not particularly limited as long as it can seal the through holes (in this embodiment, the first through hole 31 and the second through hole 41). The sealing member 65 may be a metallic blind rivet. After sealing, treatments such as initial charging and aging are performed, and the electricity storage device 100 is produced.

[0046] The inventors have been considering using a cylindrical case body with two openings on opposing sides, sealing one side with a positive electrode sealing plate to which a positive electrode terminal is attached, and sealing the other side with a negative electrode sealing plate to which a negative electrode terminal is attached. The electrode body included in such an energy storage device may have a positive electrode tab at one end of its long side and a negative electrode tab at the other end. Therefore, inside the case, spaces for the positive electrode tab and the negative electrode tab may be provided at both ends of the long side. This eliminates the need to provide space for the positive electrode tab and the negative electrode tab around the periphery connecting the two open sides, thereby reducing dead space within the case. The volume of the electrode body within the case can be increased by the amount of dead space reduced. As a result, the electrical capacity of the energy storage device can be improved. This effect may be enhanced as the long sides of the case body are longer than the long and short sides of the openings at both ends.

[0047] However, the longer the length of the long side of the case body (the distance between the positive electrode sealing plate and the negative electrode sealing plate), the longer it may take for the electrolyte to permeate the electrode assembly after the electrolyte is poured into the case.

[0048] In the embodiment described above, the electricity storage device 100 includes a cylindrical case body 12, an electrode assembly 20, an electrolyte 50, a positive electrode terminal 35, a negative electrode terminal 45, a positive electrode sealing plate 30, and a negative electrode sealing plate 40. The cylindrical case body 12 has openings on two opposing sides. The electrode assembly 20 is housed within the case body 12. The electrolyte 50 is housed within the case body 12. The positive electrode terminal 35 is connected to the electrode assembly 20. The negative electrode terminal 45 is connected to the electrode assembly 20. The positive electrode sealing plate 30 has a positive electrode mounting hole 32 formed therein to which the positive electrode terminal 35 is attached. The positive electrode sealing plate 30 closes one of the two opposing sides (in this embodiment, the side on which the opening 12h1 is formed). The negative electrode sealing plate 40 has a negative electrode mounting hole 42 formed therein to which the negative electrode terminal 45 is attached. The negative electrode sealing plate 40 closes the other of the two opposing surfaces (in this embodiment, the surface on which the opening 12h2 is formed). A first through-hole 31 is formed in the positive electrode sealing plate 30, through which the electrolyte solution 50 can be poured. A second through-hole 41 is formed in the negative electrode sealing plate 40, through which the electrolyte solution 50 can be poured. In such an electricity storage device 100, the electrolyte solution 50 can be poured from both the positive electrode sealing plate 30 and the negative electrode sealing plate 40. Since the time required to pour the electrolyte solution 50 is shortened, the productivity of the electricity storage device 100 is good. Improving the productivity of the electricity storage device 100 can reduce manufacturing costs.

[0049] In the above-described embodiment, in the long side direction Y, the surfaces where the positive electrode 22 and the negative electrode 24 are stacked with the separator 26 interposed therebetween are exposed on the side surfaces 20a, 20b of the electrode assembly 20 (see FIG. 4 ). The electrolyte solution 50 is poured from the surfaces (the positive electrode sealing plate 30 and the negative electrode sealing plate 40) that face the side surfaces 20a, 20b of the electrode assembly 20 in the long side direction Y. Because the distance between the positive electrode sealing plate 30 and the negative electrode sealing plate 40, into which the electrolyte solution 50 is poured, and the side surfaces 20a, 20b of the electrode assembly 20 is short, the electrolyte solution 50 can quickly reach the side surfaces 20a, 20b of the electrode assembly 20. This speeds up the impregnation of the electrolyte solution 50 into the electrode assembly 20, and can improve the productivity of the electricity storage device 100. This effect can be better the closer the distances between the positive electrode sealing plate 30 and the negative electrode sealing plate 40 and the side surfaces 20a, 20b of the electrode body 20 are.

[0050] In the embodiment described above, the first through hole 31 and the second through hole 41 are arranged at positions that are parallel to the positive electrode sealing plate 30 and the negative electrode sealing plate 40 and that are rotationally symmetrical about the central axis A of the case body 12 (see FIGS. 1 and 2). With this configuration, the position into which the nozzle 70 is inserted during injection is the same for the positive electrode sealing plate 30 and the negative electrode sealing plate 40. Therefore, the device and procedure for injection can be standardized for both the positive electrode sealing plate 30 and the negative electrode sealing plate 40.

[0051] It should be noted that the injection of the electrolyte solution 50 does not necessarily have to be carried out from both the positive electrode sealing plate 30 and the negative electrode sealing plate 40. Even when the electrolyte solution 50 is injected from one of the first through hole 31 and the second through hole 41 provided in the positive electrode sealing plate 30 and the negative electrode sealing plate 40, the injection can be carried out using the same device and in the same procedure, regardless of which through hole the electrolyte solution is injected.

[0052] In the embodiment described above, the positive electrode sealing plate 30 and the negative electrode sealing plate 40 are members having the same shape. Therefore, it is not necessary to prepare different members for the positive electrode sealing plate 30 and the negative electrode sealing plate 40. This improves the productivity of the electricity storage device 100.

[0053] In the embodiment described above, sealing members 60 are provided between the positive electrode sealing plate 30 and the positive electrode terminal 35, and between the negative electrode sealing plate 40 and the negative electrode terminal 45. The configuration of the sealing member 60 may be different on the positive electrode side and the negative electrode side. Below, an electricity storage device 100A according to another embodiment in which different sealing members are used on the positive electrode side and the negative electrode side will be described.

[0054] <Electricity storage device 100A> Like the electricity storage device 100 (see FIGS. 1 and 2), the electricity storage device 100A includes a case body 12, an electrode assembly 20, an electrolyte 50, a positive electrode terminal 35, a negative electrode terminal 45, a positive electrode sealing plate 30, and a negative electrode sealing plate 40. Except for the sealing members provided on the positive electrode sealing plate 30 and the negative electrode sealing plate 40, the electricity storage device 100A is similar to the electricity storage device 100, and duplicated descriptions will be omitted where appropriate.

[0055] FIG. 6 is a cross-sectional view of the positive electrode sealing plate 30 of the power storage device 100A. FIG. 7 is a cross-sectional view of the negative electrode sealing plate 40 of the power storage device 100A. FIGS. 6 and 7 show cross sections of the positive electrode sealing plate 30 and the negative electrode sealing plate 40 taken along the wide surface portions 12b and 12c. The positive electrode tab 23 and the negative electrode tab 25 are omitted from illustration in FIGS. 1 and 2 . The power storage device 100A includes a first sealing member 61, a second sealing member 62, and a third sealing member 63, as shown in FIGS. 1 and 2 . The first sealing member 61 is interposed between the positive electrode terminal 35 and the positive electrode sealing plate 30. The second sealing member 62 is interposed between the negative electrode terminal 45 and the negative electrode sealing plate 40.

[0056] <First sealing member 61> As shown in FIG. 6 , the first sealing member 61 seals the gap between the positive electrode mounting hole 32 and the positive electrode terminal 35. The first sealing member 61 is disposed between the positive electrode sealing plate 30 and the positive electrode terminal 35 and the positive electrode current collector 23a, and insulates the positive electrode sealing plate 30 from the positive electrode terminal 35 and the positive electrode current collector 23a. A material with excellent chemical resistance may be used for the first sealing member 61. The first sealing member 61 may be a resin member. The same member as the sealing member 60 may be used for the first sealing member 61. The first sealing member 61 airtightly seals the positive electrode mounting hole 32. The first sealing member 61 is formed by integral resin molding with the positive electrode sealing plate 30 and the positive electrode terminal 35. The integral resin molding will be described later in conjunction with the second sealing member 62 (see FIG. 7 ).

[0057] The first sealing member 61 has a flat plate portion 61a, a cylindrical portion 61b, a seat portion 61c, and a side wall portion 61d. In this embodiment, the first sealing member 61 is configured from a single member. In other words, the flat plate portion 61a, the cylindrical portion 61b, the seat portion 61c, and the side wall portion 61d are integrally formed.

[0058] The flat plate portion 61a is provided inside the case 10. The flat plate portion 61a is a flat portion that follows the inner surface 30b of the positive electrode sealing plate 30. The flat plate portion 61a is generally rectangular. The flat plate portion 61a is interposed between the inner surface 30b of the positive electrode sealing plate 30 and the positive electrode current collector 23a that is generally parallel to the positive electrode sealing plate 30. The flat plate portion 61a is longer than the positive electrode current collector 23a in the up-down direction, and provides insulation between the positive electrode sealing plate 30 and the positive electrode current collector 23a. A through hole 61a1 is formed in the flat plate portion 61a, through which the shaft portion 35b of the positive electrode terminal 35 is inserted. A tubular portion 61b extends generally vertically from the edge of the through hole 61a1.

[0059] The tubular portion 61b is provided in the positive electrode mounting hole 32 of the positive electrode sealing plate 30. The tubular portion 61b extends along the inner circumferential surface of the positive electrode mounting hole 32 and the outer circumferential surface of the shaft portion 35b of the positive electrode terminal 35. The tubular portion 61b is generally cylindrical. The tubular portion 61b extends from the inside of the case 10 to the outside. The tubular portion 61b is provided from the inner surface 30b of the positive electrode sealing plate 30 to the bottom portion 30a2 of the recess 30a1 formed in the outer surface 30a. As a result, the tubular portion 61b insulates between the positive electrode sealing plate 30 and the shaft portion 35b of the positive electrode terminal 35. The tubular portion 61b is disposed in the positive electrode mounting hole 32 and ensures airtightness of the case 10. A seat portion 61c extends radially outward from the right end of the tubular portion 61b.

[0060] The seat 61c is a flat portion that fits along the bottom 30a2 of the recess 30a1 of the positive electrode sealing plate 30. The seat 61c is interposed between the bottom 30a2 of the recess 30a1 and the underside of the head 35a of the positive electrode terminal 35. This allows the seat 61c to provide insulation between the positive electrode sealing plate 30 and the head 35a. A side wall 61d extends from the outer end of the seat 61c along the inner circumferential side surface of the recess 30a1.

[0061] The side wall 61d is a cylindrical portion that follows the inner peripheral side surface of the recess 30a1. In this embodiment, the recess 30a1 and the head 35a are generally rectangular. Therefore, the side wall 61d is generally rectangular. The side wall 61d is interposed between the inner peripheral side surface of the recess 30a1 and the side surface of the head 35a of the positive electrode terminal 35. As a result, the side wall 61d insulates the positive electrode sealing plate 30 from the head 35a.

[0062] <Second sealing member 62> As shown in FIG. 7 , the second sealing member 62 seals the gap between the negative electrode mounting hole 42 and the negative electrode terminal 45. The second sealing member 62 is disposed between the negative electrode sealing plate 40 and the negative electrode terminal 45 and the negative electrode current collector 25a, and insulates the negative electrode sealing plate 40 from the negative electrode terminal 45 and the negative electrode current collector 25a. A material with excellent chemical resistance may be used for the second sealing member 62. The second sealing member 62 may be a resin member. The same member as the sealing member 60 may be used for the second sealing member 62. The second sealing member 62 hermetically seals the negative electrode mounting hole 42. The second sealing member 62 has a flat plate portion 62a, a cylindrical portion 62b, a seat portion 62c, and a side wall portion 62d. In this embodiment, the second sealing member 62, like the first sealing member 61, is composed of a single member. In other words, the flat plate portion 62a, the cylindrical portion 62b, the seat portion 62c, and the side wall portion 62d are integrally formed. The second sealing member 62 has the same shape as the first sealing member 61 (see FIG. 6) except for the flat plate portion 62a. Therefore, a description of the cylindrical portion 62b, the seat portion 62c, and the side wall portion 62d of the second sealing member 62 will be omitted.

[0063] The flat plate portion 62a is provided inside the case 10, similar to the flat plate portion 61a of the first sealing member 61. The flat plate portion 62a is a flat portion that extends along the inner surface 40b of the negative electrode sealing plate 40. The flat plate portion 62a is interposed between the inner surface 40b of the negative electrode sealing plate 40 and the negative electrode current collector 25a that is substantially parallel to the negative electrode sealing plate 40. The flat plate portion 62a is longer than the negative electrode current collector 25a in the vertical direction and provides insulation between the negative electrode sealing plate 40 and the negative electrode current collector 25a. A through hole 62a1 is formed in the flat plate portion 62a, through which the shaft portion 45b of the negative electrode terminal 45 is inserted. A cylindrical portion 62b extends substantially vertically from the edge of the through hole 62a1.

[0064] In this embodiment, the flat portion 62a has an extending portion 62a2 that extends upward beyond the upper end of the negative electrode current collector 25a. The extending portion 62a2 is a flat portion that extends along the inner surface 40b of the negative electrode sealing plate 40. The extending portion 62a2 extends upward beyond the second through hole 41 that is located in the upper part of the negative electrode sealing plate 40. In other words, the upper end of the extending portion 62a2 is located above the second through hole 41. Furthermore, the width of the extending portion 62a2 is larger than the diameter of the second through hole 41. As a result, the extending portion 62a2 of the flat portion 62a seals the second through hole 41.

[0065] The second sealing member 62 is formed integrally with the negative electrode sealing plate 40 and the negative electrode terminal 45 by resin molding.

[0066] 8 and 9 are schematic diagrams showing the procedure for integrally resin-molding second sealing member 62 with negative electrode sealing plate 40 and negative electrode terminal 45. As shown in FIG. 8, the integral resin molding is performed using molds 80, 85. Molds 80, 85 include a lower mold 80 and an upper mold 85. An example of the procedure for integral resin molding will be described below, along with the configuration of molds 80, 85.

[0067] First, negative electrode current collector 25a, negative electrode sealing plate 40, and negative electrode terminal 45 are placed in lower mold 80. Hereinafter, negative electrode current collector 25a, negative electrode sealing plate 40, and negative electrode terminal 45 will also be referred to as current collector 25a, terminal 45, and sealing plate 40, respectively.

[0068] The lower mold 80 is formed with a recess 81 in which the current collector 25a is to be placed. The recess 81 is provided with a first portion 81a in which the current collector 25a is to be placed and a second portion 81b into which the resin is to be poured. The first portion 81a forms the lower portion of the recess 81. The second portion 81b forms the upper portion of the recess 81. Both the first portion 81a and the second portion 81b are formed in positions that will overlap with the mounting hole 42 when the sealing plate 40 is placed in the lower mold 80.

[0069] The first portion 81a is formed along the outer shape of the current collector 25a. In this embodiment, the first portion 81a has a recessed shape that is approximately rectangular parallelepiped. The second portion 81b has a dimension that covers the first portion 81a in a plan view along the depth direction of the recess 81. In other words, the second portion 81b protrudes from the first portion 81a. The second portion 81b has a dimension that covers the second through-hole 41 and the mounting hole 42 when the sealing plate 40 is placed in the lower mold 80. The second portion 81b includes a portion 81b2 that extends from a portion 81b1 that is interposed between the first portion 81a and the sealing plate 40 toward the second through-hole 41. The portion 81b2 that extends toward the second through-hole 41 extends from the portion 81b1 that is interposed between the first portion 81a and the sealing plate 40 to a position that overlaps with the second through-hole 41. An injection hole 82 for injecting resin is connected to the second portion 81b. The injection hole 82 penetrates the lower mold 80 from the lower surface 80a of the lower mold 80.

[0070] The current collector 25a is placed in the first portion 81a of the recess 81 of the lower mold 80. The sealing plate 40 is placed on the upper surface 80b of the lower mold 80 (the surface facing the upper mold 85). At this time, the sealing plate 40 is placed on the lower mold 80 so that the second through-hole 41 and the mounting hole 42 of the sealing plate 40 overlap the second portion 81b. The shaft portion 45b of the terminal 45 is inserted into the mounting hole 42 so that the lower end of the shaft portion 45b is inserted into the through-hole 25a1 of the current collector 25a, and the terminal 45 is placed on the lower mold 80. The head 45a of the terminal 45 protrudes above the outer surface 40a of the sealing plate 40.

[0071] After the current collector 25a, the sealing plate 40, and the terminal 45 are arranged on the lower mold 80, an upper mold 85 is placed on the sealing plate 40. The upper mold 85 has dimensions sufficient to cover the second through-hole 41 and the mounting hole 42. A recess 86 is formed in the upper mold 85 to accommodate the head 45a of the terminal 45. The recess 86 is formed on the surface 85a that will be placed on the sealing plate 40 (the surface facing the lower mold 80). The recess 86 has dimensions sufficient to cover the head 45a in a plan view taken along the depth direction of the recess 86. The depth of the recess 86 is approximately the same as the length by which the head 45a protrudes from the outer surface 40a of the sealing plate 40. Therefore, when the upper mold 85 is placed on the sealing plate 40, the top surface of the head 45a contacts the bottom of the recess 86 of the upper mold 85. The upper mold 85 may be provided with a protrusion 87 that is inserted into the second through hole 41 of the sealing plate 40. The protrusion 87 has an outer diameter that is approximately the same as the inner diameter of the second through hole 41. The length of the protrusion 87 is approximately the same as the thickness of the sealing plate 40.

[0072] When the current collector 25a, the sealing plate 40, and the terminal 45 are placed in the molds 80, 85, a space 89 is formed inside the molds 80, 85. The space 89 is formed in the second portion 81b of the recess 81 of the lower mold 80, and between the terminal 45 and the mounting hole 42 of the sealing plate 40.

[0073] 9, resin R is injected into space 89 through injection hole 82 of lower mold 80. Resin R is injected into space 89 within molds 80, 85 from a resin supply device (not shown) via transfer pipe 82a. After the resin R is injected, molds 80, 85 are cooled. As a result, second sealing member 62, sealing plate 40, and terminal 45 are integrally molded with second sealing member 62 interposed between sealing plate 40 and terminal 45 and current collector 25a.

[0074] The sealing plate 40 and the terminal 45 may be treated to improve their adhesion to the second sealing member 62. In this embodiment, the sealing plate 40 has a roughened surface 40c with fine irregularities formed on its surface. The roughened surface 40c is provided at the interface with the flat plate portion 62a of the second sealing member 62 and at the bottom 40a2 of the recess 40a1. The roughened surface 40c is provided around the mounting hole 42 on the outer surface 40a and the inner surface 40b of the sealing plate 40. This allows the mounting hole 42 to be more airtightly sealed by the second sealing member 62. The roughened surface 40c is provided around the second through hole 41 on the inner surface 40b of the sealing plate 40. The roughened surface 40c is provided from the mounting hole 42 to the second through hole 41.

[0075] The roughened portion 40c can be formed by processes such as laser irradiation, sandblasting, and chemical etching. The surface roughness of the roughened portion 40c is higher than that of a portion that is not roughened. The roughened portion 40c has fine irregularities formed therein, which make it easier for the resin R to penetrate into the fine irregularities when the resin R is injected into the molds 80 and 85. This can improve the bonding strength between the sealing plate 40 and the second sealing member 62 after the resin R hardens. The surface roughness of the roughened portion 40c can be appropriately set depending on the viscosity of the resin R, etc. The roughened portion may also be provided at the interface between the terminal 45 and the second sealing member 62 of the terminal 45.

[0076] After the resin R has hardened, the sealing plate 40 with the second sealing member 62 integrally molded from the resin is removed from the molds 80, 85. Through the above procedure, the second sealing member 62 can be integrally molded from the resin with the sealing plate 40 and the terminal 45. After the sealing plate 40 is removed from the molds 80, 85, the terminal 45 and the current collector 25a can be connected by welding, crimping, or the like.

[0077] The configuration of the second sealing member 62 is not limited to the above-described embodiment. FIGS. 10 to 12 are schematic diagrams illustrating a second sealing member 62 according to other embodiments. The second sealing member 62 illustrated in FIGS. 10 to 12 can be fabricated by modifying the shapes of the molds 80 and 85. The second sealing member 62 illustrated in FIG. 10 has a portion 62e that fits into the second through hole 41. The portion 62e that fits into the second through hole 41 is in contact with the inner circumferential surface of the second through hole 41 and is accommodated in the second through hole 41. This prevents the sealing member 62 from coming off the second through hole 41. Furthermore, the airtightness of the second through hole 41 is improved. The portion 62e that fills the second through hole 41 extends upward from the extension portion 62a2. The second sealing member 62 illustrated in FIG. 11 has a portion 62f that seals the second through hole 41 from the outer surface 40a of the sealing plate 40. The portion 62f that seals the second through hole 41 extends from the upper end of the side wall portion 62d toward the second through hole 41 and seals the second through hole 41. The second sealing member 62 shown in FIG. 12 includes a first member 62g that fills the space between the mounting hole 42 and the terminal 45, and a second member 62h that seals the second through hole 41. In other words, the first member 62g of the second sealing member 62 and the second member 62h of the second sealing member 62 are separate members. From the viewpoint of more firmly bonding the second sealing member 62 and the sealing plate 40, the sealing plate 40 may be provided with a roughened portion 40c (see FIGS. 8 and 9) at the interface that contacts the second sealing member 62 shown in FIGS. 10 to 12.

[0078] The first sealing member 61, the positive electrode sealing plate 30, and the positive electrode terminal 35 can be integrally molded with resin by the same method as the procedure described above. The first sealing member 61, the positive electrode sealing plate 30, and the positive electrode terminal 35 are integrally molded with resin so as not to block the first through-hole 31 of the positive electrode sealing plate 30. For example, the integral resin molding can be performed using the lower mold 80 described above, which has a recess 81 formed therein that does not have the portion 81b2 extending toward the second through-hole 41.

[0079] In the above-described embodiment, the first sealing member 61 is formed by integral resin molding with the positive electrode sealing plate 30 and the positive electrode terminal 35. The second sealing member 62 is formed by integral resin molding with the negative electrode sealing plate 40 and the negative electrode terminal 45. As a result, the positive electrode sealing plate 30 and the positive electrode terminal 35, and the negative electrode sealing plate 40 and the negative electrode terminal 45 can be sealed by a single sealing member, respectively. This allows insulation and sealing between the sealing plate and the terminals to be achieved with a minimum number of parts. Furthermore, the sealing members are formed by a single integral resin molding. Therefore, the sealing between the sealing plate and the terminals can be achieved with a small number of steps.

[0080] A positive electrode sealing plate 30 having a first sealing member 61 formed thereon and a negative electrode sealing plate 40 having a second sealing member 62 formed thereon are attached to the case body 12. When the openings 12h1, 12h2 of the case body 12 are closed by the positive electrode sealing plate 30 and the negative electrode sealing plate 40, the electrolyte 50 is poured into the case 10.

[0081] FIG. 13 is a schematic diagram showing the state in which the electrolyte solution 50 is poured into the case 10. In this embodiment, of the positive electrode sealing plate 30 and the negative electrode sealing plate 40, the second through-hole 41 formed in the negative electrode sealing plate 40 is sealed with a second sealing member 62 (see FIG. 7). The first through-hole 31 formed in the positive electrode sealing plate 30 is not sealed (see FIG. 6). As shown in FIG. 13, a nozzle 70 is inserted into the unsealed first through-hole 31, and the electrolyte solution 50 is poured. After the electrolyte solution 50 is poured, the first through-hole 31 through which the nozzle 70 has been inserted is sealed with a third sealing member 63 (see FIG. 1).

[0082] <Third sealing member 63> As shown in FIG. 1 , the third sealing member 63 is a member that seals one of the first through hole 31 and the second through hole 41. The third sealing member 63 seals the other of the first through hole 31 and the second through hole 41 that is not sealed by the first sealing member 61 and the second sealing member 62. In this embodiment, the third sealing member 63 seals the first through hole 31, which serves as a liquid inlet. The third sealing member 63 is not particularly limited as long as it can seal the liquid inlet. For example, a blind rivet can be used as the third sealing member 63.

[0083] In this way, one of the first through hole 31 and the second through hole 41 (in this embodiment, the first through hole 31) is sealed by the third sealing member 63. The other of the first through hole 31 and the second through hole 41 (the second through hole 41) is sealed by the sealing member (the second sealing member 62) of the first sealing member 61 and the second sealing member 62 that is provided on the sealing plate (negative electrode sealing plate 40) that has the other through hole (the second through hole 41).

[0084] The second sealing member 62 described above has a first sealing portion 62b and a second sealing portion 62a2 (see FIG. 7). The first sealing portion 62b and the second sealing portion 62a2 are integrally formed. The first sealing portion 62b is a portion that seals the space between the negative electrode mounting hole 42 and the negative electrode terminal 45. Here, the cylindrical portion 62b corresponds to the first sealing portion 62b. The second sealing portion 62a2 is a portion that seals a through-hole other than the negative electrode mounting hole 42 (in this embodiment, the second through-hole 41). Here, the extending portion 62a2 of the flat plate portion 62a corresponds to the second sealing portion 62a2.

[0085] The positive electrode sealing plate 30 and the negative electrode sealing plate 40 each have a through hole through which liquid can be poured. Here, the second through hole 41 in the negative electrode sealing plate 40 is sealed in advance, before liquid is poured, by the second sealing member 62 that seals the negative electrode mounting hole 42. In other words, the second through hole 41 and the negative electrode mounting hole 42 are sealed by a single second sealing member 62. This reduces the number of parts required to seal the holes formed in the negative electrode sealing plate 40. Furthermore, the second through hole 41 and the negative electrode mounting hole 42 are sealed in the same process. This eliminates the need for a process to seal each of the second through holes 41 in the negative electrode sealing plate 40. The reduction in the number of parts and processes can improve the productivity of the electricity storage device.

[0086] The positive electrode sealing plate 30 and the negative electrode sealing plate 40 may be made of a material having a common shape. By using a common material for the positive electrode sealing plate 30 and the negative electrode sealing plate 40, the number of steps required for designing the sealing plates can be reduced. Furthermore, by using a common material for the positive electrode sealing plate 30 and the negative electrode sealing plate 40, the positive electrode sealing plate 30 and the negative electrode sealing plate 40 can be sealed simply by changing the configuration of the sealing members (in this embodiment, the first sealing member 61 and the second sealing member 62). An electricity storage device having such a configuration has good productivity because the sealing plates are made common and the holes formed in the sealing plates can be sealed with a small number of steps.

[0087] The configuration of second sealing member 62 described above can also be used for devices other than power storage device 100A that includes case body 12 with two opposing faces that are open, and positive electrode sealing plate 30 and negative electrode sealing plate 40 that close openings 12h1 and 12h2, respectively.

[0088] Fig. 14 is a schematic diagram of an electricity storage device 100B. As shown in Fig. 14, the electricity storage device 100B includes a case main body 112, an electrode assembly 120, a positive electrode terminal 135, a negative electrode terminal 145, a sealing plate 150, and a sealing member 162. The electrode assembly 120 is connected to the positive electrode terminal 135 via a positive electrode current collector 123a. The electrode assembly 120 is connected to the negative electrode terminal 145 via a negative electrode current collector 125a.

[0089] The case body 112 has a bottom and a rectangular cylindrical shape. The case body 112 includes a bottom surface 112a and side surfaces 112b. The bottom surface 112a is generally rectangular. The side surfaces 112b extend upward from each side of the bottom surface 112a and are generally rectangular cylindrical. An opening 112h is formed in the upper surface of the case body 112 (the surface facing the bottom surface 112a). The opening 112h is closed by a sealing plate 150. A positive electrode mounting hole 132, a negative electrode mounting hole 142, and through holes 151 and 152 are formed in the sealing plate 150. A positive electrode terminal 135 is attached to the positive electrode mounting hole 132 via a sealing member 161. A negative electrode terminal 145 is attached to the negative electrode mounting hole 142 via a sealing member 162. The positive electrode mounting hole 132 is provided at the left end of the sealing plate 150. The negative electrode terminal 145 is provided at the right end of the sealing plate 150. The through holes 151, 152 are holes having dimensions that allow an electrolyte to be poured therethrough. The first through hole 151 is provided closer to the positive electrode mounting hole 132 than the negative electrode mounting hole 142. The second through hole 152 is provided closer to the negative electrode mounting hole 142 than the positive electrode mounting hole 132.

[0090] In this embodiment, only the first through hole 151 is used for injecting the electrolyte solution. The second through hole 152, which is not used for injecting the electrolyte solution, is blocked in advance by a sealing member 162. The sealing member 162 has a first sealing portion 162a and a second sealing portion 162b. The first sealing portion 162a seals the space between the negative electrode mounting hole 142 and the negative electrode terminal 145. The second sealing portion 162b seals the second through hole 152. The configurations of the negative electrode mounting hole 142, the second through hole 152, and the sealing member 162 can be similar to the configurations of the negative electrode mounting hole 42, the second through hole 41, and the second sealing member 62 described above (see FIG. 7), and therefore detailed description thereof will be omitted.

[0091] When the injection of the electrolyte solution through the through hole 151 is completed, the through hole 151 is sealed with a sealing member 163. The configurations of the positive electrode mounting hole 132, the first through hole 151, and the sealing members 161 and 163 can be similar to the configurations of the positive electrode mounting hole 32, the first through hole 31, the first sealing member 61, and the third sealing member 63 described above (see FIG. 6 ), and therefore detailed description thereof will be omitted.

[0092] With this configuration, the same sealing plate 150 can be used whether the electrolyte is poured through one of the through holes 151, 152 or through both of the through holes. There is no need to change the configuration of the sealing plate 150 depending on the conditions during the pouring process. Furthermore, the through holes 151, 152 can be sealed as needed before the pouring process by simply changing the configuration of the sealing member. This makes the sealing plate 150 highly versatile. The electricity storage device 100B having such a sealing plate 150 can have, for example, a high degree of freedom in pouring the electrolyte solution and good productivity.

[0093] The technology disclosed herein has been described in various ways. Unless otherwise specified, the embodiments and the like described herein do not limit the present invention. Furthermore, the technology disclosed herein can be modified in various ways, and as long as no particular problems arise, each component and each process described herein can be omitted or combined as appropriate. Furthermore, this specification includes the disclosures described in the following sections.

[0094] Section 1: A cylindrical case body with two opposing open sides; an electrode body housed in the case body; an electrolyte solution contained in the case body; a positive electrode terminal connected to the electrode body; a negative electrode terminal connected to the electrode body; a positive electrode sealing plate having a positive electrode mounting hole to which the positive electrode terminal is attached and closing one of the two opposing surfaces; a negative electrode sealing plate having a negative electrode mounting hole for mounting the negative electrode terminal thereon and closing the other of the two opposing surfaces; Equipped with a first through-hole through which the electrolyte can be injected is formed in the positive electrode sealing plate; The negative electrode sealing plate has a second through-hole formed therein through which the electrolyte solution can be injected. Energy storage device.

[0095] Section 2: Item 2. The energy storage device according to item 1, wherein the first through hole and the second through hole are arranged in positions that are parallel to the positive electrode sealing plate and the negative electrode sealing plate and rotationally symmetrical with respect to the central axis of the case body.

[0096] Section 3: Item 3. The electricity storage device according to item 1 or 2, wherein the positive electrode sealing plate and the negative electrode sealing plate are members having a common shape.

[0097] Section 4: a first sealing member that seals the gap between the positive electrode mounting hole and the positive electrode terminal; a second sealing member that seals the gap between the negative electrode mounting hole and the negative electrode terminal; a third sealing member that seals one of the first through hole and the second through hole; and Furthermore, 4. The energy storage device according to any one of items 1 to 3, wherein one of the first sealing member and the second sealing member provided on a sealing plate having the other of the first through hole and the second through hole seals the other through hole.

[0098] Section 5: the first sealing member is formed by integral resin molding with the positive electrode sealing plate and the positive electrode terminal, Item 5. The power storage device according to item 4, wherein the second sealing member is formed by integral resin molding with the negative electrode sealing plate and the negative electrode terminal. [Explanation of symbols]

[0099] 10 cases 12 Case body 12a,12d Narrow side part 12b,12c Wide surface part 12d1 Welded section 12e1,12e2 End 12h1,12h2 opening 20 Electrode body 20a,20b side 22 Positive electrode 23 Positive electrode tab 23a Positive electrode current collector 23a1 Through hole 24 Negative electrode 25 Negative electrode tab 25a Negative electrode current collector 25a1 Through hole 26 Separator 28 Insulating film 30 Positive electrode sealing plate 30a,40a outer surface 30a1, 40a1 recess 30a2,40a2 bottom 30b,40b inner surface 31 First through hole 32 Positive electrode mounting hole 35 Positive terminal 35a,45a head 35b,45b Shaft part 40 Negative electrode sealing plate 40c roughened surface 41 Second through hole 42 Negative electrode mounting hole 45 Negative terminal 50 Electrolyte 60,65 Sealing member 61 First sealing member 61a,62a Flat plate part 61a1,62a1 Through hole 61b,62b Cylindrical part 61c,62c seat 61d,62d Side wall part 62 Second sealing member 62a2 Extension part (second sealing part) 62b 1st sealing part 62e,62f parts 62g First component 62h Second member 63 Third sealing member 70 nozzles 80 Lower mold (mold) 80a bottom side 80b top surface 81,86 Recess 81a Part 1 81b Part 2 81b1,81b2 parts 82 Injection hole 82a Transfer pipe 85 Upper mold (mold) 87 Convex 89 Space 100, 100A, 100B Energy Storage Device 112 Case body 112a Bottom part 112b Side part 112h opening 120 Electrode body 123a Positive electrode current collector 125a Negative electrode current collector 132 Positive electrode mounting hole 135 Positive terminal 142 Negative electrode mounting hole 145 Negative terminal 150 Sealing plate 151 First through hole 152 Second through hole 161,162,163 Sealing member 162a 1st sealing part 162b Second sealing part

Claims

1. a cylindrical case body having two opposing open sides; an electrode body housed in the case body; an electrolyte solution contained in the case body; a positive electrode terminal connected to the electrode body; a negative electrode terminal connected to the electrode body; a positive electrode sealing plate having a positive electrode mounting hole to which the positive electrode terminal is attached and closing one of the two opposing surfaces; a negative electrode sealing plate having a negative electrode mounting hole for mounting the negative electrode terminal thereon and closing the other of the two opposing surfaces; Equipped with a first through-hole through which the electrolyte can be injected is formed in the positive electrode sealing plate; The negative electrode sealing plate has a second through-hole formed therein through which the electrolyte solution can be injected. Energy storage device.

2. The power storage device according to claim 1 , wherein the first through hole and the second through hole are arranged at positions parallel to the positive electrode sealing plate and the negative electrode sealing plate and rotationally symmetrical with respect to a central axis of the case body.

3. The electricity storage device according to claim 1 , wherein the positive electrode sealing plate and the negative electrode sealing plate are members having a common shape.

4. a first sealing member that seals a gap between the positive electrode mounting hole and the positive electrode terminal; a second sealing member that seals the gap between the negative electrode mounting hole and the negative electrode terminal; a third sealing member that seals one of the first through hole and the second through hole; and Furthermore, 3. The energy storage device according to claim 1, wherein one of the first sealing member and the second sealing member provided on a sealing plate having the other of the first through hole and the second through hole seals the other through hole.

5. the first sealing member is formed by integral resin molding with the positive electrode sealing plate and the positive electrode terminal, The power storage device according to claim 4 , wherein the second sealing member is formed integrally with the negative electrode sealing plate and the negative electrode terminal by resin molding.

Images