JP2002329483A - Battery case and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery case, where countermeasures to a temperature rise of a battery are taken although the performance of the conventional case made of resin is maintained, and its manufacturing method. SOLUTION: The battery case 1 of this invention is characterized by constituting with having a opening, a side part, and a bottom part, and having a case body 2 made of hollow-like resin having a bottom, of which the inside turns into a battery forming part or a battery storing part 10, and by forming a metal layer 3 integrated in one by being formed in a state of adhesion with this case body 2 in all or a part of outside face ranging from its side part to its bottom part. Since cooling is performed efficiently as a whole battery case 1, without stagnating heat locally, this suppresses the internal temperature rise.

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 battery mounted on a vehicle or the like in which a power source uses electric power or an electric power and an internal combustion engine in combination, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, transport equipment powered by an internal combustion engine represented by an automobile has been facing the problem of air pollution due to exhaust gas and the problem of global warming, and it has been necessary to employ a power source other than the internal combustion engine. Have been. As an alternative power source, there is a method using electric power as a power source which has been actively developed. For example, in the case of automobiles, EVs (Electoric Vehicles) employing secondary batteries, HEVs (Hybrid Electoric Vehicles) using both secondary batteries and internal combustion engines, and the like have been put to practical use.

In order to improve the battery performance such as electromotive force and charging capacity in a limited battery space and maintain a high output, it is important to increase the cooling efficiency so as to effectively release the heat generated by the battery. . As the battery case, a resin case is often used for insulation and weight reduction, but since the thermal conductivity of the resin is not generally high, it is usual to employ aggressive cooling means.

Conventionally, as a means for suppressing the temperature rise of a battery, for example, there is a method of air cooling a battery case containing a battery. As shown in FIG. 5B, a plurality of battery cases 1 ′ are used in series, and the projections 11 are provided so that the battery cases 1 ′ do not adhere to each other when they are connected. Since the projection 11 plays a role of a spacer, a gap is generated between the battery case 1 'and the battery case 1'. Then, air is sent into the gap to promote heat dissipation, thereby suppressing an increase in battery temperature. Also, the heat dissipation can be improved by reducing the thickness of the battery case.

[0005]

However, since the battery case for storing the battery is made of a resin having poor thermal conductivity, it is necessary to sufficiently cool the battery stored in the case when the outside air temperature is high. Can not. However, it is not desirable to make the entire battery case made of metal having excellent heat dissipation from the viewpoints of weight reduction and prevention of short circuit. Further, when the thickness of the battery case itself is reduced in order to enhance heat dissipation, a new problem that desired strength cannot be obtained arises. SUMMARY OF THE INVENTION An object of the present invention is to provide a battery case and a method for manufacturing the same in which measures are taken against a rise in battery temperature while maintaining the performance of a conventional resin case.

[0006]

Means for Solving the Problems and Action / Effect To solve the above problems, a battery case of the present invention has an opening, a side portion, and a bottom portion, and has a hollow inside with a bottom where a battery forming portion or a battery housing portion is formed. Having a resin-shaped case body, and all or a part of the outer surface extending from the side to the bottom of the case body,
The metal layer is formed integrally with and in close contact with the case body.

The battery case of the present invention has a form in which a resin case body is covered with a metal covering layer having good heat conductivity. A metal has better heat conductivity (has a higher thermal conductivity) than a resin, so it is easy to maintain thermal parallel with the surrounding atmosphere, and there is also a strong tendency to keep the entire metal itself in thermal parallel. Further, since the metal layer is formed not only in contact with the resin case body but also in an integral and close contact state, a resin case body and a metal container for housing the case body are provided. The heat conductivity between the case body and the metal layer becomes better as compared with the case of separately manufacturing and then combining them. As a result, when the metal layer is cooled by the surrounding refrigerant, the metal layer quickly conducts heat in an attempt to maintain its own temperature distribution, and as a result, heat exchange with the case body in close contact with the metal layer. Is also performed uniformly over the entire area of the parts that are in contact with each other. In other words, since the entire battery case is efficiently cooled without local heat stagnation in the case body, the rise in internal temperature is suppressed, the electromotive force of the battery is reduced, and the electrolyte and electrodes are deteriorated. There is no hassle.

[0008] Such a battery case of the present invention which is excellent in cooling performance is provided with an opening, a side portion, and a bottom portion in a concave portion formed in a mold, and has a hollow inside with a bottom serving as a battery forming portion or a battery housing portion. A resin case body molded into a shape is inserted from the bottom side of the case body, and a metal melt having a melting point lower than that of the resin is melted in a cavity formed by the outer peripheral surface of the case body and the concave portion of the mold. To cover the outer peripheral surface of the case body and open the mold after cooling.

According to the battery case manufacturing method of the present invention, since the molten metal is directly fixed to the resin case body, the resin case body and the metal layer made of the molten metal are integrally formed in close contact with each other. be able to. And since the metal mold | die which has the recessed part for forming a metal layer becomes very simple, it also contributes to reduction of manufacturing cost.
Since the molten metal has a very high fluidity, it does not naturally reach every corner of the cavity, and does not cause "sink" in injection molding.

If a plurality of projections are formed on the outer peripheral surface of the case main body, the positioning of the case main body 2 with respect to the mold 30 is automatically performed by the projections 11 as shown in FIG. The layer can be easily formed. Furthermore, since the metal layer is formed in such a manner as to mesh with the protruding portion 11 and the bonding force is improved, it is possible to prevent the metal layer from peeling off during use.

[0011]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1A is a perspective view showing one embodiment of the battery case of the present invention. A battery case 1 of the present invention has an opening, a side portion, and a bottom portion, and has a bottomed hollow resin case body 2 in which the inside is a battery forming portion or a battery housing portion 10 (hereinafter, referred to as a battery housing portion only). The metal layer 3 is formed integrally with and in close contact with the case main body 2 on all or a part of the outer surface extending from the side to the bottom of the case main body 2. The case body 2 can be formed in accordance with the shape of the battery to be housed. In the present embodiment, a case in which a substantially rectangular parallelepiped shape is adopted as an example is exemplified.

The case main body 2 can be configured as a form in which a plurality of cylindrical battery housing portions 10 are connected. That is, a desired electromotive force can be obtained by inserting existing batteries into these individual battery storage units 10 and connecting them in parallel. Further, as shown by the broken line in FIG. 1A, the required power is adjusted by using a plurality of battery cases 1 in series. In addition, each of the battery storage units 10 is partitioned by the partition wall 12, so that insulation between the battery storage units 10, 10 is ensured. Note that the bottom side of the case body 2 is wider in the direction in which the battery housing portions 10 are arranged than the opening side in order to improve sitting.

The battery case 1 of the present invention can accommodate any form of battery.
As shown in (a) and (b), the Japanese paper 43 is sandwiched between the anode 42 and the cathode 41, and can be used for a nickel-hydrogen battery 40 in which the electrolytic solution is infiltrated into the Japanese paper 43. . As shown in FIG. 4B, the nickel-hydrogen battery 40 has a plurality of stacked Japanese paper 43 and electrodes 42 and 41, and as shown in FIG. Is provided. Such a nickel-hydrogen battery 40 has the function of a battery by itself, but requires a case to be stored when used. In particular,
If the periphery is not coated with a resin or the like, the electrolyte impregnated in the Japanese paper 43 leaks to the periphery,
Since the performance of the battery cannot be maintained due to volatilization, a battery case is required. Although not shown, after the battery is stored in the battery case 1 of the present invention, the battery case is closed and a sealed battery storage portion is formed inside.

FIG. 1B is a cross-sectional view perpendicular to the direction in which the battery housing portions 10 are arranged and parallel to the battery housing direction. As shown in this figure, the side surface of the case main body 2 can be an uneven surface having a plurality of protrusions 11 integrally formed with the case main body 2. Generally, ribs (reinforcing ribs) are provided on the outer periphery of a resin container or case to increase rigidity.
Alternatively, a boss (contact boss) is provided on the contact surface with another container (see the battery case 1 'in FIG. 5). By providing such ribs and bosses also in the battery case 1 of the present invention, not only the rigidity of the case body 2 can be increased, but also the bonding between the metal layer 3 and the case body 2 is strengthened and the battery body 1 is separated. It is desirable because it becomes difficult to do. That is, the close contact between the metal layer 3 and the case main body 2 is firmly maintained, and good heat conductivity is maintained. Needless to say, such a protrusion 11 may be formed on the bottom of the case body 2.

As the resin material constituting the case body 2, various materials can be adopted, but it is inexpensive, easy to mold, excellent in heat resistance, and resistant to acid and base (resistance to acid). Chemical properties) should be taken into consideration. For example, a resin material in which various resins are added to a polypropylene resin, an ABS resin, or the like can be suitably used.

On the other hand, the metal layer 3 can be made of an alloy having a melting point lower than that of the resin forming the case body 2.
0 is formed in the shape of a common side part. Of course, the metal layers 3 may also be formed on the sides of the case body 2 located at both ends in the direction in which the battery housing sections 10 are arranged. However, since it is a portion having a small surface area, it can be omitted as in this embodiment, except when a remarkable cooling effect is recognized.

Although the manufacturing method will be described later, the case main body 2 is made of the above-mentioned resin, and the melting point of the resin is approximately 200 ° C. to 250 ° C. Therefore, if the metal layer 3 is to be welded, it must have a lower melting point than those resins. As a low melting point metal,
For example, Bi-containing alloy, Bi-Pb alloy, Bi-S
An n alloy, a Bi-Ga alloy, a Bi-In alloy, etc. can be used in the present invention because they have a melting point lower than the melting point of those resins in a certain composition. Among them, Bi-Pb alloy, Bi
Each of the -Sn alloys is preferable because it is also excellent in raw material cost.

The metal layer 3 may be composed of a metal powder layer formed by applying or spraying a metal powder through a binder, or may be composed of a metal powder layer from which the binder is substantially removed. May be. In this configuration, the metal that can be used is not limited, as in the case of the low-melting alloy described above,
This is advantageous in that it can be manufactured at lower cost.
Further, as compared with the case of casting with a low melting point alloy, the battery case 1 is excellent in that the weight of the whole battery case 1 is not significantly increased, but in terms of ease of heat transmission, it is castable. It can be said that the form is superior.

The above-described battery case 1 of the present invention comprises:
For example, as shown in the cross-sectional view of FIG. 2, by applying the present invention to a cooling unit 20 that cools a bottom portion, a better cooling effect can be obtained. The cooling unit 20 is provided with a coolant such as water inside, and has a cooling effect by contacting the bottom of the battery case 1. In the conventional battery case, when the bottom is water-cooled, the heat conductivity of the resin itself is not good, so that the resin cannot be sufficiently cooled. On the other hand, according to the battery case 1 of the present invention, even if only the bottom portion is in contact with the cooling unit, the heat conductivity of the metal layer 3 is good, so that the case body 2 covered with the metal layer 3 is uniformly uniform as a whole. A cooling effect can be obtained. That is, there is no problem that the bottom side is sufficiently cooled but the opening side is hardly cooled.

The battery case 1 of the present invention described above
An example of a method for producing the above is described below. The case main body 2 can be easily manufactured by a known injection molding method in which a resin is injected into a cavity formed in a mold and molded. After manufacturing the case main body 2, as shown in FIG. 3, a recess formed in a mold different from the one that manufactured the case main body 2, that is, a mold 30 for forming the metal layer 3 is provided.
A resin-made case main body 2 having an opening, a side part, and a bottom part and having a hollow inside with a bottom serving as a battery forming part or a battery storage part is inserted from the bottom side, and the outer peripheral surface of the case main body 2 is Cavity 31 formed by the recess of the mold 30
Then, by melting and pouring an alloy having a lower melting point than the resin constituting the case main body 2, the outer peripheral surface of the case main body 2 is covered, and after cooling, the mold 30 is opened.
The battery case 1 of the present invention is obtained.

At this time, if the projection 11 formed on the side of the case body 2 is designed to contact the inner peripheral surface of the mold 30, the inside of the recess of the mold of the case body 2 is formed. This is preferable because the positioning is naturally performed. Of course, the projection 11 may be formed on the bottom of the case body 2.

In addition, instead of the molten alloy, a metal powder mixed with an appropriate binder and fluidized is injected to cover the outer peripheral surface of the case body 2, and after cooling, the mold 30 is opened. May be adopted. In this case, as described above, it is possible to obtain battery case 1 having metal layer 3 made of powdered metal. Alternatively, a substantially similar metal layer 3 can be formed by applying or spraying a metal powder mixed with a binder.

The binder may be removed after the mold opening step. Since the most common method for removing the binder is to perform a heat treatment, the binder used for the battery case 1 of the present invention should be removed by a heat treatment at or below the melting point of the resin material constituting the case body 2. Whatever is possible can be adopted. In addition, the metal layer 3 for the case body 2 can be formed by using a known forming method such as plating, vacuum deposition, sputtering, or spraying of molten metal.

As described above, the present invention is not limited to the embodiment, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the invention. In addition, it is to be noted that the drawings are schematic diagrams for understanding.

[Brief description of the drawings]

FIG. 1 is a perspective view and a sectional view showing an embodiment of a battery case of the present invention.

FIG. 2 is a schematic cross-sectional view when the battery case of the present invention is water-cooled.

FIG. 3 is a process explanatory view illustrating a method for manufacturing a battery case of the present invention.

FIG. 4 is a schematic view of a box-type nickel-hydrogen battery.

FIG. 5 is a schematic cross-sectional view illustrating a state in which a conventional battery case is air-cooled.

[Description of Signs] 1 Battery case 2 Case body 3 Metal layer 10 Battery storage unit (or battery formation unit) 11 Projection unit 30 Mold

Claims (8)

[Claims] 1. A case body having an opening, a side part, and a bottom part and having a hollow bottomed resin body inside which serves as a battery forming part or a battery storage part, and an outer surface extending from the side part to the bottom part of the case body. A battery case, wherein a metal layer is formed in a whole or a part of the case body integrally and in close contact with the case body. 2. The battery case according to claim 1, wherein the metal layer is made of a metal having a lower melting point than a resin forming the case body, and is formed by casting the case body. 3. The battery case according to claim 1, wherein the metal layer comprises a metal powder layer formed by applying or spraying a metal powder via a binder. 4. The battery according to claim 1, wherein the case main body has a form in which a plurality of the battery forming portions or the battery housing portions are connected.
The battery case according to any one of the above. 5. The battery case according to claim 1, wherein the outer peripheral surface of the case main body has a plurality of protrusions integrally formed with the case main body. 6. A resin-made case body which is provided with an opening, a side part, and a bottom part in a concave part formed in a mold, and is formed into a bottomed hollow shape in which the inside becomes a battery formation part or a battery storage part. Inserted from the bottom side of the body, into the cavity formed by the outer peripheral surface of the case body and the recess of the mold,
A method for manufacturing a battery case, comprising: casting a melt of a metal having a lower melting point than the resin to cover an outer peripheral surface of the case body; and opening the mold after cooling. 7. A resin-made case body which is provided with an opening, a side part, and a bottom part in a concave part formed in a mold, and is formed into a bottomed hollow shape in which the inside becomes a battery formation part or a battery storage part. Inserted from the bottom side of the body, into the cavity formed by the outer peripheral surface of the case body and the recess of the mold,
Inject metal powder mixed with binder and fluidized,
A method for manufacturing a battery case, wherein the outer peripheral surface of the case body is covered, and the mold is opened after cooling. 8. The method according to claim 7, wherein a step of removing the binder is performed after the step of opening the mold.