KR20220040611A - battery case manufacturing methods and battery case therby - Google Patents

Abstract

The present invention relates to a method for manufacturing a battery case, which secures convenience of anodizing by performing extrusion-heat treatment-anodizing-processing-welding in order and can secure soundness of welding quality by welding after processing, and a battery case manufactured thereby.

Description

Battery case manufacturing method and battery case made thereby {battery case manufacturing methods and battery case therby}

The present invention relates to a method for manufacturing a battery case and a battery case made by the method, which is made in the order of extrusion-heat treatment-anodizing-processing-welding to secure convenience for anodizing, and to secure the soundness of welding quality by welding after processing. It relates to a method for manufacturing a battery case that can be used and to a battery case made thereby.

Also, the present invention relates to a method for manufacturing a battery case having light weight and excellent heat transfer characteristics, and to a battery case made by the method.

The battery of a transport device is to provide electricity that is the power of the transport device, and a pouch or small box-shaped battery cell, a battery case that can contain the battery cell, and a battery tray that can hold the battery case (aka, tray, It can be divided into units, packs, cases, etc.).

A plurality of battery cases for electric vehicles are installed to store a large amount of electricity required for driving a vehicle, and various types of battery cases have been developed to stably store such a large number of batteries, for example, Patent Document 1 There are 4 to 4.

Patent Document 1 is a base plate; A secondary tray installed on the upper portion of the base plate and divided into a plurality of independent regions along the longitudinal direction of the base plate, a battery mounting region in which a plurality of battery cells are mounted in close contact with the inner region of the secondary tray, and battery cells a tray having an unmounted battery area; and first and second heat sinks in close contact along the outer longitudinal direction of the tray, the inner regions of which are divided into lower and upper sides by partition protrusions, respectively, and the flow of cooling water is provided, wherein the heat radiation unit flows into the first heat sink The cooled coolant is moved along the lower longitudinal direction of the heat sink and flows into the second heat sink located at the upper side, and as it moves along the upper longitudinal direction of the heat sink, it is a battery tray for electric vehicles that conducts heat from the battery cells and radiates heat. ,

Patent Document 2 is a housing; Cooling wind inlet and outlet provided at the front end and rear end of the housing; a plurality of module mounting units provided so that the battery modules are continuously mounted between the front end and the rear end of the housing; a central partition wall provided in the module mounting part located on the central side of the housing and sealing between the battery module and the housing so that the cooling wind passes only through the battery module; and a front bulkhead that is provided in the module mounting part adjacent to the front of the module mounting part provided with the central bulkhead and seals between the battery module and the housing, but the ventilation hole is formed to be spaced apart so that the cooling wind passes through the ventilation hole and the battery module; The module mounting part is provided in a plurality of rows/columns in the housing, and the central partition wall is an electric vehicle battery case configured to seal both between adjacent battery modules in the same row and between the housing,

Patent Document 3 discloses an electric vehicle battery housed therein, an upper part of which is open; and an upper cover covering the open upper part of the main body, and the height of the main body is formed higher than the height of the battery so that the battery and the upper cover are spaced apart from each other, and a cooling passage is provided between the battery and the upper cover in the main body. An inlet is formed at a position opposite to one side of the cooling passage so that external air flows into the cooling passage, and an outlet is formed at a position opposite to the other side of the cooling passage in the body to discharge the air introduced into the cooling passage to the outside; It further includes at least one auxiliary case having a support portion located on both sides of the body and a connection portion that is in close contact with the lower side of the main body and interconnects the lower side of the support portion located on both sides of the main body, and an elevating guide portion is provided on the outside of the support portion of the auxiliary case. It is a battery case for an electric vehicle formed,

Patent Document 4 discloses a battery case for an electric vehicle having a plurality of battery cells, comprising: a fixing plate disposed on the outer surfaces of both ends of the battery cells; and a deformable member formed so that both ends of both ends of the fixing plate are coupled to surround the battery cell together with the fixing plate and deformable in the expansion direction of the battery cell when the battery cell swells.

Although various battery cases have been developed as described above, they have a problem in that heat dissipation and insulation properties are inferior.

That is, the battery cell is seated inside the case and the heat dissipation efficiency is good when it is completely in close contact with the entire surface, but this is not the case. There is this.

For insulation, an insulating pad is installed inside, or the entire surface is anodized.

However, in the case of anodizing after sealing one end by welding for insulation only, there is a problem in that an air pocket is formed inside, so that anodizing is not possible or the anodizing characteristic is deteriorated.

Therefore, welding must be performed after anodizing. At this time, when welding on the surface with an anodizing layer, even if an inert gas is injected, the oxide film of anodizing is broken and it can remain inside the weld bead, and may contain air bubbles. As it can harm soundness and impair welding strength, the anodizing layer must be removed through CNC machining only in the parts that require welding in the anodized product. There is inconvenience.

Republic of Korea Patent Registration No. 10-1185720 Republic of Korea Patent No. 10-1356200 Republic of Korea Patent No. 10-1328010 Republic of Korea Patent Publication No. 10-2018-0068379

The present invention was developed to solve the problems of the prior art as described above, and after manufacturing the case body in the shape of an enclosure by extrusion, a post-processing process including heat treatment and anodizing is performed to minimize the welding portion and welding. An object of the present invention is to provide a method for manufacturing a battery case capable of minimizing distortion or post-processing after welding, and a battery case made by the method.

In particular, the present invention secures the convenience of anodizing by performing extrusion-heat treatment-anodizing-processing-welding of an aluminum material in the order of, and welding after processing to secure the soundness of welding quality, as well as light weight and heat transfer characteristics. An object of the present invention is to provide an excellent method for manufacturing a battery case and a battery case made thereby.

In the battery case manufacturing method according to the present invention for solving the above object, in the manufacturing method of the battery case configured by installing a cover on the open part of the case body, the space in which the battery cells are stored by extruding an aluminum alloy a body extrusion step of extruding a case body having a plurality of heat dissipation blades formed on its surface and having both ends open; A cover manufacturing step of manufacturing a plate-shaped cover by extruding or lining with the same material as the case body; A heat treatment step of removing the internal stress of the extruded case body and cover and heat-treating for uniformity of the structure; Anodizing step of forming an insulating film by anodizing the extruded case body and the plate-shaped cover with both ends open to prevent air pockets from being generated; A machining step of cutting or cutting the anodized case body and the welding part of the cover to machine; It characterized in that it comprises a welding step of welding the cover to the open end of the case body.

If necessary after the welding step, a bead removal step of removing the bead generated in the welding portion may be further performed.

The anodizing thickness in the anodizing step is preferably 12 to 18um.

The battery case manufacturing method according to the present invention and the battery case made by the method are made of aluminum or an alloy thereof having high thermal conductivity, which is light and has the effect of providing a battery case having excellent heat dissipation characteristics.

In addition, the present invention can reduce the deformation due to welding by minimizing the welding portion, and can minimize the post-welding treatment process, thereby simplifying the manufacturing process as well as reducing the manufacturing cost.

In addition, the present invention has the effect of securing the convenience of anodizing and securing the soundness of the welding quality by welding after processing.

1 is a process diagram of a method for manufacturing a battery case according to the present invention;
2 is a photograph of an example of the case body extruded during the manufacturing process of the battery case according to the present invention;
3 is a cross-sectional view of another example of a welding part of the case body and the cover made by the battery case manufacturing method according to the present invention;
4 is a partially enlarged photograph of a battery case made by the method for manufacturing a battery case according to the present invention;
5 is an enlarged photograph of a welding part of a battery case made by the method for manufacturing a battery case according to the present invention;

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and will be described with reference to the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing each figure, like reference numerals have been used for like elements. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The present invention secures convenience for anodizing, and by welding after processing, not only can secure the soundness of welding quality (uniformity of tissue, appropriateness of mechanical properties), but also provide a battery case with light weight and excellent heat transfer characteristics. can

As shown in FIG. 1, the battery case manufacturing method according to the present invention is a manufacturing method of a battery case configured by installing a cover 20 on an open part of the case body 10, and extruding an aluminum alloy to the inside of the battery cell A body extrusion step of extruding the case body 10 having the space to be stored, a plurality of heat dissipation wings 11 are formed on the surface, and both ends are open; A cover manufacturing step of manufacturing a plate-shaped cover by extruding or lining with the same material as the case body; A heat treatment step of removing the internal stress of the extruded case body and cover and heat-treating for homogenization of the tissue; Anodizing step of forming an insulating film by anodizing the extruded case body and the plate-shaped cover with both ends open to prevent air pockets from being generated; A machining step of cutting or cutting the anodized case body and the welding part of the cover to machine; and a welding step of welding the cover to the open end of the case body.

The body extruding step is a step of extruding the case body 10 in a cylindrical shape with both ends open as shown in FIG. 2, made by extruding an aluminum alloy material, and the extruded case body 10 is a plurality of of the heat dissipation blade 11 is formed.

The heat dissipation wing can be made by various modifications, but it is preferable to maximize the heat dissipation area to increase the possible heat dissipation efficiency.

That is, the battery case of the present invention has a space in which battery cells are stored, and it is possible to increase the heat dissipation effect that can dissipate heat to the outside in order to prevent the life span from being reduced due to the heat generated during discharging of the battery cells. Preferably, for this, the present invention uses an aluminum alloy, and a plurality of heat dissipation blades are formed on the surface.

Of course, there are copper alloys, aluminum alloys, magnesium alloys, etc., which have excellent heat dissipation properties as materials. However, in the case of copper alloys, heat transfer is the best, but since they are too heavy, they can damage the battery performance of transportation equipment. It has excellent heat dissipation properties and is light enough to be used as a heat sink, but it is weak against corrosion and has poor formability, so it is difficult to manufacture it by a method such as extrusion. Accordingly, the present invention uses an aluminum alloy as a material.

The aluminum alloy, which is a material of the battery case of the present invention, is a light metal, so it can increase battery efficiency, has very good heat transfer properties, and has excellent corrosion resistance. There are advantages to using

In addition, as the heat dissipation wing 11 is further formed as described above, the surface area of the portion exposed to the outside is maximized to maximize the heat dissipation characteristics.

The cover manufacturing step can be manufactured using an extruded material or a rolled material, which is the same material as the case body, and the part in contact with the body and the cover is machined after anodizing for welding soundness.

The heat treatment step carried out after the extrusion is a step for removing the internal stress of the case body and the cover and obtaining a uniform structure, and the homogeneous condition can be processed at 150 to 230° C. for 3 to 15 hours.

The anodizing step is a step of forming an insulating film for insulation of the battery case, the case body proceeds in a state in which both ends are open, and the cover is performed in a plate state, and the anodizing thickness is preferably 12 to 18 μm.

That is, when anodizing is performed with one end of the case body blocked, when the length is 5 times or more compared to the distance between both ends, the anodizing inside the hollow shape member may be formed non-uniformly. That is, in this phenomenon, as the current flows through the anode and the cathode, the cathode takes on a shape facing each other, so the movement of electrons between the cathode and the cathode is not smooth. There are cases in which the electrons are inserted to make the movement of electrons smooth, but it is inconvenient to hang the auxiliary anode during every anodizing, and if the connection of the auxiliary anode is incomplete, there may be a problem in that the anodizing is not smooth.

Accordingly, by increasing the anodizing time based on the thickness of the thinnest anodizing layer inside, the thickness of the anodizing layer capable of securing insulating properties can be secured on the entire inner surface, and the anodizing thickness is preferably at least 12 μm or more.

Various problems may occur when anodizing is performed with one end blocked by welding before anodizing. That is, when one end is blocked, an air pocket may be formed on the inside of the blocked end, and this air pocket is formed when the product is immersed in the anodizing solution, and the air remaining inside the product cannot escape and remains during the anodizing. As hydrogen gas is generated through a reaction with sulfuric acid on the surface of the material, the hydrogen gas cannot escape but gathers upwards and occupies a certain space to form an air pocket. There is a method of fixing the end so that the end faces upward, but in this way, every time it is taken out of each tank after anodizing, the same phenomenon occurs as the container is filled with water and goes to the next tank, so a large amount of chemical loss occurs, Since a large amount of chemicals are transferred to the next process, a phenomenon occurs that the concentration of chemicals in each tank cannot be matched. Therefore, it is preferable to use a rotatable rack or lift the case body in an inclined state when lifting with a crane, but it is not easy to implement, and there is a problem that the drugs filled inside may not come out quickly.

Accordingly, in the present invention, it is preferable to use a method in which both ends of the extruded case body are anodized in an open state, and then one side is blocked by welding.

The machining step is a step of cutting and cutting the welded portion before welding.

In other words, when the anodized case body and the cover are welded as they are, oxides and gases are introduced into the welded part to cause cracks along the weld bead, and there is a problem in that a lot of pores are generated inside when checking the weld cross section. Accordingly, the welding part is machined to remove the insulating film.

Of course, the part where the case body and the cover contact each other is processed as shown in FIG. 3 to make the jaws 10d and 20d ( FIGS. 3 (a) to (c )), or the inclined contact surfaces 10s, 20s ( FIG. 3 ( e)) is machined, and in the case of processing as shown in (a) to (b) or (e) of FIG. 3, the cover can be formed so that it can be located inside the left and right side walls.

The welding step is a step of welding the cover to the open end of one side of the case body to be integrated, and it is preferable to weld through laser welding or FSW welding.

After the welding step, a bead removal step of removing the bead generated in the welding portion may be further performed.

The melting point may have different precision depending on the operator or device, and a bead may be generated during the welding process, and it is removed by cutting it in the bead removal step.

10: case body 11: heat dissipation wing
20: cover

Claims (4)

In the manufacturing method of the battery case configured by installing the cover 20 on the open part of the case body 10,
a body extruding step of extruding an aluminum alloy having a space in which battery cells are stored therein, a plurality of heat dissipation wings 11 are formed on the surface, and extruding the case body 10 with both ends open;
A cover manufacturing step of extruding or rolling the same material as the case body to produce a plate-shaped cover;
A heat treatment step of heat-treating to remove the internal stress of the extruded case body and cover and obtain a uniform structure;
Anodizing step of forming an insulating film by anodizing the extruded case body and the plate-shaped cover with both ends open to prevent air pockets from being generated;
A machining step of cutting or cutting the anodized case body and the welding part of the cover to machine;
A method of manufacturing a battery case comprising a welding step of welding the cover to the open end of the case body. The method of claim 1,
Battery case manufacturing method, characterized in that further performing a bead removal step of removing the bead generated in the welding portion after the welding step. The method of claim 1,
A battery case manufacturing method, characterized in that the anodizing thickness in the anodizing step is 12 to 18um. A battery case made by the method of manufacturing the battery case of any one of claims 1 to 3.

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