Title of Invention | SAFETY DEVICE OF BATTERY |
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Abstract | A safety device of a battery includes a pressure releasing unit provided at a cell (400) and releasing pressure when internal pressure of the cell exceeds set pressure, and a space forming cap covering the pressure releasing unit and forming a space therein. Thus, when the internal pressure of the cell exceeds the set pressure, the pressure releasing unit is accurately operated to release the pressure of the cell to the outside, thereby preventing explosion of the battery. |
Full Text | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery of a mobile terminal, and particularly, to a safety device of a battery capable of improving safety of a battery by smoothly releasing pressure to the outside of a battery when the internal pressure of the battery exceeds the set pressure. 2. Description of the Background Art A mobile terminal is a communication device that a user carries with him or her to make voice communication with another party anywhere. The mobile terminal is provided with a detachable battery for supplying power thereto, and the battery is a second battery, which is recharged when electrically discharged after being used for a certain period of time and then is reused. The battery that is used for the mobile terminal is commonly a lithium battery. As for an operational principle of the lithium battery, lithium ions are generated by oxidation from both poles formed of lithium oxide, and the lithium ions move through an electrolyte and are reduced by reduction occurring at a negative (-) pole formed of material such as carbon or the like, thereby generating electric energy. By the electric energy, the mobile terminal is operated. BRIEF DESCRIPTION OF THE INVENTION Figure 1 is a perspective view which illustrates one example of the battery, and Figure 2 is a perspective which illustrates the battery excluding a cover member constituting the battery. As shown, the battery includes a cell 100 formed as a hexahedral shape and filled with an electrolyte or the like, a protection circuit assembly 200 connected to one side of the cell 100 and serves to secure stability of a current within the cell 100 at the time of electric discharge or recharge, and a cover member 300 protecting the protection circuit assembly 200 by surrounding the protection circuit assembly and reinforcing a coupling force between the protection circuit assembly 200 and the cell 100. The cell is formed of an aluminum material and the inside thereof is in a hermetically closed state. Terminals 210 constituting the protection circuit assembly 200 are respectively connected to a terminal portion of the cell 100. The cover member 300 is formed by performing low temperature lower pressure injection with resin, which is synthetic resin of a nylon series, after the protection circuit assembly 200 is connected to the cell 100. If an overcharged state or a high temperature state of the battery is maintained in its use, the internal pressure of the cell 100 is increased, and the cell 100 finally explodes when the pressure exceeds the set pressure. If the battery mounted to the mobile terminal or the like explodes, not only the mobile terminal is damaged but also the user may hurt. Therefore, many research efforts on securing stability of the battery are being conducted. As one of methods for securing the battery safety, as shown in Figure 3, a pressure releasing portion 110 for releasing pressure when the internal pressure of the cell 100 exceeds the set pressure is provided at one side of a front surface of the cell 100 coupled with the protection circuit assembly 220. The pressure releasing portion 110 has a certain area and a thickness which is smaller than that of another portion of the cell 100. Namely, the pressure releasing portion 110 is formed, as a groove shape having a certain area and a certain depth, at one side of the front surface of the ceil 100, and a portion corresponding of a region of the groove has a thickness that is smaller than that of another portion of the cell 100 by the groove. In such a structure, when the internal pressure of the cell 100 is increased, the pressure releasing portion 110 having a relatively small thickness is torn to release the pressure before the internal pressure of the cell 100 increases to the explosion pressure, thereby preventing explosion of the cell 100. However, in such a structure, as shown in Figure 4, a molten injection material for molding a cover member 300 is filled in the groove forming the pressure releasing portion and is solidified in a process of injection molding of the cover member 300 for the purpose of making tight coupling between the cell and the protection circuit assembly 200 and encompassing the protection circuit assembly 200. For this reason, one portion of the cover member 300 blocks the pressure releasing portion 11. If the internal pressure of the cell increases because the portion of the cover member 300 blocks the pressure releasing portion 110, the pressure releasing portion is not normally operated, namely, is not easily torn, which may cause the cell 100 to explode. Therefore, an object of the present invention is to provide a safety device of a battery capable of improving safety of the battery by smoothly releasing pressure to the outside of the battery when the internal pressure increases up to the set pressure or more. To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a safety device of a battery comprising: a pressure releasing unit provided at a cell and releasing pressure when the internal pressure of the cell exceeds the set pressure; and a space forming cap covering the pressure releasing unit and forming a space therein. The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a unit of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings: Figure 1 is a perspective view which illustrates a general battery; Figure 2 is a perspective view which illustrates the battery excluding a cover member constituting the battery; Figure 3 is a perspective view which illustrates a cell of the battery employing a safety structure of the conventional battery; Figure 4 is a sectional view which illustrates a state that an injection material is filled in the safety structure of the conventional battery; Figure 5 is a perspective view which illustrates a battery provided with a battery safety device in accordance with one embodiment of the present invention; Figure 6 is a perspective view which illustrates a space forming cap and a cell constituting the battery safety device; Figure 7 is a sectional view which illustrates the battery safety device in accordance with the present invention; Figures 8, 9 and 10 are sectional views which illustrate the battery safety device in accordance with different embodiments of the present invention, respectively; and Figure 11 is a sectional view which illustrates an operational state of the battery safety device in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Figure 5 is a perspective view which illustrates a battery provided with a battery safety device in accordance with one embodiment of the present invention, Figure 6 is a perspective view which illustrates a space forming cap and a cell constituting the battery safety device, and Figure 7 is a sectional view which illustrates the battery safety device in accordance with the present invention. As shown, the battery includes a cell 40 filled with an electrolyte or the like, a protection circuit assembly 500 connected to one side of the cell 400 and serving to secure stability of a current at the time of electric charge and discharge within the cell 400, a cover member 600 protecting the protection circuit assembly 500 by encompassing the protection circuit assembly 500 and reinforcing a coupling force between the protection circuit assembly 500 and the cell 400, and a safety device releasing the pressure when the internal pressure of the cell 400 exceeds the set pressure. The cell 400 is formed as a hexahedral shape and preferably made of aluminum. A process of fabricating the cell 400 will now be described. First, an electrolyte or the like is inserted in a can having one open side, then, the opened portion of the can is covered with a plate having a certain area, and the plate is bonded to the can by laser welding or the like. Thusly, the cell 400 is in a hermetically closed state. The protection circuit assembly 500 includes terminals 510, and the terminals 510 of the protection circuit assembly 500 are respectively connected to a terminal portion of the cell 400. The terminals 510 of the protection circuit assembly 500 and the terminal portion of the cell 400 are bonded together by spot welding. The cover member 600 is formed by being injection-molded with resin of a nylon series after the protection circuit assembly 500 is connected to the cell 400. The safety device includes a pressure releasing unit 410 provided at the cell 400 and releasing pressure when the internal pressure of the cell 400 exceeds the set pressure, and a space forming cap 700 placed between the cell 400 and the cover member 600, covering the pressure releasing unit 410 and forming a space therein. The pressure releasing unit 410 includes a thin film portion 412 having a thickness smaller than that of another portion of the cell 400 by a groove 411 formed at a front surface of the cell 400 with a predetermined area and depth. The groove 411 is formed at an outer surface of the cell 400. The pressure releasing unit 410 is provided on a surface of the cell 400 to which the protection circuit assembly 500 is coupled. The space forming cap 700 is formed as a cap shape having an opened one side. The space forming cap 700 is provided at the front surface of the cell 400, forming a predetermined space at the front side of the pressure releasing unit 410. The cover member 600 is coupled to encompass the space forming cap 700. A method in which the space forming cap 700 and the cover member 600 are coupled together is as follows. The protection circuit assembly 500 is coupled to the front surface of the cell 400 and the space forming cap 700 is attached to the front surface of the cell 400 to cover the pressure releasing unit 410. Then, the cover member 600 is formed by low temperature low pressure injection to encompass the protection circuit assembly 500 and the cell 400. Here, because a molten injection material is not introduced into the space forming cap 700, a space is formed within the space forming cap 700. The pressure releasing unit 410 is placed within the space. As another method of coupling the space forming cap 700 with the cover member 600, insertion molding may be used. The space forming cap 700 is formed of a material whose melting temperature is higher than that of the cover member 600. For example, the cover member 600 is formed of synthetic resin of a nylon series, and the space forming cap 700 is formed of heat resistant synthetic resin, preferably, LCP (Liquid Crystalline Polyester). The space forming cap 700 may be made of a metallic material, but the metallic material is expensive as compared to the synthetic resin and is not integrally coupled with the cover member 700, which degrades durability. For this reason, preferably, the synthetic resin which is cheap and has high durability by integral coupling is used. When the internal pressure of the cell 400 exceeds the set pressure, the pressure is released through the pressure releasing unit 410, and the pressure released through the pressure releasing unit 410 is released to the outside through the space forming cap 700 and a surface of the cell 400 which comes in contact with the space forming cap 700. A special device for releasing pressure to the outside may be provided at the space forming cap 700 and the cover member 600. As shown in Figure 8, in the structure, a through hole (H) allowing a space of the cover member 600 and the outside to communicate with each other is formed at the space forming cap 700 and the cover member 600, and an auxiliary pin 800 is formed to block the through hole (H). In such a structure, when the internal pressure of the cell 400 exceeds the set pressure, the pressure is released through the pressure releasing unit 410 and the auxiliary pin 800 inserted in the through hole (H) is separated from the hole, thereby releasing the pressure. As another modified example of the pressure releasing unit 410, as shown in Figure 9, the pressure releasing unit 410 includes a thin film portion 414 having a thickness smaller than that of another portion of the cell by a groove 413 formed with a certain area and depth at an inner wall of the front surface of the cell 400. Namely, the groove is formed at an inner surface of the cell 400. The pressure releasing unit 410 may be implemented in various types beside those two described above. As shown in Figure 10, a battery safety device in accordance with another embodiment of the present invention includes a pressure releasing unit 410 provided at a cell 400 and releasing pressure when the internal pressure of the cell 400 exceeds the set pressure, and a space portion 610 forming a space in the cover member 600 encompassing the protection circuit assembly 500 coupled to the cell 400.The space portion 610 is placed at a portion facing the pressure releasing unit 410. Namely, the space portion 610 is formed at the cover member 600 without forming a space using the aforementioned space forming cap 700. The cover member 600 may be formed by injection or may be formed as a separate member to be coupled to the cell 400. An operational effect of the battery of the present invention will now be described. The battery provided with the battery safety device in accordance with the present invention is detachably mounted to a mobile terminal or the like and is used as a power supply source. When totally discharged by being used as the power supply source, the battery is separated from the mobile terminal, is recharged and is reused. As shown in Figure 11, when the pressure within the cell 400 is increased up to the set pressure or more because the battery is over-charged or maintains a high temperature state in use, the pressure releasing unit 410 explodes and the pressure within the cell 400 is released to the outside. The pressure released through the pressure releasing unit 410 is released to the outside through the space of the space forming cap 600, the space forming cap 700 and a portion of the cell 400 contacting with the space forming cap 700. If the through hole (H) is formed at the space forming cap 700 and the cover member 600 and the auxiliary pin 800 is inserted in the through hole (H), the pressure is released to the outside through the through hole (H) as the auxiliary pin 800 is separated from the through hole (H) by the pressure released from the space forming cap 700. In the present invention, when the cover member 600 is formed by injection after the cell 400 is attached to the space forming cap 700, an injection material for forming the cover member 600 does not block the pressure releasing unit 410 thanks to the space forming cap 700. Because a predetermined space is formed at the front of the pressure releasing unit 410, the pressure releasing unit 410 is not affected by another portion thereof when the internal pressure of the cell 400 exceeds the set pressure. Accordingly, the pressure releasing unit 410 is accurately operated. As described so far, in the safety device of the battery in accordance with the present invention, when the internal pressure of the cell exceeds the set pressure, the pressure releasing unit is accurately operated to release the pressure of the cell to the outside. Thus, explosion of the battery is prevented so that reliability of the battery is improved and the user is protected from getting hurt by the explosion of the battery. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims. WE CLAIM : 1. A safety device of a battery, comprising: a pressure releasing unit provided at a cell of the battery, and the pressure releasing unit configured to release an internal pressure within the cell when the internal pressure of the cell exceeds a predetermined set pressure; a space forming cap covering the pressure releasing unit and configured to form an empty space around the pressure releasing unit such that when the internal pressure of the cell exceeds the predetermined set pressure, the released internal pressure is released into the empty space formed by the space forming cap; a protection circuit assembly coupled to a surface of the cell provided with the pressure releasing unit; an injection-molded cover member encompassing the space forming cap and the protection circuit assembly; a through hole formed through the cover member and the space forming cap and configured to allow the empty space formed around the pressure releasing unit to communicate with an outside of the cover member; and an auxiliary pin inserted in the through hole, and configured to be pushed out of the through hole when the pressure is released into the empty space. 2. The device as claimed in claim 1, wherein the space forming cap is formed of a material having a melting temperature that is higher than a melting temperature of the cover member. 3. The device as claimed in claim 2. wherein the space forming cap is formed of liquid crystalline polyester (LCP). 4. The device as claimed in claim 1. wherein the pressure releasing unit includes a thin film portion having a thickness smaller than that of another portion of the cell by a groove formed at the cell with a certain area and depth. 5. The device as claimed in claim 4. wherein the groove is formed at an outer surface of the cell. 6. The device as claimed in claim 6, wherein the groove is formed at an inner surface of the cell. 7. The device as claimed in claim 1, wherein when pressure is released to the pressure releasing unit, the pressure is released to the outside through the space forming cap and a surface of the cell contacting with the space forming cap. |
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00993-kol-2005-description complete.pdf
993-KOL-2005-CANCELLED PAGES.pdf
993-KOL-2005-CORRESPONDENCE 1.1.pdf
993-kol-2005-correspondence-1.2.pdf
993-KOL-2005-CORRESPONDENCE.pdf
993-KOL-2005-DESCRIPTION (COMPLETE) 1.1.pdf
993-kol-2005-examination report.pdf
993-kol-2005-granted-abstract.pdf
993-kol-2005-granted-claims.pdf
993-kol-2005-granted-description (complete).pdf
993-kol-2005-granted-drawings.pdf
993-kol-2005-granted-form 1.pdf
993-kol-2005-granted-form 2.pdf
993-kol-2005-granted-specification.pdf
993-kol-2005-priority document.pdf
993-kol-2005-reply to examination report-1.1.pdf
993-KOL-2005-REPLY TO EXAMINATION REPORT.pdf
993-kol-2005-translated copy of priority document.pdf
Patent Number | 246614 | ||||||||
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Indian Patent Application Number | 993/KOL/2005 | ||||||||
PG Journal Number | 10/2011 | ||||||||
Publication Date | 11-Mar-2011 | ||||||||
Grant Date | 07-Mar-2011 | ||||||||
Date of Filing | 02-Nov-2005 | ||||||||
Name of Patentee | LG ELECTRONICS INC. | ||||||||
Applicant Address | 20, YOIDO-DONG, YONGDUNGPO-GU, SEOUL | ||||||||
Inventors:
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PCT International Classification Number | H04B 1/38 | ||||||||
PCT International Application Number | N/A | ||||||||
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PCT Conventions:
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