JPH11176400A - Battery case - Google Patents

Abstract

(57) [Summary] [Problems] Aluminum plates (2a, 3)
a and these aluminum plates 2a, 3a
By providing the uneven reinforcing portions 2b and 3b on the battery case, a lightweight and sufficiently strong battery case is provided. SOLUTION: Upper and lower cases 2 and 3 are made of aluminum plate 2.
The resin frame 2 is formed by insert molding on the periphery of
c, 3c were formed, and uneven reinforcing portions 2b, 3b were provided on the plate surfaces of these aluminum plates 2a, 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery case for accommodating a sheet container such as an aluminum laminate sheet enclosing a power generating element.

[0002]

2. Description of the Related Art With the rapid miniaturization of portable electronic devices in recent years, there has been a demand for the development of lightweight, thin and high-energy density secondary batteries for batteries as power sources. ing. Therefore, a non-aqueous electrolyte secondary battery is used as a secondary battery having a high energy density, and a card-type battery that is lightweight and thin by making this non-aqueous electrolyte secondary battery into a card type has been conventionally developed. I have.

As shown in FIG. 8, a card type battery is an aluminum laminated sheet container 1 in which a flat power generating element is sealed.
Is covered with a battery case composed of an upper case 2 and a lower case 3 and housed inside. Each of the upper and lower cases 2 and 3 is formed by forming resin frames 2c and 3c by insert molding on the periphery of flat stainless steel plates 2e and 3e. The aluminum laminate sheet container 1 is accommodated inside by joining the frames 2c and 3c to each other by ultrasonic welding.

[0004]

However, the battery case of the conventional card-type battery has sufficient strength because the stainless steel plates 2e and 3e are used for the upper and lower cases 2 and 3, but the weight is too heavy. However, there is a problem that the weight of the battery is hindered.

When the stainless steel plates 2e and 3e are used, the stainless steel plates 2e and 3e are used to insulate them from the lead wires 1a drawn from the aluminum laminate sheet container 1.
It is necessary to affix an insulating tape to the inner surfaces of e and 3e, and there has been a problem that the number of working steps in assembling the battery increases.

The present invention has been made in view of such circumstances, and has as its object to provide a battery case in which the weight of the battery can be reduced by using aluminum plates for the upper and lower cases. An object of the present invention is to provide a battery case that is lightweight and has sufficient strength by providing a concave or convex reinforcing portion on an aluminum plate.

[0007]

According to a first aspect of the present invention, an upper case and a lower case, each having a resin frame formed by insert molding on a peripheral portion of an aluminum plate formed in a dish shape, and a power generating element sealed between the upper case and the lower case. The present invention is characterized in that the sheet containers are accommodated and stacked, and the resin frames are joined together.

According to the first aspect of the invention, since the aluminum plates are used for the upper and lower cases, the weight of the battery can be reduced as compared with the case where a stainless steel plate is used. Here, if sufficient strength cannot be obtained with the same thickness as the stainless steel plate, it is necessary to form the aluminum plate to a certain thickness, but since the specific gravity of the aluminum plate is very small compared to the stainless steel plate, Even if the plate thickness is increased to some extent, it is possible to sufficiently reduce the weight. Note that an aluminum plate refers to a plate made of aluminum or an aluminum alloy.

According to a second aspect of the present invention, the upper case and the lower case, each having a resin frame formed by insert molding on the peripheral portion of the metal plate, are overlapped and the resin frames are joined to each other.
In a battery case in which a sheet container enclosing a power generating element is housed between the upper and lower cases, aluminum plates are used as metal plates of the upper and lower cases, and a concave or convex reinforcing portion is provided on the surface of these aluminum plates. Is provided.

According to the second aspect of the present invention, the aluminum plates are used for the upper and lower cases.
Battery weight can be reduced as compared with the case where a stainless steel plate is used. Moreover, since a sufficient strength can be obtained by providing a concave or convex reinforcing portion on the surface of these aluminum plates, it is possible to achieve a plate thickness similar to that of a stainless steel plate, further reducing weight. Can be planned. Further, by providing the reinforcing portion, it is possible to prevent the plate surface of the aluminum plate from warping due to heating during insert molding.

A third aspect of the present invention is characterized in that the aluminum plate has an insulating oxide film formed on the surface by alumite treatment.

According to the third aspect of the present invention, since the surfaces of the aluminum plates of the upper and lower cases are covered with the insulating oxide film formed by the alumite treatment, it is not necessary to perform the insulation treatment with the internal lead wires and the like. Can be reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the first embodiment of the present invention and is an exploded perspective view showing the structure of a card-type battery.
Components having the same functions as those of the conventional example shown in FIG. 8 are denoted by the same reference numerals.

In this embodiment, a card type battery in which a non-aqueous electrolyte secondary battery is made into a card type as in the conventional example will be described. The card type battery has an aluminum laminate sheet container 1 housed in a battery case composed of an upper case 2 and a lower case 3. In the aluminum laminate sheet container 1, for example, a power generating element which is flattened by winding and crushing positive and negative electrodes via a separator is enclosed together with a non-aqueous electrolyte. Then, two flexible aluminum laminate sheets are overlapped to seal the periphery, or one aluminum laminate sheet is folded to seal the periphery other than the folds to seal the inside. However, lead wires 1a connected to the positive and negative electrodes of the internal power generation element are drawn out of the sealing portion of the aluminum laminate sheet container 1, respectively. The aluminum laminate sheet is a sheet in which a PET (polyethylene terephthalate) film, a polyethylene film, or the like is laminated on an aluminum foil, and can be sealed by heat welding by superposing the surfaces on the side of the polyethylene film or the like and pressing with heat. . In addition, an eval resin film or the like is interposed in the lead portion of the lead wire 1a to ensure the sealing of the interface with the metal.

The upper case 2 is formed by forming a resin frame 2c on the periphery of an aluminum plate 2a. Further, the lower case 3 is also formed by forming a resin frame 3c on the periphery of the aluminum plate 3a. These aluminum plates 2a, 3a
Is a rectangular plate made of aluminum or an aluminum alloy mainly composed of aluminum. These aluminum plates 2a and 3a are formed in a dish shape in order to increase bending rigidity. The resin frames 2c and 3c are frames formed by insert molding on the peripheral portions of the aluminum plates 2a and 3a. In order to continuously insert-mold a plurality of aluminum plates 2a and 3a, adjacent aluminum plates 2a and 3a are connected with bridge portions 2d and 3d, and resin frames 2c and 3d are connected.
Each of the bridge portions 2d and 3d is cut after molding c.

The upper and lower cases 2 and 3 form a battery case by being overlapped from above and below with an aluminum laminated sheet container 1 interposed therebetween. At this time, upper and lower cases 2,
Electrolyte-resistant resin sheets 4 and 4 are adhered to the inner surface of 3. The lead wire 1a drawn out of the aluminum laminate sheet container 1 is connected to terminals (not shown) provided on the resin frames 2c, 3c of the upper case 2 or the lower case 3 inside the battery case. The upper and lower cases 2 and 3 thus overlapped are welded to each other by ultrasonic welding so that the lower surface of the resin frame 2c and the upper surface of the resin frame 3c are welded to complete the battery case.

The above-mentioned resin sheets 4 and 4 allow the non-aqueous electrolytic solution to be supplied to the aluminum plate 2 even when a highly reactive non-aqueous electrolytic solution leaks from the inside of the aluminum laminate sheet container 1.
This is a protective film for eroding a and 3a so as not to go outside. Therefore, the inner surfaces of the aluminum plates 2a and 3a may be previously coated with a resin film of the same material as the resin sheets 4 and 4, and the resin frames 2c and 3c may be insert-molded in this state. These resin sheets 4 and 4 are made of aluminum plates 2a and 4a in the same manner as the conventional insulating tape attached to the inner surfaces of stainless steel plates 2e and 3e.
It also plays the role of insulation between the inner surface of 3a and the lead wire 1a.

According to the battery case having the above structure, since the lightweight aluminum plates 2a, 3a are used for the upper and lower cases 2, 3, the heavy stainless steel plate 2 as in the conventional example shown in FIG.
It is possible to reduce the weight of the battery as compared with the case where e and 3e are used. That is, these aluminum plates 2a, 3a
Is weak at the same thickness as the stainless steel plates 2e and 3e, so it is usually necessary to use a somewhat thicker one.
Since the specific gravity of aluminum or aluminum alloy is much smaller than that of stainless steel, even if the plate thickness is increased to some extent, the weight can be sufficiently reduced.

In the present embodiment, the aluminum plate 2
Although the case where the resin sheets 4 and 4 are adhered to the inner surfaces of the a and 3a and the resin film is coated has been described, the aluminum plate 2a is previously subjected to alumite treatment to form an insulating oxide film on the surface. Is also good. By forming such an insulating oxide film, it is possible to prevent erosion by the nonaqueous electrolyte and to insulate the lead wire 1a.
The step of attaching the resin sheets 4 and 4 and covering the resin film becomes unnecessary.

2 to 7 show a second embodiment of the present invention. FIG. 2 is an exploded perspective view showing the structure of a card-type battery, and FIG. 3 is an exploded longitudinal section showing the structure of a card-type battery. Figure,
FIG. 4 is an exploded longitudinal sectional view showing the structure of another upper and lower case of the card type battery, FIG. 5 is a plan view showing a case where an X-shaped reinforcing portion is provided on an aluminum plate of the upper and lower cases, and FIG. FIG. 7 is a plan view showing a case where a parallel reinforcing portion is provided on an aluminum plate, and FIG. 7 is a plan view showing a case where a logo-like reinforcing portion is provided on the aluminum plate of the upper and lower cases. Note that the same reference numerals are given to constituent members having the same functions as those of the first embodiment shown in FIG.

In this embodiment, as in the first embodiment, a card type battery in which the nonaqueous electrolyte secondary battery is a card type will be described. As shown in FIG. 2, the card type battery has an aluminum laminate sheet container 1 housed in a battery case including an upper case 2 and a lower case 3. The same aluminum laminate sheet container as that shown in the first embodiment is used.

The upper case 2 is formed by forming a resin frame 2c around the periphery of an aluminum plate 2a.
The resin frame 3c is formed on the periphery of the aluminum plate 3a. These aluminum plates 2a, 3a
As in the embodiment, a rectangular plate made of aluminum or an aluminum alloy mainly containing aluminum,
The resin frames 2c, 3c are also formed of these aluminum plates 2a, 3
It is a frame integrally formed by insert molding on the peripheral portion of FIG. However, the aluminum plates 2a and 3a are
As shown in FIG. 2, a reinforcing member 2b, 3b having a central portion protruding in a rectangular shape by pressing is used. These aluminum plates 2a and 3a are previously subjected to alumite treatment to form an insulating oxide film on the surface. In addition, these aluminum plates 2
a, 3a are the same as in the first embodiment.
After the molding of c and 3c, the one obtained by cutting each of the bridge portions 2d and 3d can be used.

The upper and lower cases 2 and 3 are overlapped from above and below with the aluminum laminated sheet container 1 interposed therebetween, and the lower surface of the resin frame 2c and the upper surface of the resin frame 3c are welded and joined by ultrasonic welding. Battery case.
At this time, the lead wire 1a drawn out of the aluminum laminate sheet container 1 is connected to terminals (not shown) provided on the resin frames 2c, 3c of the upper case 2 or the lower case 3 inside the battery case.

According to the battery case having the above structure, since the lightweight aluminum plates 2a and 3a are used for the upper and lower cases 2 and 3, the weight of the battery can be reduced as in the first embodiment. Moreover, these aluminum plates 2a,
Since the uneven portions 2b, 3b are formed on the plate surface of 3a, sufficient strength can be obtained even if a plate having the same thickness as the stainless steel plates 2e, 3e having high rigidity is used. it can. That is, in the case of using the aluminum laminated sheet container 1 on which a strong PET film or the like is laminated as in the present embodiment, the same strength as the stainless steel plates 2e and 3e having the same thickness is not necessary, and such an aluminum plate is not required. 2
Even if the reinforcing portions 2b and 3b are formed only on the a and 3a, a sufficient strength for protecting the inside of the battery can be obtained.
Also, by making these aluminum plates 2a, 3a approximately the same thickness as the conventional stainless steel plates 2e, 3e,
The weight can be reduced more than in the first embodiment.

Assuming that the aluminum plates 2a and 3a are flat as in the case of the first embodiment, when the resin frames 2c and 3c are formed by insert molding, heat is applied during this forming process. This may cause the plate surfaces of the aluminum plates 2a and 3a to warp. However, if the uneven portions 2b, 3b are formed on the aluminum plates 2a, 3a as in the above configuration, the occurrence of the warpage can be prevented.

Further, according to the battery case having the above structure,
Since the aluminum plates 2a, 3a of the upper and lower cases 2, 3 are covered with an insulating oxide film, the aluminum laminate sheet container 1
In order to insulate the lead wire 1a drawn out from the container and to prevent erosion by the non-aqueous electrolyte leaked from the aluminum laminate sheet container 1, these aluminum plates 2a,
A troublesome work process of attaching the insulating tape or the resin sheets 4 and 4 to the inner surface of 3a is not required, and the assembling work can be simplified.

In the above embodiment, the reinforcing portions 2b and 3b protruding outside the battery case are shown. However, as shown in FIG. 4, the reinforcing portions 2b and 3b may protrude inside the battery case. Further, in the above embodiment, these reinforcing portions 2b,
Although 3b is a rectangular protrusion, the present invention is not limited to this, and a protrusion of any shape can be used. For example, as shown in FIGS. 5 and 6, reinforcing strips 2b and 3b in which two elongated rib-shaped projections cross each other in a cross shape or arranged in parallel can be provided. As shown in FIG. A suitable logo can be displayed on the protrusions to form the reinforcing portions 2b, 3b.

Further, in the first and second embodiments,
Ultrasonic welding is used to join the upper and lower cases 2 and 3, but any other joining means such as welding means or adhesion can be used.

Further, in the first and second embodiments, the aluminum laminated sheet container 1 is used. However, the present invention is not necessarily limited to this, and any sheet material can be used for the sheet container. Also, the battery is not limited to the card type. In addition, the configuration of the power generating element sealed inside is arbitrary, and the present invention can be similarly applied to batteries other than the non-aqueous electrolyte secondary battery.

[0031]

As is apparent from the above description, according to the battery case of the present invention, the weight of the battery can be reduced by using aluminum plates for the upper and lower cases.

By providing a concave or convex reinforcing portion on the surface of the aluminum plate, sufficient strength can be obtained and the occurrence of warpage during insert molding can be prevented.

Further, by forming an insulating oxide film by alumite treatment on the surfaces of the aluminum plates of the upper and lower cases, the work of attaching an insulating tape to the inner surface of the aluminum plate can be eliminated.

[Brief description of the drawings]

FIG. 1, showing a first embodiment of the present invention, is an exploded perspective view showing a configuration of a card-type battery.

FIG. 2, showing a second embodiment of the present invention, is an exploded perspective view showing a configuration of a card-type battery.

FIG. 3, showing a second embodiment of the present invention, is an exploded vertical sectional view showing a configuration of a card-type battery.

FIG. 4 shows the second embodiment of the present invention, and is an exploded longitudinal sectional view showing the configuration of another upper and lower case of a card-type battery.

FIG. 5 is a plan view showing a second embodiment of the present invention and showing a case where a cross-shaped reinforcing portion is provided on aluminum plates of upper and lower cases.

FIG. 6 shows the second embodiment of the present invention, and is a plan view showing a case where parallel reinforcing portions are provided on aluminum plates of upper and lower cases.

FIG. 7 shows the second embodiment of the present invention, and is a plan view illustrating a case where a logo-shaped reinforcing portion is provided on an aluminum plate of upper and lower cases.

FIG. 8 is an exploded perspective view showing a conventional example and showing a configuration of a card-type battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum laminated sheet container 2 Upper case 2a Aluminum plate 2b Reinforcement part 2c Resin frame 3 Lower case 3a Aluminum plate 3b Reinforcement part 3c Resin frame

Claims (3)

[Claims] An upper case and a lower case, each having a resin frame formed by insert molding on a peripheral portion of an aluminum plate formed in a dish shape, are overlapped by accommodating a sheet container enclosing a power generation element therebetween. A battery case comprising frames joined together. 2. A sheet container in which a power generating element is sealed by overlapping an upper case and a lower case having a resin frame formed by insert molding on a peripheral portion of a metal plate and joining the resin frames to each other. A battery case, wherein aluminum plates are used as metal plates of upper and lower cases, and a concave or convex reinforcing portion is provided on a surface of the aluminum plate. 3. The battery case according to claim 1, wherein the aluminum plate has an insulating oxide film formed on its surface by alumite treatment.