JP2012186125A - Battery case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a battery case having electromagnetic wave shield and sufficient strength, facilitating mold machining, and having high impact resisting strength.SOLUTION: A battery case 11 used for a truck of an electric vehicle or a truck of an electric hybrid vehicle, is composed of a case body 12 for storing a battery and a lid 13. The battery case 11 is made from impact resistance resin, anc covers the inside of the lid 13 and the case body 12, and a peripheral edge portion of an opening portion of the case body which contacts with the lid 13, with a plurality of electromagnetic wave shielding sheets. The electromagnetic wave shielding sheets are joined by a conductive adhesive. Side edges or end edges which contact with each other are selected from a first layout for making a side edge or an end edge of one electromagnetic wave shielding sheet and a side edge or an end edge of another electromagnetic wave shielding sheet adjacent to each other, and a second layout for superimposing a side edge or an end edge of one conductive sheet on one side edge or an end edge of another conductive sheet. In the first layout, the side edges or the end edges of both adjacent electromagnetic wave shielding sheets are electrically connected by conductive material.

Description

  The present invention relates to a battery case used for a truck of an electric vehicle or a truck of an electric hybrid vehicle.

  An electric vehicle (EV) or an electric hybrid vehicle (HEV) is a vehicle that can run by an electric motor using electricity as a whole or a part of a power source, and extends a running distance by charging during running.

  In a conventional automobile, a metal battery case is used as a battery. When this battery case is used as it is for an EV or HEV, the weight of the battery affects the travel distance of the electric motor. For this reason, it can be considered that the battery case is made of resin.

  However, in this case, it is observed that electromagnetic waves are emitted from the vicinity of the battery when charging during EV or HEV travel, and the resin does not have an electromagnetic wave shielding effect. It will be discharged to the outside of the case. This electromagnetic wave may affect the control system of the automobile, and it is necessary to prevent the electromagnetic wave from being stopped.

  Also, in a truck, unlike a passenger car, the battery is exposed to the outside. For this reason, the battery case used for EV and HEV trucks also requires strength.

  On the other hand, as described in Patent Document 1, a battery case made of a reinforced resin material having a wire mesh that reflects electromagnetic waves interposed between fiber reinforced resin layers containing glass fiber and unsaturated polyester is used. Is being considered.

Japanese Patent Laid-Open No. 08-186390

  By the way, the battery case described in Patent Document 1 requires a predetermined wire mesh to be inserted in the fiber reinforced resin, and the molding process becomes complicated.

  Moreover, in the battery case of patent document 1, it is thought that all the electromagnetic waves of the wavelength which should be cut off about 500 Hz-100 MHz cannot be cut off. In particular, the high frequency (20 MHz or higher) shielding effect is considered to be weak.

  Further, regarding the strength, the resin material of Patent Document 1 certainly increases the strength (strength against static load), but the impact strength is not high. It is important that the truck battery case does not puncture against impact.

  Therefore, an object of the present invention is to obtain a battery case having an electromagnetic wave shield, sufficient strength, easy molding, and high impact strength.

The present invention is a battery case used for an electric vehicle truck or an electric hybrid vehicle truck, and the battery case includes a case main body and a lid for storing the battery, and the battery case is made of an impact-resistant resin. A plurality of electromagnetic wave shielding sheets are arranged and covered inside the lid and the case body, and the electromagnetic wave shielding sheets are electrically conductive at the periphery of the upper open portion of the case body that is in contact with the lid. Cover with glue,
The electromagnetic wave shielding sheet is bonded using a conductive adhesive, and the arrangement of the side edge or the edge where the plurality of electromagnetic wave shielding sheets are in contact with each other is the side edge or the edge of one electromagnetic wave shielding sheet and another electromagnetic wave. From the first arrangement in which the side edge or edge of the shielding sheet is adjacent, and from the second arrangement in which the side edge or edge of one conductive sheet overlaps the side edge or edge of another conductive sheet In the first arrangement, the problem is solved by conducting the side edges or edges of both adjacent electromagnetic wave shielding sheets with a conductive material.

In the present invention, since the battery case is made of an impact-resistant resin, it can withstand external impacts even when used for a truck.
In addition, since the electromagnetic waves from the battery generated during charging / discharging are generated from the upper half of the battery, they are generated by covering the peripheral edge of the upper open part of the case body in contact with the lid by covering it with a conductive sheet. It can prevent electromagnetic waves from being guided to the conductive sheet and leaking outside.
Further, when a plurality of conductive sheets are used as the conductive sheet covering the peripheral edge of the upper open portion of the case body, electromagnetic waves may leak from the side edges or the edges where the plurality of conductive sheets contact each other. In contrast, in an arrangement in which one conductive sheet and another conductive sheet are adjacent to each other, the side edges or edges of both adjacent conductive sheets are covered with a conductive tape, and the side edges of one conductive sheet or In the arrangement in which the edge overlaps the side edge or edge of another conductive sheet, the side edge or edge of the conductive sheet is covered by covering the side edge or edge of the one conductive sheet with a conductive tape. Electromagnetic waves can be prevented from leaking from the edge.

(A) The perspective view which shows the example of the battery case concerning this invention, (b) The partial expanded sectional view of the hook vicinity vicinity of (a) (A) Sectional drawing which shows the example of how to affix the conductive sheet and conductive tape to the collar part, (b) Cross-sectional view which shows the other example of the method of affixing the conductive sheet and conductive tape to the collar part Schematic diagram showing an example of blow molding Schematic diagram showing impact test method Schematic diagram showing the electromagnetic shielding performance measurement method

  The battery case according to the present invention is a battery case used for an electric vehicle (EV) truck or an electric hybrid vehicle (HEV) truck.

As shown in FIG. 1, the battery case 11 includes a case body 12 that houses a battery and a lid 13. Since this battery case 11 is arranged in a form exposed to the outside, it is made of an impact resistant resin. Examples of such an impact resistant resin include high-density polyethylene and polycarbonate. Among these, it is preferable to use high-density polyethylene, particularly polyethylene having a density of 0.93 g / cm ³ or more from the viewpoint of moldability and chemical resistance. Polyethylene having a density of 0.93 g / cm ³ or more can be appropriately selected from commercially available products and used from the viewpoints of rigidity, impact resistance, moldability, drawdown resistance, gasoline resistance, etc. such density is more preferably from 0.95~0.98g / cm ^3, more preferably from 0.96~0.98g / cm ^3.

Further, the high load melt flow rate (HLMFR) of polyethylene having a density of 0.93 g / cm ³ or more is preferably 1 to 50 g / 10 min (190 ° C., 21.60 kg under load) from the viewpoint of moldability. More preferably, it is 1 to 10 g / 10 min (190 ° C., under a load of 21.60 kg).

  The inside of the lid 13 and the case body 12 is covered with an electromagnetic wave shielding sheet 16. Further, the periphery of the upper opening 14 of the case body 12 that contacts the lid 13, for example, the flange 15, is covered with an electromagnetic wave shielding sheet 16. As these electromagnetic wave shielding sheets 16, a plurality of electromagnetic wave shielding sheets 16 are usually used. Further, the electromagnetic wave shielding sheet 16 is joined to the case main body 12 and the lid 13 through the conductive adhesive 17. The conductive adhesive 17 is applied in advance to one surface of the electromagnetic wave shielding sheet 16, and is joined to the electromagnetic wave shielding sheet 16 when the electromagnetic wave shielding sheet 16 is disposed on the case body 12 or the lid 13.

  Since electromagnetic waves from the battery generated during charging / discharging are generated from the upper half of the battery, by arranging the electromagnetic wave shielding sheet 16 in this portion, the generated electromagnetic waves are guided to the electromagnetic wave shielding sheet 16 and leak to the outside. Can be prevented.

  A conductive tape 18 is disposed between the case body 12 and the lid 13. With this conductive tape 17, the electromagnetic waves accumulated in the lid 13 can be sent to the electromagnetic wave shielding sheet 16 of the case body 12 via the conductive tape 17, and by the ground attached to the battery case 11 itself. Electromagnetic waves can flow outside.

  The electromagnetic wave shielding sheet 16 is obtained by adding conductivity to a normal sheet by blending a conductive material. Examples of the conductive material include aluminum, copper, steel, and carbon fiber. Examples of the sheet include ordinary sheets such as a polyester sheet, a nylon sheet, and a polyolefin sheet.

  The conductive adhesive 17 imparts conductivity to the sheet by blending a conductive material with an adhesive such as an epoxy, urethane, silicon, acrylic adhesive, or acrylic adhesive. Is. Examples of the conductive material include those similar to the conductive material used for the electromagnetic wave shielding sheet 16 described above. Specific examples of the conductive adhesive 17 include an acrylic conductive adhesive (metal particle dispersion type), a conductive adhesive containing a silver powder filler, and the like.

  Examples of the constituent material of the conductive tape 18 include the same kind of material as that of the electromagnetic wave shielding sheet 16.

  It is sufficient if the electromagnetic wave shielding sheet 16 can be covered by one sheet without overlapping the entire peripheral edge portion of the upper open portion 14, but a plurality of electromagnetic wave shielding sheets 16 are often used depending on the shape of the covered portion. . At this time, as the arrangement of the side edge or the edge portion where the plurality of electromagnetic wave shielding sheets 16 are in contact with each other, one electromagnetic wave shielding sheet 16a and another electromagnetic wave shielding sheet 16b as shown in FIG. The side edge or edge of one electromagnetic wave shielding sheet 16a as shown in FIG. 2 (b) and the side edge of another electromagnetic wave shielding sheet 16b as shown in FIG. Alternatively, at least one arrangement selected from arrangements that overlap each other on the edge or an arrangement that has both of them (hereinafter referred to as “second arrangement”) will be employed.

  In the first arrangement as shown in FIG. 2A, the side edges or the edges of the adjacent electromagnetic wave shielding sheets 16a and 16b are preferably covered with a conductive adhesive tape 19.

  An example of the conductive adhesive tape 19 is one in which a conductive adhesive 17 is applied to one side of the electromagnetic wave shielding sheet 16 or the conductive tape 18.

  In the second arrangement as shown in FIG. 2B, there is a layer made of the conductive adhesive 17 on the lower surface of the electromagnetic wave shielding sheet 16a riding on the electromagnetic wave shielding sheet 16b. Prevents leakage of electromagnetic waves.

  The structure of the case body 12 constituting the battery case 11 is preferably a double wall structure. This is because the double wall structure can increase the rigidity and is suitable for loading heavy batteries. The thickness of one wall is preferably 2 to 10 mm from the viewpoint of providing rigidity for loading a heavy battery.

  The case main body 12 and the lid 13 having the double wall structure can be manufactured by various methods such as blow molding. When the blow molding method is adopted, it can be produced by the following method. As shown in FIG. 3, with the left and right molds 21 and 22 opened, the molten resin is extruded from a die 23 to form a parison. Then, the molds 21 and 22 are closed while the parison extruded to a predetermined length remains in the cavity, and the shape of the case body 12 is formed. The same applies to the lid 13.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded.

<Measurement method>
[Melt flow rate (HLMFR)]
According to JIS K-7210 (2004 edition), Annex A Table 1-Condition G, the measured value at a nominal load of 2.16 kg was shown as MFR.

[density]
It measured according to JIS K-7112 (2004 edition).

[Shock test]
After creating the battery case, the side part was cut into a size of 100 mm □ × 3 mmt to create a test piece 24.
The temperature of the test piece 24 is adjusted to −40 ± 2 ° C., and then the test piece is placed on a support 25 having an inner diameter of φ70 mm and a width of 15 mm, and the Ministry of Land, Infrastructure, Transport and Tourism-Road Transport Vehicle Safety Standard Details [2003.09.26] According to Attachment 16 (Technical Standard for Plastic Fuel Tank for Passenger Cars), as shown in FIG. The impact body 26 is a pyramid having a regular triangular side surface and a square bottom surface. The impact body 26 is made of steel, has an effective mass of 15 kg, and is rounded with a radius of 3 mm at the apex and both parts.
In the judgment of the impact test, the case where the impact body 26 did not penetrate was regarded as acceptable (“◯”), and the case where it was penetrated was regarded as unacceptable (“×”).

[Alcohol resistance]
After creating the battery case, the side part was cut into a size of 100 mm × 10 mm × 3 mmt to create a test piece. The obtained test piece was immersed in methyl alcohol and allowed to stand at 23 ° C. for 10 days. After immersion, the sample was taken out, wiped off the methyl alcohol adhering to the surface, and examined for the presence or absence of surface cracks.

<Raw materials>
(Molded resin material)
HDPE: high density polyethylene resin, manufactured by Nippon Polyethylene Co., Ltd .: Novatec HD HB111R, density: 0.945 g / cm ³ , weight average molecular weight: 250,000, HLMFR: 6 g / 10 min. PP: polypropylene resin, Nippon Polypro Co., Ltd. ): Novatec EC9-EV, MFR (190 ° C., 2.16 kg load): 0.5 g / 10 min. PC: Polycarbonate resin, manufactured by Mitsubishi Engineering Plastics: Novalex M7027BF, MFR (280 ° C., 2 .16 kg load): 1.9 g / 10 min

(Electromagnetic wave shielding sheet)
・ Aluminum sheet (JIS 1050)

(Conductive adhesive)
・ Dotite D-723S manufactured by Fujikura Kasei Co., Ltd.

(Conductive tape)
・ Teraoka Seisakusho Co., Ltd .: Conductive baseless double-sided tape No. 7025

(Conductive adhesive tape)
-Conductive aluminum tape: Teraoka Seisakusho Co., Ltd .: Conductive aluminum foil adhesive tape No. 830
・ Non-conductive aluminum tape: Made by Nitoms Co., Ltd .: Aluminum tape J3130

[Example 1]
As shown in FIG. 3, a mold was opened, and a molten resin of a molding resin material was extruded from a die to form a parison having a predetermined length. Next, before the heat of the parison dropped, the case was closed with a mold to produce a case body and a lid as shown in FIG.
Using this, each said test and the following electric field shielding test were done. The results are shown in Table 1.

(Electric field shielding)
An electromagnetic wave shielding property test was conducted in accordance with the KEC method.
First, after creating a battery case, the side part was cut out to a size of 100 mm □ × 3 mmt to create a test piece 27. On the center line of the test piece 27, as shown in FIGS. 5 (a) and 5 (b), a loop-shaped antenna 28 is vertically penetrated.
Further, two electromagnetic wave shielding sheets 16 listed in Table 1 coated with a conductive adhesive 17 on the bottom surface are arranged so that the side edges are in contact with each other, and the upper surface of the boundary portion is covered with the conductive adhesive tape 19, An electromagnetic wave shielding material 29 was configured.
The electromagnetic wave shielding material 9 was placed on the center line of the prepared test piece 27 so as to crush the loop antenna 28 and joined to the test piece 27. At this time, the sample (FIG. 5A) in which the direction of the conductive adhesive tape 19 of the electromagnetic wave shielding material 29 is the same as that of the loop antenna, and the direction of the conductive adhesive tape 19 of the electromagnetic wave shielding material is defined as the loop antenna. Both samples (FIG. 5 (b)) oriented in a perpendicular direction were produced.
Using these samples, the amount of electromagnetic waves leaking onto the electromagnetic wave shielding sheet 16 was measured.
The measurement range was 0.1 to 1000 MHz, and the effective measurement area was 55 mm □. Judgment of the electric field shielding performance was determined to be acceptable (“◯”) when the shield specification at 50 MHz was 80 dB or more, and when it was less than that, it was determined to be unacceptable (“×”).

[Comparative Example 1]
The same method as in Example 1 was used except that a non-conductive aluminum tape was used in the electric field shielding test using the case main body and lid manufactured in the same manner as described above. The results are shown in Table 1.

[Comparative Example 2]
The same method as in Example 1 was used except that a polypropylene resin was used as the molding resin material. The results are shown in Table 1.

[Comparative Example 3]
A battery case and cover were prepared using polycarbonate resin as the molding resin material, and the inner surface was covered with conductive aluminum tape.

DESCRIPTION OF SYMBOLS 11 Battery case 12 Case main body 13 Cover | cover 14 Upper opening part 15 Ridge part 16, 16a, 16b Electromagnetic wave shielding sheet 17 Conductive adhesive 18 Conductive tape 19 Conductive adhesive tape 21 Mold 22 Mold 23 Die 24 Test piece 25 Support 26 Impactor 27 Test piece 28 Loop antenna 29 Electromagnetic wave shielding material

Claims (4)

It is a battery case used for electric vehicle trucks or electric hybrid car trucks,
The battery case is composed of a case body for storing the battery and a lid,
The battery case is made of impact-resistant resin,
A plurality of electromagnetic wave shielding sheets are arranged and covered on the inside of the lid and the case body, and a plurality of electromagnetic wave shielding sheets are provided on the periphery of the upper open portion of the case body that is in contact with the lid. Covered through,
The electromagnetic wave shielding sheet is bonded using a conductive adhesive,
The arrangement of the side edge or edge where the plurality of electromagnetic wave shielding sheets are in contact with each other is the first arrangement in which the side edge or edge of one electromagnetic wave shielding sheet is adjacent to the side edge or edge of another electromagnetic wave shielding sheet. And at least one arrangement selected from the second arrangement in which the side edge or the edge of one conductive sheet is superimposed on the side edge or the edge of another conductive sheet;
In the first arrangement, the battery case is characterized in that the side edges or the edges of the adjacent electromagnetic wave shielding sheets are made conductive with a conductive material.   The battery case according to claim 1, wherein the battery case is made of high-density polyethylene. The battery case according to claim 1 or 2, wherein the battery case is obtained by blow molding high density polyethylene. 4. The battery case according to claim 1, wherein the battery case body has a double wall structure.

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