Electricity storage device and method for manufacturing electricity storage device

Abstract

The invention relates to an electricity storage device and a method for manufacturing the electricity storage device. The purpose of the present invention is to improve the anchoring effect and sealing performance of an insulating resin member with respect to a concave-convex surface formed at a sealing portion of a connection portion between a collector terminal and a housing member that is connected to the insulating resin member, to shorten the pressure holding / cooling time when molding the insulating resin member, and to improve productivity. An electricity storage device (10) includes a collector terminal (3), a case member (4), and an insulating resin member (5), the collector terminal and the case member are provided with seal portions (31T, 41T) at connection portions (3T, 4T) connected to the insulating resin member, and the seal portions are roughened surfaces (3S, 4S). The insulating resin member has a thermoplastic resin material containing a high molecular weight body having a molecular weight of 10000 or more and a low molecular weight body having a molecular weight of 500-5000, the thermoplastic resin material containing 5-15 wt% of the low molecular weight body, and the low molecular weight body is biased toward the roughened surface.

Description

Technical Field

[0001] The disclosed technology relates to a power storage device and a method for manufacturing the power storage device. Background Art

[0002] For example, Patent Document 1 discloses a sealed storage battery in which an insulating resin member is integrally molded with a collector terminal and a shell member in a manner that fills between the terminal insertion holes of the collector terminal and the shell member (insert molding). In addition, by forming a roughened surface in at least a portion of the abutting portion that abuts against the insulating resin member in the collector terminal and the shell member, the anchoring effect of the insulating resin member on the roughened concave and convex surface is improved. The insulating resin member is a resin material having heat resistance, moldability, insulation, sealing, and resistance to electrolyte, and PPS resin (polyphenylene sulfide resin) is exemplified.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-86813 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, the insulating resin components such as the above-mentioned PPS resin generally contain a large amount of high molecular weight bodies with a molecular weight of more than 10,000. The molecular size of the high molecular weight body in the molten state is large, and it tends to be difficult to penetrate the narrow gaps between the convex parts in the roughened concave-convex surface. Therefore, there is the following problem: during molding, the molten resin of the insulating resin component cannot fully penetrate the gaps between the roughened concave-convex surface, and the anchoring effect of the insulating resin component on the concave-convex surface cannot be improved. In addition, since the molten resin of the insulating resin component cannot fully penetrate the gaps between the roughened concave-convex surface, cavities are formed in the gaps between the concave-convex surface, and there is a problem of reduced sealing of the insulating resin component at the abutting portion with the collector terminal and the shell component.

[0008] In addition, the molecular size of the insulating resin component of the high molecular weight body in the molten state is large, and it is difficult for the molten resin to penetrate into the narrow gap of the roughened concave and convex surface during molding. Therefore, after the molten resin is injected into the mold cavity of the molding die, it is necessary to spend time while holding the pressure (maintaining the pressure) and cooling to force the molten resin to penetrate into the gap of the concave and convex surface. Therefore, there is a problem that the time of holding the pressure and cooling is long, and the productivity is reduced.

[0009] The disclosed technology is completed in view of this problem. The first problem to be solved is to improve the anchoring effect and sealing performance of the insulating resin member to the roughened concave-convex surface in the power storage device in which the sealing part of the connection part of the collector terminal and the shell member connected to the insulating resin member is formed with a roughened surface. In addition, the second problem to be solved is to shorten the pressure holding and cooling time when the insulating resin member is integrally molded (insert molding) with the collector terminal and the shell member, thereby improving its productivity.

[0010] Means for solving problems

[0011] (1) One solution of the disclosed technology for solving the above-mentioned problems is a power storage device, comprising: a collector terminal, a shell member having a terminal insertion hole for inserting the collector terminal, and an insulating resin member insert-molded with the collector terminal and the shell member in a manner that connects the hole insertion portion of the collector terminal to the hole outer edge portion and the hole periphery portion of the terminal insertion hole, wherein the collector terminal and the shell member have a sealing portion for ensuring airtightness in the shell at a connection portion connected to the insulating resin member, the sealing portion is a roughened surface each having a concave and convex surface, and the insulating resin member has a thermoplastic resin material containing a high molecular weight body having a molecular weight of 10,000 or more and a low molecular weight body having a molecular weight of 500 to 5,000, the thermoplastic resin material contains 5 to 15% by weight of the low molecular weight body, and the low molecular weight body is biased toward the roughened surface.

[0012] (2) According to the power storage device described in (1), the uneven surface is formed to have an arithmetic mean roughness of 30 to 500 nm, and in the resin surface layer portion close to the uneven surface, the low molecular weight body with a molecular weight of 500 to 1500 is increased compared with the resin inner layer portion separated from the uneven surface.

[0013] (3) A method for manufacturing an energy storage device is a method for manufacturing an energy storage device according to (1) or (2), comprising a resin injection step, wherein a molding die is used to insert the collector terminal and the shell member and to injection-mold the insulating resin member, and before the molten insulating resin member is injected into the mold cavity of the molding die, the insulating resin member is used to fill the gaps between the convex portions of the concave-convex surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is an exploded perspective view of one mode (this example) of the power storage device according to the present embodiment.

[0015] Figure 2 for Figure 1 AA section view shown.

[0016] Figure 3 for Figure 2 An enlarged cross-sectional view of portion B is shown.

[0017] Figure 4 To show Figure 3 The graph shows an integrated molecular weight distribution curve of 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.

[0018] Figure 5 To show Figure 3 , which is a differential molecular weight distribution graph showing the distribution state of each molecular weight 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.

[0019] Figure 6 For schematic illustration Figure 3 In the resin surface layer of the roughened surface shown in Figure 4 , Figure 5 FIG. 2 is a schematic cross-sectional view showing the positional relationship between a high molecular weight body and a low molecular weight body in the thermoplastic resin material of the insulating resin member of the present embodiment.

[0020] Figure 7 For schematic illustration Figure 3 In the resin surface layer of the roughened surface shown in Figure 4 , Figure 5 Schematic cross-sectional view showing the positional relationship between a high molecular weight body and a low molecular weight body in the thermoplastic resin material of the insulating resin member of the comparative example shown.

[0021] Figure 8 This is a cross-sectional view showing a mold clamping state of a molding die used in a method for manufacturing an electric storage device according to another embodiment.

[0022] Fig. 9 For use Figure 8 The molding die shown is a flow chart of a method for manufacturing the present power storage device.

[0023] Description of Reference Numerals

[0024] 3 Collector terminal

[0025] 3S, 4S roughened surface

[0026] 3T, 4T connection part

[0027] 4 Shell components, shell cover

[0028] 5 Insulating resin components

[0029] 6 Forming die

[0030] 10.10B Power storage devices

[0031] 31 hole insertion part

[0032] 31S, 41S Concave and convex surface

[0033] 31T, 41T seal

[0034] 41 Terminal insertion hole

[0035] 61 Cavity

[0036] 311S, 411S convex part

[0037] 411 hole outer edge

[0038] 412 hole surrounding area

[0039] KB High molecular weight

[0040] NJ Thermoplastic Resin Material

[0041] P Resin inner layer

[0042] Q Resin surface

[0043] S2 Resin injection process

[0044] SK Gap

[0045] TB, TB1, TB2 low molecular weight DETAILED DESCRIPTION

[0046] <Description of this energy storage device>

[0047] Next, one embodiment (this embodiment) of the power storage device 10 according to the embodiment of the above-mentioned disclosed technology will be described in detail with reference to the drawings. Figure 1 An exploded perspective view of one embodiment (this example) of the power storage device according to this embodiment is shown in FIG. Figure 2 Shown in Figure 1 The AA section is shown. Figure 3 Shown in Figure 2 An enlarged cross-sectional view of portion B is shown.

[0048] like Figure 1 to Figure 3 As shown, an embodiment of the present technology involves a scheme (this embodiment) of the storage device 10, which includes: a collector terminal 3; a shell member 4 having a terminal insertion hole 41 for inserting the collector terminal 3; and an insulating resin member 5 insert-molded with the collector terminal 3 and the shell member 4 in a manner that connects the hole insertion portion 31 of the collector terminal 3 with the hole outer edge portion 411 and the hole surrounding portion 412 of the terminal insertion hole 41.

[0049] Among them, the present power storage device 10 has an electrode body 1; a shell body 2 having an opening 21 and accommodating the electrode body 1; a collector terminal 3 electrically connected to the electrode body 1; a shell cover (equivalent to a "shell member") 4 having a terminal insertion hole 41, a collector terminal 3 inserted in the terminal insertion hole 41, and a shell body 1 through the collector terminal 3, and sealing the opening 21 of the shell body 2; an insulating resin member 5 molded with the collector terminal 3 and the shell member 4 (insert) in a manner that connects the hole insertion portion 31 of the collector terminal 3 with the hole outer edge portion 411 and the hole surrounding portion 412 of the terminal insertion hole 41. However, the present power storage device 10 may not necessarily be limited to the above-mentioned structure. For example, the terminal insertion hole 41 may be formed in the shell body 2.

[0050] Among them, the power storage device 10 means all power storage devices that can take out electric energy, such as primary batteries, secondary batteries, double-layer capacitors, etc. In addition, the electrode body 1 is a known electrode body in which a positive electrode body having an active material layer of a positive electrode and a negative electrode body having an active material layer of a negative electrode are stacked via a separator (partition). The shell body 2 is a bottomed cylindrical body with an opening 21 formed at the upper end, for example, made of aluminum or an aluminum alloy. The collector terminal 3 is composed of a positive collector terminal 3a connected to the positive side of the electrode body 1 and a negative collector terminal 3b connected to the negative side. The positive collector terminal 3a is, for example, made of aluminum or an aluminum alloy, and the negative collector terminal 3b is, for example, made of copper or a copper alloy. The shell cover (shell member) 4 is, for example, made of aluminum or an aluminum alloy, and is formed as a flat cover. The housing cover (housing member) 4 is provided with a terminal insertion hole 41 for inserting the current collecting terminal 3, a known safety valve 42, and a liquid injection hole 43 for injecting the electrolyte. The insulating resin member 5 has a thermoplastic resin material NJ having heat resistance, moldability, insulation, sealing, resistance to the electrolyte, etc. Among them, the thermoplastic resin material NJ uses PPS resin (polyphenylene sulfide resin), but is not limited to this. In addition, the insulating resin member 5 may contain reinforcing members such as glass fibers, elastomers, etc. in the thermoplastic resin material NJ.

[0051] In addition, if Figure 3As shown, the collector terminal 3 and the shell member 4 have sealing portions 31T and 41T at the connection portions 3T and 4T connected to the insulating resin member 5 for ensuring the airtightness in the shell. The sealing portion 31T of the collector terminal 3 is formed in an annular band shape around the entire circumference of the hole insertion portion 31, and the sealing portion 41T of the shell member 4 is formed in an annular band shape along the terminal insertion hole 41 at the hole surrounding portion 412. The collector terminal 3 has an external connection portion 32 bent at a right angle relative to the hole insertion portion 31, and the shell member 4 side of the external connection portion 32 is connected to the insulating resin member 5. In addition, the sealing portions 31T and 41T are roughened surfaces 3S and 4S having concave-convex surfaces 31S and 41S, respectively. As for the concave-convex surfaces 31S and 41S, for example, they are formed to have an arithmetic mean roughness of 30 to 500 nm. Furthermore, Figure 3 P shown in the figure represents the inner layer of the resin (core layer) whose distance d1 from the connecting portion 3T, 4T is more than 500 μm, and Q represents the surface layer of the resin (surface layer) whose distance d2 from the connecting portion 3T, 4T is about 10 to 20 μm. In addition, the concave-convex surface 31S, 41S with an arithmetic mean roughness of 30 to 500 nm can be formed by irradiating the surface of the connecting portion 3T, 4T with a pulsed laser traveling in a certain direction, for example, so that fine mist-like metal vapor is dispersed, and the metal vapor is accumulated and solidified in a forest shape.

[0052] In addition, Figure 4 Shown in Figure 3 The integrated molecular weight distribution curves of the proportions 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 are shown in FIG. Figure 5 Shown in Figure 3 The differential molecular weight distribution curve diagram of the distribution state of each molecular weight in the thermoplastic resin material of the insulating resin member of this embodiment and the thermoplastic resin material of the insulating resin member of the comparative example is shown in FIG. Figure 6 A schematic diagram is shown in Figure 3 In the resin surface layer of the roughened surface shown in Figure 4 , Figure 5 The schematic cross-sectional view of the positional relationship between the high molecular weight body and the low molecular weight body in the thermoplastic resin material of the insulating resin member of this embodiment is shown. Figure 7 A schematic diagram is shown in Figure 3 In the resin surface layer of the roughened surface shown in Figure 4 , Figure 5 Schematic cross-sectional view showing the positional relationship between a high molecular weight body and a low molecular weight body in a thermoplastic resin material of an insulating resin member of a comparative example shown in FIG.

[0053] in, Figure 4 The integrated molecular weight distribution curve and Figure 5The differential molecular weight distribution curve shown can be obtained by the GPC method (Gel Permeation Chromatography) using the following steps. First, the resin sample is dissolved in a solvent to prepare a sample solution. Next, the sample solution is passed through a column filled with a porous granular gel having fine pores, and a detector is used to detect the size of molecules in the solution passing through, and the detection intensity of the molecular size relative to the detection time is obtained as a chromatogram. Next, a calibration curve is obtained using a standard substance whose relationship between the detection time and the molecular weight is known, and the detection time is converted into a molecular weight. Then, the molecular weight (logarithmic value) is plotted on the horizontal axis, and the concentration fraction is plotted on the vertical axis. Figure 4 For the integrated molecular weight distribution curve shown in FIG. 1 , the concentration fractions plotted are accumulated in sequence, the molecular weight (logarithmic value) is plotted on the horizontal axis, and the cumulative value of the concentration fraction is plotted on the vertical axis. The "cumulative value of the concentration fraction" is equivalent to the "proportion of the total resin", so Figure 4 The vertical axis represents the "ratio (wt%) in the entire resin".

[0054] Secondly, in Figure 4 In the integrated molecular weight distribution curve shown, the slope (differential value) of the curve for each molecular weight was determined. Figure 5 The differential molecular weight distribution curve shown 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 becomes "dW / d(LogM)" (the value of differentiating the concentration fraction with the logarithmic value of the molecular weight), which is proportional to the "concentration fraction" and is therefore expressed here as the "concentration index". Furthermore, specifically, a high-temperature GPC device (equipment No. GPC-H-2, PL-GPC220 manufactured by Polymer Laboratories), a detector (differential refractive index detector RI: Refractive Index Detector), a column (Shodex UT-G (Guard Column), and a solvent liquid (1-chloronaphthalene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)) were used. In addition, as for the sample solution, after filtering with a 0.5μm filter, 0.2mL of the sample solution was injected into the column heated to 210°C at a flow rate of 0.7mL / min. Furthermore, Figure 4 The integrated molecular weight distribution curve and Figure 5 The differential molecular weight distribution curve shown can be automatically prepared using application software attached to a high temperature GPC apparatus (Apparatus No. GPC-H-2, PL-GPC220 manufactured by Polymer Laboratories).

[0055] Figure 4The integral molecular weight distribution curve 5W shown represents the proportion of the molecular weight of the thermoplastic resin material NJ of the insulating resin component 5 of this embodiment in the entire resin, and the integral molecular weight distribution curve 5CW represents the proportion of the molecular weight of the thermoplastic resin material NJ of the insulating resin component 5C of the comparative example in 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 component 5 of this embodiment has about 10% by weight of low molecular weight bodies TB with a molecular weight of 500 to 5000, and has about 77% by weight of high molecular weight bodies KB with a molecular weight of 10000 or more. The thermoplastic resin material NJ of the insulating resin component 5C of the comparative example has about 3% by weight of low molecular weight bodies TB3 with a molecular weight of 1000 to 5000, and has about 78% by weight of high molecular weight bodies KB with a molecular weight of 10000 or more. Therefore, the thermoplastic resin material NJ of the insulating resin component 5 of the present embodiment and the thermoplastic resin material NJ of the insulating resin component 5C of the comparative example are the same in that they have slightly less than 80% by weight of the high molecular weight body KB with a molecular weight of 10,000 or more, but the proportions of the low molecular weight bodies TB and TB3 with a molecular weight of 5,000 or less in the entire resin are greatly different. In addition, with regard to the low molecular weight body with a molecular weight of 1,000 or less, the thermoplastic resin material NJ of the insulating resin component 5 of the present embodiment contains the low molecular weight body with a molecular weight of 1,000 or less, but the thermoplastic resin material NJ of the insulating resin component 5C of the comparative example does not contain the low molecular weight body with a molecular weight of 1,000 or less, which is a great difference.

[0056] Among them, the low molecular weight TB with a molecular weight of 500 to 5000 has a smaller molecular size in the molten state than the high molecular weight KB with a molecular weight of more than 10000, and has high fluidity and wettability in the molten state. Therefore, it has the property of easily aggregating on the roughened surfaces 3S and 4S during molding.

[0057] Therefore, the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment is as follows: Figure 6As shown, during molding, the low molecular weight body TB with a molecular weight of 500 to 5000 is separated from the high molecular weight body KB with a molecular weight of 10,000 or more along with the fountain flow (water jet flow) of the molten resin, and is gathered in large quantities in the resin surface layer (surface layer) Q close to the roughened surface 3S, 4S, and becomes a state in which it is relatively easy to penetrate even into the narrow gap SK sandwiched between the convex parts 311S, 41S in the roughened concave-convex surface 31S, 41S. As a result, the resin containing the low molecular weight body TB with a molecular weight of 500 to 5000 is filled in the narrow gap SK of the concave-convex surface 31S, 41S, and the anchoring effect of the insulating resin member 5 on the concave-convex surface 31S, 41S can be improved. In addition, by filling the resin containing the above-mentioned low molecular weight body TB in the narrow gap SK of the concave-convex surface 31S, 41S, it is difficult to generate a cavity in the gap SK, and the sealing performance of the insulating resin member 5 is improved.

[0058] The thermoplastic resin material NJ of the insulating resin member 5C of the comparative example contains only about 3 wt % of the low molecular weight substance TB3 having a molecular weight of 1000 to 5000. Figure 7 As shown, during molding, even if the low molecular weight body TB3 with a molecular weight of 1000 to 5000 is separated from the high molecular weight body KB with a molecular weight of 10000 or more as the molten resin flows in the fountain (water jet flow), it only gathers in a small amount in the resin surface layer (surface layer) Q close to the roughened surface 3S, 4S, and does not easily enter the narrow gap SK sandwiched between the convex parts 311S, 411S in the roughened concave-convex surface 31S, 41S. As a result, the low molecular weight body TB3 with a molecular weight of 1000 to 5000 is not filled in the narrow gap SK of the concave-convex surface 31S, 41S, and the anchoring effect of the insulating resin member 5 on the concave-convex surface 31S, 41S is reduced. In addition, since the low molecular weight body TB3 is not filled in the narrow gap SK of the concave-convex surface 31S, 41S, a void KD is generated in the gap SK, and the sealing performance of the insulating resin member 5C is also reduced.

[0059] On the other hand, if the low molecular weight body TB with a molecular weight of 500 to 5000 increases excessively, for example, if the low molecular weight body TB is contained in about 20% by weight of the entire resin material in the thermoplastic resin material NJ of the insulating resin member 5, the heat resistance and the like are reduced, and it is difficult to maintain the characteristic values ​​required for the power storage device 10. Therefore, the content of the low molecular weight body TB with a molecular weight of 500 to 5000 in the entire resin material in the thermoplastic resin material NJ of the insulating resin member 5 is preferably not more than 15% by weight.

[0060] The following insights are obtained from the above: in the storage device 10 of the present embodiment, the insulating resin component 5 preferably has a thermoplastic resin material NJ containing a high molecular weight body KB with a molecular weight of more than 10,000 and a low molecular weight body TB with a molecular weight of 500 to 5,000, and the thermoplastic resin material NJ contains 5 to 15 weight % of the low molecular weight body TB, and the low molecular weight body TB tends to be close to the roughened surfaces 3S, 4S.

[0061] Secondly, Figure 5 The differential molecular weight distribution curve 5AZ shown shows the concentration index of the molecular weight of the thermoplastic resin material NJ in the resin inner layer portion P of the insulating resin member 5 of the present 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 portion Q of the insulating resin member 5 of the present 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 portion Q of the insulating resin member 5C of the comparative example. X1 of the horizontal axis represents a molecular weight of 500, X2 represents a molecular weight of 1500, X3 represents a molecular weight of 5000, X4 represents a molecular weight of 10000, and X5 represents a molecular weight of 200000.

[0062] like Figure 5 As shown, the concentration index of the molecular weight 5000 of the thermoplastic resin material NJ of the insulating resin member 5 of the present embodiment and the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example is about 35, and there is almost no difference between the two. However, the concentration index of the molecular weight 1500 of the thermoplastic resin material NJ of the insulating resin member 5 of the present embodiment is about 15, but the concentration index of the molecular weight 1500 of the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example is about 5, and the concentration index is greatly different in the region below the molecular weight 1500. In particular, in the thermoplastic resin material NJ of the insulating resin member 5 of the present embodiment, the second low molecular weight body TB2 with a molecular weight of 500 to 1500 increases in the resin surface layer Q compared with the resin inner layer P, and the concentration index of the molecular weight 500 to 1500 in the low molecular weight body TB is maintained at a high level of about 13 to 17. On the other hand, in the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example, the concentration index of the low molecular weight body TB3 is reduced from the concentration index 3 of the molecular weight 1500 to the concentration index 0 of the molecular weight 1000 even in the resin surface layer portion Q.

[0063] Therefore, if Figure 6As shown, the second low molecular weight body TB2 with a smaller molecular weight of 500 to 1500 of the thermoplastic resin material NJ of the insulating resin member 5 of this embodiment is accumulated in large quantities in the resin surface layer (surface layer) Q close to the roughened surface 3S, 4S, and is in a state where it is easy to penetrate even the very narrow gap SK sandwiched between the convex parts 311S, 411S in the concave-convex surface 31S, 41S with an arithmetic mean roughness of 30 to 500 nm. As a result, the resin containing the second low molecular weight body TB2 with a molecular weight of 500 to 1500 is filled in the narrow gap SK of the concave-convex surface 31S, 41S, and the anchoring effect of the insulating resin member 5 on the concave-convex surface 31S, 41S can be further improved. In addition, by filling the resin containing the second low molecular weight body TB2 in the narrow gap SK of the concave-convex surface 31S, 41S, it is difficult to generate a void in the gap SK, and the sealing performance of the insulating resin member 5 is further improved.

[0064] In the thermoplastic resin material NJ of the insulating resin member 5C of the comparative example, the concentration index of the low molecular weight body TB3 in the resin surface layer Q is also reduced from the concentration index 3 of the molecular weight 1500 to the concentration index 0 of the molecular weight 1000. Figure 7 As shown, the resin containing the low molecular weight body TB3 with a molecular weight of less than 1500 is only slightly gathered in the resin surface portion (surface layer) Q, resulting in a portion where the narrow gap SK sandwiched between the convex portions 311S and 41S in the concave-convex surface 31S and 41S is not filled, and the anchoring effect of the insulating resin member 5 on the concave-convex surface 31S and 41S is reduced. In addition, since the above-mentioned low molecular weight body TB3 is not filled in the narrow gap SK of the concave-convex surface 31S and 41S, a void KD is generated in the gap SK, and the sealing performance of the insulating resin member 5C is also reduced.

[0065] As described above, it is found that in the power storage device 10B of the present embodiment, it is more preferable that the arithmetic mean roughness of the concavoconvex surfaces 31S and 41S of the roughened surfaces 3S and 4S is formed to be 30 to 500 nm, and the second low molecular weight body TB2 with a molecular weight of 500 to 1500 is increased in the resin surface layer portion Q close to the concavoconvex surfaces 31S and 41S as compared with the resin inner layer portion P separated from the concavoconvex surfaces 31S and 41S. That is, regarding the low molecular weight body TB, it is found that it is further preferable that the second low molecular weight body TB2 with a molecular weight of 500 to 1500 is contained in the resin surface layer portion Q close to the concavoconvex surfaces 31S and 41S as compared with the first low molecular weight body TB1 with a molecular weight of 500 to 5000 in the resin inner layer portion P separated from the concavoconvex surfaces 31S and 41S.

[0066] Therefore, according to this embodiment, in the storage device 10, 10B in which the sealing portion 31T, 41T of the connecting portion 3T, 4T of the collector terminal 3 and the shell member 4 connected to the insulating resin member 5 forms a roughened surface 3S, 4S, the anchoring effect and sealing performance of the insulating resin member 5 on the roughened concave-convex surface 31S, 41S can be improved.

[0067] <Description of the manufacturing method of the present electricity storage device>

[0068] Next, a method for manufacturing an electric storage device according to another embodiment of the disclosed technology will be described in detail with reference to the accompanying drawings. Figure 8 A cross-sectional view showing a mold clamping state of a molding die used in a method for manufacturing an electric storage device according to another embodiment is shown in FIG. Fig. 9 Shown in the use Figure 8 The molding die shown is a flow chart of a method for manufacturing the present power storage device.

[0069] like Figure 8 , Fig. 9 As shown, the manufacturing method of the present power storage device is the manufacturing method of the above-mentioned power storage device 10, 10B, including a resin injection step S2, wherein a molding die 6 is used to insert (insert) the collector terminal 3 and the shell member 4 and to injection-mold the insulating resin member 5, and in the mold closing state of the molding die 6, before the molten insulating resin member 5 is injected into the mold cavity 61 of the molding die 6 (until the molten insulating resin member 5 is injected into the mold cavity 61 of the molding die 6), the insulating resin member 5 is used to fill the gap SK between the convex parts 311S, 411S in the concave-convex surface 31S, 41S.

[0070] like Figure 8 As shown, the molding die 6 includes a fixed die 62 and a movable die 63 that form a cavity 61 in which the collector terminal 3 and the case member 4 are inserted and the insulating resin member 5 can be injection-molded in a clamped state. The fixed die 62 and the movable die 63 are provided with pipes 621 and 631 for heating and cooling the mold temperature. In addition, the movable die 63 is provided with a sliding die 632 that can move between an advanced position for pressing the curved portion of the collector terminal 3 and a retreated position for inserting and removing the collector terminal 3.

[0071] In addition, if Fig. 9As shown, in the manufacturing method of the energy storage device 10, 10B, it includes: a component installation (component setting) step S1 of installing the collector terminal 3 and the shell member 4 in the molding die 6; a resin injection step S2 of injecting the molten insulating resin member 5 into the mold cavity 61 of the molding die 6; a pressure holding and cooling step S3 of applying internal pressure to the molten insulating resin member 5 while cooling it to a temperature at which it can be demolded; and a demolding step S4 of opening the fixed mold 62 and the movable mold 63 to remove the insert-molded insulating resin member 5, the collector terminal 3 and the shell member 4 from the molding die 6.

[0072] The method for manufacturing the power storage device includes a resin injection step S2, wherein the gap SK between the convex parts 311S and 411S in the concave-convex surface 31S and 41S is filled with the insulating resin member 5 until 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 molding) with the collector terminal 3 and the case member 4, after the molten resin of the insulating resin member 5 is injected into the cavity 61 of the molding die 6, it is not necessary to allow the molten resin to intrude into the gap SK of the concave-convex surface 31S and 41S while holding pressure and cooling. Therefore, the time for holding pressure and cooling after the injection of the molten resin can be shortened, and its productivity can be improved. In addition, until the molten resin is injected into the cavity 61 of the molding die 6, the gap SK between the concave and convex surfaces 31S and 41S is filled with the insulating resin component 5. Therefore, even if the holding and cooling time after the injection of the molten resin is shortened, the anchoring effect of the insulating resin component 5 on the concave and convex surfaces 31S and 41S can be improved, thereby improving the sealing performance of the insulating resin component 5.

[0073] Therefore, according to the manufacturing method of the present power storage device, in the power storage device 10, 10B in which the roughened surfaces 3S, 4S are formed in the sealing portions 31T, 41T of the connecting portions 3T, 4T connected to the insulating resin member 5 in the collector terminal 3 and the shell member 4, the anchoring effect and sealing performance of the insulating resin member 5 with respect to the roughened concave-convex surfaces 31S, 41S can be improved, the pressure holding and cooling time when the insulating resin member 5 is integrally molded (insert molding) with the collector terminal 3 and the shell member 4 can be shortened, and its productivity can be improved.

[0074] The embodiments described in detail above are merely examples and do not limit the technology disclosed herein. Therefore, the technology disclosed herein can be modified and altered in various ways without departing from the spirit and scope of the invention.

Claims

1. Electricity storage devices, including: Collector terminal, a housing member having a terminal insertion hole through which the current collecting terminal is inserted, and an insulating resin member insert-molded with the collector terminal and the case member in such a manner that the hole insertion portion of the collector terminal is connected to the hole outer edge portion and the hole periphery portion of the terminal insertion hole, The collector terminal and the case member are provided with a sealing portion at a connection portion with the insulating resin member to ensure airtightness in the case. The sealing portion is a roughened surface with concave and convex surfaces formed respectively, and the insulating resin component has a thermoplastic resin material containing a high molecular weight body with a molecular weight of more than 10,000 and a low molecular weight body with a molecular weight of 500 to 5,000, and the thermoplastic resin material contains 5 to 15 weight % of the low molecular weight body, and the low molecular weight body tends to be close to the roughened surface.

2. The power storage device according to claim 1, wherein The concavoconvex surface is formed to have an arithmetic mean roughness of 30 to 500 nm, and in a resin surface layer portion close to the concavoconvex surface, a low molecular weight substance having a molecular weight of 500 to 1500 is increased compared to a resin inner layer portion separated from the concavoconvex surface.

3. A method for manufacturing an electric storage device, the method for manufacturing an electric storage device according to claim 1 or claim 2, comprising a resin injection step, wherein: A molding die is used to insert the collector terminal and the case member and to injection-mold the insulating resin member. Before the molten insulating resin member is injected into the cavity of the molding die, the insulating resin member fills the gaps between the convex portions of the concave-convex surface.

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