Battery tray and manufacturing method of battery using same

Abstract

The battery tray of the present invention has a plurality of insertion holes into which charge / discharge terminals are inserted and a plurality of heat dissipation holes for air flow formed in the bottom portion of the housing in which the battery is accommodated, so that heat generated from the battery flows smoothly through the heat dissipation holes, thereby reducing temperature variation even if there is a difference in the position where the battery is stored, whether in the center or the outer edge of the tray.

Description

Technology Field

[0001] The present invention relates to a battery tray capable of improving temperature variation during the activation process of a battery, and a method for manufacturing a battery using the same. Background Technology

[0003] Currently commercialized rechargeable batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium-ion batteries. Among these, lithium-ion batteries are gaining attention due to their advantages, such as high energy density, low self-discharge rates, and virtually no memory effect compared to nickel-based batteries.

[0004] These lithium secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative active materials, respectively. A lithium secondary battery comprises an electrode assembly formed by combining unit cells, each having a structure in which a positive plate, in which a positive active material is coated on a positive current collector, and a negative plate, in which a negative active material is coated on a negative current collector, are arranged with a separator in between; and an outer casing, namely a battery case, that seals and houses this electrode assembly together with an electrolyte. Depending on the shape of the battery case, lithium secondary batteries are classified into can-type secondary batteries, in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type secondary batteries, in which the electrode assembly is housed in a pouch made of an aluminum laminate sheet.

[0005] Meanwhile, as secondary batteries are manufactured through a process of assembling cells and activating the battery, the battery activation stage involves mounting the battery on a tray and performing charging, discharging, and aging under the conditions necessary for activation.

[0006] During this activation phase, self-heating of the battery occurs up to a temperature higher than the set temperature due to chemical reactions during charging, discharging, and high-temperature aging. Since this self-heating can cause degradation of the battery's performance, the battery is cooled to an appropriate temperature, such as by blowing air onto the battery, in order to control the self-heating.

[0007] FIG. 1 is a top view of a conventional battery tray that stores multiple conventional cylindrical batteries. Referring to FIG. 1, the conventional battery tray (10) is provided with pockets (2) for storing multiple batteries at a constant pitch. These pockets (12) are formed at a constant pitch in the X direction (horizontal direction) and the Y direction (vertical direction), respectively, and one battery is stored in each pocket (12).

[0008] A partition wall (11) is installed in the battery tray (10), and a square-shaped pocket (12) is formed by surrounding all four sides by this partition wall (1). Additionally, an insertion hole (13) into which a charge / discharge terminal is inserted is formed in the bottom portion, so that the charge / discharge terminal is electrically connected to the batteries stored inside the tray through the insertion hole, so that charging and discharging can be performed under conditions necessary for activation while the batteries are stored in the tray.

[0009] Meanwhile, to activate multiple batteries, the battery tray performs an activation step with multiple trays containing batteries stacked on top of each other. In this case, conventional battery tray structures do not allow for smooth heat flow, which can cause uneven cooling depending on the location where the batteries are housed.

[0010] Therefore, there is a need to develop technology for battery trays that can improve heat flow in the center and outer parts of the tray, as well as heat flow in the upper and lower parts when the trays are stacked. Prior art literature

[0012] Korean Patent Publication No. 10-2015-0049972 The problem to be solved

[0013] The present invention aims to solve the problems of the prior art described above by providing a battery tray with a novel structure that can improve the thermal flow of the tray and thereby improve the temperature variation according to the storage position of the battery. means of solving the problem

[0015] A battery tray according to one embodiment of the present invention is a battery tray for accommodating a plurality of batteries in a battery manufacturing process, wherein a plurality of insertion holes into which charge / discharge terminals are inserted and a plurality of heat dissipation holes for air flow are formed in the bottom portion of the housing in which the batteries are accommodated.

[0016] A battery tray according to one embodiment of the present invention includes a partition wall forming a plurality of rectangular pockets for storing one battery each.

[0017] In one embodiment of the present invention, for each pocket, one insertion hole is formed in the bottom portion thereof.

[0018] In one embodiment of the present invention, the insertion hole is formed at the center of the bottom portion of the pocket.

[0019] In one embodiment of the present invention, the heat release hole is formed around the insertion hole.

[0020] In one embodiment of the present invention, for each insertion hole, 2 to 5 heat dissipation holes are formed around the outer periphery.

[0021] In one embodiment of the present invention, the diameter of the heat release hole is 3 mm to 12 mm.

[0022] In one embodiment of the present invention, the housing comprises: a bottom portion; and side walls each extending vertically from four corner portions of the bottom portion and having a predetermined height.

[0023] In one embodiment of the present invention, a plurality of sidewall heat release holes are formed in the sidewall.

[0024] A battery tray according to one embodiment of the present invention has a structure capable of stacking a plurality of battery trays in a vertical direction.

[0025] A battery tray according to one embodiment of the present invention has an open upper surface, and the pocket is configured to accommodate a cylindrical battery in an upright position.

[0026] The method for manufacturing a battery according to the present invention comprises storing a plurality of batteries in the battery tray and performing an activation process. Effects of the invention

[0028] The battery tray of the present invention is provided with a heat dissipation hole in the bottom portion, so that heat generated from the battery flows smoothly through the heat dissipation hole, thereby reducing temperature variation even if there is a difference in the position where the battery is stored, whether in the center or the outer edge of the tray.

[0029] In addition, this invention has the effect of improving the problem in conventional trays where poor heat flow in the central part reduces the cooling efficiency for batteries stored in that area, which can lead to battery degradation. Brief explanation of the drawing

[0031] FIG. 1 is a top view of a conventional battery tray that accommodates multiple conventional cylindrical batteries. FIG. 2 is a perspective view of a battery tray according to one embodiment of the present invention. FIG. 3 is a top view of a battery tray according to one embodiment of the present invention. FIG. 4 is a drawing showing a stacked battery tray according to one embodiment of the present invention. FIG. 5 is an enlarged view of one vertex of the upper view of a battery tray according to another embodiment of the present invention. FIG. 6 is a diagram showing the temperature measurement results of the experimental example for the tray of Example 2 of the present invention. Figure 7 is a diagram showing the temperature measurement results of the experimental example with respect to the tray of the comparative example. Specific details for implementing the invention

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0033] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0035] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 2 to 4.

[0036] FIG. 2 is a perspective view of a battery tray according to one embodiment of the present invention, FIG. 3 is a top view of a battery tray according to one embodiment of the present invention and an enlarged view of a part thereof, FIG. 4 is a drawing showing a stacked battery tray according to one embodiment of the present invention.

[0037] Referring to FIGS. 2 to 4, the battery tray (100) has a housing (110) for receiving batteries formed in a square shape with an open top side, and a plurality of batteries can be stored in an upright position therein. In the battery tray (100), a plurality of insertion holes (120) into which charge / discharge terminals are inserted and a plurality of heat dissipation holes (130) for air flow are formed in the bottom portion of the housing (110).

[0038] The above-mentioned heat dissipation holes facilitate the flow of heat generated from the battery from the center of the tray to the outer edge, and when the trays are stacked, facilitate the flow of heat from the bottom to the top of the stacked trays. Therefore, the battery tray of the present invention facilitates the flow of heat emitted from the battery during the activation step, thereby reducing the temperature difference between batteries depending on the location where the batteries are stored. In conventional tray structures, when a battery is stored in the center of the tray, the heat cannot move to the outer edge and remains there, which can lead to the battery not being properly cooled and its performance degrading; however, this problem can also be improved.

[0039] A battery tray (100) is provided with a plurality of pockets (140) for storing a plurality of batteries at a constant pitch. These pockets (140) are formed at a constant pitch in the X direction (horizontal direction) and the Y direction (vertical direction), respectively, and one battery is stored in each pocket (140).

[0040] A partition wall (150) is installed in the battery tray (100), and a rectangular pocket (140) is formed by surrounding all sides by the partition wall (150). The partition wall (150) is formed along the horizontal direction (X direction) and vertical direction (Y direction) of the battery tray.

[0041] The pocket (140) allows the cylindrical battery to be kept upright. In other words, the pocket is designed so that the cylindrical battery can be stored in an upright position. The cylindrical battery is placed upright on the bottom of the pocket.

[0042] The above insertion hole (120) is provided with one insertion hole at the center of the bottom portion of each pocket (140), and the charging / discharging terminal of the battery is inserted into this insertion hole.

[0043] The above heat dissipation hole (130) facilitates the flow of heat generated from the battery during the activation process and is formed on the bottom of the tray. The heat dissipation hole is formed around the outer periphery centered on the insertion hole, and for each insertion hole, 2 to 5 heat dissipation holes are formed around the outer periphery.

[0044] The diameter of the heat dissipation hole is 3 mm to 12 mm, preferably 4 mm to 10 mm, and more preferably 5 mm to 9 mm. A larger diameter of the heat dissipation hole allows for smoother airflow within the tray, which is advantageous in terms of heat flow; however, if the diameter of the heat dissipation hole is too large, the rigidity of the battery tray may be weakened, so it is preferable that the diameter of the heat dissipation hole be within the above range.

[0045] Meanwhile, in order to ensure that the airflow moves uniformly, the arrangement of the heat dissipation holes at the bottom of one pocket is such that heat dissipation holes are arranged around each of the four vertices of the bottom of the pocket, as shown in FIG. 3.

[0046] The above housing (110) accommodates a plurality of batteries inside and includes a bottom portion; and side walls (112) that extend vertically from each of the four corner portions of the bottom portion and have a predetermined height.

[0047] The bottom portion is a rectangular shape and is the part where the lower surface of the battery housed inside the housing comes into contact. On the four outer sides of the bottom portion, namely the vertical left side, vertical right side, horizontal left side, and horizontal right side, side walls extending vertically are installed.

[0048] In the above side wall (112), a plurality of side wall heat release holes (160) are formed to facilitate heat flow of the tray, similar to the bottom portion. These side wall heat release holes (160) are formed in each of the four side walls, and the side wall heat release holes may be formed spaced apart from each other at a constant interval. By forming heat release holes in the side walls as well, heat generated from the battery can flow through the side of the tray, making it more effective for achieving the purpose of the present invention.

[0049] Referring to FIG. 4, the battery tray of the present invention has a structure that allows a plurality of battery trays to be stacked in a vertical direction.

[0050] The height of the above side wall is higher than the height of the partition wall, so that when the battery trays are stacked vertically, the partition wall of the lower tray does not interfere with the bottom surface of the upper tray. Specifically, the height of the partition wall may be 50% to 95% of the height of the above side wall.

[0051] Such battery trays can be manufactured by injection molding of industrial thermoplastic plastics, such as engineering plastics. By making the cavity of the mold for manufacturing the battery tray into a shape that takes into account the partition wall, insertion hole, and heat dissipation hole of the present invention, and then performing injection molding, a battery tray with the partition wall, insertion hole, and heat dissipation hole formed therein can be manufactured as a single unit.

[0053] Meanwhile, the present invention provides a method for manufacturing a battery in which a plurality of batteries are stored in the battery tray and an activation process is performed.

[0054] The above activation process may include a process of initially charging the battery to an SOC of 20% to 60%, a process of aging the battery, and a process of fully charging and fully discharging the battery so that the assembled battery can be used. Since the specific details of the activation process are based on known methods, further explanation is omitted.

[0055] Since the battery tray of the present invention improves heat flow, when the activation process is performed with the battery stored in the battery tray of the present invention, the temperature variation according to the storage position of the battery is reduced, and the temperature rise rate and cooling rate are standardized, thereby having the effect of significantly improving capacity variation.

[0057] FIG. 5 is a top view of a battery tray according to another embodiment of the present invention. Referring to FIG. 5, a partition wall (250) is installed in the battery tray (200) of the present invention, and a square-shaped pocket (240) is formed so as to be surrounded on all sides by the partition wall (250). The partition wall (250) is formed along the diagonal direction of the battery tray (200). The embodiment shown in FIG. 5 has a modified arrangement of pockets compared to the pockets of the embodiments shown in FIG. 2 and 3. That is, the battery tray of the embodiment shown in FIG. 5 is configured such that the pockets are rotated 45°, that is, in a form in which they are in face-to-face contact along the diagonal direction of the battery tray (200), thereby reducing wasted space and allowing a larger number of batteries to be stored.

[0058] Referring to Fig. 5, the bottom pocket of the leftmost column touches the lower horizontal edge, and the top pocket of the next rightmost column touches the upper horizontal edge. In this way, when comparing two adjacent columns, the pockets are arranged in a zigzag pattern, with one column touching the lower horizontal edge and the other touching the upper horizontal edge. That is, instead of simply arranging multiple columns vertically with the corners of the pockets meeting in a horizontal direction, multiple columns are arranged horizontally, with one column facing downward and the adjacent column facing upward, so that there are no empty spaces. As a result, more pockets can be arranged in the battery tray without any wasted space, allowing more pockets to be arranged within the same area.

[0060] The present invention will be described in more detail below through examples and the like. However, since the configurations described in the examples described in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0062] Example 1

[0063] A battery tray as shown in FIGS. 2 and 3 (with an outer diameter of 540 mm x 540 mm, a pocket pitch of 30 mm, and a total of 256 pockets) was prepared. At the bottom of each pocket of the prepared tray, one insertion hole for inserting a charge / discharge terminal and four heat dissipation holes with a diameter of 5.6 mm each are formed around the four corners.

[0065] Example 2

[0066] In the battery tray of Example 1, a battery tray was prepared in which the diameter of the heat dissipation hole was changed to 7.0 mm.

[0068] Example 3

[0069] In the battery tray of Example 1, a battery tray was prepared in which the diameter of the heat dissipation hole was changed to 8.4 mm.

[0071] Comparative example

[0072] In the battery tray of Example 1, a battery tray without heat dissipation holes was prepared.

[0074] Experimental Example: Temperature Measurement

[0075] In each of the battery tray pockets of Example 2, a cylindrical battery with a diameter of 21.45 mm was stored, and the trays containing the batteries were stacked in five layers, and initial charging and high-temperature aging were performed on the batteries.

[0076] Subsequently, under an atmosphere with a temperature of 25°C, the ambient temperature of the central and outer parts of the three-layer tray in the center of the tray stack was measured over time, and the results are shown in Fig. 6.

[0077] For the battery tray of the comparative example, the same experiment was performed as described above, and the results are shown in Fig. 7.

[0078] Referring to FIGS. 6 and FIGS. 7, in both the tray according to Example 2 and the comparative example, the temperature of the surrounding area rises due to the self-heating of the battery, so the temperature of the temperature measurement area shows an increasing trend in the beginning.

[0079] The tray of Example 2 showed a maximum measured temperature of 72°C and a minimum of 67°C, with a deviation of only 5°C. Additionally, the outer part, where heat flow is favorable, reached temperature equilibrium after 5 hours, while the central part, where heat flow is relatively unfavorable, reached temperature equilibrium after 8 hours.

[0080] The tray of the comparative example showed a maximum measured temperature of 79°C and a minimum of 69°C, with a deviation of 10°C. In other words, the temperature deviation depending on the position of the tray is much greater compared to the tray of the example. Furthermore, the central part, where heat flow is relatively unfavorable, showed a continuing trend of rising temperature even after 18 hours, so it is assessed that the battery stored in the central part is not cooled, which could lead to degradation of battery performance.

[0082] Experimental Example 2: Measurement of Thermal Fluidity

[0083] For the trays of Examples 1 to 3, DT_max was measured, and the results are shown in Table 1. DT_max represents the maximum temperature difference across the entire volume of the tray, and a smaller DT_max indicates that it is more favorable for heat flow.

[0084] Example 1 Example 2 Example 3 DT_max 2.8 1.5 1.0

[0085] Referring to Table 1, it can be seen that the larger the diameter of the heat release hole, the smaller the DT_max value becomes, which is advantageous for heat flow.

[0087] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0089] 10, 100, 200: Battery tray 110: Housing 112: Sidewall 13, 120: Insertion holes 130: Heat dissipation hole 12, 140, 240: Pocket 11, 150, 250: Partition wall 160: Sidewall heat dissipation vents

Claims

Claim 1 A battery tray for accommodating multiple batteries in a battery manufacturing process, comprising a partition wall forming multiple rectangular pockets for accommodating one battery each, wherein the bottom portion of the housing in which the batteries are accommodated has multiple insertion holes into which charge / discharge terminals are inserted and multiple heat dissipation holes for air flow formed therein, wherein for each pocket, one insertion hole is formed in the bottom portion thereof, and the arrangement of the heat dissipation holes in the bottom portion of one pocket is such that heat dissipation holes are arranged around each of the four vertices of the pocket bottom portion. Claim 2 delete Claim 3 delete Claim 4 In claim 1, the insertion hole is a battery tray formed at the center of the bottom portion of the pocket. Claim 5 In claim 1, the heat dissipation hole is a battery tray formed around the outer periphery centered on the insertion hole. Claim 6 In claim 5, a battery tray having 2 to 5 heat dissipation holes formed around the outer periphery of each insertion hole. Claim 7 In claim 1, the battery tray wherein the diameter of the heat dissipation hole is 3 mm to 12 mm. Claim 8 In claim 1, the housing comprises: a bottom portion; and a battery tray having side walls that extend vertically from each of the four corner portions of the bottom portion and have a predetermined height. Claim 9 In claim 8, a battery tray having a plurality of sidewall heat dissipation holes formed in the sidewall. Claim 10 In claim 8, the battery tray is a battery tray having a structure capable of stacking a plurality of battery trays in a vertical direction. Claim 11 In claim 1, the battery tray has an open upper surface, and the pocket is configured to accommodate a cylindrical battery in an upright position. Claim 12 A method for manufacturing a battery, wherein a plurality of batteries are stored in a battery tray according to claim 1, and an activation process is performed.

Images