Patent ID: 12230818

Reference Numerals:1. Circuit Assembly;11. PCB;12. Low-Voltage Positive Cap;13. High-Voltage Positive connecting piece;14. Low-Voltage Positive Elastic Connecting Piece;15. Negative Elastic Sheet;16. Charging Interface;2. Plastic Frame;21. Upper Frame;22. Lower Frame;3. Wound Battery Core Assembly;31. Positive Tab;32. Negative Tab;33. Wound Battery Core;34. Upper isolating piece;35. Lower isolating piece;4. First Metal Housing;41. contracted portion;42. positioning hole;43. Open Hole;44. Spun Edge;5. Second Metal Housing;6. Insulating Seal;61. Annular Protrusion;62. Horizontal Sealing Portion;7. Insulating Sheath;71. Open Hole;8. Metal Screw;9. Plastic Nut;10. Positive And Negative Electrode isolating piece;100. Circumferential Welding Spot.

DETAILED DESCRIPTION

The present application will be further described in detail below with reference toFIGS.1to14.

Referring toFIGS.1to5, the present application discloses a voltage-reduced lithium battery, which is specifically an AAA battery, and includes a circuit assembly1, a plastic frame2, a wound battery core assembly3, a first metal housing4, a second metal housing5, an insulating seal6and an insulating sheath7. The circuit assembly1and the plastic frame2are arranged in the first metal housing4, and the plastic frame2is configured to fix the circuit assembly1. The wound battery core assembly3is arranged in the second metal housing5. The first metal housing4docks with the second metal housing5, and they are fixed with each other by circumferential welding. The insulating seal6is arranged between the first metal housing4and the second metal housing5and configured to seal the second metal housing5. The insulating sheath7covers the first metal housing4and the second metal housing5.

The insulating sheath7is preferably made of polyvinyl chloride (PVC), and wraps the first metal housing4and the second metal housing5by thermal shrinkage to achieve double effects of insulating and covering a circumferential welding spot100.

Referring toFIGS.6and8, a lower end of the first metal housing4is provided with a contracted portion41, and the insulating seal6is partially clamped between the contracted portion41and the second metal housing5. The first metal housing4and the second metal housing5have a same outer diameter, therefore, the insulating seal6cannot be arranged when the first metal housing4and the second metal housing5dock with each other. However, due to the providing of the contracted portion41, the insulating seal6can be sleeved and pressed on the contracted portion41, to achieve good sealing effect and prevent an electrolyte from leaking out. In addition, an outer annular surface of the insulating seal6is provided with one or more annular protrusions61which can increase a sealing performance between the insulating seal and the second metal housing5. A horizontal sealing portion62also extends inwards from a bottom of the insulating seal6, and the horizontal sealing portion62is attached to a lower surface of the first metal housing4, which can improve a sealing performance between the horizontal sealing portion and the first metal housing4.

In the present application, the wound battery core assembly3is directly placed in the second metal housing5, the plastic frame2and the circuit assembly1are sealed in the first metal housing4, and then, an upper end of the second metal housing5is completely sealed by the first metal housing4and the insulating seal6. The first metal housing4and the second metal housing5dock to restrict an up-and-down movement amplitude of the wound battery core assembly3. The insulating seal6is arranged between the first metal housing4and the second metal housing5which are then fixed by circumferential welding, such that the first metal housing4and the second metal housing5have high connection strength, damage is not prone to occurrence, a sealing performance is good, and the electrolyte can be effectively prevented from leaking out. The circumferential welding spot100is covered by the insulating sheath7, to avoid influencing user experience. The plastic frame2can achieve an isolation effect to prevent unnecessary contact between the circuit assembly1and the first metal housing4, a short circuit is not prone to occurrence, and electrical safety is guaranteed. Only one steel housing is provided outside the wound battery core assembly3, and compared with the prior art, one steel housing or soft housing is reduced, and a material cost is reduced.

Chinese Patent Application No. CN117673498A titled “Low-Voltage Lithium Battery” discloses a low-voltage lithium battery which can be industrialized, in which, in actual production, a rooling groove is first processed on a metal housing, a wound battery core assembly is fixed in the metal housing, and then, a positive tab is pulled out and welded to a bottom wall of an inner conductive cap, such that a plastic middle frame and a circuit assembly can be put into the metal housing. Due to the above processing process limitation, especially deep extending of an upper end of the wound battery core assembly into the metal housing, a longer positive tab is required; after the lithium battery is assembled, the positive tab is limited in a narrow space, a radial position is uncontrollable, the positive tab has a chance of contacting an inner wall of the metal housing to cause a short circuit, and there exists a serious potential safety hazard.

Referring toFIGS.3and11, a positioning hole42is formed in a bottom wall of the first metal housing4, a metal screw8is arranged at the positioning hole42, and the metal screw8is fixed at the positioning hole42by a plastic nut9. The horizontal sealing portion62extends between the metal screw8and the bottom wall of the first metal housing4and is configured to insulate the metal screw8relative to the first metal housing4. The metal screw8is also configured to seal the positioning hole42, such that the electrolyte cannot permeate into the first metal housing4through the positioning hole42.

Referring toFIGS.3and9, the circuit assembly1includes a printed circuit board (PCB)11, a low-voltage positive cap12, a high-voltage positive connecting piece13, a low-voltage positive elastic connecting piece14and a negative elastic sheet15, and the low-voltage positive elastic connecting piece14, the high-voltage positive connecting piece13and the negative elastic sheet15are all welded on the PCB11. The negative elastic sheet15is in elastic contact with the first metal housing4, the high-voltage positive connecting piece13is in elastic contact with an upper end of the metal screw8, a positive tab31of the wound battery core assembly3is welded to a lower end of the metal screw8, and a negative tab32of the wound battery core assembly is welded to the second metal housing5. The low-voltage positive cap12is arranged on the plastic frame2, and the low-voltage positive elastic connecting piece14is in elastic contact with the low-voltage positive cap12. The metal screw8penetrates through the positioning hole42of the first metal housing4, is insulated from the first metal housing4, and electrically connects the high-voltage positive connecting piece13and the positive tab31by utilizing conductivity of the metal screw, so as to provide high-voltage power input for the circuit assembly1.

Referring toFIGS.5and8, a charging interface16and the PCB11are both vertically placed, and the low-voltage positive cap12is placed on the plastic frame2and is not directly welded to the PCB11, such that the low-voltage positive elastic connecting piece14is arranged on the PCB11. The low-voltage positive elastic connecting piece14contacts an inner wall of the low-voltage positive cap12to realize positive output of a low voltage of 1.5V. The low-voltage positive elastic connecting piece14may be a metal elastic sheet, a spring or an elastic ejector pin.

Referring toFIG.6, the circuit assembly1further includes the charging interface16which is specifically a TYPE-C interface, and other standard interfaces can be adopted. The charging interface16is welded on the PCB11. Openings43,71are formed in corresponding positions of the first metal housing4and the insulating sheath7respectively. The first metal housing4and the second metal housing5are used as common negative electrodes.

Referring toFIG.8, the plastic frame2includes an upper frame21and a lower frame22, the upper frame21and the lower frame22are fixed by snap connection, and the PCB11is fixed between the upper frame21and the lower frame22. Certainly, the upper frame21and the lower frame22can be fixed using other ways, such as ultrasonic welding, glue pasting, or the like.

Referring toFIGS.3and5, a spun edge44is inwards provided at an upper end of the first metal housing4and configured to tightly press the plastic frame2, a positive and negative electrode isolating piece10is further arranged below the spun edge44(or above the spun edge, as long as the spun edge44and the low-voltage positive cap12are not overlapped to cause the short circuit), the positive and negative electrode isolating piece10is effectively prevented from falling off, and part of an upper surface of the positive and negative electrode isolating piece10is further wrapped by the insulating sheath7, thus further preventing the positive and negative electrode isolating piece10from falling off.

Referring toFIG.7, the wound battery core assembly3includes a wound battery core33, an upper isolating piece34and a lower isolating piece35. The positive tab31penetrates out of a central hole of the upper isolating piece34, and an end portion of the positive tab is welded to a lower surface of the metal screw8. The negative tab32is wound from a side surface to a bottom surface of the wound battery core33, and an end portion of the negative tab is welded to a bottom wall of the second metal housing5. In the present application, the wound battery core33is directly placed in the second metal housing5, and compared with a soft-package lithium battery core or a hard-housing lithium battery core in the prior art, a wrapping housing is omitted, and a cost is lower.

In the present application, a circuit has the specific connection principle that the positive tab31of the wound battery core assembly3is connected to the PCB11through the metal screw8and the high-voltage positive connecting piece13, the negative tab32of the wound battery core assembly3is connected to the PCB11through the second metal housing5, the first metal housing4and the negative elastic sheet15, and after a voltage-reduced by the circuit on the PCB11, a positive voltage of 1.5V is output from the low-voltage positive cap12, and the negative electrode of the lithium battery is output from the second metal housing5.

A manufacturing method of the voltage-reduced lithium battery according to the present embodiment includes the following steps:S1: sleeving the lower end of the first metal housing4with the insulating seal6, and fixing the metal screw8and the plastic nut9at the positioning hole42of the first metal housing4;S2: fixing the circuit assembly1on the plastic frame2, then mounting the circuit assembly and the plastic frame into the first metal housing4, making the high-voltage positive connecting piece13in the circuit assembly1elastically contact the metal screw8, and making the negative elastic sheet15in the circuit assembly1elastically contact the first metal housing4;S3: placing the low-voltage positive cap12at the plastic frame2, making the low-voltage positive cap12elastically contact the low-voltage positive elastic connecting piece14, pasting the positive and negative electrode isolating piece10on the low-voltage positive cap12, manufacturing the spun edge44at the upper end of the first metal housing4, and tightly pressing the plastic frame2, the low-voltage positive cap12and the positive and negative electrode isolating piece10in the first metal housing4, the positive and negative electrode isolating piece10being capable of preventing the short circuit between the spun edge44and the low-voltage positive cap12;S4: mounting the wound battery core assembly3into the second metal housing5, and welding the positive tab31of the wound battery core assembly3on a bottom surface of the metal screw8;S5: pressing the insulating seal6and the lower end of the first metal housing4into the second metal housing5, and performing circumferential welding on the first metal housing4and the second metal housing5; andS6: sleeving the obtained assembly with the insulating sheath7, and performing heating shrinkage to wrap the insulating sheath7on the first metal housing4and the second metal housing5.

The manufacturing method according to the present application has a reasonable process and a high yield, and can realize industrialization and large-scale production.

In the present application, the first metal housing4and the second metal housing5are arranged, the circuit assembly1and the plastic frame2are sealed in the first metal housing4, the wound battery core assembly3is arranged in the second metal housing5, and the upper end of the wound battery core assembly3is located at a shallow position in the second metal housing5, such that a required length of the positive tab31is shortened. Although the radial position is uncontrollable, the positive tab is not long enough to contact the inner wall of the metal housing, and the short circuit cannot be caused. In addition, the horizontal sealing portion62also extends inwardly from the bottom of the insulating seal6, the lower surface of the first metal housing4can be covered, the positive tab31is prevented from contacting the lower surface of the first metal housing4, the short circuit can also be avoided, and therefore, the risk of the short circuit between the positive tab31and the metal housing is completely solved.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited thereby, and therefore, equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.