KR100813812B1 - Battery Pack of Frame Member Having Groove for Inserting - Google Patents

Abstract

The present invention provides a battery cell in which an electrode assembly is sealed in a laminated sheet case made of a resin layer and a metal layer, a vertically open frame member having a structure in which the battery cell can be mounted, and a battery cell in the frame member. It includes an outer film surrounding the outer surface in the mounted state, the upper or lower sides of the frame of the frame member consists of a fastening groove which can be inserted by inserting the side sealing portion of the battery cell vertically It provides a battery pack.

Such a battery pack has various advantages, such as a very thin thickness, excellent binding force of the battery cell to the frame member, a narrow overall width of the battery pack, and an easy finishing process of the battery pack.

Description

Battery Pack with Fastening Groove in Frame Member {Battery Pack of Frame Member Having Groove for Inserting}

1 is a perspective view of an external battery pack;

2 is a perspective view of a built-in battery pack according to the prior art including a rectangular battery cell;

3 is a perspective view of a built-in battery pack according to the prior art including a pouch-type battery cell;

4 is an exploded perspective view of the battery pack of FIG. 3, and FIG. 5 is a perspective view of a partially assembled state;

6 is a plan view of a battery pack according to the prior art, and FIG. 7 is a sectional view taken along line A-A;

8A and 8B are partial enlarged views of the portion B before and after ultrasonic welding in FIG. 7;

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

FIG. 10A is a schematic enlarged cross-sectional view of a portion C in which the battery cell of FIG. 9 is mounted on the frame member; FIG.

10B is a schematic enlarged cross-sectional view of a portion D in a state in which the battery cell of FIG. 9 is mounted on the frame member;

11A to 11H are diagrams illustrating steps of a process of manufacturing a battery pack according to an embodiment of the present invention.

The present invention relates to a small battery pack, and more particularly, a battery pack in which the battery cell is mounted on the upper and lower open frame members, and a fastening groove into which the side sealing part of the battery cell is inserted in the side frame is formed, and thus the frame It relates to a battery pack excellent in the binding force of the battery cell to the member, easy to finish the battery pack, the overall thickness and width is small.

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 according to their appearance, and are classified into lithium ion batteries and lithium ion polymer batteries according to the type of electrolyte. Due to the recent trend toward miniaturization of mobile devices, there is an increasing demand for small square and pouch type batteries.

In addition, according to the form in which the secondary battery is mounted in the case, it is generally classified into an external battery pack (hard pack) and an internal battery pack (inner pack). A representative example of an external battery pack is disclosed in FIG. 1. Referring to FIG. 1, the external battery pack 10 forms an external part of the external device 12 to which it is mounted. Although it has an easy advantage, it has a relatively expensive and less compatible problem because the case (housing: 11) to be designed according to the type of the external device in a state in which a battery cell (not shown) is built.

On the other hand, since the built-in battery pack 20 covers the cover forming a part of the external device while being mounted inside the external device as shown in FIG. 2, the mounting is relatively cumbersome, but the design is difficult. It is easy, inexpensive and has the advantage of compatibility.

As a battery cell that is the main body of the built-in battery pack 20, a square battery and a pouch-type battery are used. A square battery is a battery in which an electrode assembly is embedded in a battery can such as aluminum or stainless steel, and a pouch type battery is a battery in which an electrode assembly is embedded in a pouch type battery case of an aluminum laminate sheet. In recent years, there is an increasing demand for pouch-type batteries which are light in weight, low in price, and easily deformable according to capacity and output.

3 to 5 are a perspective view of a built-in battery pack according to the prior art including a pouch-type battery cell, a separate perspective view and a perspective view of the assembly process, respectively.

Referring to these drawings, the battery pack 30 may include a pouch-type battery cell 31 and a battery cell 31 in which the electrode assembly of the positive electrode, the negative electrode, and the separator and the electrolyte are sealed. A lower case 32 having a space and an upper case 33 coupled to the lower case 32 in which the battery cells 31 are housed are sealed to the battery cells 31. In addition, a double-sided tape 34 is interposed between the battery cells 31 and the upper and lower cases 32 and 33 to stably fix the battery cells 31 in the spaces inside the cases 32 and 33.

After the upper case 31 is coupled to the lower case 32 in which the battery cells 31 are accommodated, the outer case 31 further enhances the coupling force between the cases 31 and 32 and prevents foreign substances from entering the coupling site or the case. Wrapped with a film 35.

The upper case 33 and the lower case 32 are made of a plastic material such as PC and ABS, respectively, and are assembled by mutual coupling 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 specific details of coupling the lower case and the upper case by ultrasonic welding may be described with reference to FIGS. 6 to 9. For convenience of explanation, hereinafter, the upper case is denoted by 40 and the lower case is denoted by 50.

6 and 7 show a top view of the upper case 40 mounted on the lower case 50 and its vertical cross section (A-A cross section of FIG. 8), respectively. With the upper case 40 mounted on the lower case 50, both end surfaces of the upper case 40 and both ends of the lower case 50 are in contact with each other. An enlarged view of such a contact portion B and a variation in ultrasonic welding are shown in Figs. 8A and 8B, respectively. As shown in FIG. 8A, a wedge-shaped welding peak 41 is formed on the lower surface of the upper case 40, and a welding surface that the welding peak 41 contacts the corresponding part of the lower case 50 ( 51) is formed. When high frequency vibration is applied for ultrasonic welding, the contact surfaces of the welding acid 41 and the welding surface 51 are melted, and mutual adhesion is performed.

However, as the demand for battery packs with smaller and thinner thicknesses increases, the thickness of the lower case 40 and the upper case 50 is recently reduced to 0.3 to 0.35 mm, respectively, and accordingly, mold processing and injection molding are performed. As the difficulty increases, the welding peak 41 and the welding surface 51 decrease, and the welding failure rate increases, such as weak welding strength.

In addition, since the ultrasonic welding between the upper and lower cases of a thin thickness is relatively inferior in bonding strength, it is possible to secure the bonding force necessary for use as a battery pack and to prevent foreign substances from flowing into the battery pack through the coupling portion or the battery pack. It is desired to apply the outer surface of the battery pack with a film-like exterior film.

Accordingly, there is a high need for a battery pack which can be manufactured without ultrasonic welding, provides adequate strength against external impact, and has a simple manufacturing process due to the low manufacturing cost.

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.

The inventors of the present invention after the in-depth study and various experiments on the structure of the battery pack, the battery pack is manufactured in a structure in which the battery cell is mounted on the frame member of the top and bottom open type, in particular to form a fastening groove in the side frame of the frame member The battery pack having a structure in which the side sealing portion of the battery pack is bent and inserted into the fastening groove is not only excellent in structural stability against dropping or external impact, but also excellent in binding force of the battery cell to the frame member. It has been confirmed that the finishing process is easy and has a variety of advantages, such as being able to manufacture a small thickness and width as a whole, and came to complete the present invention.

Accordingly, the battery pack according to the present invention includes a battery cell in which an electrode assembly is sealed in a laminated sheet case made of a resin layer and a metal layer, a top and bottom open frame member having a structure in which the battery cell can be mounted, and It includes an outer film surrounding the outer surface when the battery cell is mounted on the frame member, the fastening groove which can be inserted into the top or bottom of the side frame of the frame member vertically bent by the side sealing portion of the battery cell It is comprised by what is formed.

Therefore, since the battery pack according to the present invention has a small number of parts and can be assembled without performing ultrasonic welding, the assembly process of the battery pack is very simple, and the upper and lower surfaces of the battery cell are directly in contact with the exterior film in the state of being mounted on the frame member. Since the side sealing part of the battery cell is inserted into and coupled to the fastening groove of the frame member, the overall thickness and width of the battery pack can be significantly reduced, and at the same time, the structural stability is excellent and the finishing treatment is neat.

The battery case of the battery cell is made of a sheet structure of a laminate structure including a metal layer and a resin layer. Representative examples of such a battery cell is a pouch type battery cell using a laminate sheet of aluminum and resin as the exterior member. In the pouch-type battery cell, the exterior member may have various structures. For example, the exterior member may be a folding member of one unit having a lower end connected integrally, and the electrode assembly may be accommodated in an accommodating part formed on the upper or lower inner surface. And a structure for sealing the upper and lower contact portions. Accordingly, in the pouch-type battery cell, the upper and lower contact portions form a sealing portion when the pouch-type battery cell is sealed in a state in which the electrode assembly is embedded. In the case of the folding unit of one unit as described above, the sealing portion is formed on both sides and the upper surface where the electrode terminal is located.

The electrode assembly is composed of a positive electrode and a negative electrode to enable charge and discharge, for example, a structure in which the positive electrode and the negative electrode are laminated with a separator interposed therebetween, a jelly-roll method or a stacked type. The positive electrode and the negative electrode of the electrode assembly may have a form in which electrode tabs thereof protrude directly to the outside of the battery, or the electrode tabs may be connected to separate leads and protrude out of the battery.

Preferably, as the battery cell, a lithium secondary battery such as a lithium ion battery, a lithium ion polymer battery, or a lithium polymer battery may be used.

The frame member has a structure in which only the outer portion thereof is wrapped so that both surfaces of the battery cell are exposed. That is, the frame member is a lattice structure in which side frames contacting both sides of the battery cell, and upper and lower frames contacting the top and bottom of the battery cell, respectively, are integrally formed. Openings are formed in the upper frame to expose external input / output terminals.

As such, despite the structure in which both surfaces of the battery cell are exposed, the battery pack according to the present invention shows excellent safety. In general, when the battery pack falls or an external impact is applied to the battery pack, the external force tends to be concentrated on the outer portion of the battery cell, that is, the top, bottom or both sides, causing the battery pack to break. The upper surface of the battery pack (upper surface of the battery cell) and the lower surface (lower surface of the battery cell) are not significantly affected unless vertical external force is applied, and the possibility of applying such external external force is the overall effect of the external force on the battery pack. Considering this, it is relatively low. Therefore, considering the tendency of the external force action and the high demand for the battery pack of thin thickness, the configuration of the battery pack by the upper and lower open frame members of the present invention satisfies both of the above requirements.

Furthermore, the battery pack according to the present invention has fastening grooves to which side sealing portions of the battery cells are inserted and coupled to both side frames, thereby further increasing the coupling force of the battery cells to the frame members, and the battery cells are connected to the frame. It is characterized by providing a neat finish state by preventing the side sealing portion from protruding in the mounted state.

In general, both side sealing portions of the pouch-type battery cell are mounted in the pack case in a vertically bent state, as shown in FIG. 4 to reduce the size of the battery pack. The side seal ring portion does not have a separate function except for sealing the electrode assembly of the battery cell, and the size of the battery pack is increased by the bent width. On the other hand, in the present invention, since the side sealing portion of the vertically bent battery cell is inserted into and coupled to the frame member, unlike the prior art, the size of the battery pack does not increase.

In addition, when the side sealing portion is mounted to the frame member in a vertical bent state, the bonding force is weak because the fixing force of the battery cell to the frame member depends only on the outer film. This is the same in FIG. 4 of the structure in which the battery cell is mounted in the box-type pack case, and in this case, the fact that the double-sided tape is separately attached to fix the battery cell has been described. On the other hand, in the present invention, since the side sealing portion of the battery cell is mounted to the frame member in a state of being inserted / coupled to the fastening groove, it provides a high coupling force.

In addition, the side sealing portion of the battery cell has a sharp edge and tends to protrude to the outer surface according to the degree of bending may be difficult to finish by the exterior film. On the other hand, in the present invention, since the sharp end of the side sealing portion is located inside the fastening groove of the frame member, this problem can be solved.

As such, the fastening groove of the side frame into which the side sealing part of the battery cell is inserted is preferably formed at the top or bottom of the side frame to a depth corresponding to the bending height of the side sealing part. In some cases, the sealing aid may be partially filled in the fastening groove to further increase the bonding force and the sealing force in the inserted state. Such sealing aids include adhesives, silicone resins and the like.

The material of the frame member is not particularly limited as long as it provides a desired level of strength. Preferably, the frame member is made of a plastic resin having a low weight and exhibiting electrical insulation.

In one preferred example, the outer surface of the side frame, that is, the opposing surface of the surface where the battery cells are in contact, consists of a curved outer circumferential surface. This curved outer circumferential surface provides a smooth coating state when applying the exterior film, and facilitates the mounting of the battery pack to a predetermined device. The radius of curvature of the curved outer circumferential surface is preferably larger than the thickness of the side frame.

In one preferred embodiment of the present invention, the inner surface of the lower frame, that is, the surface in contact with the battery cell is tapered in the upper or lower direction in which the fastening groove is formed in the side frame, the lower surface of the corresponding battery cell is reverse Consists of a tapered structure. For example, when the fastening groove is formed at the lower end of the side frame, a downward tapered surface (inclined surface) is formed on the inner surface of the lower frame, and an upwardly inclined surface is formed on the lower surface of the battery cell. Since the interface of the lower frame and the battery cell is made of an inclined surface as described above, it is easy to remove the battery cell upward of the lower frame, but difficult to remove downward. On the other hand, since the fastening groove of the side frame is formed at the bottom, when inserting the side sealing portion of the battery cell into the fastening groove of the side frame, the battery cell should be mounted in the downward direction of the frame member. Therefore, the tapered structure of the lower frame and the lower surface of the battery cell has a function of suppressing the detachment of the battery cell in the insertion direction of the side sealing portion with respect to the fastening groove of the side frame, thereby stably maintaining the mounting state of the battery cell to the frame member. I support it.

The taper angle of the bottom frame and the bottom surface of the battery cell may be determined in a range capable of the above function, for example, may be in the range of 10 to 45 degrees. If the taper angle is too small, it is difficult to expect the above effects due to the formation of the inclined surface. On the contrary, if the taper angle is too large, the mounting of the battery cell to the frame member is not easy.

The exterior film supports the fixing state of the battery cell to the frame member, serves to protect the battery cell from the outside, and also functions as a label for displaying the configuration, use method, source, and the like of the battery pack.

The material of the exterior film is not particularly limited, and for example, a plastic material such as PC, polyethylene terephthalate (PET), a metal material of a thin film, and the like may be used, and a plastic material is particularly preferable. The preferred thickness of the film may be about 0.05 to 0.3 mm, but not limited thereto, in consideration of the thickness of the battery pack and its function as a protective member.

Hereinafter, the present invention will be further described with reference to the drawings according to embodiments of the present invention, but the scope of the present invention is not limited thereto.

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

Referring to FIG. 9, the battery pack 100 includes a battery cell 200 having an electrode assembly therein, a grid frame member 300, and an exterior film 400.

The battery cell 200 is embedded in a case in which the electrode assembly is sealed in the case 210 of the pouch-type laminate sheet, and sealing portions are formed at the top and side surfaces thereof in the sealing process. Accordingly, the upper sealing portion 220 and the side sealing portion 230 are mounted to the frame member 300 in a state where the upper sealing portion 220 is vertically bent upwardly. The bent upper sealing part 220 is equipped with a protection circuit module 240 in which an external input / output terminal 242 is formed.

The frame member 300 is a lattice-shaped member surrounding the outer side of the battery cell 200, and an opening 312 is formed in the upper frame 310 to expose the external input / output terminals 242 of the protection circuit module 240. It is. In addition, the side frames 320 and 330 have fastening grooves (not shown) to which the vertically bent side sealing part 230 of the battery cell 200 is inserted and fastened. This will be described in more detail with reference to FIG. 10A.

10A is an enlarged cross-sectional view schematically illustrating a portion C of FIG. 9 in a state where the battery cell is mounted on the frame member. Referring to FIG. 10A, the outer surface 322 of the side frame 320 forms a curved outer circumferential surface and a fastening groove 324 is formed at a lower end thereof. The side sealing part 230 of the battery cell 200 is vertically bent upwardly and is inserted into and coupled to the fastening groove 324 of the side frame 320. Accordingly, the width of the battery pack is prevented from increasing due to the vertical bending of the side sealing part 230, while the coupling force of the battery cell 200 to the frame member is increased, and the end portion 232 of the side sealing part 230 is increased. ) Can be prevented from protruding. In addition, the inner surface 326 of the side frame 320 is inclined in a shape corresponding to the side surface 212 of the battery cell 200, thereby improving adhesion.

9, the bottom frame 340 in contact with the bottom surface of the battery cell 200 has a downward tapered structure. This will be described in more detail with reference to FIG. 10B.

FIG. 10B is an enlarged cross-sectional view schematically illustrating a portion D of FIG. 9 with the battery cell mounted on the frame member. Referring to FIG. 10B, the inner surface 342 of the lower frame 340 is tapered downward, and the lower surface 214 of the battery cell 200 is tapered upward in a corresponding structure. Therefore, due to the tapered structure of the interface, the battery cell 200 can be easily separated from the top, but not easily separated to the bottom. On the other hand, as shown in Figure 10a, since the side sealing portion 230 of the battery cell 200 is coupled to the fastening groove 324 formed on the lower end of the side frame 320, the battery cell 200 is a side frame ( Although it is impossible to separate the upper side of 320, it is easy to separate the lower side. Therefore, due to the mutual structure, the mounting state of the battery cell to the frame member is very stable.

Referring back to FIG. 9, in a state in which the battery cell 200 is mounted on the frame member 300, a space S between the upper surface 216 of the battery cell and the protection circuit module 220 is covered with a cover ( 350) to protect. In some cases, instead of the cover 350, the separation part S may be filled with resin to prevent a material from penetrating from the outside, and a short circuit may be prevented when the battery pack 100 is dropped.

The exterior film 400 wraps the outer surfaces of the battery cell 200 and the frame member 300, thereby supporting their coupled state and protecting the battery cell 200.

11A to 11H are diagrams illustrating steps of a process of manufacturing a battery pack according to one embodiment of the present invention.

In FIG. 11A, the upper sealing part 220 and the side sealing part 230 of the battery cell 200 are vertically bent upwardly, and the first insulating member 250 is mounted on the upper sealing part 220. The electrode lead 260 is bent and attached.

In FIG. 11B, nickel plates 270 for electrical connection are welded to the positive and negative lead 260, respectively.

In FIG. 11C, a second insulating member 242 is attached to the nickel plate 270 coupled to the electrode lead 260. By attaching the insulating member 252, the upper end of the battery cell 200 is electrically insulated from the outside except for the bent end 272 of the nickel plate 270.

Referring to FIG. 11D, the end 272 of the nickel plate 270 is welded to the rear surface of the protection circuit module 240 in FIG. 11C.

Referring to FIG. 11E, the upwardly bent side sealing part (not shown) of the battery cell 200 in which the protection circuit module 240 is mounted is connected to the lower fastening groove of the side frame 320 of the frame member 300 (not shown). And not) to couple the frame member 300 in the upward direction of the battery cell 200.

Referring to FIG. 11F, the cover 350 is coupled to the outer surface of the separation portion between the upper frame 310 and the upper surface of the battery cell 200.

Referring to FIG. 11G, the moisture pad 410 is attached to the upper frame 310.

Referring to FIG. 11H, the battery pack 100 is completed by applying an exterior film 400 to the outer surface of the battery cell (not shown) and the frame member 300 at the same time.

The foregoing has been described above with reference to some embodiments according to the present invention, but those skilled in the art to which the present invention pertains to various applications and modifications within the scope of the present invention based on the above information. It will be possible.

As described above, the battery pack according to the present invention has the following advantages.

First, it can be manufactured in very thin thickness.

Secondly, it is possible to manufacture without ultrasonic welding.

Third, the structural stability is excellent against falling or external impact.

Fourth, the bonding force between the frame member and the battery cell is excellent.

Fifthly, the finishing state is smooth when the exterior film is attached.

The battery pack according to the present invention having these various advantages can be particularly preferably used in the built-in battery pack.

Claims (10)

A battery cell in which an electrode assembly is sealed in a laminated sheet case made of a resin layer and a metal layer, a top and bottom open frame member having a structure in which the battery cell can be mounted, and a battery cell mounted in the frame member. The battery pack includes an outer film surrounding the outer surface, and the fastening grooves are formed at the upper or lower ends of both side frames of the frame member to vertically bend and insert the side sealing parts of the battery cells. . The battery pack according to claim 1, wherein the battery cell is a pouch-type battery cell using a laminate sheet of aluminum and resin as an exterior member. The method of claim 2, wherein the outer member is a unit of foldable member is connected to the lower end is a structure that seals the upper and lower contact parts after receiving the electrode assembly in the housing formed on the upper or lower inner surface. A battery pack, characterized in that. The battery pack as claimed in claim 1, wherein the battery cell is a lithium secondary battery. The battery pack according to claim 1, wherein the fastening groove is formed in the side frame to a depth corresponding to the bending height of the side sealing portion. The battery pack as claimed in claim 1, wherein a sealing aid is partially filled in the fastening groove. The battery pack according to claim 1, wherein an outer surface of the side frame is formed of a curved outer circumferential surface. According to claim 1, wherein the inner surface of the lower frame in contact with the lower surface of the battery cell in the frame member forms an inclined surface tapered in the upper or lower direction in which the fastening groove is formed in the side frame, the corresponding of the battery cell The bottom surface of the battery pack, characterized in that tapered in the reverse direction with respect to the inclined surface. The battery pack according to claim 8, wherein the taper angle between the lower frame and the lower surface of the battery cell is in a range of 10 to 45 degrees. The battery pack according to claim 1, wherein the battery pack is a built-in battery pack.

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