KR20080058965A - Battery pack case of metal material - Google Patents

Abstract

A battery pack casing made of a metal is provided to realize improved battery capacity by reducing the volume of a casing, and to improve the workability during the manufacture of battery packs. A battery pack casing(100) in which cells(200) capable of repeating charge/discharge is received comprises a metallic lower casing(300) having side walls(310) for receiving the cells and an opened top, and a metallic upper casing(400) mounted on and coupled to the lower casing. The lower casing includes at least one extended coupling portion(314) on the side wall, wherein the extended coupling portion is bent toward the top surface of the upper casing and coupled thereto while the upper casing is mounted on the lower casing.

Description

Battery Pack Case of Metal Material {Battery Pack Case of Metal Material}

1 is a perspective view of a typical battery pack;

2 is an exploded perspective view of a battery pack prior to assembly according to the prior art;

3A is a plan view of the battery pack of FIG. 2 with the top cover mounted on the case body, and FIG. 3B is a vertical cross-sectional view taken along the line A-A of FIG. 3A;

FIG. 4A is an enlarged view of the portion B of FIG. 3B, and FIG. 4B is a change diagram during ultrasonic welding in FIG. 4A;

5 is an exploded perspective view of a battery pack according to an embodiment of the present invention;

6 and 7 are schematic views of a process of combining the lower case and the upper case;

8 is an enlarged view of portion A of FIG. 5;

9 is a schematic view of a lower case according to another embodiment of the present invention.

The present invention relates to a battery pack case of a metal material, and more particularly, a pack case in which a battery cell capable of charging and discharging is incorporated, and a metal material having a sidewall formed in an open structure to accommodate a battery cell. A lower case and an upper case of a metal material mounted on and coupled to the lower case, wherein one or more extensions are bent and coupled to an upper surface of the upper case in a state in which the upper case is mounted on sidewalls of the lower case; It relates to a battery pack case consisting of a fastening portion is formed.

As the development and demand for mobile devices increases, the demand for secondary batteries as energy sources is increasing rapidly. Among them, many researches have been conducted and commercialized and widely used for lithium secondary batteries with high energy density and discharge voltage. It is used.

Lithium secondary batteries are classified into cylindrical batteries, square batteries, pouch-type batteries, and the like, depending on their appearance, and may be classified into lithium ion batteries, lithium ion polymer batteries, and lithium polymer batteries according to the type of electrolyte.

Due to the recent trend toward miniaturization of mobile devices, there is an increasing demand for thinner rectangular batteries and pouch-type batteries. The shape of a typical battery pack of a secondary battery having such a small thickness is shown in FIG. 1, and the state of separation before assembly thereof is shown in FIG. 2.

Referring to FIGS. 1 and 2, the battery pack 40 may accommodate a rectangular battery cell 10 and a battery cell 10 in which an electrode assembly of an anode, a cathode, and a separator and an electrolyte are sealed. It consists of a case body 20 having an inner space capable of, and an upper cover 30 coupled to the case body 20 in which the battery cells 10 are stored to seal the battery cells 10.

In general, the battery pack 40 of such a structure is assembled by mutually coupling the case body 20 and the upper cover 30 made of a plastic material such as PC, ABS, etc. by ultrasonic welding. The ultrasonic welding method is, for example, a method in which friction heat is generated by vibration using a high frequency of 20,000 Hz to melt-bond two surfaces to be bonded.

More details of coupling the case body 20 and the upper cover 30 by ultrasonic welding may be described with reference to FIGS. 3A and 3B and FIGS. 4A and 4B. 3A and 3B show a plan view of the upper cover 30 mounted on the case body 20 and its vertical cross section (A-A cross section of FIG. 3A), respectively. In a state where the top cover 30 is mounted on the case body 20, both end surfaces of the top cover 30 and both ends of the case body 20 are in contact with each other. An enlarged view of such a contact portion B and a change in ultrasonic welding are shown in Figs. 4A and 4B. As shown in FIG. 4A, a wedge-shaped welding peak 30a is formed on the lower surface of the upper lid 30, and a welding surface (to which the welding peak 30a abuts) is formed on a corresponding portion of the case body 20. 20a) is formed. When high frequency vibration is applied for ultrasonic welding, the contact surfaces of the welding acid 30a and the welding surface 20a are melted, and mutual adhesion is performed.

However, as the demand for thinner battery packs increases, the thickness of the case body 20 and the upper cover 30 becomes thinner to 0.3 to 0.35 mm, respectively. The difficulty is large, and the welding peak 30a and the welding surface 20a are also small, and the welding failure rate is high, such as weak welding strength.

In addition, in manufacturing the case body and the top cover of the battery pack, the insert injection molding method is mainly used to mold a specific shape, in order to use the insert injection molding method, the inconvenience of having to manufacture and install a separate injection molding machine. In addition, the thick plastic case has a problem that the capacity of the battery cell is reduced in size compared to the same standard.

In this regard, Japanese Patent No. 3412471 discloses a battery pack case in which a top portion and a bottom portion in the form of a metal plate and a side portion made of a synthetic resin are assembled using a connecting member such as a screw. It is. However, the battery pack case is composed of a member consisting of a metal plate and a synthetic resin, respectively, and a pack case formed of a synthetic resin thicker than the metal reduces the size of the battery cell compared to the same standard, in order to ensure the battery capacity of the same standard The increase in size of the pack is inevitable, the manufacturing cost of the pack case itself is high, and the assembly method is also complicated.

In addition, Korean Patent No. 0516146 discloses a battery pack equipped with a battery cell including a housing composed of an upper wall, a lower wall, and a side wall, wherein flat ribs for reinforcing the housing and a recess of a plastic substrate therebetween ( Disclosed is a battery pack case having a substantially flat frame having recesses, the sidewalls forming a portion of an exterior envelope comprising a portion of a thin metal plating provided around the frame. . However, since the frame composed of ribs and recesses in the patent is formed of a synthetic resin having a thickness of about 3 mm, it has the problems of the above-mentioned Japanese Patent No. 3412471, and the flange portion of the housing Since the frame is connected using glue, there is a disadvantage in that the bonding force is lower than the method of bending and welding the extension joint of the present invention as described later.

As a technology for manufacturing a battery pack case using only a metal material to solve the above problems, Korean Patent Registration No. 0392340, the upper and lower cases are each made of a metal material, the hole in the flange portion of the upper case at appropriate intervals Is formed, and a welding lip is formed at a position corresponding to the hole of the upper case at the edge of the lower case, and a battery having a structure in which the welding lip of the lower case is inserted into the hole of the upper case and then joined by ultrasonic welding. A pack case is disclosed.

However, according to the patent, since the flange portion for forming a hole in the upper case is required to increase the size of the battery pack, the edge of the lower case should be thick enough to form a weld lip, so the pack case is made of a metal material There is a drawback in not making the most of the benefits that make up.

Therefore, there is a high need for a battery pack case having a low manufacturing cost because it provides a suitable strength for external impact while using a thin metal case and a simple manufacturing process.

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

After various experiments and in-depth studies of the battery pack case, the inventors of the present application, in the metal case of the upper case and the lower case, one or more extensions coupled to the upper case on the side wall of the lower case In the case of using a metal pack case including a fastening part, it was confirmed that the battery capacity can be improved according to the volume reduction of the battery pack case, and the manufacturing processability of the battery pack can be greatly improved, and the present invention has been completed.

Accordingly, the battery pack case of the metal material according to the present invention is a pack case in which a battery cell capable of charging and discharging is embedded, and a lower case of a metal material having a sidewall formed in an open top structure to accommodate the battery cell. And an upper case of a metal material mounted on and coupled to the lower case, and the sidewall of the lower case includes one or more extension fastening parts that are bent and coupled to an upper surface of the upper case in a state where the upper case is mounted. It consists of doing.

That is, the battery pack case according to the present invention is made of a metal material has the effect of improving the battery capacity by a high mechanical strength compared to the same size, and bending the extension fastening portion of the lower case in the state where the upper case is mounted Since only a process can be achieved, the upper and lower cases can be combined without a separate connection member, thereby greatly improving the processability of the battery pack.

The extended fastening portion protruding from the side wall of the lower case is bent to the upper surface of the upper case in a state where the upper case is mounted to serve to fix the upper case and the lower case. Therefore, the extension fastening portion is not particularly limited as long as it has a structure to play such a role, for example, it may be a small protrusion structure in the form of an integral part with the lower case.

The extension fastening portion is preferably made of a structure that is bent to the upper surface of the upper case and then welded to further improve the bonding force of the upper and lower cases. Since the welding can be performed at a portion bent to the upper surface of the upper case of the extension fastening portion, the joining by welding is achieved between the bent portion of the extension fastening portion and the upper surface of the upper case.

The side wall may be manufactured by bending one metal plate, and the sidewall of the lower case may be formed by vertically bending an end portion of the metal plate.

In general, the battery pack is equipped with an insulating cover on the top and bottom of the battery cell, respectively, for the purpose of mounting safety devices, ensuring insulation, enhancing durability. Therefore, in one preferred battery pack according to the present invention, the side wall is bent on both sides of the battery cell to be mounted on the receiving portion, and the insulating and shock absorbing materials are respectively formed on the upper and lower surfaces of the open lower case. The upper cover and the lower cover having an insulation of a substantially rectangular shape of may be further mounted structure.

Preferably, the open lower surface of the lower case is formed with a fastening protrusion bent from the side wall of the lower case and the bottom of the main body, the lower cover has a structure formed with a fastening groove corresponding to the fastening protrusion along its outer peripheral surface As an assembly of the battery, the fastening groove of the bottom cover may be fixed to the fastening protrusion of the lower case in a fastening manner. The conventional insulating cover is mounted by applying an adhesive to a contact part with the battery cell, curing it in a state where it is combined with the battery cell, and then pressing the bar appropriately. It is one of the factors that raises costs. On the other hand, the fitting fastening method as in the present invention can omit the attachment process by the adhesive, there is an advantage that can greatly shorten the manufacturing process.

In some cases, the fastening protrusions are formed not only in the lower case but also in the corresponding portions of the upper case, so that the four surface edges of the lower cover can be fixed by the fitting fastening method of the fastening groove-fastening protrusion.

In another preferred example, the side wall may be formed of a structure that is formed on both sides and the bottom surface of the battery cell to be mounted on the receiving portion, respectively. That is, by forming the side walls by bending the metal plate on both side surfaces as well as the lower surface portion, the side walls can be formed on each of the three surfaces.

In this case, it is preferable that an insulating and shock absorbing member ('lower member') is further added to the inner surface of the lower sidewall. The lower member may be positioned between the lower sidewall and the battery cell, thereby improving safety and insulation against the addition of external force.

In addition, a top cover of an insulating and shock absorbing material may be additionally added to the open upper ends of the upper and lower cases. The top cover may be located on the outer surface of the PCM, thereby preventing electricity from flowing out of the PCM and the battery pack, and absorbing the external force applied upon application of an external force such as falling onto the battery pack vertical section, thereby protecting the battery pack internal components. .

The upper case mounted on the lower case in a state in which the battery cell is mounted has a structure that substantially matches the shape of the lower case except that sidewalls are not formed. On the outer circumferential surface of such an upper case, the indentation part is formed in the position corresponding to the extension fastening part of a lower case preferably.

As described above, the extension fastening part of the lower case is bent and coupled to the upper surface of the upper case to fix the upper case and the lower case, so that when the outer circumferential shape of the upper case and the lower case are the same, the extension fastening part is bent in the coupled state. Protruding structure is created. On the other hand, as described above, if the indentation is formed on the outer circumferential surface of the upper case at a position corresponding to the extension fastening portion of the lower case, it is possible to prevent the protrusion phenomenon to the side in the bent state. Furthermore, since the mounting of the upper case to the lower case can be easily performed in place, the manufacturing processability of the battery pack can be greatly improved.

In some cases, the thickness of the extension fastening portion may be made relatively thin or the upper surface of the upper case may be bent at a position where the extension fastening portion is bent so as to prevent protrusion of the upper fastening portion from being bent. Indented concavities and convexities corresponding to the thickness of the extension fastening portion may be formed.

The material of the upper case and the lower case is not particularly limited as long as it is a metal material having durability and chemical resistance, for example, stainless steel may be preferably used.

The present invention also provides a battery pack having a built-in battery cell capable of charging and discharging the battery pack case.

In particular, the battery pack according to the present invention has a structure in which an electrode assembly having a cathode / separation membrane / cathode structure is mounted on a laminate sheet including a resin layer and a metal layer, specifically, an aluminum laminate sheet, and the outer peripheral surface is heat-sealed. The battery pack may be preferably applied to a battery pack having a built-in type battery cell. Since the pouch-type battery cell is inferior in mechanical rigidity to the battery cell using the metal can, the mechanical rigidity can be compensated by using the battery pack case of the metal material.

In general, in a battery pack having a built-in pouch-type battery cell, the battery cell has a structure (terrace structure) that is not bent the upper sealing portion of the battery case made of the heat-sealing is less space utilization, the impact on the terminal portion When removed, the protection circuit element (PCM) tends to detach or cause severe damage to the battery cell. That is, in the conventional battery pack, only the two side sealing parts of the battery cell are vertically bent to closely adhere to the battery cell body, and the upper sealing part is maintained in an unbent state, and the PCM is mounted on the unbended terrace portion. Therefore, the capacity of the battery compared to the same standard is reduced due to the unbended terrace portion, and due to the structurally weak unfolded terrace portion, many problems may be caused when the battery pack is dropped or an external impact is applied.

On the other hand, the battery pack according to the present invention, in one preferred embodiment, by vertically bending the upper sealing portion of the battery case to be in close contact with the upper end of the battery cell, it is made of a structure having a protective circuit element (PCM) mounted thereon Higher space utilization and excellent structural stability can be achieved.

The battery pack according to the present invention can be used regardless of the form in which the battery cell is mounted in the pack case, and preferably, it can be preferably applied to the built-in battery pack.

Hereinafter, although described with reference to the drawings according to an embodiment of the present invention, this is for easier understanding of the present invention, the scope of the present invention is not limited thereto.

5 is an exploded perspective view schematically showing a battery pack according to an embodiment of the present invention.

Referring to FIG. 5, the battery pack 100 may include a pouch-type battery cell 200 and a lower case of a metal material having a sidewall 310 formed in an open top to accommodate the battery cell 200 ( 300, the upper cover 500 made of an insulating and shock-absorbing material mounted on the upper and lower surfaces of the upper case 400 of the metal material to be mounted on the lower case 300, the upper and lower surfaces of the open lower case 300, respectively ) And a lower cover 510, a protection circuit module (PCM: 600) having external input / output terminals formed to control overcharge, overdischarge, overcurrent, etc. of the battery and to be connected to a corresponding device (not shown) on the outside. It consists of an exterior member 700 and the like applied to the outer surface of the case of the assembled battery pack.

The lower case 300 has sidewalls 310 formed at both ends thereof, and a plurality of extension fastening portions 314 that are bent and coupled to the upper surface of the upper case 400 protrude from the sidewalls 310, and have an open upper surface. Fastening protrusions 320 and 322 that are bent from the side wall 310 and the bottom of the case are formed on the bottom and bottom surfaces.

Fastening grooves 512 corresponding to the fastening protrusions 320 and 322 are formed in the upper and lower covers 500 and 510 along the outer circumferential surface thereof, and the lower case 300 is fastened when the battery pack 100 is assembled. The fastening grooves 512 of the lower cover 510 may be formed in the protrusions 320 and 322 to be fixed in a fitting fastening manner.

6 and 7 schematically show a process of combining the lower case and the upper case.

Referring to these drawings, a small protruding extension fastening portion 314 protrudes upward from the lower case side wall 310, and an extension fastening portion 314 of the lower case side wall 310 on the outer circumferential surface of the upper case 400. Indentations 410 corresponding thereto are formed at corresponding positions.

When the extension fastening portion 314 protruding upward from the lower case side wall 310 is positioned at the indentation portion 410, the excess portion of the extension fastening portion 314 protruding from the upper case 400 is bent and welded. , Solid coupling of the upper case 400 and the lower case is achieved.

FIG. 8 is a partially enlarged view of portion A of FIG. 5.

Referring to FIG. 8, the battery cell 200 formed of a battery case of an aluminum laminate sheet has its upper sealing portion 210 vertically bent upward and closely adhered to the main body of the battery cell 200. 600 is mounted. The electrode lead 220 protruding from the upper sealing part 210 is vertically bent again and connected to the connection terminal of the PCM 600. Therefore, dead space due to the upper sealing part 210 can be reduced, and the PCM 600 can be mounted stably.

9 schematically illustrates a structure of a lower case according to another embodiment of the present invention.

Referring to FIG. 9, sidewalls 310 and 330 are formed on both side and bottom surfaces thereof, respectively, based on the battery cell 200 to be mounted in the housing 340. That is, by forming the sidewalls 330 by bending the metal plate not only on both sides but also on the bottom surface portion, a structure in which the sidewalls 310 and 330 are formed on the three surfaces, respectively.

In this structure, an inner surface of the lower sidewall 330 is additionally provided with a member 800 having insulation and shock absorbing properties. The shock absorbing member 800 may be positioned between the lower sidewall 330 and the battery cell (not shown) to improve safety and insulation against the addition of external force.

Although described above with reference to the drawings according to an embodiment of the present invention, those skilled in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

As described above, the battery pack case of the metal material according to the present invention has a structure that is coupled to the upper case by an extended fastening portion protruding from the lower case side wall, the upper case and the lower portion in a simple structure without a separate connection member Since the case can be combined there is an effect that can greatly improve the manufacturing processability of the battery pack.

Claims (15)

A pack case in which a battery cell capable of charging and discharging is embedded, and a lower case of a metal material having a sidewall formed in an open structure to accommodate a battery cell, and an upper portion of a metal material mounted on and coupled to the lower case. And a case, wherein at least one or more extension fastening parts are formed on sidewalls of the lower case and bent and coupled to an upper surface of the upper case in a state where the upper case is mounted. The battery pack case according to claim 1, wherein the extension fastening part is bent to the upper surface of the upper case and then welded. The battery pack case according to claim 1, wherein the side wall is formed by bending a metal plate. According to claim 1, wherein the side wall is formed on both sides of the side of the battery cell to be mounted on the receiving portion, characterized in that the bottom cover of the insulating and shock-absorbing material is further mounted on the lower surface of the open lower case. Battery pack case. The lower surface of the lower case is formed with a fastening protrusion bent from the side wall and the bottom of the main body, and the lower cover is provided with a fastening groove corresponding to the fastening protrusion along its outer circumferential surface. Battery pack case, characterized in that. The battery pack case according to claim 5, wherein a fastening protrusion is formed at a corresponding portion of the upper case. The battery pack case of claim 1, wherein the sidewalls are formed on both side surfaces and bottom surfaces thereof, respectively, based on the battery cells to be mounted in the storage unit. 8. The battery pack case of claim 7, wherein an insulating and shock absorbing member is further added to an inner surface of the lower sidewall. The battery pack case of claim 1, wherein an upper end cover of an insulating and shock absorbing material is attached to an open upper end of the upper and lower cases. The battery pack case according to claim 1, wherein an indentation portion is formed at a position corresponding to an extension fastening portion of the lower case on an outer circumferential surface of the upper case. The battery pack case according to claim 1, wherein the upper case and the lower case are made of stainless steel. A battery pack comprising a battery cell capable of charging and discharging a battery pack case according to any one of claims 1 to 11. The battery pack according to claim 12, wherein the battery cell has a structure in which an electrode assembly having a cathode / separation membrane / cathode structure is mounted on a battery case of a laminate sheet including a resin layer and a metal layer, and the outer peripheral surface is heat-sealed. The battery pack according to claim 13, wherein the upper sealing part of the battery case made by thermal fusion is bent to be in close contact with the upper end of the battery cell, and a protective circuit element (PCM) is mounted thereon. The method of claim 12, wherein the battery pack is a battery pack, characterized in that the built-in structure.

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