Apparatus for manufacturing battery cell to enhance electrode wetting through vibration, and manufacturing method of battery cell using the same

Abstract

An apparatus for manufacturing a battery cell to enhance the electrolyte wettability to an electrode assembly in the battery cell is provided. The apparatus includes a battery cell tray in which one or more preliminary battery cells are housed and an excitation unit which makes a contact opposite to contacting one side of the battery cell tray to apply megasonic vibration to the preliminary battery cell in a state in which the preliminary battery cell is housed. A method for manufacturing a battery cell using the apparatus is also provided.

Claims

1. A battery cell manufacturing apparatus for enhancing the wetting of an electrolyte to an electrode assembly in a battery cell, the apparatus comprising: a battery cell tray configured to house at least one preliminary battery cell; and an excitation unit contacting one side of the battery cell tray to apply megasonic vibration to the at least one preliminary battery cell when the at least one preliminary battery cell is housed in the battery cell tray, wherein the megasonic vibration is a vibration having a frequency of 500 kHz to 3000 kHz.

2. The apparatus according to claim 1, wherein the battery cell tray has an opened lower part, and wherein the excitation unit applies the megasonic vibration while being in direct contact with the at least one preliminary battery cell.

3. The apparatus according to claim 1, wherein the battery cell tray has a closed lower part, and wherein the excitation unit is fixed opposite to the closed lower part to apply megasonic vibration to the battery cell tray such that the megasonic vibration is transmitted to the at least one preliminary battery cell.

4. The apparatus according to claim 1, further comprising a liquid medium in the battery cell tray, and wherein the at least one preliminary battery cell is immersed in the liquid medium when the at least one battery cell is housed in the battery cell tray.

5. The apparatus according to claim 4, wherein the liquid medium is water.

6. The apparatus according to claim 4, wherein a temperature of the liquid medium is 20 degrees Celsius to 70 degrees Celsius.

7. The apparatus according to claim 1, further comprising a temperature control unit.

8. The apparatus according to claim 7, wherein the temperature control unit is included in the excitation unit.

9. The apparatus according to claim 7, wherein the temperature control unit is a chamber housing the battery cell tray and the excitation unit, and wherein the chamber is temperature-adjustable.

10. The apparatus according to claim 1, further comprising a moving unit configured to move the at least one preliminary battery cell vertically relative to the excitation unit when the at least one preliminary battery cell is housed in the battery cell tray.

11. The apparatus according to claim 1, further comprising a vacuum-applying unit at an upper surface of the battery cell tray, the vacuum-applying unit being configured to apply a vacuum to the at least one preliminary battery cell when the at least one preliminary battery cell is housed in the battery cell tray.

12. The apparatus according to claim 4, further comprising a temperature control unit.

13. The apparatus according to claim 4, further comprising a moving unit configured to move the at least one preliminary battery cell vertically relative to the excitation unit when the at least one preliminary battery cell is housed in the battery cell tray.

14. The apparatus according to claim 4, further comprising a vacuum-applying unit at an upper surface of the battery cell tray, the vacuum-applying unit being configured to apply a vacuum to the at least one preliminary battery cell when the at least one preliminary battery cell is housed in the battery cell tray.

15. The apparatus according to claim 4, further comprising an oscillator immersed in the liquid medium.

16. The apparatus according to claim 15, wherein the oscillator is an ultrasonic horn.

17. A method of manufacturing a battery cell using the apparatus according to claim 1, the method comprising the steps of: a) manufacturing the at least one preliminary battery cell by sealing an electrode assembly in a state of being housed inside a battery case together with an electrolyte; b) housing the at least one preliminary battery cell in the battery cell tray of the apparatus; and c) applying megasonic vibration to the at least one preliminary battery cell through the excitation unit.

18. The method of manufacturing a battery cell according to claim 17, wherein the battery cell tray includes a liquid medium therein, and the at least one preliminary battery cell is immersed in the liquid medium.

19. The method of manufacturing a battery cell according to claim 17, wherein the step c) is performed while a vacuum is applied to the at least one preliminary battery cell.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a photograph showing a state where bubbles are generated in a conventional battery cell;

(2) FIG. 2 is a photograph and graph showing a boundary layer of each vibration and a removable bubble size;

(3) FIG. 3 is a schematic view showing a process in which bubbles are removed by a megasonic vibration;

(4) FIG. 4 is a schematic view showing a form in which a prismatic battery cell is housed in a battery cell tray;

(5) FIG. 5 is a schematic view showing a form in which a cylindrical battery cell is housed in a battery cell tray;

(6) FIG. 6 is a schematic view showing a form in which a pouch-type battery cell is housed in a battery cell tray;

(7) FIG. 7 is a schematic view showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to one embodiment of the present disclosure;

(8) FIG. 8 is a schematic view showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to another embodiment of the present disclosure;

(9) FIG. 9 is a schematic view showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to another embodiment of the present disclosure;

(10) FIG. 10 is a schematic view showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to yet another embodiment of the present disclosure;

(11) FIG. 11 is a schematic view showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to yet another embodiment of the present disclosure;

(12) FIG. 12 is a schematic view showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to still yet another embodiment of the present disclosure;

(13) FIG. 13 is a schematic view showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to still yet another embodiment of the present disclosure;

(14) FIG. 14 is a schematic view showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to a further embodiment of the present disclosure;

(15) FIG. 15 is a photograph showing an experimental method of Example 1 and Comparative Example 1.

(16) FIG. 16 is a comparative photograph according to Experimental Example 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(17) Now, the present disclosure will be described in more detail with reference to the accompanying drawings based on Examples. These examples are provided for illustrative purposes only and should not be construed as limiting the scope of the present disclosure.

(18) FIGS. 7 and 8 show schematic views schematically showing a structure of an electrolyte wetting apparatus for manufacturing a battery cell according to one embodiment of the present disclosure.

(19) First, referring to FIG. 7, the electrolyte wetting apparatus 100 has a structure including: a battery cell tray 120 for housing one or more preliminary battery cells 111, 112 and 113; and a megasonic excitation unit 130 which make contact opposite to one side of the battery cell tray and includes megasonic vibration elements 131 therein.

(20) The battery cell tray 120 has a shape in which an upper surface is opened based on the ground and is concavely recessed in a direction of a lower surface, and its lower part is closed so that the excitation unit 130 is fixed opposite to the lower surface of the battery cell tray 120.

(21) Therefore, the preliminary battery cells 111, 112 and 113 can be more easily housed and removed through the opened upper surface of the battery cell tray 120, and the megasonic vibration is applied to the battery cell tray 120 to be transmitted to the preliminary battery cells 111, 112 and 113.

(22) Further, the excitation unit includes one or more megasonic vibration elements 131, which are spaced apart at a predetermined interval.

(23) Referring to FIG. 8, the battery cell tray 220 of the electrolyte wetting apparatus 200 has a structure in which the lower part is opened, and thus, is the same as in FIG. 7 except that megasonic vibration is applied in a state in which the excitation unit 230 is in a state of being in direct contact with the preliminary battery cells 211, 212 and 213.

(24) Therefore, the megasonic vibration can be applied to the preliminary battery cells, and thus, it is possible not only to easily wet the electrolyte, but also to remove even small-sized bubbles.

(25) FIGS. 9 to 13 show electrolyte wetting apparatuses for manufacturing a battery cell having a structure in which preliminary battery cells are immersed in a liquid medium according to another embodiment of the present disclosure.

(26) Referring to FIG. 9, the electrolyte wetting apparatus 300 for manufacturing a battery cell includes: a battery cell tray 320 for housing one or more preliminary battery cells 311, 312 and 313; and a megasonic excitation unit 330 which faces and makes a contact opposite to one side of the battery cell tray and includes megasonic vibration elements therein, wherein the preliminary battery cells 310 are immersed in a liquid medium 340 in a state of being housed in the battery cell tray.

(27) At this time, the liquid medium 340 may be water, and the temperature of the liquid medium 340 may be raised to increase the internal temperature of the preliminary battery cells 311, 312 and 313, thereby further lowering a boundary layer.

(28) For this purpose, FIGS. 10 and 11 schematically show an electrolyte wetting apparatus further comprising a temperature control unit according to still another embodiment of the present disclosure.

(29) Referring to FIG. 10, the electrolyte wetting apparatus 400 for manufacturing a battery cell further includes a temperature control unit 432, and has the same structure as in FIG. 9, except that the temperature control unit 432 is included in the excitation unit 430 in a form of a heating wire.

(30) Meanwhile, an electrolyte wetting apparatus 500 for manufacturing a battery cell shown in FIG. 11 has a structure including a chamber 550 capable of controlling temperature as a temperature control unit.

(31) As the apparatus further includes the temperature control unit in this way, the internal temperature of the preliminary battery cells can be increased to further lower the boundary layer.

(32) Moreover, FIGS. 12 to 14 show electrolyte wetting apparatuses for manufacturing a battery cell, in which an additional unit is added to more smoothly perform the bubble removal.

(33) First, referring to FIG. 12, an electrolyte wetting apparatus 600 for manufacturing a battery cell has a structure in which the preliminary battery cells 611, 612 and 613 are immersed in the liquid medium 640, similarly to FIG. 9, and at the same time, an oscillator such as an ultrasonic horn 641 is immersed together in the liquid medium 640 to add additional vibrations to the preliminary battery cells 611, 612 and 613. Therefore, the electrolyte wettability and the bubble removal effect can be further improved.

(34) Further, referring to FIG. 13, an electrolyte wetting apparatus 700 for manufacturing a battery cell further includes a moving unit 750 for moving the preliminary battery cells 711, 712 and 713 in a vertical direction, wherein the preliminary battery cells 711, 712 and 713 can be swept in a vertical direction to add similar vibrations to the preliminary battery cells 711, 712 and 713 as a whole, thereby effectively preventing problems such as damage or short circuit of the preliminary battery cell which may occur by concentrating the vibrations in a specific area, and also maximizing the effects of the present disclosure.

(35) Finally, referring to FIG. 14, an electrolyte wetting apparatus 800 for manufacturing a battery cell further includes a vacuum-applying part 850 to apply vacuum to the preliminary battery cells 811, 812 and 813, thereby improving the effects of the present disclosure.

(36) Hereinafter, preferred examples will be provided to assist in the understanding of the present disclosure, but the following examples are presented for illustrative purposes only. It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the invention. Thus, it is intended that the present disclosure covers the modifications and variations of the invention provided they come within the scope of the appended claims and their equivalents.

Example 1

(37) A jelly roll electrode assembly (18650 HB7, LG Chem. Ltd.) having a diameter of 18 mm and a height of 65 mm was placed in a cylinder, and then, an electrolyte was injected into the cylinder until 30 ml of the electrolyte was filled (This is an amount sufficient to completely immerse the jelly roll electrode assembly). As the electrolyte, an electrolyte of EC:EMC:DMC=3:3:4 (Vol %) in which 1M LiPF.sub.6 was dissolved was used.

(38) The cylinder was placed to be erected in a tray to which a megasonic oscillator was attached, and the tray was filled with water (25° C.) so that the cylinder was properly filled (approximately 18 ml scale).

(39) As shown in FIG. 9, the megasonic vibration (1 MHz) was applied to the secondary battery for 60 minutes (See the figure on the left of FIG. 15)

Comparative Example 1

(40) This was performed as in Example 1, except that no megasonic vibration was applied (See the figure on the right of FIG. 15).

Comparative Example 2

(41) This was performed as in Example 1, except that an ultrasonic vibration (100 kHz) was added for 60 minutes using an ultrasonic horn instead of the megasonic vibration.

Experimental Example 1

(42) The jelly roll electrode assemblies of Example 1 and Comparative Examples 1 and 2 were unfolded and photographed to confirm whether the electrolyte was wetted and whether the electrodes were damaged, and the results are shown in FIG. 16.

(43) Referring to FIG. 16, it was confirmed that in the case of Example 1 in which the megasonic was applied, the electrolyte was well penetrated into a separator between the positive electrode and the negative electrode, whereas in the case of Comparative Example 1, the electrolyte was not well wetted inside the middle (see the stripe pattern in the middle)

(44) On the other hand, it can be seen that in the case of Comparative Example 2 in which the ultrasonic vibration was applied, the electrode layer was significantly damaged. In conclusion, the ultrasonic wave penetrates the electrolyte well, but it is difficult to use because it applies a great impact to the electrode layer (see the figure at the bottom of FIG. 16)

(45) Although the exemplary embodiments of the present disclosure have been disclosed for illustrative purposes, those skilled in the art will appreciate that various application and modifications can be made, without departing from the scope and spirit of the invention.

ADDITIONAL REFERENCE SIGN

(46) 440: liquid medium 540: liquid medium 720: battery cell tray 730: excitation unit 740: liquid medium 820: battery cell tray 830: excitation unit 840: liquid medium

INDUSTRIAL APPLICABILITY

(47) As described above, the electrolyte wetting apparatus for manufacturing a battery cell according to the present disclosure applies a megasonic vibration to a preliminary battery cell to increase a direct physical contact between an electrode assembly and a electrolyte due to the vibration, whereby it is possible not only to improve the electrolyte wettability, but also to remove even small-sized bubbles. Therefore, since the bubbles inside the battery cell can be effectively removed, it is possible to prevent a decrease in a capacity of the battery cell and to improve safety and further to save time and cost for manufacturing the battery cell.

(48) Moreover, it is possible to effectively remove even fine bubbles having a smaller size, by using a method of immersing the preliminary battery cell in a liquid medium and increasing the temperature, or adding an additional vibration, or adding a moving unit and applying a vacuum, etc.