JP3721611B2 - Cylindrical secondary battery and its assembled battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical secondary battery suitable for use as a power source for an electric vehicle, for example, and an assembled battery thereof.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, as a cylindrical secondary battery, an electrode spiral body in which a strip-like positive electrode and a negative electrode are spirally wound through a separator is housed in a cylindrical metal case such as a battery case made of stainless steel. Proposed.
[0003]
When a plurality of cylindrical secondary batteries of a metal battery case are connected and housed in an assembled battery case and used as an assembled battery, when the metal battery cases of the cylindrical secondary battery are short-circuited, Since a current flows between the short-circuited cylindrical secondary batteries, the metal battery case is covered with an insulating shrink tube made of synthetic resin.
[0004]
However, since the insulating film of the insulating shrink tube has no adhesion to the metal battery case, if the insulating film is scratched, the crack proceeds and the insulating film is peeled off.
[0005]
In particular, when this assembled battery is used as a power source for an electric vehicle, vibrations are constantly applied to the assembled battery, so that there is a disadvantage that the insulating film is easily peeled off as described above.
[0006]
In addition, when using this assembled battery as a power source for an electric vehicle, it is necessary to firmly fix the cylindrical secondary battery when it is connected and housed in an assembled battery case. An attachment portion is provided on the battery and fastened to the assembled battery case with a bolt or the like. However, in this case, there is a disadvantage that a relatively large space is required and the weight is increased.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to make it possible to satisfactorily insulate a metal battery case and to make a battery pack relatively small and light.
[0008]
[Means for Solving the Problems]
The cylindrical secondary battery of the present invention is a cylindrical secondary battery in which an electrode spiral body obtained by spirally winding a belt-like positive electrode and a negative electrode through a separator is housed in a cylindrical metal battery case. Urethane rubber elastic insulator layer having a film thickness of 50 μm or more and 200 μm or less obtained by pretreating the surface of the metal battery case with liquid honing, and then applying a liquid urethane rubber elastic insulator, drying and fixing the surface. Is provided.
[0009]
According to the present invention, since the urethane rubber elastic insulator layer is provided on the surface of the metal battery case, even if the urethane rubber elastic insulator layer is damaged, the urethane rubber elastic insulator layer can be peeled off. The surface of the metal battery case can be well insulated.
[0010]
Further, the assembled battery of the cylindrical secondary battery of the present invention is a cylindrical lithium battery in which an electrode spiral body in which a strip-like positive electrode and a negative electrode are spirally wound through a separator is housed in a cylindrical metal battery case. This is an ion secondary battery. The surface of this metal battery case is pretreated by liquid honing, and then a liquid urethane rubber elastic insulator is applied, dried and fixed, and the film thickness is 50 μm or more and 200 μm or less. An assembled battery in which a plurality of cylindrical secondary batteries provided with a urethane rubber elastic insulator layer are connected and accommodated in an assembled battery case. The assembled battery case includes an upper cover, an intermediate cover, a lower cover The upper cover, the middle cover, and the lower cover are provided with contact ribs that contact the cylindrical secondary battery, and urethane elastic sealants are provided in the grooves of the contact ribs. Is adhered and fixed to the assembled battery case.
[0011]
According to the present invention, the urethane rubber elastic insulator layer is provided on the surface of the metal battery case of the cylindrical secondary battery, and the cylindrical secondary battery is bonded and fixed to the assembled battery case with the urethane elastic sealant. Therefore, the cylindrical secondary battery can be firmly fixed to the assembled battery case, and a relatively small and light assembled battery can be obtained.
[0012]
Further, according to the present invention, since the cylindrical secondary battery having the urethane rubber elastic insulator layer on the surface is bonded and fixed to the assembled battery case with the urethane elastic sealant, vibration resistance and impact resistance are improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example in which the cylindrical secondary battery of the present invention and its assembled battery are applied to a cylindrical lithium ion secondary battery that is a cylindrical non-aqueous electrolyte secondary battery and its assembled battery will be described with reference to the drawings.
[0014]
1 to 3, a cylindrical lithium ion secondary battery according to this example has an electrode spiral body 14 in which a strip-like positive electrode 2 and a negative electrode 3 are spirally wound with a separator 8 interposed therebetween, for example, a stainless steel plate. It is made to accommodate in the cylindrical metal battery case 10 comprised.
[0015]
The negative electrode 3 is produced as follows. That is, the negative electrode active material 6 of this negative electrode 3 uses petroleum pitch as a starting material, introduces 10 to 20% of a functional group containing oxygen (so-called oxygen crosslinking), and then in an inert gas stream at 1000 ° C. A carbon material having properties close to glassy carbon is obtained by heat treatment, and a carbon material powder having an average particle diameter of 20 μm obtained by grinding the carbon material is used.
[0016]
90 parts by weight of the carbon material powder and 10 parts by weight of polyvinylidene fluoride (PVDF) as a binder are mixed, and the mixture is dispersed in a solvent N-methylpyrrolidone to form a slurry. As shown in FIG. 2, the material 6 is uniformly applied to both surfaces of a negative electrode current collector 7 made of a strip-shaped copper foil having a thickness of 10 μm to prepare a negative electrode original plate having a thickness of 180 μm, which is 348 mm × 6940 mm in size. As shown in FIG. 2, strip-like leads 7a having a predetermined width and a predetermined length are provided at a predetermined pitch so as to extend from one side of the negative electrode current collector 7 as shown in FIG. . In this case, in this example, the strip-like leads 7a have a pitch of 15 mm, a width of 10 mm, and a length of 30 mm.
[0017]
The positive electrode 2 is manufactured as follows.
91 parts by weight of LiCoO ₂ powder having an average particle size of 15 μm, 6 parts by weight of graphite as a conductive agent, and 3 parts by weight of vinylidene fluoride as a binder were mixed, and this mixture was mixed with a solvent N-methylpyrrolidone. As shown in FIG. 2, the slurry-like positive electrode active material 4 was uniformly applied to both surfaces of a positive electrode current collector 5 made of a strip-shaped aluminum foil having a thickness of 20 μm to form a positive electrode having a thickness of 150 μm. An electrode original plate is prepared, and is cut into a strip of 344 mm × 7150 mm, and as shown in FIG. 2, a strip having a predetermined width and a predetermined length at a predetermined pitch so as to extend from the other side of the positive electrode current collector 5. A strip-like positive electrode 2 was obtained by providing a strip-like lead 5a. In this case, in this example, the pitch of the strip-like leads 5a is 15 mm, the width is 10 mm, and the length is 30 mm.
[0018]
As the separator 8, a polyethylene sheet in which micropores having a thickness of 38 μm are formed and cut into a size of 353 mm × 7600 mm is used.
[0019]
In this example, as shown in FIG. 2, the strip-shaped separator 8, the strip-shaped negative electrode 3, the strip-shaped separator 8 and the strip-shaped positive electrode 2 are sequentially overlapped and wound around the inner core 11 in a spiral shape. Body 14 was obtained.
[0020]
In this case, a strip-shaped lead 5a extending in the short side direction of the positive electrode current collector 5 of the positive electrode 2 and a strip-shaped lead 7a extending in the short side direction of the negative electrode current collector 7 of the negative electrode 3 are respectively provided in this electrode spiral body. 14 on one side and the other side.
[0021]
The inner core 11 is, for example, an aluminum cylinder having an outer diameter of 17 mm, an inner diameter of 14 mm, and a length of 354 mm.
[0022]
As shown in FIGS. 1 and 3, a disc-like portion 12a made of aluminum and a cylindrical portion 12b protruding from the central portion are formed on the inner core 11 of the electrode spiral body 14 on the side of the strip-like lead 5a from the positive electrode current collector 5. The positive electrode terminal 12 is fixed via an insulating collar 13, and laser welding is performed with the strip-shaped lead 5 a sandwiched between the presser fittings 17 over the entire circumference of the disk-shaped portion 12 a of the positive electrode terminal 12. Try to fix the connection.
[0023]
Further, as shown in FIG. 1, a negative electrode terminal having a disc-like portion 15a made of copper and a columnar portion 15b protruding from the center portion on the inner core 11 on the side of the strip-shaped lead 7a from the negative electrode current collector 7 of the electrode spiral body 14. 15 is fixed through an insulating collar 16, and is connected and fixed by laser welding in a state where the strip-like lead 7a is sandwiched between presser fittings 17 over the entire outer periphery of the disk portion 15a of the negative electrode terminal 15. To do.
[0024]
Circular top plates 20a and 20b each made of a stainless steel plate having a predetermined thickness are respectively attached to the cylindrical portions 12b and 15b of the positive electrode terminal 12 and the negative electrode terminal 15 fixed to both ends of the electrode spiral body 14, respectively. The ceramic abutments 22a and 22b are fitted with ceramic washers 23a and 23b, respectively, and then tightened with nuts 24a and 24b to fix the portions in a sealed state. Further, bolts 27a and 27b for fixing a connector for connection are screwed to the cylindrical portions 12b and 15b of the positive electrode terminal 12 and the negative electrode terminal 15, respectively.
[0025]
Thereafter, the electrode spiral body 14 to which the top plates 20a and 20b are fixed is inserted into a cylindrical battery case 10 made of, for example, a stainless steel plate having a thickness of 0.4 mm, and then one end and the other end of the battery case 10 are connected. The outer peripheries of the top plates 20a and 20b are laser-welded and fixed in an airtight manner.
[0026]
In the drawings, reference numerals 25a and 25b respectively denote meklet plugs for sealing the electrolyte solution inlet, and reference numerals 26a and 26b denote openings for venting the internal gas when the pressure inside the battery case 10 exceeds a predetermined pressure. The valve device is shown.
[0027]
In this example, the electrolytic solution is injected from the electrolytic solution injection port. As this electrolytic solution, LiPF ₆ was dissolved in a mixed solvent of propylene carbonate and diethyl carbonate at a ratio of 1 mol / l.
[0028]
In this example, a urethane rubber elastic insulator layer 30 is provided on the surface of the cylindrical battery case 10. In order to provide the urethane rubber elastic insulator layer 30 on the surface of the battery case 10, the surface of the cylindrical battery case 10 is pretreated by liquid honing, and then a liquid urethane rubber elastic insulator is applied. Dry and fix.
[0029]
The thickness of the urethane rubber elastic insulator layer 30 is preferably 50 μm or more in order to satisfy the insulation performance, and is preferably 200 μm or less in consideration of an increase in battery weight and volume.
[0030]
According to this example, since the urethane rubber elastic insulator layer 30 is provided on the surface of the cylindrical battery case 10, even if the urethane rubber elastic insulator layer 30 is damaged, the urethane rubber elasticity. The insulator layer 30 is not peeled off, and the surface of the battery case can be well insulated.
[0031]
Further, in this example, as shown in FIG. 4, a plurality of cylindrical lithium ion secondary batteries 40 as described above, for example, eight, are connected in series and housed in an assembled battery case 41 to form an assembled battery.
[0032]
This assembled battery case 41 is produced by resin molding using acrylonitrile-butadiene-styrene copolymer resin (ABS), polybutylene terephthalate (PBT), etc., and this assembled battery case 41 is this cylindrical lithium ion secondary battery. The upper cover 41a, the middle cover 41b, and the lower cover 41c are fixed to the upper cover 41a, the middle cover 41b, and the lower cover 41c. Ribs 42 that contact the battery case 10 are formed.
[0033]
In this example, each of the ribs 42 is provided with a groove, and the groove of the rib 42 is filled with a urethane-based elastic sealant such as Hamatite WS-55 made by Yokohama Rubber Co., Ltd. The cylindrical lithium ion secondary battery 40 and the upper cover 41a, the middle cover 41b, and the lower cover 41c are bonded and fixed together.
[0034]
In FIG. 4, reference numeral 43 denotes a connector for connecting the eight cylindrical lithium ion secondary batteries 40 in series, and 41d and 41e constitute the assembled battery case 41. The cylindrical lithium ion secondary battery 40 shows a front terminal cover and a back terminal cover covering the positive and negative terminal portions of 40, and the front terminal cover 41d and the back terminal cover 41e are adhesively fixed to the upper cover 41a, the middle cover 41b and the lower cover 41c with an adhesive, Integrate with them.
[0035]
The assembled terminal electrode terminals 44a and 44b are provided on the front terminal cover 41d.
[0036]
In the present example, as described above, the urethane rubber elastic insulator layer 30 is provided on the surface of the battery case 10 of the cylindrical lithium ion secondary battery, and the cylindrical lithium ion secondary battery 40 is assembled with the urethane elastic sealant 31 to form an assembled battery case. 41, the cylindrical lithium ion secondary battery 40 can be firmly fixed to the assembled battery case 41, and a relatively small and lightweight assembled battery can be obtained. it can.
[0037]
Further, according to this example, the cylindrical lithium ion secondary battery 40 having the urethane rubber elastic insulator layer 30 on the surface is bonded and fixed to the assembled battery case 41 by the urethane elastic sealant 31, and this urethane rubber elastic insulation is provided. Since the body layer 30 and the urethane-based elastic sealant 31 are elastic bodies, they absorb vibration and impact, and have excellent vibration resistance and impact resistance.
[0038]
In the above embodiment, the present invention is applied to a cylindrical lithium ion secondary battery. However, it can be easily understood that the present invention can be applied to other cylindrical secondary batteries. In the above embodiment, the battery case 10 is formed of a stainless steel plate, but other metals may be used.
[0039]
Further, the present invention is not limited to the above-described embodiments, and various other configurations can be adopted without departing from the gist of the present invention.
[0040]
【The invention's effect】
According to the present invention, since the urethane rubber elastic insulator layer is provided on the surface of the metal battery case, even if the urethane rubber elastic insulator layer is damaged, the urethane rubber elastic insulator layer is not peeled off. There is an advantage that the surface of the metal battery case can be well insulated.
[0041]
Further, according to the present invention, the urethane rubber elastic insulator layer is provided on the surface of the metal battery case of the cylindrical secondary battery, and the cylindrical secondary battery is bonded and fixed to the assembled battery case with the urethane elastic sealant. There is an advantage that the cylindrical secondary battery can be firmly fixed to the assembled battery case, and a relatively small and lightweight assembled battery can be obtained.
[0042]
In addition, according to the present invention, since the cylindrical secondary battery having the urethane rubber elastic insulator layer on the surface is bonded and fixed to the assembled battery case with the urethane elastic sealant, there is a benefit that vibration resistance and impact resistance are good. is there.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one embodiment of a cylindrical secondary battery of the present invention.
FIG. 2 is a diagram for explaining a main part of FIG. 1;
FIG. 3 is a partially enlarged sectional view of FIG. 1;
FIG. 4 is an exploded perspective view showing an embodiment of an assembled battery of a cylindrical secondary battery according to the present invention.
FIG. 5 is a diagram for explaining a main part of FIG. 4;
[Explanation of symbols]
2 positive electrode 3 negative electrode 5 positive electrode current collector 5a strip-shaped lead 7 negative electrode current collector 7a strip-shaped lead 8 separator 10 metal battery case 11 inner core 12 positive electrode terminal 15 negative electrode terminal 30 urethane rubber elastic insulator layer 31 urethane system Elastic sealant 41 Battery case 42 Rib

Claims (2)

In a cylindrical secondary battery in which an electrode spiral body in which a strip-like positive electrode and a negative electrode are spirally wound via a separator is housed in a cylindrical metal battery case,
Urethane rubber elastic insulator having a film thickness of 50 μm or more and 200 μm or less obtained by pretreating the surface of the metal battery case with liquid honing, then applying a liquid urethane rubber elastic insulator, drying and fixing the surface. A cylindrical secondary battery comprising a layer. A cylindrical lithium ion secondary battery in which an electrode spiral body obtained by spirally winding a belt-like positive electrode and a negative electrode through a separator is housed in a cylindrical metal battery case,
Urethane rubber elastic insulator having a film thickness of 50 μm or more and 200 μm or less obtained by pretreating the surface of the metal battery case with liquid honing, then applying a liquid urethane rubber elastic insulator, drying and fixing the surface. An assembled battery in which a plurality of cylindrical secondary batteries provided with a layer are connected and stored in an assembled battery case,
The assembled battery case includes an upper cover, an intermediate cover, a lower cover, a front cover, and a back cover,
The upper cover, the middle cover, and the lower cover are provided with contact ribs that contact the cylindrical secondary battery, and the grooves of the contact ribs are filled with urethane-based elastic sealant to be bonded and fixed to the assembled battery case. An assembled battery of a cylindrical secondary battery characterized by the above.

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