JP2021194778A - Integral structure of copper material and pps-based resin composition and method for manufacturing the same - Google Patents

Abstract

To provide a seal structure for a copper electrode for extracting electricity to the outside of a battery box in a lithium ion battery or the like which prevents intrusion of moisture, oxygen and other gases into the battery box.SOLUTION: A structure can be applied to a lid of a lithium ion battery in which a copper electrode having a chemically converted surface and a specific polyphenylene sulfide-based resin composition are directly and integrally bonded to each other. The polyphenylene sulfide-based resin composition is a resin composition containing a polyphenylene sulfide resin as a main component and a modified polyolefin resin as a sub-component, and is added with 15-25 wt.% of a glass short fiber based on the whole resin composition as a reinforcement material component. A bonding force between the copper electrode and the polyphenylene sulfide-based resin composition is 40 MPa or more in measurement of a shear bond strength, and a shear bond viscous value that prevents breakage even when an external force in a shear direction due to continuous 300 times of repeating is applied thereto is 33 MPa or more.SELECTED DRAWING: Figure 8

Description

The present invention relates to an integrated structure of a copper material and a PPS-based resin composition and a method for producing the same. More specifically, a copper material and a PPS-based resin composition used for an electrode drawing portion of a lithium ion battery or the like and having a sealing structure capable of suppressing the invasion of foreign substances such as water molecules into the electrolytic solution from the outside. Regarding the integrated structure and its manufacturing method.

A lithium ion battery (hereinafter referred to as "LIB") has a positive electrode material, a copper material, and a negative electrode in order to collect electricity from a positive electrode and a negative electrode immersed in an electrolytic solution and take out electric power from the main body container of the LIB. Some materials use aluminum alloy materials. This electrode material needs to seal the fixed joint portion of the LIB with the container material so that the electrolytic solution does not leak, and for this purpose, an O-ring or the like is generally used. Instead of this O-ring structure, the applicant has a structure in which an electrode material, which is a copper material or an aluminum alloy material, is inserted into an injection molding mold, and the resin for the lid material of the container is injected into this to seal the structure, and the structure thereof. A method for manufacturing a structure was proposed (see Patent Documents 1, 5, etc.). That is, a joint surface (fixed surface) between a rod-shaped object made of an aluminum alloy for drawing out for a negative electrode (hereinafter referred to as "Al alloy") and a battery lid made of synthetic resin that supports the rod, and a positive electrode. This is an improved joint surface (fixing surface) between the copper rod-shaped material for drawing out the electrodes and the battery lid. The present inventors have improved the bonding surface (fixing surface) between the metal and resin portions, and can suppress the molecular quantity of water molecules and oxygen molecules passing through ultrafine gaps as much as possible. A method and a synthetic resin composition used for the method were proposed.

LIB is an excellent secondary battery and has already been put into practical use and used all over the world. For example, in the natural environment in Japan, the amount of stored electricity tends to decrease sharply in about 5 years. It is said that one of the causes of this deterioration is the intrusion of foreign substances such as water into the electrolytic solution, which should be completely anhydrous. In particular, the above-mentioned joint surface between the metal and resin portions has a problem that the adhesive strength between the metal and the resin, which are different materials, cannot withstand the secular change due to the difference in the coefficient of linear expansion and the like. Further, the seal between the metal and the resin is required to have a high degree of gas sealing property and durability against repeated creep stress due to thermal stress for the above reason. The inventors of the present invention (hereinafter referred to as "inventors") have described the above-mentioned LIB pull-out electrode material (copper material and Al alloy material) and the synthetic resin used for the lid material to be bonded (fixed) to the lead-out electrode material (copper material and Al alloy material). Poly Phenylene Sulfide Resin (hereinafter referred to as "PPS")-based composition "For example," SGX120 "(Tosoh Co., Ltd. (Headquarters: Tokyo, Japan))" (hereinafter referred to as "SGX120") I thought it was the best and proposed it. Both or one of the surfaces of the proposed "copper material and Al alloy material" has been subjected to a specific chemical conversion treatment (see Patent Documents 1, 4, and 5).

Among those proposed by the inventors in the past, those performed using an injection molding machine as a technique for strongly and directly bonding a metal and a crystalline thermoplastic resin, that is, to many engineers related to injection molding already. Is already known, but there are joining techniques called "injection joining method", "injection joining technique" and the like. Among the injection joining technologies, there are "NMT" and "new NMT" developed and named by the inventors (see Patent Documents 11, 12, etc.). If this NMT or new NMT is used in the production of LIB, when an Al alloy or pure copper material is inserted into an injection molding die and injection bonding is performed using a PPS-based resin composition (for example, "SGX120"). The bonding force (shear bonding strength) between the resin portion and the metal portion was about 40 MPa, and it was found that the bonding strength was very strong. Therefore, it was thought that these Al alloys and the injection bonding technology for copper materials could be used for technology that can seal not only liquid between the inside of the LIB battery box and the outside air, but also gas sealing.

Based on this technical idea, the invention described in Patent Document 1 is to design a structural plan of the lid portion of the LIB and disclose the structure. However, the injection joining technique described in Patent Document 1 and used for the electrode drawing portion of the LIB lid portion is only related to Al alloy. At that time, the surface treatment method for injection bonding to Al alloys was improved, and the NMT2 treatment method named by the present inventors was invented. Although the one described in Patent Document 1 proposes and discloses a structural proposal of the LIB lid portion, the basis of the chemical conversion treatment is the NMT2 treatment method, which is a new surface treatment method developed mainly for Al alloy materials. Is. The gas sealing property of the joint surface portion of the injection joint between the NMT2-treated Al alloy material and the PPS-based resin "SGX120" is high. At that time, the injection joint using C1100 copper subjected to the new NMT treatment method had a gas sealing property on the joint surface that was more than an order of magnitude higher in the helium gas leak experiment than the conventional O-ring sealing method. , It wasn't something that couldn't be used. However, the gas sealing property of the injection joint of the Al alloy material and the PPS-based resin "SGX120" is two orders of magnitude higher than that when the C1100 copper material is used. Therefore, for gas sealing, only the technology using Al alloy material was used.

(Gas sealing technology using injection joints)
As described above, the one described in Patent Document 1 is mainly invented for injection bonding technology relating to Al alloys, and exhibits the high performance found in experiments regarding the gas sealing property of Al alloys and resins. It was disclosed. Further development was carried out on the injection joint using this Al alloy. A test was conducted to confirm the strength of the moisture resistance and heat resistance of the joint portion of this injection joint. This test is performed on an injection bond (test piece for bonding strength) of the shape shown in FIG. 1 attached herein, which is exposed at a temperature of 85 ° C. and in an environment of 85% humidity for 8,000 hours. We are conducting a high temperature and high humidity test. In this high-temperature and high-humidity test, the shear bonding strength between the metal and resin parts hardly decreased, and a bonding method with high moisture and heat resistance could be realized (see Patent Document 2). Similarly, a specific shape design method has already been proposed as an injection joint in which the bonding force between the metal and the resin does not decrease even when a temperature shock of -50 ° C / + 150 ° C is applied for 3,000 cycles (see Patent Document 3). ). In short, if the battery lid of the LIB is made of a PPS-based resin composition and the electrode extraction portion is an Al alloy material, the strength of the bonding can be obtained by manufacturing with the injection bonding technology published in Patent Documents 1, 2, 3 and the like. There is no decrease in the amount of water, and there is no contamination of foreign substances such as moisture. That is, the speed at which gas leaks, to be correct, the speed at which water molecules, oxygen molecules, etc. enter and leave the battery body is significantly suppressed at the penetration portion of the resin plate-like object of the Al alloy metal rod, which is close to complete gas sealing. I was able to realize something.

On the other hand, regarding the injection junction of C1100 copper, which is pure copper, and "SGX120", which is the PPS-based resin composition, the chemical conversion treatment recommended by the present inventors at that time (for example, the treatment method described in Patent Document 1). The one subjected to)) was able to achieve a shear bonding strength of about 40 MPa. It was confirmed that the gas sealing property of this joint was superior to that of the conventional silicone rubber O-ring. However, for the reasons described above, the LIB battery lid structure proposal described in Patent Document 1 does not adopt the injection joining technique for the copper portion. Therefore, an invention in which the chemical conversion treatment of the copper electrode was improved was subsequently proposed (see Patent Document 5). Further, after that, a further improved version of this invention was also proposed (see Patent Document 4).

(Changes in Surface Treatment Method for Injection Bonding to Copper Material (Preliminary Test of the Present Invention, Development Process))
On the other hand, the method for measuring the bonding force between metal and resin in an injection junction has been internationally standardized as ISO19095, which is a public standardization of the method used by the present inventors as an experiment from the beginning. Is. The injection joint for measuring the shear joint strength is shown in FIG. That is, the shear bond strength of copper or copper alloy disclosed in Patent Documents 5 and 4 described above is a measurement value before being standardized by ISO1909. However, since it is a numerical value obtained from a test piece of the same shape shown in FIG. 1 and has the same shear joint strength, it can be used as a similar numerical index as an evaluation index of the present invention. Whether or not the surface treatment method for increasing the bonding strength was improved was determined by whether or not the shearing bonding strength of the injection joint by this test method was improved. However, in this measurement test method, the numerical value tends to be saturated when the bonding force becomes strong to some extent. For example, in the case of using the above-mentioned "SGX120" which is a PPS-based resin, the maximum value is 41 to 42 MPa even if the chemical conversion treatment of copper or a copper alloy is improved, and no higher value can be obtained. The present inventors have made progress in the improvement, and when the shear joint strength exceeds 38 MPa, it becomes difficult to evaluate the improved product after that. That is, in the case of hard metal materials, not limited to copper or copper alloys, the effect and evaluation of gas sealing properties, which are considered to be related to the strength of the true bonding force, are correct only by the above method for measuring the shear bonding strength. It turned out that it could not be evaluated.

In order to deal with this, the present inventors have a new concept of "shear joint tenacity", which is a new concept of joint force measurement method, that is, an external force of the same numerical value in the shear direction is continuously applied 300 times repeatedly, and the joint force is not broken. We proposed a method to measure the maximum external force that can be withstood in (details will be described later). Then, this evaluation method was used as an evaluation index for the development of a new treatment method. That is, the present inventors have developed various new treatment methods as an evaluation method for the development of a new treatment method by this evaluation method after making the invention described in Patent Document 4. Therefore, C1100 copper pieces by the three new surface chemical treatment methods described in Patent Document 4 are also injection-bonded to obtain a test piece of the shape shown in FIG. 1, and the "shear-bonded stickiness" value of each is obtained. A confirmation test was conducted to measure. As a result, all of the three types of surface-treated products shown in Patent Document 4 were clearly improved from the previous products, and one of the three types of surface-treated products was particularly excellent. It turned out to be.

Similarly, an injection joint was obtained with the C1100 copper piece treated by the three types of surface treatment methods described in Patent Document 4 and the above-mentioned "SGX120", and the bonding force between the metal and the resin was measured. The shear joint strength of all three types of test pieces was about 40 MPa, which was sufficiently high. In addition, for a simple high-temperature, high-humidity test, a test piece was immersed in a household electric kettle and immersed in pure water at a temperature of 98 ° C for 72 hours, and only one of the three types was used. After soaking for 72 hours, it showed a shear bonding strength of 38 MPa and showed high moisture and heat resistance. One of the excellent test pieces is shown in FIG. 5 as an electron micrograph of 100,000 times. When observing this electron micrograph, the entire surface is covered with whiskers having a diameter of about 10 nm, and many whiskers grow while being entwined, and the shape of these whiskers is like human hair.

This whisker was found to be copper oxide by analytical electron microscopy. As far as the inventor and others know, it is rare for a metal piece whose entire surface is covered with a dense whisker as shown in the electron micrograph (hereinafter referred to as "electron micrograph") shown in Patent Document 4. In the present invention, in order to measure the "shear joint stickiness" of the above-mentioned three types, three types including the dense whiskers-generated copper pieces are re-created, and an injection junction of "SGX120" is prepared from these to prepare their "shear". "Joint stickiness" was measured. As a result, the measurement results of the three types were all higher than those described in Patent Document 5, which is the basic invention of the surface treatment of copper, and one of the dense whiskers type was higher than the other two types. .. In short, this kind of whisker type is an injection bonding product using Al alloy in all of shear bonding strength, shear bonding stickiness, and bonding strength moisture resistance as an injection bonding product using "SGX120", which is a PPS-based resin composition. It showed a high value close to.

[Development process of the present invention]
In such a process, among the chemical conversion treatment methods described in Patent Document 4, the surface treatment method for producing copper pieces that generate whiskers is further finely adjusted by trial and error, and the shear bonding stickiness is improved. We searched for a higher processing method. Then, it was positioned as an improved invention of the invention described in Patent Document 4, and was named "latest new NMT treatment method 1" in copper in the present invention. Then, it was determined that C1100 copper could be treated by this "latest new NMT treatment method 1" and used for LIB. In short, the injection joint using this copper piece not only has a high shear joint strength of about 42 MPa, but also has moisture resistance and heat resistance in its bonding force. Since this injection joint showed a high value of 35.3 MPa even in the "shear joint stickiness" value, it was predicted that the gas sealing property of the joint surface portion was also high. The reason for this is that the injection bond between the Al alloy and the PPS resin composition not only has a high shear bond strength of about 40 MPa, but also has a moisture resistance to the bond force and a "shear bond stickiness" value of C1100 copper material. It is as high as 35.3 MPa obtained. In short, due to this improvement, the injection joint has high values equivalent to those of the injection joint using Al alloy in all of the shear joint strength, the shear joint tenacity, and the bonding force, moisture resistance and heat resistance.

[Joinability of whisker type copper surface]
Since the Al alloy and the copper material basically have physicochemically equivalent bonding characteristics to the PPS-based resin, it is presumed that the gas sealing properties at the bonding portion are also similar. However, with the current technology, it is observed whether the injection resin flows to the hairline of the whiskers in a short time and invades the ultra-fine uneven surface where whiskers grow like hair on the surface of the copper material. Can't. An electromicrograph of the surface of the Al alloy (see, for example, Fig. 4) in which an injection junction of Al alloy / PPS resin that is close to complete encapsulation was realized shows the depth of the recesses with such a fine uneven period. This is because it is shallower than the recess depth (here, the thickness of the whiskers layer) obtained from the photograph of the whiskers surface (see, for example, FIG. 5).

In short, the surface on which the whiskers are formed is not a simple ultrafine uneven surface shape. That is, as for the gas sealing property, there is a possibility that a nano-level space remains at the hairline of the whiskers, and this whisker structure may be slightly inferior in gas sealing property even if the bonding strength does not change. It is presumed that there is no such thing. Therefore, the present invention has also developed a surface treatment method for producing a non-whisker type surface for C1100 copper pieces having a shear bond strength and a "shear bond stickiness" value that are exactly the same as those of a whisker-treated copper piece. As a result of these improvements in the surface treatment method, it was expected that the gas sealing property on the copper electrode side would be surely improved from that described in Patent Document 4, and that the performance would be almost the same as that of the aluminum electrode portion. Based on this result, the structure of the LIB battery lid as shown in FIG. 8 was proposed. For this reason, the shape example of this structure by the new surface treatment method has been greatly simplified as compared with the above-mentioned LIB battery lid structure proposal (structure shown in FIG. 11 described in Patent Document 1).

(Other problems with copper surface treatment)
The above-mentioned aqueous solution of the surface treatment used for the copper material having a whisker-shaped surface contains chromium nitrate hydrate at a concentration of 0.1%, which is a very small amount. When a large amount of copper pieces are treated, the treatment liquid also deteriorates, so it is necessary to replace it with a new liquid, and waste liquid is generated. Naturally, wastewater containing trivalent chromium, which is very thin, is generated and cannot be released into the natural environment, so investment for wastewater treatment equipment is required. Since the amount of chromium contained in wastewater is very thin, this treatment cost is not large, but at least the investment cost is incurred. The present inventors considered that they should show a high degree of environmental conservation above the level of satisfying legal standards from the viewpoint of environmental protection, not from this cost consciousness. Therefore, it is desirable to change the treatment liquid used for treating the surface of the copper material so that it does not contain chromium. Moreover, the injection bonding product between the copper material treated by this and the PPS-based resin must have a bonding strength equal to or higher than that treated with a treatment liquid containing chromium in its injection bonding force. It doesn't become. The chemical conversion treatment method of the present invention has also reached the point of producing this bonded product. As will be described later, the treatment methods treated with the treatment liquid containing no chromium are referred to as "latest new NMT treatment method 2" and "latest new NMT treatment method 3" (described later) shown in Table 1 below. Call. No copper oxide whiskers are formed on the surface of the copper material treated by these two new treatment methods.

(Injection joining technology)
The above-mentioned "injection joining technology" will be described in detail again. Technology for strongly joining metal and synthetic resin is required not only in the parts manufacturing industry such as automobiles, home appliances, and various industrial equipment, but also in a wide range of industrial fields, and many adhesives have been developed for this purpose. Such joining technology is a core technology in all manufacturing industries. On the other hand, when joining a metal and a resin, a joining method that does not use an adhesive has been conventionally studied and variously proposed. The above-mentioned "NMT (abbreviation of Nano Molding Technology)" and "New NMT (abbreviation of New Nano Molding Technology)" developed and named by the present inventors. NMT referred to in the present invention is a joining technique of an Al alloy surface-treated by a specific chemical conversion treatment and a resin composition, and is a crystalline thermoplastic resin in an Al alloy piece previously inserted into an injection molding mold. Is injected to form the resin portion, and at the same time, the molded product and the Al alloy piece are joined. Further, the new NMT referred to in the present invention is a bonding technique similar to that of all metal species including Al alloy and a resin composition, and is different from NMT in the basic theory regarding the surface treatment method for metals performed before insertion. It's different. The technique of joining a solid substance such as a metal material and a thermoplastic resin via an injection molding machine in this way, or the technique thereof, is referred to by the inventors as "injection joining" or "injection joining technique".

(NMT)
The present inventors have specified the following 4 or 5 conditions as the necessary conditions for the establishment of NMT, which is an injection joining technology using an Al alloy. First, regarding the Al alloy side, the following (1) and (2) are necessary conditions. The chemical treatment of the Al alloy surface so as to satisfy these two points was referred to as "NMT treatment".
(1) The entire surface is covered with ultrafine recesses having a diameter of 20 to 50 nm.
(2) And the water-soluble amine compound is chemically adsorbed on the surface layer.
Next, regarding the resin composition side to be injected, the following two or three points are necessary conditions.
(3) The resin composition used is a resin composition containing a highly crystalline thermoplastic resin as a main component.
(4) The highly crystalline thermoplastic resin chemically reacts with amine-based molecules at high temperatures.
(5) The resin composition can be made into a main component resin by adding a third component resin as a secondary component resin, even if it is a resin that is compatible with the main component resin or a resin that is incompatible with the main component resin. Contains a resin that is compatible or partially compatible.
The above (1) to (4) are indispensable necessary conditions, and if the above condition (5) is added, the injection bonding force becomes stronger. An NMT that satisfies the above conditions (1) to (5) and has hydrated hydrazine selected as the amine compound of the above (2) has been put into practical use.

(NMT2, NMT5 to NMT8)
The present inventors have discovered that a strong bonding force can be obtained by injection-bonding a PBT (polybutylene terephthalate) -based resin composition to an NMT-treated Al alloy. After that, the inventors have discovered that the PPS-based resin composition can be injection-bonded to the NMT-treated Al alloy (Patent Document 12). Next, as described in Patent Document 1, the surface treatment method of the Al alloy was improved to develop the "NMT2" treatment method, and the injection bonding force between this treated product and the above-mentioned PBT-based resin and PPS-based resin was increased. I found it to improve. In particular, in the case of PPS-based resin-based products, the shear bonding strength is about 40 MPa, and the injection bonded product is exposed to 85% humidity at a temperature of 85 ° C. for 6,000 to 8,000 hours or more, and the shear bonding strength is as high as 37 to 40 MPa. For the first time, we have found that a metal-resin integrated product that is maintained and has the highest degree of moisture resistance and heat resistance can be obtained. The present inventors referred to this technique as NMT2.

The inventors used NMT2 as the highest level of injection bonding technology for Al alloys and PPS-based resins, but problems still emerged in subsequent experiments. That is, when the Al alloy is treated with NMT2 and then stored for one week or more and the injection bonding step of the PPS-based resin composition is performed, the moisture and heat resistance of the shear bonding strength tends to decrease. The applicant has carried out NMT2 on the largest scale in the manufacture of the Al alloy body of the Al alloy smartphone. At this time, it was found that if the chemical-treated Al alloy was stored for one week or longer, the desired bonding strength could not be obtained, and to be correct, the shear bonding strength could be obtained, but the long-term heat resistance was lowered. .. As a countermeasure, the NMT2 treatment method was improved, and a chemical conversion treatment method called NMT5, NMT7, NMT8 treatment method, etc. for various Al alloys was developed. When these new treatment methods are used, the above-mentioned effective storage days are 4 weeks or more. In addition, when a new new NMT treatment method (described later) such as NMT5-Oxy, NMT7-Oxy, NMT5-Ano, NMT7-Ano treatment method named by the present inventors is used for various Al alloys. The above-mentioned effective storage days have been several months or more, and the weak points of NMT2 have been completely eliminated (Patent Document 2).

(New NMT)
The present inventors have invented a new NMT capable of injection-bonding various metal materials and resin compositions, and have invented and proposed a principle treatment method for each metal type (Patent Documents 5 to 9). That is, it is disclosed as an injection joining technology corresponding to almost all kinds of practical metals supplied to the market such as Mg alloys, Al alloys, copper, stainless steels, general steel materials, and special steel plates. The highly crystalline thermoplastic resin used here was the same as the injection bonding resin for NMT.

The conditions for establishing the "new NMT" are the following five necessary conditions according to the definition of the inventor and the like. The following three points are necessary conditions for the metal materials used. The chemical treatment that satisfies these three points ((1) to (3) below) is called "new NMT treatment". That is,
(I) The metal material has a fine rough surface with a period of 0.8 to 10 μm, and (ii) an ultrafine uneven surface shape with a period of 5 to 300 nm (preferably 50 to 100 nm) is formed on the rough surface. To have and
(Iii) The surface layer is covered with a thin layer of hard ceramic material such as metal oxide and metal phosphor oxide.
The following two points are necessary conditions on the injection resin side. That is,
(IV) Use a resin composition containing a highly crystalline thermoplastic resin as a main component,
(V) The resin composition may be a resin that is compatible with the main component resin or a resin that is incompatible with the main component resin as a component resin other than the highly crystalline thermoplastic resin that is the main component. Even if there is, the third component resin contains a resin that promotes compatibility even partially with the main component resin.

The new NMT has been developed for all metal species. The first invention for which a patent was filed for a new NMT of copper was the invention described in Patent Document 5, and the improvement of the chemical conversion treatment method for the surface thereof was carried out through the treatment method described in Patent Document 1 and then in Patent Document 4. It was mentioned above that the processing method described has been reached. In the invention described in Patent Document 4, in the surface treatment method of C1100 copper disclosed therein, there is a treated product in which a short copper oxide whisker covers the surface of a copper plate like a head hair as an ultrafine uneven surface. It is to be. When this copper plate is used to form an injection bond with "SGX120", its shear bond strength is about 40 MPa. When this is left at a temperature of 85 ° C. under 85% humidity for 3,000 hours and then dried and measured, the shear bonding strength drops to 32 MPa. However, judging from the results of this harsh acceleration test, it was judged that the bonding strength is sufficiently high in moisture and heat resistance in practical use under the general atmospheric environment on the earth's surface. These disclosed inventions are surface treatment methods related to the latest injection bonding technology for copper materials as far as the present invention and the like are known.

WO2012 / 070654 JP-A-2019-188651 JP-A-2019-217704 JP-A-2017-132243 WO2008-047811 WO2008-069252 WO2008-081933 WO2008-078714 WO2009-011398 WO2009-116484 Japanese Patent Application Laid-Open No. 2003-103563 WO2004-041532

[Gas sealing property of copper member and resin]
By using the methods described in Patent Documents 1, 2 and 3 described above, the battery lid structure itself including the electrode extraction portion of the LIB is provided with a near-perfect gas sealing property. That is, the injection joint portion formed by the PPS-based resin and the Al alloy rod has a nearly perfect sealing property of helium gas, and the injection joint portion formed by the PPS-based resin composition and the copper rod material is described in Patent Document 1. The shape shown in FIG. 11 is shown in FIG. 11, that is, the copper rod portion is wound up with an Al alloy thin plate having a thickness of about 1 mm, and the copper and the Al alloy are joined by "tightening" accompanied by plastic deformation. If this is used as a member for the positive electrode extraction part, advanced surface treatment for the Al alloy material is performed, and injection bonding is performed with the PPS-based resin "SGX120", this copper-resin bonding portion is also equivalent to the above-mentioned Al alloy material. The helium gas sealing property is generated. That is, Patent Document 1 has already shown a proposal to make the space between the electrolytic solution portion of the LIB and the outside air almost completely gas-sealing, but it relies only on the excellent surface treatment method of the Al alloy material. , The electrode drawing member for LIB includes a slightly troublesome processing step.

The present invention discloses that the copper injection bonding technique has made great progress, and shows that the same technique can be used more concisely as a copper electrode lead-out part of a LIB, and that a long-life LIB production can be made more easily. It is a thing. Further, the injection junction using a copper material according to the present invention uses an aqueous solution containing a small amount of trivalent chromium as one of the surface treatment liquids (the surface of the copper material is covered with whiskers). ) And those that do not use chromium material as a treatment liquid at all. Although the data on the bonding force between the copper material and the resin are the same in both cases, the gas sealing properties of the bonding surface layer may be slightly different, although both are high. It is difficult to determine what the slight difference will ultimately be in terms of the life of the commercialized LIB. First of all, from the viewpoint of advanced environmental problems, it is better to avoid products that use treatment solutions containing chromium-based compounds.

From the above background, the present invention achieves the following object.
An object of the present invention is to provide an integrated structure of a copper material and a PPS-based resin composition having high gas-sealing properties and a method for producing the same.
Another object of the present invention is to provide an integrated structure of a copper material and a PPS-based resin composition having high shear joint strength and shear joint tenacity, and a method for producing the same.
Still another object of the present invention is copper, which has high shear bonding strength and shear bonding stickiness, without using an aqueous solution containing chromium nitrate hydrate as one of the treatment liquids in the surface treatment process of copper material. It is an object of the present invention to provide an integrated structure of a material and a PPS-based resin composition, and a method for producing the same.

The present invention adopts the following means in order to solve the above problems.
The integrated structure of the copper material and the PPS-based resin composition of the present invention 1 is
A structure in which a surface-treated copper piece and a specific polyphenylene sulfide-based resin composition are directly bonded and integrated.
The polyphenylene sulfide-based resin composition is a resin in which the main component of the resin portion is polyphenylene sulfide resin, the secondary component is a modified polyolefin resin, and 15 to 25% by weight of short glass fibers of the entire resin composition is added as a reinforcing material component. It is a composition
The bonding force between the copper material and the polyphenylene sulfide resin composition is 40 MPa or more as measured by the shear bonding strength of the injection bonded product specified in the Japanese Industrial Standards (ISO19095), and
The injection joint is characterized by having a shear joint tenacity value of 33 MPa or more, which is defined as a tensile force that does not break even when an external force in the shear direction is applied by continuous repetition of 300 times.

In the present invention 1, the integrated structure of the copper material and the PPS-based resin composition of the present invention 2 is a rod-shaped material, which forms a lead-out portion of a negative electrode, and has been surface-treated by a chemical conversion treatment. A rod-shaped object made of an aluminum alloy forms a lead-out portion of a positive electrode, and a battery lid in which the negative electrode portion and the lead-out portion of the positive electrode portion penetrate to the outside is formed, and the material of the battery lid is the polyphenylene sulfide-based resin. It is characterized in that it is a structure around the electrode pull-out portion of the lithium ion battery which is the composition.

The integrated structure of the copper material and the PPS-based resin composition of the present invention 3 is a pure copper material having a purity of 99.90% or more in the present invention 1 or 2, and is bonded to the copper material. The thickness of the polyphenylene sulfide-based resin composition is 1 mm or less.

The method for producing an integrated structure of a copper material and a PPS-based resin composition according to the present invention 1 is the method for producing an integrated structure of a copper material and a PPS-based resin composition according to the present inventions 1 to 3.
By inserting the copper member having a chemical conversion treatment on the surface into an injection molding die and injecting the polyphenylene sulfide-based resin composition, the copper member and the polyphenylene sulfide-based resin composition are directly integrated. It is characterized by materialization.

Hereinafter, the above-mentioned components constituting the present invention, description of the manufacturing method, reasons, and ideas will be described.
[PPS-based resin composition used in the present invention]
The resins used are all injection bonding resins, and are resin compositions containing the crystalline thermoplastic resin described in the above-mentioned NMT theory and new NMT theory as a main component and at least a different polymer as a secondary component. Specifically, when the main component is PPS, a modified polyolefin resin is used as a secondary component, and a small amount of a third component resin is added so as to increase the affinity between PPS and the modified polyolefin resin as a result. did. In short, the crystallization rate of PPS molecules during quenching was significantly slower than that of the single resin composition, and injection bonding became easier. In such a process, as described above, as the PPS-based resin composition most suitable for injection bonding, the above-mentioned "SGX120" and the like can be mentioned.

[Injection joining technology]
In the injection bonding as used in the present invention, a copper material and / or an aluminum alloy is inserted into an injection molding die, the injection molding die is closed, and a PPS-based resin composition is injected into the cavity to inject a metal and PPS. It means joining the based resin composition. These injection molding conditions are performed by general injection molding required for PPS-based resin compositions.
[Aluminum alloy (Al alloy)]
Any general pure aluminum or aluminum alloy may be used, regardless of whether it is a wrought material such as Al-Cu-based, Al-Mn-based, Al-Si-based, or Al-Mg-based, or a casting material. It is preferable to use a general-purpose and standardized one.

[Copper material]
As the copper material used in the present invention, any pure copper-based copper material can be used. It is preferable to use a general-purpose and standardized one. As a preferable chemical conversion treatment method for this surface, a new NMT type treatment method described in detail in Patent Document 4 or an improved chemical conversion treatment method thereof is used (specifically described in an experimental example described later). Among them, a treatment method in which the surface of the C1100 copper piece forms a whisker is preferable. The shear joint strength of the injection joint (shape in FIG. 1) between the C1100 copper material subjected to this treatment and the above-mentioned "SGX120" is about 42 MPa, and the "shear joint stickiness" value is 35.3 MPa. However, this surface treatment method includes a dipping step using an aqueous solution containing a small amount of trivalent chromium. The surface of the copper material that has been completely immersed has a surface shape in which copper oxide whiskers are densely grown like hair. However, evidence that the whiskers themselves contain chromium has not been confirmed at least by the time of the invention of the present invention.

Generally speaking, there are no laws and regulations that repel the product itself for metal materials treated with a treatment liquid containing chromium, and if these products themselves are to be repelled, special steel including stainless steel and chromium are used. It will avoid important materials that support modern society, such as treated zinc-plated steel sheets. To be precise, in the process of manufacturing them, chromium-containing wastewater and waste are always generated. Therefore, in a newly proposed product such as the present invention, wastewater and waste generated in the manufacturing process are always generated. The processing process such as, etc. should also be legally regulated and its management should be strengthened. For this reason, the idea of environmental protection that the manufacturing process itself should be changed to be a chromium agent-free type is also born. The present invention was developed based on this idea, and also considers the future environment. That is, it does not include the judgment as to whether the wastewater treatment and waste treatment in compliance with public regulations should be done in compliance with the law or more. In the present invention, both are included as usable techniques. That is, in the embodiment of the present invention described later, the treatment method containing a chromium-containing treatment liquid is the "latest new NMT treatment method 1", and the treatment liquid containing no chromium-containing substance is the "latest new NMT treatment method 1". "NMT processing method 2" and "latest new NMT processing method 3".

In short, the inventors have also developed a new excellent NMT treatment method for C1100, which has an ultrafine uneven surface without using a chromium-containing treatment liquid. The injection joint (test piece) of the shape shown in FIG. 1 described in ISO19095 was made of "SGX120", C1100 copper piece treated by this new surface treatment method, and copper piece covered with copper oxide whiskers. Was compared. The shear bond strength of the copper piece treated by the new surface treatment method is 41.4 MPa, the "shear bond stickiness" value is 35.3 MPa, and the shear bond strength when using the copper piece covered with copper oxide whisk is. The "shear joint stickiness" value is 42.6 MPa and the value is 35.3 MPa, both of which are almost the same value. The copper material treatment method using the chromium-free treatment liquid at this time is the above-mentioned "latest new NMT treatment method 2". In addition, the copper material treatment method "latest new NMT treatment method 3", which also uses a chromium-free treatment liquid, is not suitable because the surface-treated product of the above treatment method 2 has a slightly different appearance color tone when dried. It is a treatment method with improved stability.

[Temperature impact of -50 ° C / + 150 ° C thousands of cycles test of injection bonding technology]
The coefficient of linear expansion of Al alloy is 2.3 × 10 ^-5 K ^-1 , the coefficient of linear expansion of copper is 1.8 × 10 ^-5 K ^-1 , and the coefficient of linear expansion of the above “SGX120” molded product is about 4 ×. It is ^10-5 K- ^1. Therefore, in the integrated product of the Al alloy and the above-mentioned "SGX120", when there is a temperature change, an internal stress in the direction opposite to the bonding force is generated in the vicinity of the bonding surface. In short, the difference in linear expansion coefficient between the Al alloy and the above-mentioned "SGX120" is ^{about 1.7 x 10-5} K- ¹ , and the difference in linear expansion coefficient between copper and the above-mentioned "SGX120" is 2.2 x. It is about ^10-5 K- ^1. When the shape of these injection joints is the shape shown in FIG. 1, the joint surface is 0.5 cm ² of 10 mm × 5 mm. For example, when an environmental temperature change of 200 ° C is applied, an Al alloy material is used. 1.7 × 10 ^-5 K ^-1 × 200 ° C = 0.0034 = 0.34%, and 2.2 × 10 ^-5 K ^-1 × 200 ° C = 0.0044 = 0 with C1100 copper material. A dimension of .44% occurs compared to before the temperature change.

Since the longest portion of this joint surface is 11.2 mm, a deviation of 0.038 mm occurs in this length in the case of an Al alloy material, and it is 0.049 mm in the case of a copper material. If this is repeated thousands of times, the portion of the outer peripheral portion of the joint surface where the bonding force cannot be maintained will increase, and the bonding force will decrease. In the case of the above temperature change, the thermoplastic resin molded product has creep property, and when the temperature change progresses slowly, the internal stress that should be caused by the difference in linear expansion coefficient is hardly observed. In short, when the temperature changes slowly, the resin part is forcibly loaded with tensile and compressive forces due to the deformation of the metal material near the joint surface, so the amorphous part (polymers are entangled and shaped) in the resin. The entangled pattern of the part) changes to cause a slight change in shape, and the generated internal stress is relieved. This is the explanation of the creep phenomenon itself, but therefore, the temperature change between early morning and early afternoon in the day, and the large but slow temperature change in the four seasons have the above-mentioned difference in linear expansion rate due to creep. Does not go to break.

However, in the case of LIB, a drastic temperature change during its use occurs, for example, when preparing for a winter automobile used in Alaska, Siberia, etc., which are known as cold regions. In cold regions, the outside air temperature is about -50 ° C when the car is parked, and when the car is running, there is heat in the LIB, and the heat of the engine and the heat of the room heating are also present, so the temperature is about 80 ° C when it is high. Such a temperature change is a temperature shock rather than a temperature change. This temperature shock has no direct relation to the creep characteristics and does not affect it. Therefore, medium-sized LIBs used for mobile machines must sufficiently withstand a temperature impact of about 3,000 cycles at -50 ° C / + 100 ° C. After performing a temperature impact 3,000 cycle test on an injection joint of Al alloy and "SGX120" by the method described in Patent Document 3, the joint surface was observed. After creating the shape (test piece) shown in FIG. 1, the resin portion is scraped off, and the shape of the resin portion is changed from 3 mm to 2 mm in the original shape as shown in FIGS. 6 and 7. Make it 1 mm thick.

Then, the shaped objects of FIGS. 1, 6 and 7 were subjected to a temperature shock 3,000 cycle test at −50 ° C./+ 150 ° C., and then all of them were broken and the traces of the joint surface on the metal side were observed. For those using NMT5-7 treated Al alloy, the resin part 3 mm thick product (test piece) in FIG. 1 is clear with no resin powder at the four corners of the joint surface of ^{10 mm × 5 mm and area 0.5 cm 2.} In the center, black resin powder remained. The above "SGX120" is a black resin containing carbon black, and the fact that the resin powder in the central portion of the joint surface remains indicates that the joint surface was maintained in the black portion. .. The four corners of the rectangular joint without black color are the parts where the resin portion has already been extracted from the fine recesses on the metal surface and the bonding force is zero. That is, in the above-mentioned temperature impact test, it is shown that the peeling has progressed to just before breaking. In the portion where the joint portion shown in FIG. 6 was 2 mm thick, a portion where there was little resin powder was observed in two of the four corners, and the bonding force was lost in a very narrow area. Then, in the portion where the joint portion shown in FIG. 7 was 1 mm thick, no resin leakage occurred at all including the four corners.

From this result, the present inventors have stated that when the resin thickness is 1.5 mm at the boundary and the thickness is 1.5 mm or less, the resin molded product is bonded to such an excellent surface-treated Al alloy. It was judged that the resin would continue to join even if there were thousands of cycles of temperature impact regardless of the area. On the other hand, the same experimental test was also performed on C1100 copper pieces. That is, it is an experimental example "A5" in the examples described later, and this experiment is injection-bonded to the above-mentioned "SGX120". For this, only the shape (test piece) shown in FIG. 7 was prepared and subjected to a temperature impact of 3,000 cycles at −50 ° C./+ 150 ° C. As described above, the copper material has a larger difference in linear expansion coefficient from the Al alloy material than the Al alloy material. Therefore, when this temperature impact test is performed on a resin material having a resin thickness of 3 mm and a resin thickness of 2 mm, the Al alloy material It was predicted that the results would be worse than the experimental results. As an experiment, it was observed whether a slight peeling phenomenon occurred on the joint surface in the injection joint (test piece) having the shape shown in FIG. 7 and having a resin thickness of 1 mm.

The results are shown in Examples described later. If the wall thickness of the resin at the joint is 1 mm, it can be said that the joint structure can withstand this severe temperature impact test regardless of the joint area. Then, in the present invention, the design of the injection joint with "SGX120" containing both copper and Al alloy material having a wall thickness of 1 mm or less is carried out in accordance with the basic design method described in Patent Document 3. Can be done. The cross-sectional shape shown in FIG. 8 is an example of the shape when applied to the lid of the main body container of the LIB.

[Injection joining operation and annealing process]
In the injection bonding of the present invention, as described above, a mold for injection bonding is created, a surface-treated metal piece is inserted into an open mold, the injection molding mold is closed, and molten resin is injected. be. No special technical features are required for this injection joining operation. If you dare to say it, it is the temperature and holding time of the injection molding die. The mold temperature may be in the temperature range specified by the resin manufacturer, but basically it is better to set it higher within this range. Specifically, when the above "SGX120" is used, the mold temperature is preferably around 140 ° C. Then, the obtained injection junction is not allowed to cool as it is to be a final product, but is heat-treated (annealed) at 150 ° C. for about 1 hour within a few hours to sufficiently crystallize the resin. It is preferable to complete the entire injection joining process after proceeding to. For the above reasons, it is preferable that the integrated structure of the copper material of the present invention and the PPS-based resin composition is annealed after injection molding.

[Measurement of shear bond strength and shear bond stickiness value]
ISO19095 defines a method for measuring the shear strength (tensile lap-shear strength) and the tensile strength (tensile strength) between a metal portion and a resin molded product in an injection joint. According to this, a method of tensilely breaking a shaped object (test piece) shown in FIG. 1 with a tensile tester and measuring its shear joint strength, and a method of tensilely breaking the shaped object shown in FIG. 2 with a tensile tester and performing the same. A method for measuring the tensile joint strength is described. The basis of this ISO standard for shear joint strength is a strength test method that has been used and proposed by the present inventors since the invention described in Patent Document 12. This method for measuring the tensile joint strength has been used by the present inventors from around 2015 after various processes. Neither can be measured by the method specified in the Japanese Industrial Standards (JISK6849, 6850), which is the conventional method for measuring adhesive strength and bonding strength. It was specified as a standard (ISO19095).

[About "shear joint stickiness"]
Furthermore, the present inventors have proposed a new recording evaluation method of joining force called "shear joining tenacity (force)" as well as shear joining strength, and this "shear joining tenacity" is calculated from the value of shear joining strength. Emphasis was placed on it. That is, this uses the PPS-based resin composition "SGX120" to create an injection joint (the shape shown in FIG. 1), and applies an external force in the shear direction to the joint surface to make it resistant to the external force. It was measured. In this case, the shear bonding strength was 39 to 42 MPa at the maximum regardless of the metal type, and no more was observed. In short, regardless of the type of metal material and the surface treatment method, when a breaking test is performed on a test piece having the shape shown in FIG. 1 in an experiment using the above "SGX120", a numerical value that seems to be an upper limit is reached. Therefore, the shear bonding strength approaches about 40 MPa depending on whether the surface treatment method of the metal alloy piece is further improved and its shear bonding strength is evaluated and the improvement is made or rather deteriorated without improvement. It becomes difficult to find out.

Therefore, the present inventors have newly proposed a measurement called "shear joint tenacity (force)", and if the value is high, it is judged that a better surface treatment method can be achieved. This "shear joint tenacity (force)" is a kind of fatigue test of a joint. The "shear joint tenacity" as used in the present invention refers to the result (shear joint strength) obtained by the following experimental method. First, the test piece (the shape shown in FIG. 1) is broken by a tensile tester, and the "shear joint strength" is measured and determined in advance. Then, a test is performed in which a tensile force of about 75% of this "shear joint strength" is continuously and repeatedly applied to this test piece only 300 times. The method of applying the load is performed by a tensile tester, and the operation software of the control device of the tester is set. The operation software operates with the maximum tensile force set to 75% of the above-mentioned "shear joint strength" value, the minimum tensile force set to about 2/3 of the above-mentioned maximum tensile force, and the tensile speed set to ± 10 mm / min as one cycle. ..

If the shear fracture is not caused by the continuous repeated load of 300 cycles, the maximum tensile load is increased by about 2 MPa, and the same test is performed in which the repeated load is applied 300 times. If it still does not break, further add about 2 MPa and repeat the same operation until the test piece shown in FIG. 1 breaks. After fracture, the maximum tensile force before fracture is displayed in MPa or in kg / 0.5 cm ² in gravitational units. In this experiment in the present invention, this is referred to as "shear joint tenacity". And said. The reason why the display of kg / 0.5 cm ² is that the force display of the tensile tester is kg and the joint area of the joint surface of the shape shown in FIG. 1 is 0.5 cm ² .

The integrated structure of the copper material and the PPS-based resin composition of the present invention not only has strong shear joint strength and shear joint tenacity, but also has moisture and heat resistance against the shear fracture resistance. It was also found that the physicochemical properties of both of them have high gas-sealing properties in the joint surface layer. In particular, a new surface treatment method for copper materials can be developed, and as the surface treatment method, both a treatment liquid containing an aqueous solution of a trivalent chromium compound and a surface treatment liquid containing no chromium compound are used. Established a new surface treatment method. The Al alloy material to which these chemical conversion treatments have been applied and the LIB using the copper material can seal the invasion of water molecules into the electrolytic solution at a practical level.

FIG. 1 is an external view of an injection joint for measuring the shear joint strength between a metal portion and a resin portion in the metal-resin joint integrated product specified in ISO19095. FIG. 2 is an external view of an injection joint for the purpose of measuring the tensile joint strength between the metal portion and the resin portion in the metal-resin joint integrated product specified in ISO19095. FIG. 3 is an external view of an auxiliary jig used when measuring the shear joint strength in the metal-resin joint integrated product specified in ISO19095. FIG. 4 is an electron micrograph of the surface of Experimental Example A-1 of A5052Al alloy after chemical conversion treatment. FIG. 4 (a) is 1000 times, FIG. 4 (b) is 10,000 times, and FIG. 4 (c) is. It is a 100,000 times photo. FIG. 5 is an electron micrograph of a surface-treated product of C1100 copper, which is an electron micrograph of the surface after chemical conversion treatment of Experimental Example A-4. FIG. 6 is a test piece in which the upper part of the joint surface of the resin portion in the shape shown in FIG. 1 is machined to reduce the original thickness of 3 mm to 2 mm. FIG. 7 is a test piece in which the upper part of the joint surface of the resin portion in the shape shown in FIG. 1 is machined to reduce the original thickness of 3 mm to 1 mm. FIG. 8 is an example of the shape of the injection joint according to the present invention, and is a cross-sectional view when applied to the lid of the main body container of the LIB.

An embodiment of the integrated structure of the copper material and the PPS-based resin composition of the present invention will be described as an experimental example of the examples shown below.

Hereinafter, examples of the integrated structure of the copper material and the PPS-based resin composition of the present invention will be described as experimental examples described below. The outline of the equipment used in the experiment and the test method is as follows.
(A) Measurement of joint strength 1
The breaking force at the time of tensile breaking of the injection joints (FIGS. 1 and 2) by the tensile tester was defined as the shear joint strength and the tensile joint strength. However, in the measurement of the shear joint strength, the auxiliary jig shown in FIG. 3 was used. The tensile tester used was "AG-500N / 1kN (manufactured by Shimadzu Corporation (Headquarters: Kyoto, Japan))" and measured at a tensile speed of 10 mm / min. This measurement method was based on the method specified in ISO1909.
(B) Measurement of joint strength 2
The above-mentioned "shear joint tenacity" value is measured by using an injection joint (test piece shown in FIG. 1) by ISO19095 and using the above tensile tester "AG-500N / 1kN" at a tensile speed of ± 10 mm / min. gone. The specific operation method of the testing machine is as described above.
(C) Electron microscope observation SEM type electron microscope "S-4800 (Hitachi High-Technologies Corporation (Headquarters: Tokyo, Japan))" and "JSM-6700F (JEOL Ltd. (Headquarters: Tokyo, Japan))" Made) ”was used and observed at 1 to 2 KV.

[Experimental Example A] Surface Treatment Method for Metal Pieces [Experimental Example A-1] Surface Treatment of A5052Al Alloy (referred to as "NMT7 Treatment" in the present invention)
An A5052Al alloy plate having a thickness of 1.5 mm was cut into 45 mm × 18 mm to obtain an Al alloy piece. An aqueous solution containing 10% of the aluminum degreasing agent "NA-6 (Meltex Inc. (Headquarters: Tokyo, Japan))" (hereinafter referred to as "NA-6") in the immersion tank was set at 60 ° C. and described above. After immersing the Al alloy piece for 5 minutes, it was washed with public tap water (Ota City, Gunma Prefecture). Next, a caustic soda aqueous solution having a concentration of 10% at 40 ° C. was prepared in another dipping tank, and the Al alloy piece was immersed for 1 minute and washed with water. Next, an aqueous solution containing 1% hydrated aluminum chloride at 40 ° C. and 5% hydrochloric acid was prepared in another immersion tank, and an Al alloy piece was immersed in the aqueous solution for 6 minutes and then washed with water. Next, in another immersion tank, an aqueous solution containing 1 hydrogen 2-fluorinated ammon at a concentration of 2% and sulfuric acid at a concentration of 10% was prepared at 40 ° C., and an Al alloy piece was immersed in this solution for 4 minutes and then washed with water. .. Next, a caustic soda aqueous solution having a concentration of 1.5% at 40 ° C. was prepared in another dipping tank, and an Al alloy piece was immersed in this for 1 minute and then washed with water. Next, an aqueous nitric acid solution having a concentration of 3% at 40 ° C. was prepared in another dipping tank, and an Al alloy piece was immersed in the aqueous solution for 1.5 minutes and then washed with water. Next, a hydrated hydrazine aqueous solution having a concentration of 3.5% at 60 ° C. was prepared in another dipping tank, soaked in this for 1 minute, and then placed in another dipping tank at 33 ° C. for 0.5. After immersing in a% concentration hydrated hydrazine aqueous solution for 6 minutes, this was washed with water. Next, the Al alloy pieces having been subjected to the above chemical conversion treatment were dried by putting them in a warm air dryer set at 67 ° C. for 15 minutes, and these were wrapped in clean aluminum foil and stored.

The NMT7 treatment was carried out on the A5052 plate piece by the same treatment as the above treatment. The Al alloy pieces obtained by this chemical conversion treatment were observed with an electron microscope. FIG. 4 shows the electron micrograph (hereinafter referred to as an electron micrograph), the electron micrograph of 1000 times is shown in FIG. 4 (a), the electron micrograph of 10,000 times is shown in FIG. The electron micrograph of is shown in FIG. 4 (c). The observation of the 1000x photograph revealed that there are high-looking parts and wide flat areas due to the connection of small mountains, and it can be observed that the mountainous areas and plain areas with a period of several tens of μm form large uneven surfaces. When this part is visually observed, the reason why this part looks like a matte surface (pear-skin texture) is due to the presence of this rough surface. In the 10,000-fold electron micrograph, there is a fine uneven surface with a period of several μm, which is a recess in the grain boundary of the metal crystal. The 100,000x electron micrograph reveals an ultrafine uneven surface with a period of 30 to 100 nm, and the surface of the chemical conversion-treated Al alloy piece is a triple uneven surface in terms of the entire metal surface. It has a shape.

[Experimental Example A-2] Surface treatment of A6061Al alloy (referred to as "NMT8 treatment" in the present invention).
An A6061Al alloy plate having a thickness of 1.5 mm was cut into 45 mm × 18 mm to obtain an Al alloy piece. The aqueous solution containing 10% of the aluminum degreasing agent "NA-6" was heated to 60 ° C. in the dipping tank, the Al alloy piece was immersed for 5 minutes, and washed with public tap water (Ota City, Gunma Prefecture). Next, a caustic soda aqueous solution having a concentration of 10% at 40 ° C. was prepared in another dipping tank, and an Al alloy piece was immersed in this for 1 minute and then washed with water. Next, an aqueous solution containing 1% hydrated aluminum chloride at 40 ° C. and 5% hydrochloric acid was prepared in another immersion tank, and an Al alloy piece was immersed in this solution for 1 minute and then washed with water. Next, in another immersion tank, an aqueous solution containing 1 hydrogen 2-fluorinated ammon at a concentration of 2% and sulfuric acid at a concentration of 10% was prepared at 40 ° C., and an Al alloy piece was immersed in this solution for 1 minute and then washed with water. .. Next, a caustic soda aqueous solution having a concentration of 1.5% at 40 ° C. was prepared in another dipping tank, and an Al alloy piece was immersed in this for 2 minutes and then washed with water. Next, an aqueous nitric acid solution having a concentration of 3% at 40 ° C. was prepared in another dipping tank, and an Al alloy piece was immersed in the aqueous solution for 1.5 minutes and then washed with water. Next, a hydrated hydrazine aqueous solution having a concentration of 3.5% at 60 ° C. was prepared in another immersion tank and immersed in the aqueous solution for 1 minute, and then in another immersion tank at a concentration of 0.5% at 33 ° C. After immersing in the hydrated hydrazine aqueous solution for 4.5 minutes, this was washed with water. Next, a 1.5% concentration hydrogen peroxide solution was prepared in another immersion tank, soaked in the hydrogen peroxide solution for 1 minute, and then washed well with water. Next, an aqueous solution of triethanolamine having a concentration of 0.2% at 40 ° C. was prepared in another dipping tank, and the Al alloy piece was immersed in the aqueous solution for 5 minutes and then washed well with water. Next, it was placed in a warm air dryer set at 67 ° C. for 15 minutes to dry the Al alloy pieces that had undergone the above chemical conversion treatment, and these were wrapped in clean aluminum foil and stored.

[Experimental Example A-3] Surface treatment of A1100Al alloy (NMT7 treatment)
An A1100Al alloy plate having a thickness of 1.5 mm was cut into 45 mm × 18 mm to obtain an Al alloy piece. The aqueous solution containing 10% of the aluminum degreasing agent "NA-6" was heated to 60 ° C. in the dipping tank, the Al alloy piece was immersed for 5 minutes, and then washed with public tap water (Ota City, Gunma Prefecture). Next, a caustic soda aqueous solution having a concentration of 10% at 40 ° C. was prepared in another dipping tank, and an Al alloy piece was immersed in this for 1 minute and then washed with water. Next, an aqueous solution containing 1% hydrated aluminum chloride at 40 ° C. and 5% hydrochloric acid was prepared in another immersion tank, and an Al alloy piece was immersed in the aqueous solution for 10 minutes and then washed with water. Next, in another immersion tank, an aqueous solution containing 1 hydrogen 2-fluorinated ammon at a concentration of 2% and sulfuric acid at a concentration of 10% was prepared at 40 ° C., and an Al alloy piece was immersed in this solution for 1 minute and then washed with water. .. Next, a caustic soda aqueous solution having a concentration of 1.5% at 40 ° C. was prepared in another dipping tank, and the alloy pieces were immersed in the caustic soda aqueous solution for 2 minutes and then washed with water. Next, an aqueous nitric acid solution having a concentration of 3% at 40 ° C. was prepared in another immersion tank, and an Al alloy piece was immersed therein for 2 minutes and then washed with water. Next, a hydrated hydrazine aqueous solution having a concentration of 3.5% at 60 ° C. was prepared in another dipping tank, soaked in this for 1 minute, and then placed in another dipping tank at 33 ° C. for 0.5. After immersing in a% concentration hydrated hydrazine aqueous solution for 4 minutes, this was washed with water. Next, it was placed in a warm air dryer set at 67 ° C. for 15 minutes to dry the Al alloy piece after the above chemical conversion treatment, wrapped in clean aluminum foil, and stored.

[Experimental Example A-4] Surface treatment of C1100 copper (in the present invention, it is referred to as "new NMT" .: Similar surface treatment method described in Patent Document 4: A treatment agent containing chromium is used).
A C1100 copper plate having a thickness of 1.5 mm was cut into 45 mm × 18 mm, and a hole of 2 mmφ was formed at the end to form a copper plate piece. An aqueous solution containing 10% of the aluminum degreasing agent "NA-6" was placed in a dipping tank at 60 ° C., and the copper plate piece wrapped with a wire with a resin coating for horticulture was immersed for 5 minutes, and then this was immersed in public tap water (Gunma). Washed with water in Ota City, Gunma Prefecture. Next, a caustic soda aqueous solution having a concentration of 1.5% at 40 ° C. was prepared in another dipping tank, and a copper plate piece was immersed in the caustic soda solution for 1 minute and then washed with water. Next, a 10% aqueous nitric acid solution at 40 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in this for 1 minute and then washed with water. Next, in another immersion tank, an aqueous solution containing 3% nitric acid at 40 ° C. and ferric nitrate 0.25% concentration was prepared, and a copper plate piece was immersed in the aqueous solution for 10 minutes, and then this was added. Was washed with water. Next, in another immersion tank, an aqueous solution containing 2% potassium permanganate at 70 ° C., 3% potassium caustic, and 0.1% chromium nitrate hydrate was prepared, and a copper plate piece was prepared therein. Was soaked for 35 minutes and then washed with water. Next, an aqueous solution containing 5% sodium chlorate and 10% caustic soda at 55 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 20 minutes and then washed with water. Next, it was placed in a warm air dryer set at 80 ° C. for 15 minutes to dry the copper plate piece after the above chemical conversion treatment, and the copper plate piece was wrapped in clean aluminum foil and stored. An electron micrograph of the surface of the copper plate piece is shown in FIG. 5, and the appearance of dense whiskers is formed like hair (the same treatment method described in Patent Document 4).

[Experimental Example A-5] Surface treatment of C1100 copper (in the present invention, it is referred to as "1 of the latest new NMT": a treatment agent containing chromium is also used).
A C1100 copper plate having a thickness of 1.5 mm was cut into 45 mm × 18 mm, and a hole of 2 mmφ was formed at the end to form a copper plate piece. An aqueous solution containing 10% of the aluminum degreasing agent "NA-6" was placed in a dipping tank at 60 ° C., the copper plate piece was immersed for 5 minutes, and then washed with public tap water (Ota City, Gunma Prefecture). Next, a 10% aqueous nitric acid solution at 40 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 3 minutes and then washed with water. Next, in another immersion tank, an aqueous solution containing 3% nitric acid at 40 ° C. and ferric nitrate 0.25% concentration was prepared, and a copper plate piece was immersed in the aqueous solution for 25 minutes, and then this was added. Was washed with water. Next, in another immersion tank, an aqueous solution containing 2% potassium permanganate at 70 ° C., 3% potassium caustic, and 0.1% chromium nitrate hydrate was prepared, and a copper plate piece was placed therein. After soaking for 15 minutes, it was washed with water. Next, an aqueous solution containing 5% sodium chlorate and 10% caustic soda at 55 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 8 minutes and then washed with water. Next, the copper plate pieces having been subjected to the above chemical conversion treatment were dried by putting them in a warm air dryer set at 80 ° C. for 15 minutes. These were wrapped together in clean aluminum foil and stored.

[Experimental Example A-6] Surface treatment of C1100 copper (referred to as "latest new NMT 2" in the present invention).
A C1100 copper plate having a thickness of 1.5 mm was cut into 45 mm × 18 mm, and a hole of 2 mmφ was formed at the end to form a copper plate piece. In the dipping tank, an aqueous solution containing 10% of the aluminum degreasing agent "NA-6" was heated to 60 ° C., and the copper plate piece suspended by a wire with a resin coating for horticulture was immersed for 5 minutes, and then this was immersed in public tap water (public tap water). Washed with water in Ota City, Gunma Prefecture). Next, a 10% aqueous nitric acid solution at 40 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 3 minutes and then washed with water. Next, in another immersion tank, an aqueous solution containing 3% nitric acid at 40 ° C. and ferric nitrate 0.25% concentration was prepared, and a copper plate piece was immersed in the aqueous solution for 25 minutes, and then this was added. Was washed with water. Next, an aqueous solution containing 2% potassium permanganate and 3% potassium caustic at 70 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 15 minutes and then washed with water. Next, an aqueous solution containing 5% sodium chlorate and 10% caustic soda at 55 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 8 minutes and then washed with water. Next, it was placed in a warm air dryer set at 50 ° C. for 20 minutes, and further placed in a warm air dryer set at 67 ° C. for 10 minutes to dry the copper plate pieces. The dried copper plate pieces were wrapped together in clean aluminum foil and stored.

In the copper pieces obtained by this chemical conversion treatment method, an end portion in the direction opposite to the hole in the copper piece, and a linear portion having a slightly different color tone were observed about 5 mm from the end. Since the wet copper pieces obtained after the whole liquid treatment were hung in the dryer and forcibly dried, alkaline ions were concentrated and remained at the end where the adhered water remained at the end of this different color tone. It is presumed that some kind of fine shape change or chemical change was caused. The present inventors considered that it is necessary to avoid such a change in color tone caused by the drying process because it may cause a variation in quality. Therefore, in this Experimental Example A6, it is naturally necessary to carefully wash the water after the final step with sufficient ion-exchanged water or the like. Furthermore, such non-uniformity of the copper plate surface is not observed in the above-mentioned Experimental Examples A4 and A5. Experimental example A7, which will be described later, is a new idea in which an attempt is made to replace an alkaline substance remaining in the washing water by immersing it in a very dilute aqueous solution of a water-soluble amine for a short time. The uniformity was improved.

[Experimental Example A-7] Surface treatment of C1100 copper (referred to as "latest new NMT 3" in the present invention).
A C1100 copper plate having a thickness of 1.5 mm was cut into 45 mm × 18 mm, and a hole of 2 mmφ was formed at the end to form a copper plate piece. An aqueous solution containing 10% of the aluminum degreasing agent "NA-6" was placed in a dipping tank at 60 ° C., the copper plate piece was immersed for 5 minutes, and then washed with public tap water (Ota City, Gunma Prefecture). Next, a 10% aqueous nitric acid solution at 40 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 3 minutes and then washed with water. Next, in another immersion tank, an aqueous solution containing 3% nitric acid at 40 ° C. and ferric nitrate 0.25% concentration was prepared, and a copper plate piece was immersed in the aqueous solution for 25 minutes, and then this was added. Was washed with water. Next, an aqueous solution containing 2% potassium permanganate and 3% potassium caustic at 70 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 15 minutes and then washed with water. Next, an aqueous solution containing 5% sodium chlorate and 10% caustic soda at 55 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 8 minutes and then washed with water. Next, an aqueous solution of 0.02% concentration diethanolamine (DEA) at 40 ° C. was prepared in another immersion tank, and a copper plate piece was immersed in the aqueous solution for 0.5 minutes and then washed well with water. Next, put it in a warm air dryer set at 50 ° C for 20 minutes, and then put it in a warm air dryer set at 67 ° C for 10 minutes to dry the copper plate pieces, and then wrap them in clean aluminum foil and store them. did.

[Experimental Example B] An injection joint having the shape shown in FIG. 1 was prepared, and the bonding force between the metal and the resin was measured. As the injection resin, the above-mentioned PPS-based resin composition "SGX120" was used to prepare an injection joint. The values of "shear joint strength" and "shear joint tenacity" of the prepared injection joint were measured. The results are shown in Table 1. From Table 1, the NMT7 and NMT8 treated products developed from the NMT2 treatment method for all Al alloys show a shear bond strength of about 40 MPa, and the value of "shear bond stickiness" is about 85% of the shear bond strength. As shown, it has a sufficiently high strength bond. Further, in the A1100Al alloy containing 1% of impurities close to pure aluminum, the shear bonding strength is slightly low because the Al alloy material is slightly soft (low hardness).

On the other hand, of A4 to A7 of C1100 copper materials, A4 and A5 are types in which whiskers are formed on the surface thereof, and those containing chromium ions in the treatment liquid are used to form whiskers. The same treated product as the surface treatment method described in Patent Document 4 is A4, and the improved product used in the present invention is A5, and the "shear joint stickiness" is improved. Although a chromium ion-containing aqueous solution that requires strict wastewater treatment is used, it is presumed that having a whisker-shaped surface may cause some advantageous aspects, and it can be used in the present invention.

The surface of the treatment liquid containing no chromium ion was subjected to chemical conversion treatment in A6 and A7 of the above experiment shown in Table 1, and the treatment method of A6 is almost the same as that of A5 (chromium ion). Only the use of non-containing treatment liquid is different). A6 and A7 in the above experiment are treatment methods in which whiskers are not formed, but the shear bonding strength and shear bonding stickiness are not comparable to those in the chemical conversion treatment in which whiskers are formed. In the copper piece of A6, as described above, there was a portion having a different color tone at a portion of about 5 mm at the end, and the non-uniform portion was included in the injection joint surface. From Table 1, no particular abnormality was found in the shear joint strength in A6, and the shear joint tenacity was not particularly bad. Next, the treatment method of Experimental Example A7 was carried out as a countermeasure. That is, an operation of cleaning the surface was added by immersing in a dilute aqueous amine solution for a short time. Washing with this dilute aqueous amine solution eliminated the non-uniformity, at least with the naked eye.

[Experimental Example C] Implementation of Moisture and Heat Resistance Test Using Injection Bonds of Fig. 1 The injection joint with "SGX120", which is the PPS-based resin composition, using C1100 copper according to Experimental Examples A5 and A6. Judging from the results shown in Table 1, it is judged that the copper material of the present invention and the PPS-based resin composition can be used in an integrated structure. Specifically, for example, when it is used for the lid of a battery box using these for LIB parts, the structure in the joint surface layer is not changed by the humidity in the atmosphere, so that it is most suitable. In short, the important evaluation index cannot be put into practical use if the bonding force of the bonding portion between the copper material and the resin molded product decreases when it is placed in the atmosphere including humidity for a long period of time. Therefore, although it is a harsh accelerated test, a high-temperature and high-humidity test was conducted in which the product was exposed to 85% humidity for 1000 hours at a temperature of 85 ° C. The results are shown in Table 2. In this test, after taking out the test piece from the high-temperature and high-humidity tester, the primary drying was performed at 80 ° C. × 48 hours, and then the secondary drying was performed at 150 ° C. × 4 hours, and this was released. After cooling, the shear joint strength was measured. The drying step at 150 ° C. is for completely releasing the water contained in the resin of the PPS-based resin composition "SGX120" in a diffused state to the outside.

From the results in Table 2, both the shear bond strength and the shear bond stickiness are lower than the values before being put into the high temperature and high humidity tester, but the results in the harsh high temperature and high humidity test are very high. .. The downward tendency of the Al alloy and the copper material is quite similar to the injection junction of the NMT2-treated Al alloy shown in Patent Document 1 and the PPS-based resin composition "SGX120" and the data of the same high temperature and high humidity test. is doing. In the case of the Al alloy, the shear bond strength showed the lowest value in the first 500 hours, and the shear bond strength up to 1000 hours recovered slightly and returned to 37 to 39 MPa. After that, the measurement was performed for 6,000 to 8,000 hours, but the bonding force did not change. It is presumed that this is a transitional phenomenon in which the formation of aluminum rust due to the invading water molecule oxygen molecule on the Al alloy side on the joint surface fills the gap and moves toward the completely sealed type. In the case of copper, if the copper rust generated here is due to copper oxide, it means that it has reacted with oxygen molecules. Judging from the above measured values in the case of Al alloy material, what happened in 500 hours may have taken as long as 1000 hours in the case of copper. If this reasoning is correct, this high temperature and high humidity resistance test conducted at a temperature of 85 ° C. and a humidity of 85% may lead to an improvement in gas sealing performance as the test progresses. In any case, when the present invention is applied to the LIB, the battery appears to be all-weather and should be preferable in extending the battery life.

[Experimental Example D] Implementation of a temperature shock thousand-cycle test at -50 ° C / + 150 ° C An injection junction of the C1100 copper pieces prepared in Experimental Examples A5 and A6 and the PPS-based resin composition "SGX120" (in FIG. 1). Several pieces of the shape shown) were prepared, and then the resin portion was scraped off, and the thickness of the resin portion was changed from 3 mm thickness of the original shape of FIG. 1 to 1 mm thickness as shown in FIG. 7. Then, it was subjected to a temperature shock 3,000 cycle test at −50 ° C./+ 150 ° C., and then the resin portion was forcibly peeled off from the metal portion using a nipper or the like. As a result, the black powder of the resin adhered to the entire surface including the four corners of the joint surface trace of the metal portion, and the resin did not come off. From this result, it was judged that the resin of "SGX120" would continue to be bonded to C1100 copper, which had an excellent surface treatment if the resin thickness was 1 mm or less, regardless of the bonding area, regardless of the temperature impact of several thousand cycles.

On the other hand, in the same experimental test, as described in Patent Document 3 for Al alloys, in the present invention, injection using the above-mentioned PPS-based resin composition "SGX120" is based on about 1 mm. Given the thickness of the resin part in the case of the joint, it can be fully expected that the injection joint can withstand a temperature impact of 3,000 cycles of −50 ° C./+ 150 ° C.

FIG. 8 is a cross-sectional view showing a structural example of the lid portion of the LIB main body. That is, it is an example of an integrated structure of a copper material and a PPS-based resin composition according to the present invention, and is an example of being used for a lid of a LIB box. Whether the metal material of the drawer portion is a long plate shape or a round bar shape, it is surrounded by a resin, and the basic thickness of the resin portion to be joined to the metal is about 1 mm. Since the joint area is wide and easy to take, the gas sealability is good. In the above test, the temperature impact 3,000 cycle test was performed with a difference of 200 ° C from -50 ° C / + 150 ° C, but in reality, when considering the actual usage environment of LIB, it is -50 ° C / + 100 ° C. A difference of 150 ° C seems to be sufficient.

The above-mentioned embodiment was applied to a copper electrode for drawing out from the main body of the LIB, but the present invention is not limited to this, and if a copper member and a PPS composition are used, parts of other products such as electrical equipment are used. It may be used for the structure and manufacture of.

Claims (4)

A structure in which a surface-treated copper piece and a specific polyphenylene sulfide-based resin composition are directly bonded and integrated.
The polyphenylene sulfide-based resin composition is a resin in which the main component of the resin portion is polyphenylene sulfide resin, the secondary component is a modified polyolefin resin, and 15 to 25% by weight of short glass fibers of the entire resin composition is added as a reinforcing material component. It is a composition and
The bonding force between the copper material and the polyphenylene sulfide resin composition is 40 MPa or more as measured by the shear bonding strength of the injection bonded product specified in the Japanese Industrial Standards (ISO19095), and
The injection joint is a copper material and a PPS system characterized by having a shear joint tenacity value of 33 MPa or more, which is defined as a tensile force that does not break even when an external force in the shear direction is applied by continuous repetition of 300 times. Integrated structure of resin composition. In the integrated structure of the copper material and the PPS-based resin composition according to claim 1.
The copper material is a rod-shaped material that forms a lead-out portion for a negative electrode, and a rod-shaped material made of an aluminum alloy that has been surface-treated by a chemical conversion treatment forms a lead-out portion for a positive electrode. Copper characterized in that the drawer portion constitutes a battery lid penetrating to the outside, and the material of the battery lid is a structure around the electrode pull-out portion of the lithium ion battery which is the polyphenylene sulfide-based resin composition. An integrated structure of the material and the PPS-based resin composition. In the integrated structure of the copper material and the PPS-based resin composition according to claim 1 or 2.
The copper material is a pure copper material having a purity of 99.90% or more.
An integrated structure of a copper material and a PPS-based resin composition, characterized in that the thickness of the polyphenylene sulfide-based resin composition bonded to the copper material is basically 1 mm or less. In the method for producing an integrated structure of a copper material and a PPS-based resin composition according to claim 1, which is selected from claims 1 to 3.
By inserting the copper member whose surface has been chemically treated into an injection molding die and injecting the polyphenylene sulfide-based resin composition, the copper member and the polyphenylene sulfide-based resin composition are directly integrated. A manufacturing method characterized by materialization.

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