Method for manufacturing an energy storage device and an energy storage device

Abstract

To provide a method for producing a power storage device, and the like, which can prevent generation of resin burrs on a terminal top surface of a terminal member.SOLUTION: A method for producing a power storage device 1 includes an insert-molding step S1 of making resin members 60, 70 by insert-molding while terminal members 40, 50 are inserted in insertion holes 22a, 22b of a case member 22. This insert-molding step S1 is performed using a molding mold DE that includes a top-surface contact portion DE1a which is to face and tightly contact with terminal top surfaces 41m, 51m of the terminal members 40, 50, an inner annular flat portion DE1b and an outer annular flat portion DE1c to form frame top surfaces 61ma, 71ma of the resin members 60, 70, and an annular protruding portion DE1d to form annular grooves 63, 73 of the resin members 60, 70.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a power storage device such as a battery or a capacitor, and a power storage device, in which a terminal member is fixed to a case member forming a part of the case via a resin member.

Background Art

[0002] As a power storage device, a rectangular battery is known in which positive and negative terminal members are respectively fixed via insert-molded resin members to a rectangular parallelepiped box-shaped case. Specifically, the case includes a bottomed rectangular tubular main body member having a rectangular annular opening, and a rectangular plate-shaped lid member joined to the main body member over the entire circumference in a form that closes the opening. The positive and negative terminal members are respectively inserted into a pair of insertion holes provided in the lid member and extend from the inside to the outside of the case. And a pair of resin members join to the lid member and the terminal member while insulating between the lid member and the terminal member, and fix the terminal member to the lid member.

[0003] Such a battery is assembled by the following method. That is, with the positive and negative terminal members inserted into the pair of insertion holes of the lid member, a pair of resin members are insert-molded to integrate the terminal members to the lid member via the resin members. Next, the positive and negative terminal members of this lid assembly are respectively connected to the positive and negative current collecting portions of the electrode body. Then, this electrode body is inserted into the main body member, the opening of the main body member is closed with the lid member, and laser welding is performed over the entire circumference to form a case. As related prior art, for example, Patent Documents 1 and 2 can be cited (see FIG. 1, FIG. 2, paragraph (0018), etc. of Patent Document 1, and FIGS. 1 to 3, paragraph (0080), etc. of Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] Furthermore, as described above, there is a type of battery in which the positive and negative terminal members have flat terminal top surfaces. Specifically, in this battery, the terminal members are located on the outside of the lid member (case member) and have an outer terminal portion including a flat terminal top surface, while the resin member is located on the outside of the lid member (case member) and is frame-shaped, surrounding the outer terminal portion of the terminal member, and has an outer resin frame-shaped portion that is flush with the terminal top surface of the outer terminal portion. In this type of battery, during the aforementioned insert molding, some of the molten resin supplied around the outer terminal portion to form the outer resin frame-shaped portion flows further into the space between the terminal top surface of the outer terminal portion and the molding die, making it easy for resin burrs to form on the terminal top surface after insert molding.

[0006] This invention has been made in view of the current situation and provides a method for manufacturing an energy storage device and an energy storage device that can prevent resin burrs from forming on the top surface of the terminals of the terminal member. [Means for solving the problem]

[0007] (1) One aspect of the present invention for solving the above problems comprises a case member having an insertion hole, a terminal member inserted into the insertion hole of the case member, and an insert-molded resin member that insulates the case member and the terminal member from each other and fixes the terminal member to the case member, wherein the terminal member is located on the outside of the case member and has an outer terminal portion including a flat terminal top surface that is exposed as a whole, the resin member is located on the outside of the case member and has a frame-shaped resin outer frame portion that surrounds the outer terminal portion of the terminal member and includes a top surface of the frame that is flush with the terminal top surface of the outer terminal portion, and the top surface of the frame of the outer resin frame portion Inside This extends to the entire circumference of the above-mentioned outer resin frame-shaped part. The top surface of the above frame is divided into a double ring.A method for manufacturing an energy storage device having an annular groove, comprising an insert molding step of insert molding the resin member with the terminal member inserted into the insertion hole of the case member, wherein the insert molding step is performed using a molding die having a flat top surface contact portion that is in close contact with the terminal top surface of the terminal member, a double annular inner annular planar portion and an outer annular planar portion that surround the top surface contact portion and form the top frame surface of the resin member, and an annular protrusion provided between the inner annular planar portion and the outer annular planar portion that forms the annular groove of the resin member.

[0008] In the manufacturing method of the energy storage device described above, in the insert molding process, a resin member having an annular groove on the top surface of the resin outer frame is insert molded using a molding die having the aforementioned annular protrusion. In this way, the amount of molten resin supplied around the outer terminal portion of the terminal member for the formation of the resin outer frame is reduced, making it difficult for the molten resin to flow between the top surface contact portion of the molding die and the top surface of the terminal outer portion. Furthermore, by providing an annular protrusion on the molding die, it becomes difficult for the molten resin to move forcefully radially inward from the annular protrusion, making it difficult for the molten resin to flow between the top surface contact portion of the molding die and the top surface of the terminal outer portion. This prevents the formation of resin burrs on the top surface of the terminal.

[0009] (2) Another embodiment comprises a case member having an insertion hole, a terminal member inserted into the insertion hole of the case member, and an insert-molded resin member that insulates the case member and the terminal member from each other and fixes the terminal member to the case member, wherein the terminal member is located on the outside of the case member and has an outer terminal portion including a flat terminal top surface that is exposed as a whole, the resin member is located on the outside of the case member and has a frame-shaped resin outer frame portion that surrounds the outer terminal portion of the terminal member and includes a top surface of the frame that is flush with the terminal top surface of the outer terminal portion, and the top surface of the frame of the outer resin frame portion Inside This extends to the entire circumference of the above-mentioned outer resin frame-shaped part. The top surface of the above frame is divided into a double ring. It is an energy storage device having an annular groove.

[0010] In the aforementioned energy storage device, the insert-molded resin component has an annular groove extending around its entire circumference on the top surface of its outer resin frame-shaped portion. As a result, there are no resin burrs on the terminal top surface, and the entire terminal top surface is exposed. Therefore, the entire terminal top surface can be appropriately used for connection to external terminals such as busbars. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of the battery according to the embodiment. [Figure 2] This is a cross-sectional view of the battery according to the embodiment, along the battery height direction and the battery width direction. [Figure 3] This is a partially enlarged top view of the battery according to the embodiment, showing the vicinity of the terminal member and the resin member. [Figure 4] These are cross-sectional views taken along the arrow AA in Figures 3 and 5, showing the vicinity of the terminal member and resin member in the battery according to the embodiment. [Figure 5] These are cross-sectional views taken along the arrow BB in Figures 3 and 4, showing the vicinity of the terminal member and resin member in the battery according to the embodiment. [Figure 6] This is a flowchart of the battery manufacturing method according to the embodiment. [Figure 7] This is an explanatory diagram showing the process of injecting molten resin from the gate into the cavity during the insert molding process, relating to a battery manufacturing method according to an embodiment. [Figure 8] This is an explanatory diagram showing how a resin member is molded inside a cavity during the insert molding process, relating to a battery manufacturing method according to an embodiment. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 shows a perspective view of the battery (energy storage device) 1 according to this embodiment, and Figure 2 shows a cross-sectional view of the battery 1. Figure 3 shows the terminal member. 40 Figures 4 and 5 show enlarged top views of the vicinity of the resin member 60 and the terminal member. 40Figures 1 to 5 show a prismatic (rectangular) sealed lithium-ion secondary battery that is mounted in vehicles such as hybrid cars, plug-in hybrid cars, and electric vehicles.

[0013] Battery 1 consists of a case 10, a flat, wound electrode body 30 housed within the case 10, and positive electrode terminal members 40 and negative electrode terminal members 50, respectively, supported on the upper part 11 (lid member 22) of the case 10. The electrode body 30 is covered within the case 10 by a bag-shaped insulating holder 5 made of insulating film, which opens to the upper side AH1 in the battery height direction AH. The case 10 also contains an electrolyte 3, a portion of which is impregnated into the electrode body 30, and the remainder which accumulates on the bottom 12 of the case 10.

[0014] The case 10 is a rectangular box made of metal (aluminum in this embodiment), and has a rectangular case upper part 11 located on the upper side AH1 in the battery height direction AH, a rectangular case bottom part 12 facing it and located on the lower side AH2 in the battery height direction AH, and four rectangular case sides 13, 14, 15, 16 connecting these. The case 10 is composed of a bottomed rectangular cylindrical main body member 21 having a rectangular annular opening 21c on the upper side AH1, and a rectangular plate-shaped lid member (case member) 22 that is laser-welded around the entire circumference of the main body member 21 in a manner that closes the opening 21c.

[0015] The upper part of the case 10 (lid member 22) is provided with a safety valve 28 that breaks and opens the valve when the internal pressure of the case 10 exceeds the opening pressure. The lid member 22 is also provided with an injection hole 22k that connects the inside and outside of the case 10 and is airtightly sealed with a disc-shaped sealing member 29 made of aluminum. Further, in the lid member 22, rectangular insertion holes 22a and 22b are provided near the ends of one side BH1 and the other side BH2 in the battery width direction BH, respectively. In one insertion hole 22a, a terminal member 40 of the positive electrode made of aluminum is inserted and fixed to the lid member 22 in a state of being insulated from the case 10 via a resin member 60. In the other insertion hole 22b, a terminal member 50 of the negative electrode made of copper is inserted and fixed to the lid member 22 in a state of being insulated from the case 10 via a resin member 70.

[0016] These terminal members 40 and 50 are formed by punching a metal plate (the terminal member 40 of the positive electrode is an aluminum plate, and the terminal member 50 of the negative electrode is a copper plate) into a predetermined shape and then bending it, and have terminal outer portions 41 and 51 located outside the lid member 22 and terminal inner portions 42 and 52 mainly located inside the case 10 and connected to the terminal outer portions 41 and 51 through the insertion holes 22a and 22b. The terminal outer portions 41 and 51 are in the shape of a rectangular flat plate and have rectangular planar terminal top surfaces 41m and 51m. There is no resin burr on these terminal top surfaces 41m and 51m, and the entire terminal top surfaces 41m and 51m are exposed. Also, the terminal inner portion 42 of the positive electrode is joined and electrically connected to a positive electrode current collector portion 33 (to be described later) of the electrode body 30 inside the case 10. On the other hand, the terminal inner portion 52 of the negative electrode is joined and electrically connected to a negative electrode current collector portion 36 (to be described later) of the electrode body 30 inside the case 10.

[0017] Next, the resin members 60 and 70 will be described. . tree The resin member 60 insulates between the lid member 22 and Positive electrode the terminal member 40, and is joined to the lid member 22 and the terminal member 40 respectively, fixing the terminal member 40 to the lid member 22. Also Ta tree the resin member 70 insulates between the lid member 22 and Negative electrode the terminal member 50, and is joined to the lid member 22 and the terminal member 50 respectively, fixing the terminal member 50 to the lid member 22.

[0018] These resin members 60 and 70 are made of polyphenylene sulfide (PPS) and have resin outer frame-shaped portions 61 and 71 located on the outside EH of the lid member 22, and resin inner portions 62 and 72 located inside the case 10 and within the insertion holes 22a and 22b of the lid member 22, and connected to the resin outer frame-shaped portions 61 and 71. The resin outer frame-shaped portions 61 and 71 insulate the outer terminal portions 41 and 51 of the terminal members 40 and 50 from the lid member 22. On the other hand, the resin inner portions 62 and 72 insulate the inner terminal portions 42 and 52 of the terminal members 40 and 50 from the lid member 22.

[0019] The resin outer frame-shaped portions 61 and 71 are frame-shaped, surrounding the outer terminal portions 41 and 51 of the terminal members 40 and 50. They have frame top surfaces 61ma and 71ma that are flush with the top terminal surfaces 41m and 51m of the outer terminal portions 41 and 51, and frame side surfaces 61mb and 71mb that extend from the periphery of these frame top surfaces 61ma and 71ma to the lower AH2. Of these, the frame top surfaces 61ma and 71ma have rectangular annular grooves 63 and 73 formed around the entire circumference of the resin outer frame-shaped portions 61 and 71, with a V-shaped cross-section.

[0020] Next, the electrode body 30 will be described. This electrode body 30 is made by overlapping a strip-shaped positive electrode plate 31 and a strip-shaped negative electrode plate 34 with a pair of strip-shaped porous resin membrane separators 37 in between, winding them into a cylindrical shape, and then pressing them into a flat shape. The electrode body 30 is housed in the case 10 in a horizontal position. Of the electrode body 30, one end BH1 in the battery width direction BH is a positive electrode current collector portion 33 in which the positive electrode current collector foil 32 of the positive electrode plate 31 protrudes in a spiral shape. This positive electrode current collector portion 33 is joined to the inner terminal portion 42 of the positive electrode terminal member 40. Also, of the electrode body 30, the other end BH2 in the battery width direction BH is a negative electrode current collector portion 36 in which the negative electrode current collector foil 35 of the negative electrode plate 34 protrudes in a spiral shape. This negative electrode current collector portion 36 is joined to the inner terminal portion 52 of the negative electrode terminal member 50.

[0021] In the battery 1 of this embodiment, the resin members 60 and 70, which are molded by insert molding as described later, have annular grooves 63 and 73 that extend around the entire circumference on the top surfaces 61ma and 71ma of the resin outer frame-shaped parts 61 and 71. As a result, there are no resin burrs on the terminal top surfaces 41m and 51m of the terminal members 40 and 50, and the entire terminal top surfaces 41m and 51m are exposed. Therefore, the entire terminal top surfaces 41m and 51m can be appropriately used for connection to external terminals such as busbars.

[0022] Next, the manufacturing method of the battery 1 described above will be explained (see Figures 6 to 8). The lid member 22 and terminal members 40 and 50 are prepared in advance. The lid member 22 is obtained by punching an aluminum plate into a predetermined shape and forming a liquid injection hole 22k, insertion holes 22a and 22b, and a safety valve 28 therein. The positive terminal member 40 is obtained by punching an aluminum plate into a predetermined shape and bending a copper plate, and the negative terminal member 50 is obtained by punching a copper plate into a predetermined shape.

[0023] Then, in the "insert molding process S1" (see Figure 6), with the terminal members 40 and 50 inserted into the insertion holes 22a and 22b of the lid member 22, the resin members 60 and 70 are insert-molded to form the lid assembly 7 (see Figures 7 and 8). This insert molding process S1 is performed using a molding die DE having an upper mold DE1 and a lower mold DE2 (see Figure 7). The upper mold DE1 is equipped with a pair of injection nozzles NZ, and each injection nozzle NZ is configured to inject molten resin MR into a pair of cavities CV, which are composed of a lid member 22, terminal members 40 and 50, and the molding mold DE, respectively, through a gate GT formed at the tip of each nozzle NZ.

[0024] The upper mold DE1 also has a pair of flat top surface contact portions DE1a that are in close contact with the top surfaces 41m, 51m of the outer terminal portions 41, 51 of the terminal members 40, 50. The upper mold DE1 also has a double annular inner annular planar portion DE1b and an outer annular planar portion DE1c that surround each top surface contact portion DE1a and form the top frame surfaces 61ma, 71ma of the outer resin frame-shaped portions 61, 71 of the resin members 60, 70, and an annular protrusion DE1d provided between the inner annular planar portion DE1b and the outer annular planar portion DE1c that forms annular grooves 63, 73 on the top frame surfaces 61ma, 71ma. Furthermore, the upper mold DE1 has a pair of side forming portions DE1e that extend downward from each outer annular planar portion DE1c and form the frame side surfaces 61mb, 71mb of the resin outer frame-shaped portions 61, 71 of the resin members 60, 70, and a flat lid contact portion DE1f that surrounds each side forming portion DE1e and extends radially outward, and is in close contact with the outer surface 22m of the lid member 22.

[0025] On the other hand, the lower mold DE2 has a pair of inner surface forming portions DE2a that form the inner surfaces 62n and 72n of the inner resin portions 62 and 72 of the resin members 60 and 70, and a flat lid contact portion DE2b that surrounds each inner surface forming portion DE2a, extends radially outward, and is in close contact with the inner surface 22n of the lid member 22.

[0026] In the insert molding process S1, the lid member 22 is first placed in a predetermined position in the lower mold DE2. Subsequently, the terminal member is inserted into the insertion holes 22a and 22b of the lid member 22 placed in the lower mold DE2. 40, 5 0 Each is inserted. Then, the upper mold DE1 is moved downward and placed on top of the lower mold DE2, and the molding mold DE is closed. At this time, the top contact portions DE1a of the upper mold DE1 are in close contact with the terminal top surfaces 41m and 51m of the terminal members 40 and 50, and the lid contact portion DE1f is in close contact with the outer surface 22m of the lid member 22. Also, the lid contact portion DE2b of the lower mold DE2 is in close contact with the inner surface 22n of the lid member 22.

[0027] Next, molten resin MR is injected from each gate GT into the cavity CV and spread throughout the cavity CV. At this time, since the upper mold DE1 is provided with an annular protrusion DE1d, the amount of molten resin MR supplied around the outer terminal portions 41 and 51 of the terminal members 40 and 50 is less than when the annular protrusion DE1d is not provided. As a result, it becomes difficult for the molten resin MR to flow between the top surface contact portion DE1a of the upper mold DE1 and the top terminal surfaces 41m and 51m of the outer terminal portions 41 and 51. In addition, by providing the annular protrusion DE1d on the upper mold DE1, it becomes difficult for the molten resin MR to move forcefully radially inward from the annular protrusion DE1d. As a result, it becomes difficult for the molten resin MR to flow between the top surface contact portion DE1a of the upper mold DE1 and the top terminal surfaces 41m and 51m of the outer terminal portions 41 and 51.

[0028] Next, the molten resin MR that has filled each cavity CV is cooled to form the resin members 60 and 70 inside the cavities CV. Then, the upper mold DE1 is moved upward and the lid assembly 7, in which the terminal members 40 and 50 are fixed to the lid member 22 via the resin members 60 and 70, is removed from the lower mold DE2.

[0029] Next, in the "electrode body connection process S2" (see Figure 6), a positive electrode plate 31, a negative electrode plate 34, and a pair of separators 37, each in a strip shape, are wound together and pressed into a flat shape to prepare an electrode body 30. The positive electrode current collector portion 33 and the negative electrode current collector portion 36 of the electrode body 30 are ultrasonically welded to the inner terminal portions 42 and 52 of the terminal members 40 and 50 of the cover assembly 7 described above (see Figures 1 and 2). After that, the electrode body 30 is wrapped in a bag-shaped insulating holder 5.

[0030] Next, in the "electrode housing and case formation process S3," a main body member 21 is prepared, the electrode body 30 covered by the insulating holder 5 is inserted into the main body member 21, and the opening 21c of the main body member 21 is closed with a lid member 22. Then, the opening 21c of the main body member 21 and the peripheral edge of the lid member 22 are laser-welded around their entire circumference to form a case 10 in which the electrode body 30 is housed.

[0031] Next, in the "liquid injection and sealing process S4," the electrolyte 3 is injected into the case 10 through the injection hole 22k, impregnating the electrode body 30 with the electrolyte 3. Then, the injection hole 22k is covered from the outside with a sealing member 29, and the sealing member 29 is laser-welded to the lid member 22 to airtightly seal the space between the sealing member 29 and the lid member 22. Next, in the "initial charging and aging process S5," a charging device (not shown) is connected to the battery 1, and the battery 1 is given its initial charge. After that, the initially charged battery 1 is left to stand for a predetermined time to age. Thus, the battery 1 is completed.

[0032] As explained above, in the manufacturing method of battery 1, in the insert molding step S1, a molding die DE having an upper mold DE1 including an annular protrusion DE1d, etc., is used to form the top surface 61m of the resin outer frame-shaped parts 61, 71. a ,71m a Resin members 60 and 70 having annular grooves 63 and 73 are insert-molded into the upper mold. In this way, the amount of molten resin MR supplied around the outer terminal portions 41 and 51 of the terminal members 40 and 50 for the formation of the outer resin frame portions 61 and 71 is reduced, making it difficult for the molten resin MR to flow between the top surface contact portion DE1a of the upper mold DE1 and the top terminal surfaces 41m and 51m of the outer terminal portions 41 and 51. Furthermore, by providing an annular protrusion DE1d on the upper mold DE1, it becomes difficult for the molten resin MR to move forcefully radially inward from the annular protrusion DE1d, making it difficult for the molten resin MR to flow between the top surface contact portion DE1a of the upper mold DE1 and the top terminal surfaces 41m and 51m of the outer terminal portions 41 and 51. This prevents the formation of resin burrs on the top terminal surfaces 41m and 51m.

[0033] Although the present invention has been described above in reference to embodiments, it goes without saying that the present invention is not limited to these embodiments and can be modified and applied as appropriate without departing from its essence. [Explanation of Symbols]

[0034] 1. Battery (energy storage device) 10 cases 21 Main body components 22 Lid component (case component) 22a, 22b Through holes 30 Electrode body 40, 50 Terminal members 41,51 Terminal outer part 41m, 51m terminal top surface 60, 70 Resin components 61,71 Resin outer frame-shaped part 61ma, 71ma Frame top surface 63,73 Ring groove EH (outside of the lid component) DE molding die DE1 Upper mold DE1a Top surface contact area DE1b Inner annular planar section DE1c Outer annular plane part DE1d Annular protrusion DE2 lower mold MR molten resin

Claims

1. A case member having an insertion hole, A terminal member inserted into the insertion hole of the case member, The system includes an insert-molded resin member that insulates the case member and the terminal member from each other, and fixes the terminal member to the case member, while being joined to the case member and the terminal member, respectively. The above terminal member is Located on the outside of the above-mentioned case member, it has an outer terminal portion that includes a flat terminal top surface that is exposed as a whole, The above resin component is Located on the outside of the case member, it is frame-shaped, surrounding the outer part of the terminal member, and has a resin outer frame-shaped portion including a top surface of the frame that is flush with the top surface of the terminal outer part. Within the top surface of the resin outer frame, there is an annular groove that divides the top surface of the resin outer frame into a double ring shape around its entire circumference. A method for manufacturing an energy storage device, The process includes an insert molding step in which the resin member is insert-molded while the terminal member is inserted into the insertion hole of the case member, The above insert molding process is, The above terminal member has a flat top surface contact portion that is in close contact with the top surface of the terminal, Surrounding the above-mentioned top surface contact portion, the resin member has a double ring-shaped inner annular planar portion and an outer annular planar portion that form the top surface of the frame, It has an annular projection provided between the inner annular planar portion and the outer annular planar portion, which forms the annular groove of the resin member. Performed using a molding die A method for manufacturing energy storage devices.

2. A case member having an insertion hole, A terminal member inserted into the insertion hole of the case member, The system includes an insert-molded resin member that insulates the case member and the terminal member from each other, and fixes the terminal member to the case member, while being joined to the case member and the terminal member, respectively. The above terminal member is Located on the outside of the above-mentioned case member, it has an outer terminal portion that includes a flat terminal top surface that is exposed as a whole, The above resin component is Located on the outside of the case member, it is frame-shaped, surrounding the outer part of the terminal member, and has a resin outer frame-shaped portion including a top surface of the frame that is flush with the top surface of the terminal outer part. Within the top surface of the resin outer frame, there is an annular groove that divides the top surface of the resin outer frame into a double ring shape around its entire circumference. Energy storage device.

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