Method of manufacturing embedded type battery pack using hot-melt fixing structure and battery pack manufactured using the same

Abstract

Disclosed herein is a method of manufacturing a battery pack including a battery cell having an electrode assembly received in a battery case, made of a laminate sheet including a resin layer and a metal layer, together with an electrolytic solution. An upper case, a PCB, and a battery cell are simultaneously coupled to each other through a hot-melt process without using additional members, such as double-sided adhesive tape and a PCM case. In particular, a label can be removed from an embedded type battery pack. Consequently, it is possible to improve manufacturing efficiency and reduce manufacturing cost due to the reduction in the number of parts.

Claims

1. A method of manufacturing a battery pack comprising a battery cell having an electrode assembly received in a battery case, made of a laminate sheet comprising a resin layer and a metal layer, together with an electrolytic solution, the method comprising: (a) electrically connecting electrode terminals of the battery cell to electrode terminal connection parts of a protection circuit board (PCB) having a connector, which is configured to be electrically connected to a device that uses the battery pack, and a protection circuit formed thereon; (b) coupling an upper case to an upper part of the PCB; (c) bending an upper sealed portion of the battery cell, at which the electrode terminals are located, and loading the PCB, to which the upper case has been coupled, on an upper end of the battery cell such that the PCB is parallel to an outer wall of an electrode assembly receiving part of the battery cell and such that the connector protrudes upward, and thereby form a resultant structure including the upper case, the PCB, and the battery cell; (d) placing the upper case, the PCB, and the battery cell, which have been coupled to each other as the resultant structure, in a mold, which is provided in regions thereof corresponding to a peripheral edge of the battery cell with two or more injection ports, through which a hot-melt resin is injected; (e) injecting the hot-melt resin through the injection ports to perform a hot-melt process, in which the hot-melt resin fills a space defined between the upper case, the PCB, and the battery cell and the mold to form a peripheral edge of the battery cell; and (f) removing the battery pack being a combination of the resultant structure and the peripheral edge from the mold, wherein step (e) comprises fixing the PCB to the upper part of the battery cell through the hot-melt process, wherein two or more injection ports are formed in an upper part of the mold, at which the electrode terminals are located, wherein two or more injection ports are formed in a lower part of the mold, wherein one injection port is formed in a middle of each side part of the mold, wherein the hot-melt resin is injected simultaneously into at least the two or more injection ports in the upper part of the mold and the two or more injection ports in the lower part of the mold to from a single piece of resin joining the PCB to the upper part of the battery cell without an interface between the hot-melt resin injected into the upper part of the mold and the lower part of the mold, wherein the hot-melt process is performed at a temperature of 180 to 200 C., and wherein the hot-melt process is performed at a pressure of 1 bar to 2 bar.

2. The method according to claim 1, further comprising (g) wrapping outer surfaces of the PCB and the battery cell with a label after step (f), wherein steps (a) to (f) are performed in listed order.

3. The method according to claim 1, wherein the battery cell is configured to have a plate-shaped rectangular structure.

4. The method according to claim 1, wherein the battery pack is an embedded type battery pack, which is embedded in the device.

5. The method according to claim 1, wherein the connector is a flexible printed circuit board (FPCB).

6. The method according to claim 1, wherein the mold comprises a lower mold and an upper mold, which are coupled to each other such that the hot-melt process is performed, and wherein a structure corresponding to external shapes of the upper case, the PCB, and the battery cell, which have been coupled to each other, is carved in at least one selected from between the lower mold and the upper mold.

7. The method according to claim 6, wherein the injection ports are formed in the lower mold.

8. The method according to claim 1, wherein the mold has eight or more injection ports.

9. The method according to claim 1, wherein the injection ports are formed in all regions of the mold.

10. The method according to claim 1, wherein at least one of the injection ports is formed in peripheral corners of the mold.

11. The method according to claim 10, wherein the injection ports are formed in all peripheral corners of the mold.

12. The method according to claim 1, wherein a distance between the injection ports ranges from 10 mm to 15 mm.

13. The method according to claim 1, wherein the hot-melt resin is at least one selected from a group consisting of polyamide resins.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a sectional view schematically showing the structure of a mold used in a conventional hot-melt process;

(3) FIG. 2 is a schematic view showing a method of coupling an upper case, a battery cell, and a protection circuit board (PCB) according to an embodiment of the present invention;

(4) FIG. 3 is a schematic view showing the structure of the upper case, the battery cell, and the PCB that are coupled using the method of FIG. 2;

(5) FIG. 4 is a sectional view schematically showing a mold according to an embodiment of the present invention, in which the resultant structure of FIG. 3 is disposed;

(6) FIG. 5 is a sectional view schematically showing a process of injecting a hot-melt resin into the mold of FIG. 4;

(7) FIG. 6 is a sectional view schematically showing a battery pack removed from the mold after the hot-melt resin is injected as shown in FIG. 5; and

(8) FIG. 7 is a sectional view schematically showing the structure of a lower mold of FIG. 4.

BEST MODE

(9) Now, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted, however, that the scope of the present invention is not limited by the illustrated embodiments.

(10) FIG. 2 is a schematic view showing a method of coupling an upper case, a battery cell, and a protection circuit board (PCB) according to an embodiment of the present invention, FIG. 3 is a schematic view showing the structure of the upper case, the battery cell, and the PCB that are coupled using the method of FIG. 2, FIG. 4 is a sectional view schematically showing a mold according to an embodiment of the present invention, in which the resultant structure of FIG. 3 is disposed, FIG. 5 is a sectional view schematically showing a process of injecting a hot-melt resin into the mold of FIG. 4, and FIG. 6 is a sectional view schematically showing a battery pack removed from the mold after the hot-melt resin is injected as shown in FIG. 5.

(11) A method of manufacturing a battery pack 100 according to the present invention will be described with reference to FIGS. 2 to 6.

(12) Referring first to FIGS. 2 and 3, electrode terminals 320 of a battery cell 300 are electrically connected to electrode terminal connection portions 410 of a PCB 400 having a protection circuit formed thereon, and then an upper case 500 is coupled to the upper part of the PCB 400. At this time, the upper case 500 is coupled to the upper part of the PCB 400 such that a connector 420 formed on the upper surface of the PCB 400 is exposed through an opening 510 formed in the upper case 500.

(13) Subsequently, an upper sealed portion 310 of the battery cell 300, at which the electrode terminals 320 are located, is bent, and the PCB 400, to which the upper case 500 has been coupled, is loaded on the upper end of the battery cell 300 such that the PCB 400 is parallel to the outer wall of an electrode assembly receiving part of the battery cell.

(14) As shown in FIG. 4, the upper case 500, the PCB 400, and the battery cell 300, which have been connected to each other, as described above, are placed in a mold provided in regions thereof corresponding to a peripheral edge 330 of the battery cell 300 (see FIG. 6) with two or more injection ports, through which a hot-melt resin is injected. The mold includes a lower mold 210 and an upper mold 220, which are coupled to each other such that a hot-melt process is performed. The injection ports 211 are formed in the lower mold 210. Although not shown, a structure corresponding to the external shapes of the upper case, the PCB, and the battery cell, which have been coupled to each other, is carved in at least one selected from between the lower mold 210 and the upper mold 220.

(15) Subsequently, as shown in FIG. 5, a hot-melt resin is injected through the injection ports 211 to perform a hot-melt process, in which the hot-melt resin fills a space defined between the upper case 500, the PCB 400, and the battery cell 300 and the mold 210. The PCB 400 is fixed to the upper part of the battery cell 300 through the hot-melt process.

(16) That is, in the method of manufacturing the battery pack 100 according to the present invention, the upper case 500, the PCB 400, and the battery cell 300, which are coupled to each other, are placed between the lower mold 210 and the upper mold 220, the lower mold 210 and the upper mold 220 are coupled to each other, and a hot-melt resin is injected through the injection ports 211 formed in the lower mold 210 to form a peripheral edge at the battery cell 300, whereby the battery pack 100 is manufactured.

(17) In the battery pack 100 manufactured as described above, various members, such as a PCM case necessary to load the PCB 400 on the battery cell 300, a frame necessary to mount the battery cell, and a lower case for sealing the lower end of the battery pack, are not required. Consequently, the number of parts required to manufacture the battery pack is greatly reduced, whereby it is possible to reduce manufacturing cost. In addition, the size of the battery cell is increased in proportion to the volume of the omitted parts, whereby it is possible to maximize the capacity of the battery cell.

(18) In addition, the upper case 500, the PCB 400, and the battery cell 300 are coupled to each other only through a hot-melt process, whereby it is possible to improve manufacturing efficiency.

(19) Although not show in the drawings, the method of manufacturing the battery pack according to the present invention may further include a step of wrapping the battery pack 100 with a label.

(20) Meanwhile, the structure of the lower mold 210 will be described in more detail with reference to FIG. 7, which is a sectional view schematically showing the structure of the lower mold of FIG. 4.

(21) Specifically, referring to FIG. 7 together with FIG. 6, eight injection ports 211 are formed in the lower mold 210. Specifically, three injection ports 211 are formed in the upper part 210a of the lower mold 210, at which the electrode terminals are located, three injection ports 211 are formed in the lower part 210b of the lower mold 210, and one injection port 211 is formed in the middle of each side part 210c of the lower mold 210.

(22) That is, the injection ports 211 are formed in all regions of the lower mold 210, whereby it is possible to thickly form a peripheral edge of the upper part of the battery cell, at which the PCB is located, in order to stably fix and mount the PCB to the battery cell without using a conventional PCM case, to seal the lower end of the battery cell 300 and form a peripheral edge 330, which is necessary to fix the battery cell 30, at the lower end of the battery cell 300 without using a lower case, and to form a peripheral edge 330, which is necessary to protect the battery cell 300 from external impact, at the side surface of the battery cell 300 without using conventional side frames, which are provided at the battery cell.

(23) In addition, since the injection ports 211 are formed in all peripheral corners 212 of the lower mold, the hot-melt resin does not pass through bent parts of the mold when the hot-melt resin flows in the mold, whereby the mobility of the hot meld resin is improved.

(24) The distances d and d between the injection ports 211 may range from 10 mm to 15 mm.

(25) In the case in which the distances d and d between the injection ports 211 are less than 10 mm, the number of injection ports 211 formed in the lower mold 210 is excessively increased, whereby the manufacturing process is complicated and the manufacturing cost is increased. On the other hand, in the case in which the distances d and d between the injection ports 211 are greater than 15 mm, the movement distance of the hot-melt resin is increased, whereby it is difficult to achieve the desired effects of the present invention.

(26) In conclusion, in the method of manufacturing the battery pack 100 according to the present invention, the distances between the injection ports 211 are reduced, and the injection ports 211 are effectively disposed along the lower mold 210, whereby it is possible to increase the mobility of the hot-melt resin and to form the peripheral edge 330 at a low pressure, compared to the conventional art.

(27) As described above, in the method of manufacturing the battery pack according to the present invention, the upper case, the PCB, and the battery cell are simultaneously coupled to each other through the hot-melt process without using additional members, such as double-sided adhesive tape and a PCM case, whereby it is possible to improve manufacturing efficiency and reduce manufacturing cost due to the reduction in the number of parts. In addition, in the method of manufacturing the battery pack according to the present invention, two or more injection ports are formed in the mold in order to improve the mobility of the hot-melt resin in the mold, whereby it is possible to improve the efficiency with which the hot-melt resin is filled in the mold and to reduce the defect rate of molded products. Furthermore, the peripheral edge is formed at the battery cell at a low pressure, whereby it is possible to minimize the impact applied to the battery cell during the hot-melt process. Moreover, it is possible to improve the durability of the battery pack using the hot-melt fixing structure. Besides, side frames are not provided at the battery cell, whereby it is possible to increase the size of the battery cell in proportion thereto and thus to increase the capacity of the battery pack, compared to a conventional frame hot-melt type method of manufacturing the battery pack, in which both a frame and a hot-melt resin are used to mount the battery cell.

(28) Although the exemplary embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

INDUSTRIAL APPLICABILITY

(29) As is apparent from the above description, in a method of manufacturing a battery pack according to the present invention, an upper case, a PCB, and a battery cell are simultaneously coupled to each other through a hot-melt process without using additional members, such as double-sided adhesive tape and a PCM case. In particular, a label can be removed from an embedded type battery pack. Consequently, it is possible to improve manufacturing efficiency and reduce manufacturing cost due to the reduction in the number of parts. In addition, in the method of manufacturing the battery pack according to the present invention, two or more injection ports are formed in a mold in order to improve the mobility of a hot-melt resin in the mold, whereby it is possible to improve the efficiency with which the hot-melt resin is filled in the mold and to reduce the defect rate of molded products. Furthermore, the peripheral edge is formed at the battery cell at a low pressure, whereby it is possible to minimize the impact applied to the battery cell during the hot-melt process. Moreover, it is possible to improve the durability of the battery pack using the hot-melt fixing structure. Besides, side frames are not provided at the battery cell, whereby it is possible to increase the size of the battery cell in proportion thereto and thus to increase the capacity of the battery pack, compared to a conventional frame hot-melt type method of manufacturing the battery pack, in which both a frame and a hot-melt resin are used to mount the battery cell.