Power storage device and method for manufacturing the same

Abstract

To improve the anchor effect and sealing properties of an insulating resin material against the uneven surface formed in a seal portion of a connection portion that connects a current collecting terminal and an insulating resin material of a case member, thereby shortening a pressure holding and cooling time when molding the insulating resin material, and thereby improving productivity.SOLUTION: A power storage device 10 includes a current collecting terminal 3, a case member 4 having a terminal insertion hole 41, and an insulating resin member 5 connecting the current collecting terminal to a hole outer edge portion 411 and a hole surrounding portion 412 of the terminal insertion hole, the current collecting terminal and the case member have sealing portions 31T, 41T that ensure airtightness inside the case at connection portions 3T, 4T connected to the insulating resin member, the sealing portions are roughened surfaces 3S, 4S, the insulating resin member has a thermoplastic resin material NJ containing a high molecular weight substance KB having a molecular weight of 10,000 or more and a low molecular weight substance TB having a molecular weight of 500 to 5000, the low molecular weight substance is contained in the thermoplastic resin material at 5 to 15 wt.% and is unevenly distributed toward the roughened surface.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to an electricity storage device and a method for manufacturing an electricity storage device. [Background technology]

[0002] For example, Patent Document 1 discloses a sealed storage battery in which an insulating resin member is molded integrally (insert molded) with a current collector terminal and a case member so as to fill the gap between the current collector terminal and a terminal insertion hole of the case member. It also discloses that a roughened surface is formed on at least a part of the contact portion of the current collector terminal and the case member that contacts the insulating resin member, thereby enhancing the anchor effect of the insulating resin member on the roughened uneven surface. The insulating resin member is a resin material that has heat resistance, moldability, insulation properties, sealing properties, and resistance to electrolyte, and PPS resin (polyphenylene sulfide resin) is exemplified. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-86813 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the insulating resin member such as the PPS resin generally contains a large amount of high molecular weight substances having a molecular weight of 10,000 or more, and the high molecular weight substances have a large molecular size in a molten state, and tend to have difficulty penetrating into the narrow gaps between the convex portions of the roughened uneven surface. Therefore, there was a problem that the molten resin of the insulating resin member could not sufficiently penetrate into the gaps of the roughened uneven surface during molding, and the anchor effect of the insulating resin member on the uneven surface could not be enhanced. In addition, since the molten resin of the insulating resin member could not sufficiently penetrate into the gaps of the roughened uneven surface, cavities were formed in the gaps of the uneven surface, and the sealing property of the insulating resin member at the contact portion with the current collecting terminal and the case member was reduced.

[0005] In addition, the molecular size of the insulating resin material of the above-mentioned high molecular weight substance is large in a molten state, and it is difficult for it to penetrate into the narrow gaps of the uneven surface roughened during molding, so after the molten resin is completely injected into the cavity of the molding die, it is necessary to take time to force the molten resin into the gaps of the uneven surface while maintaining pressure and cooling. Therefore, there is a problem that the time required for maintaining pressure and cooling is long, which reduces productivity.

[0006] The present disclosure has been made in consideration of such problems, and the first problem to be solved is to improve the anchor effect and sealing property of the insulating resin member against the roughened uneven surface in an electricity storage device in which a roughened surface is formed in the seal portion of the connection portion where the current collector terminal and the insulating resin member of the case member are connected. The second problem is to improve productivity by shortening the pressure holding and cooling time when the insulating resin member is integrally molded (insert molding) with the current collector terminal and the case member. [Means for solving the problem]

[0007] (1) One aspect of the disclosed technique for solving the above problems is an electricity storage device comprising: a current collecting terminal; a case member having a terminal insertion hole through which the current collecting terminal is inserted; and an insulating resin member into which the current collecting terminal and the case member are insert-molded so as to connect a hole insertion portion of the current collecting terminal to an outer edge portion and a peripheral portion of the terminal insertion hole, wherein the current collecting terminal and the case member have sealing portions at connection portions where they are connected to the insulating resin member to ensure airtightness inside the case, and the sealing portions are each a roughened surface having an uneven surface formed thereon, and the insulating resin member has a thermoplastic resin material containing a high molecular weight substance having a molecular weight of 10,000 or more and a low molecular weight substance having a molecular weight of 500 to 5,000, and the low molecular weight substance is contained in the thermoplastic resin material at 5 to 15 wt % and is unevenly distributed toward the roughened surface.

[0008] (2) The electricity storage device according to (1) is preferably such that the uneven surface is formed to have an arithmetic mean roughness of 30 to 500 nm, and a low molecular weight material having a molecular weight of 500 to 1500 is increased in a resin surface layer portion adjacent to the uneven surface compared to an inner resin layer portion away from the uneven surface.

[0009] (3) A manufacturing method for an electricity storage device as described in (1) or (2) is preferably a manufacturing method for an electricity storage device, further comprising a resin injection step of using a molding die in which the current collecting terminal and the case member are inserted to injection-molde the insulating resin member, and filling gaps between convex portions on the uneven surface with the insulating resin member until the injection of the molten insulating resin member into a cavity of the molding die is completed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an exploded perspective view of one mode (the present embodiment) of an electricity storage device according to the present embodiment. [Diagram 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Diagram 3] FIG. 3 is an enlarged cross-sectional view of a portion B shown in FIG. [Figure 4] FIG. 4 is an integrated molecular weight distribution curve showing the proportion of each molecular weight in the entire resin in the thermoplastic resin material of the insulating resin member of the present embodiment and the thermoplastic resin material of the insulating resin member of the comparative example shown in FIG. [Diagram 5] FIG. 4 is a differential molecular weight distribution curve diagram showing the distribution state of each molecular weight in the thermoplastic resin material of the insulating resin member of the present embodiment shown in FIG. 3 and the thermoplastic resin material of the insulating resin member of the comparative example. [Figure 6] 6 is a schematic cross-sectional view showing the positional relationship between high molecular weight and low molecular weight molecules in the thermoplastic resin material of the insulating resin member of this embodiment shown in FIGS. 4 and 5 in the resin surface layer portion of the roughened surface shown in FIG. 3. [Figure 7] 6 is a schematic cross-sectional view showing the positional relationship between high molecular weight and low molecular weight molecules in the thermoplastic resin material of the insulating resin member of the comparative example shown in FIG. 4 and FIG. 5 in the resin surface layer portion of the roughened surface shown in FIG. 3. [Figure 8] 13 is a cross-sectional view of a molding die used in a method for manufacturing an electricity storage device according to another embodiment in a closed state. FIG. [Figure 9] 9 is a flowchart of a method for producing the electricity storage device using the molding die shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Description of this energy storage device> Next, one aspect (this embodiment) of the electricity storage device 10 according to the embodiment of the disclosed technique will be described in detail with reference to the drawings. Fig. 1 shows an exploded perspective view of one aspect (this embodiment) of the electricity storage device according to the embodiment. Fig. 2 shows a cross-sectional view taken along line AA shown in Fig. 1. Fig. 3 shows an enlarged cross-sectional view of part B shown in Fig. 2.

[0012] One form (this embodiment) of an electricity storage device 10 according to an embodiment of the disclosed technology includes a current collecting terminal 3, a case member 4 having a terminal insertion hole 41 through which the current collecting terminal 3 is inserted, and an insulating resin member 5 into which the current collecting terminal 3 and the case member 4 are insert-molded so as to connect the hole insertion portion 31 of the current collecting terminal 3 to the hole outer edge portion 411 and hole surrounding portion 412 of the terminal insertion hole 41, as shown in Figures 1 to 3.

[0013] Here, the present electricity storage device 10 includes an electrode body 1, a case body 2 having an opening 21 and housing the electrode body 1, a current collecting terminal 3 electrically connected to the electrode body 1, a case cover body (corresponding to a "case member") 4 having a terminal insertion hole 41, holding the electrode body 1 via the current collecting terminal 3 and the current collecting terminal 3 inserted into the terminal insertion hole 41 and sealing the opening 21 of the case body 2, and an insulating resin member 5 in which the current collecting terminal 3 and the case member 4 are insert-molded so as to connect the hole insertion portion 31 of the current collecting terminal 3 to the hole outer edge portion 411 and the hole surrounding portion 412 of the terminal insertion hole 41. However, the present electricity storage device 10 is not necessarily limited to the above configuration. For example, the terminal insertion hole 41 may be formed in the case body 2.

[0014] Here, the electric storage device 10 means a general electric storage device capable of extracting electric energy, and includes, for example, a primary battery, a secondary battery, an electric double layer capacitor, and the like. The electrode body 1 is a known electrode body in which a positive electrode body having a positive electrode active material layer and a negative electrode body having a negative electrode active material layer are laminated via a separator. The case body 2 is a bottomed cylindrical body having an opening 21 formed at the upper end, and is made of, for example, aluminum or an aluminum alloy. The current collector terminal 3 is composed of a positive electrode current collector terminal 3a connected to the positive electrode side of the electrode body 1, and a negative electrode current collector terminal 3b connected to the negative electrode side. The positive electrode current collector terminal 3a is made of, for example, aluminum or an aluminum alloy, and the negative electrode current collector terminal 3b is made of, for example, copper or a copper alloy. The case lid body (case member) 4 is formed as a flat plate-shaped lid body made of, for example, aluminum or an aluminum alloy. The case cover (case member) 4 is formed with a terminal insertion hole 41 through which the current collector terminal 3 is inserted, a known safety valve 42, and a liquid injection hole 43 through which the electrolyte is injected. The insulating resin member 5 has a thermoplastic resin material NJ that has heat resistance, formability, insulating properties, sealing properties, resistance to the electrolyte, and the like. Here, the thermoplastic resin material NJ is made of PPS resin (polyphenylene sulfide resin), but is not limited to this. The insulating resin member 5 may contain a reinforcing material such as glass fiber, an elastomer, or the like in the thermoplastic resin material NJ.

[0015] As shown in FIG. 3, the current collecting terminal 3 and the case member 4 are provided with seal parts 31T and 41T at the connection parts 3T and 4T connected to the insulating resin member 5 to ensure airtightness inside the case. The seal part 31T of the current collecting terminal 3 is formed in an annular shape around the entire circumference of the hole insertion part 31, and the seal part 41T of the case member 4 is formed in an annular shape along the terminal insertion hole 41 at the hole surrounding part 412. The current collecting terminal 3 is provided with an external connection part 32 bent at a right angle to the hole insertion part 31, and the case member 4 side of the external connection part 32 is connected to the insulating resin member 5. The seal parts 31T and 41T are roughened surfaces 3S and 4S on which uneven surfaces 31S and 41S are formed, respectively. The uneven surfaces 31S and 41S are formed to have an arithmetic mean roughness of, for example, 30 to 500 nm. 3 indicates a resin inner layer (core layer) having a separation distance d1 of 500 μm or more from the connecting portions 3T, 4T, and Q indicates a resin surface layer (skin layer) having a separation distance d2 of about 10 to 20 μm from the connecting portions 3T, 4T. The uneven surfaces 31S, 41S having an arithmetic mean roughness of 30 to 500 nm can be formed by, for example, irradiating the surfaces of the connecting portions 3T, 4T with a pulsed laser beam traveling in a certain direction to disperse fine mist-like metal vapor, which then accumulates in a forest-like pattern and solidifies.

[0016] FIG. 4 shows an integral molecular weight distribution curve diagram showing the ratio of each molecular weight to the whole resin in the thermoplastic resin material of the insulating resin member of this embodiment shown in FIG. 3 and the thermoplastic resin material of the insulating resin member of the comparative example. FIG. 5 shows a differential molecular weight distribution curve diagram showing the distribution state for each molecular weight in the thermoplastic resin material of the insulating resin member of this embodiment shown in FIG. 3 and the thermoplastic resin material of the insulating resin member of the comparative example. FIG. 6 shows a schematic cross-sectional view showing the positional relationship between the high molecular weight and the low molecular weight in the thermoplastic resin material of the insulating resin member of this embodiment shown in FIG. 4 and FIG. 5 in the resin surface layer part of the roughened surface shown in FIG. 3. FIG. 7 shows a schematic cross-sectional view showing the positional relationship between the high molecular weight and the low molecular weight in the thermoplastic resin material of the insulating resin member of the comparative example shown in FIG. 4 and FIG. 5 in the resin surface layer part of the roughened surface shown in FIG. 3.

[0017] Here, the integral molecular weight distribution curve shown in FIG. 4 and the differential molecular weight distribution curve shown in FIG. 5 can be obtained by the GPC method (Gel Permeation Chromatography) in the following procedure. First, a resin sample is dissolved in a solvent liquid to prepare a sample solution. Next, the sample solution is passed through a column filled with porous granular gel having fine pores, and the molecular size in the passed solution is detected by a detector, and the detection intensity of the molecular size versus the detection time is obtained as a chromatogram. Next, the detection time is converted to molecular weight using a calibration curve based on a standard substance whose relationship between detection time and molecular weight is known. Then, the molecular weight (logarithmic value) is plotted on the horizontal axis and the concentration fraction on the vertical axis. The integral molecular weight distribution curve shown in FIG. 4 is completed by sequentially accumulating the plotted concentration fractions, plotting the molecular weight (logarithmic value) on the horizontal axis and the accumulated value of the concentration fraction on the vertical axis. Since the "accumulated value of the concentration fraction" corresponds to the "proportion in the entire resin", the vertical axis in FIG. 4 is displayed as "proportion in the entire resin (weight %)".

[0018] Next, the slope of the curve (differential value) at each molecular weight is determined in the integral molecular weight distribution curve shown in Figure 4. The differential molecular weight distribution curve shown in Figure 5 is completed by plotting the molecular weight (logarithmic value) on the horizontal axis and the differential value on the vertical axis. Therefore, the vertical axis of the differential molecular weight distribution curve is "dW / d(LogM)" (the value obtained by differentiating the concentration fraction by the logarithmic value of the molecular weight), which is proportional to the "concentration fraction," and is therefore displayed here as the "concentration index." Specifically, a high-temperature GPC apparatus (instrument no. GPC-H-2, Polymer Laboratories PL-GPC220), a detector (RI: Refractive Index Detector), a column (Shodex UT-G (guard column), and a solvent (1-chloronaphthalene (Fujifilm Wako Pure Chemical Industries, Ltd.)) were used. The sample solution was filtered using a 0.5 μm filter, and then 0.2 mL was injected into the column heated to 210° C. at a flow rate of 0.7 mL / min. The integral molecular weight distribution curve shown in FIG. 4 and the differential molecular weight distribution curve shown in FIG. 5 can be automatically created using the application software attached to the high-temperature GPC apparatus (instrument no. GPC-H-2, Polymer Laboratories PL-GPC220).

[0019] The integral molecular weight distribution curve 5W shown in FIG. 4 represents the ratio of the molecular weight of the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment to the entire resin, and the integral molecular weight distribution curve 5CW represents the ratio of the molecular weight of the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example to the entire resin. X1 on the horizontal axis represents a molecular weight of 500, and X3 represents a molecular weight of 5000. The thermoplastic resin material NJ of the insulating resin member 5 of this embodiment contains about 10% by weight of low molecular weight material TB having a molecular weight of 500 to 5000, and about 77% by weight of high molecular weight material KB having a molecular weight of 10000 or more. In contrast, the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example contains about 3% by weight of low molecular weight material TB3 having a molecular weight of 1000 to 5000, and about 78% by weight of high molecular weight material KB having a molecular weight of 10000 or more. Therefore, the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment and the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example are common in that they both contain just under 80% by weight of high molecular weight material KB having a molecular weight of 10,000 or more, but they differ greatly in the proportions of low molecular weight material TB, TB3 having a molecular weight of 5,000 or less in the overall resin, and they are also greatly different in that low molecular weight material having a molecular weight of 1,000 or less is contained in the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment but not contained in the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example.

[0020] Here, the low molecular weight substance TB having a molecular weight of 500 to 5,000 has a smaller molecular size in the molten state and has high fluidity and wettability in the molten state compared to the high molecular weight substance KB having a molecular weight of 10,000 or more, and therefore has a tendency to gather on the roughened surfaces 3S and 4S during molding.

[0021] Therefore, as shown in Fig. 6, in the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment, the low molecular weight substance TB having a molecular weight of 500 to 5000 is separated from the high molecular weight substance KB having a molecular weight of 10000 or more with the fountain flow of the molten resin during molding, and is collected in large amounts in the resin surface layer portion (skin layer) Q adjacent to the roughened surfaces 3S, 4S, and is in a state where it is relatively easy to penetrate into the narrow gap SK between the convex parts 311S, 411S of the roughened uneven surfaces 31S, 41S. As a result, the resin containing the low molecular weight substance TB having a molecular weight of 500 to 5000 is filled into the narrow gap SK between the uneven surfaces 31S, 41S, and the anchor effect of the insulating resin member 5 to the uneven surfaces 31S, 41S can be enhanced. In addition, by filling the narrow gap SK between the uneven surfaces 31S, 41S with the resin containing the low molecular weight substance TB, cavities are unlikely to occur in the gap SK, and the sealing property of the insulating resin member 5 is improved.

[0022] In contrast, the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example contains only about 3% by weight of low molecular weight substance TB3 having a molecular weight of 1000 to 5000, so that even if the low molecular weight substance TB3 having a molecular weight of 1000 to 5000 is separated from the high molecular weight substance KB having a molecular weight of 10,000 or more with the fountain flow of the molten resin during molding, only a small amount of it gathers in the resin surface layer portion (skin layer) Q adjacent to the roughened surfaces 3S, 4S, and does not easily enter the narrow gap SK between the convex portions 311S, 411S of the roughened uneven surfaces 31S, 41S. As a result, there are parts where the low molecular weight substance TB3 having a molecular weight of 1000 to 5000 is not filled in the narrow gap SK between the uneven surfaces 31S, 41S, and the anchor effect of the insulating resin member 5 to the uneven surfaces 31S, 41S is reduced. Furthermore, since the low molecular weight material TB3 is not filled in the narrow gaps SK between the uneven surfaces 31S and 41S, voids KD are generated in the gaps SK, and the sealing performance of the insulating resin member 5C is also reduced.

[0023] On the other hand, if the low molecular weight substance TB having a molecular weight of 500 to 5000 is excessively increased, for example, if it is contained in an amount of about 20% by weight in the entire resin material in the thermoplastic resin material NJ of the insulating resin member 5, the heat resistance and the like will decrease, making it difficult to maintain the characteristic values ​​required for the electricity storage device 10. For this reason, it is preferable that the content of the low molecular weight substance TB having a molecular weight of 500 to 5000 in the entire resin material in the thermoplastic resin material NJ of the insulating resin member 5 does not exceed 15% by weight.

[0024] From the above, it has been found that in the electricity storage device 10 of this embodiment, the insulating resin member 5 has a thermoplastic resin material NJ containing a high molecular weight material KB having a molecular weight of 10,000 or more and a low molecular weight material TB having a molecular weight of 500 to 5,000, and that the low molecular weight material TB is contained in the thermoplastic resin material NJ at 5 to 15 weight % and is preferably concentrated toward the roughened treatment surfaces 3S and 4S.

[0025] 5 shows the concentration index of the molecular weight of the thermoplastic resin material NJ in the resin inner layer P of the insulating resin member 5 of this embodiment, the differential molecular weight distribution curve 5BZ shows the concentration index of the molecular weight of the thermoplastic resin material NJ in the resin surface layer Q of the insulating resin member 5 of this embodiment, and the differential molecular weight distribution curve 5CZ shows the concentration index of the molecular weight of the thermoplastic resin material NJ in the resin surface layer Q of the insulating resin member 5C of the comparative example. X1 on the horizontal axis indicates a molecular weight of 500, X2 indicates a molecular weight of 1500, X3 indicates a molecular weight of 5000, X4 indicates a molecular weight of 10000, and X5 indicates a molecular weight of 200000.

[0026] As shown in Fig. 5, the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment and the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example have a concentration index of about 35 at a molecular weight of 5000, and there is almost no difference between them. However, the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment has a concentration index of about 15 at a molecular weight of 1500, while the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example has a concentration index of about 5 at a molecular weight of 1500, and the concentration indexes are significantly different in the region of molecular weight of 1500 or less. In particular, the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment has an increased amount of the second low molecular weight material TB2 having a molecular weight of 500 to 1500 in the resin surface layer portion Q compared to the resin inner layer portion P, and the concentration index of the low molecular weight material TB at a molecular weight of 500 to 1500 is maintained at a high level of about 13 to 17. In contrast, in the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example, the concentration index of the low molecular weight substance TB3 in the resin surface layer portion Q also decreases from a concentration index of 3 (molecular weight 1,500) to a concentration index of 0 (molecular weight 1,000).

[0027] Therefore, as shown in Fig. 6, the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment is in a state in which the second low molecular weight substance TB2 having a smaller molecular weight of 500 to 1500 is concentrated in the resin surface layer (skin layer) Q adjacent to the roughened surfaces 3S and 4S, and easily penetrates into the very narrow gaps SK between the convex portions 311S and 411S of the uneven surfaces 31S and 41S having an arithmetic mean roughness of 30 to 500 nm. As a result, the resin containing the second low molecular weight substance TB2 having a molecular weight of 500 to 1500 is filled into the narrow gaps SK between the uneven surfaces 31S and 41S, and the anchor effect of the insulating resin member 5 to the uneven surfaces 31S and 41S can be further improved. In addition, by filling the narrow gaps SK between the uneven surfaces 31S and 41S with the resin containing the second low molecular weight substance TB2, cavities are less likely to occur in the gaps SK, and the sealing property of the insulating resin member 5 is further improved.

[0028] In contrast, in the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example, the concentration index of the low molecular weight substance TB3 in the resin surface layer Q is reduced from a concentration index of 3 for a molecular weight of 1500 to a concentration index of 0 for a molecular weight of 1000, so that only a small amount of resin containing low molecular weight substance TB3 of a molecular weight of 1500 or less gathers in the resin surface layer Q (skin layer) as shown in Fig. 7, and there are portions that are not filled in the narrow gaps SK between the convex portions 311S, 411S in the uneven surfaces 31S, 41S, and the anchor effect of the insulating resin member 5 on the uneven surfaces 31S, 41S is reduced. In addition, since the low molecular weight substance TB3 is not filled in the narrow gaps SK between the uneven surfaces 31S, 41S, a cavity KD is generated in the gaps SK, and the sealing property of the insulating resin member 5C is also reduced.

[0029] From the above, it was found that in the electricity storage device 10B of this embodiment, the uneven surfaces 31S, 41S of the roughened surfaces 3S, 4S are formed to have an arithmetic average roughness of 30 to 500 nm, and that the second low molecular weight material TB2 having a molecular weight of 500 to 1500 is increased in the resin surface layer portion Q adjacent to the uneven surfaces 31S, 41S compared to the resin inner layer portion P separated from the uneven surfaces 31S, 41S. That is, it was found that the low molecular weight material TB contains a large amount of the second low molecular weight material TB2 having a molecular weight of 500 to 1500 in the resin surface layer portion Q adjacent to the uneven surfaces 31S, 41S compared to the first low molecular weight material TB1 having a molecular weight of 500 to 5000 in the resin inner layer portion P separated from the uneven surfaces 31S, 41S.

[0030] Therefore, according to this embodiment, in the electricity storage device 10, 10B in which the roughened surfaces 3S, 4S are formed on the sealing portions 31T, 41T of the connection portions 3T, 4T that connect the collector terminal 3 and the insulating resin member 5 of the case member 4, the anchor effect and sealing property of the insulating resin member 5 against the roughened uneven surfaces 31S, 41S can be improved.

[0031] <Description of the manufacturing method of the present electricity storage device> Next, a method for manufacturing an electricity storage device according to another embodiment of the disclosed technique will be described in detail with reference to the drawings. Fig. 8 shows a cross-sectional view of a mold in a closed state used in the method for manufacturing an electricity storage device according to this embodiment. Fig. 9 shows a flow chart of the method for manufacturing the electricity storage device using the mold shown in Fig. 8.

[0032] As shown in Figures 6, 8 and 9, the manufacturing method for the present electricity storage device is a manufacturing method for the above-mentioned electricity storage devices 10, 10B, and includes a resin injection process S2 in which a molding die 6 is used in which a collector terminal 3 and a case member 4 are inserted to injection-mold an insulating resin member 5, and gaps SK between the convex portions 311S, 411S on the uneven surfaces 31S, 41S are filled with the insulating resin member 5 until the molten insulating resin member 5 is completely injected into the cavity 61 of the molding die 6 while the molding die 6 is in a closed state.

[0033] 8, the molding die 6 includes a fixed die 62 and a movable die 63 in which a cavity 61 is formed in which the current collector terminal 3 and the case member 4 can be inserted in order to injection mold the insulating resin member 5 when the die is closed. The fixed die 62 and the movable die 63 are provided with pipes 621, 631 for heating and cooling the die temperature. The movable die 63 also includes a slide die 632 that moves between an advanced position where the bent portion of the current collector terminal 3 is pressed and a retreated position where the current collector terminal 3 can be inserted and removed.

[0034] As shown in FIG. 9 , the manufacturing method for the electricity storage devices 10, 10B includes a parts setting process S1 in which the current collecting terminal 3 and the case member 4 are set in the molding die 6, a resin injection process S2 in which molten insulating resin member 5 is injected into the cavity 61 of the molding die 6, a pressure holding and cooling process S3 in which the molten insulating resin member 5 is cooled while applying internal pressure to a temperature at which it can be released from the mold, and a demolding process S4 in which the fixed die 62 and the movable die 63 are opened and the insert-molded insulating resin member 5, the current collecting terminal 3, and the case member 4 are removed from the molding die 6.

[0035] This manufacturing method for an electricity storage device includes a resin injection step S2 in which the gaps SK between the convex portions 311S, 411S of the uneven surfaces 31S, 41S are filled with the insulating resin member 5 before the injection of the molten insulating resin member 5 into the cavity 61 of the molding die 6 is completed, so that when the insulating resin member 5 is integrally molded (insert molded) with the current collecting terminal 3 and the case member 4, it is not necessary to cause the molten resin to enter the gaps SK between the uneven surfaces 31S, 41S while maintaining pressure and cooling after the injection of the molten resin of the insulating resin member 5 into the cavity 61 of the molding die 6 is completed. Therefore, the time required for maintaining pressure and cooling after the injection of the molten resin can be shortened, and the productivity can be improved. Furthermore, by the time the molten resin is completely injected into the cavity 61 of the molding die 6, the gap SK between the uneven surfaces 31S, 41S is filled with the insulating resin member 5. Therefore, even if the pressure retention and cooling time after the injection of the molten resin is shortened, the anchor effect of the insulating resin member 5 against the uneven surfaces 31S, 41S can be increased and the sealing property of the insulating resin member 5 can be improved.

[0036] Therefore, according to the manufacturing method of the present electricity storage device, in the electricity storage device 10, 10B in which the roughened surfaces 3S, 4S are formed on the sealing portions 31T, 41T of the connection portions 3T, 4T of the collector terminal 3 and the case member 4 that connect with the insulating resin member 5, the anchor effect and sealing property of the insulating resin member 5 against the roughened uneven surfaces 31S, 41S is improved, and the pressure holding and cooling time when the insulating resin member 5 is integrally molded (insert molding) with the collector terminal 3 and the case member 4 is shortened, thereby improving productivity.

[0037] The above-described embodiment is merely an example and does not limit the disclosed technology in any way. Therefore, the disclosed technology can be improved or modified in various ways without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0038] 3 Current collector terminal 3S, 4S roughened surface 3T, 4T connection part 4 Case member, case cover 5. Insulating resin material 6 Molding mold 10, 10B Energy storage device 31 Hole insertion part 31S, 41S uneven surface 31T, 41T seal part 41 Terminal insertion hole 61 Cavity 311S, 411S convex part 411 Hole Outer Edge 412 Hole Surrounding Area KB polymer NJ thermoplastic resin material P Resin inner layer Q Resin surface layer S2 Resin injection process SK Gap TB, TB1, TB2 low molecular weight

Claims

1. A current collecting terminal; a case member having a terminal insertion hole through which the current collecting terminal is inserted; an insulating resin member in which the current collecting terminal and the case member are insert-molded so as to connect a hole insertion portion of the current collecting terminal to a hole outer edge portion and a hole periphery portion of the terminal insertion hole, the current collecting terminal and the case member are provided with a seal portion at a connection portion where the current collecting terminal and the case member are connected to the insulating resin member, the seal portion ensuring airtightness within the case; The sealing portions each have a roughened surface having an uneven surface formed thereon, the insulating resin member has a thermoplastic resin material containing a high molecular weight substance having a molecular weight of 10,000 or more and a low molecular weight substance having a molecular weight of 500 to 5,000; The low molecular weight substance is contained in the thermoplastic resin material in an amount of 5 to 15% by weight and is unevenly distributed near the roughened surface. Energy storage device.

2. The power storage device according to claim 1 , The uneven surface is formed to have an arithmetic mean roughness of 30 to 500 nm, A resin surface layer portion adjacent to the uneven surface has an increased amount of low molecular weight substances having a molecular weight of 500 to 1500 compared to a resin inner layer portion away from the uneven surface. Energy storage device.

3. A method for producing the electricity storage device according to claim 1 or 2, comprising the steps of: a molding die for injection-molding the insulating resin member by inserting the current collecting terminal and the case member into the molding die; a resin injection step of filling gaps between convex portions on the uneven surface with the insulating resin material before the injection of the molten insulating resin material into the cavity of the molding die is completed. A method for manufacturing an electricity storage device.

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