Battery Tray and Method for Manufacturing Battery Using the Same

Abstract

The battery tray of the present invention has a plurality of insertion holes into which charging / discharging terminals are inserted and a plurality of heat release holes for air flow formed at the bottom of a housing in which the batteries are accommodated, and hot air generated from the batteries flows smoothly through the heat release holes, so that temperature deviation is reduced even if the position of the batteries accommodated varies depending on whether it is the center of the tray or the outer periphery.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0160203 filed on November 19, 2021.

[0002] The present invention relates to a battery tray capable of improving temperature deviation during the activation process of a battery and a method for manufacturing a battery using the same.

Background Art

[0003] Currently commercialized secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among these, lithium secondary batteries have attracted attention due to advantages such as almost no memory effect compared to nickel-based secondary batteries, free charge and discharge, low self-discharge rate, and high energy density.

[0004] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as the positive electrode active material and the negative electrode active material, respectively. A lithium secondary battery has a structure in which a unit cell having a structure in which a positive electrode plate coated with a positive electrode active material on a positive electrode current collector and a negative electrode plate coated with a negative electrode active material on a negative electrode current collector are arranged with a separator in between is combined, and an exterior material that hermetically houses this electrode assembly together with an electrolytic solution, that is, a battery case. Lithium secondary batteries are classified into can-type secondary batteries in which the electrode assembly is built into a cylindrical or rectangular metal can according to the shape of the battery case, and pouch-type secondary batteries in which the electrode assembly is built into a pouch of an aluminum laminate sheet.

[0005] On the other hand, secondary batteries are manufactured through a process of assembling cells and a process of activating the battery. In the battery activation step, the battery is mounted on a tray, and charge and discharge and aging are performed under the conditions necessary for activation.

[0006] In such an activation step, self-heating of the battery occurs until a temperature higher than the temperature set by the charge and discharge of the battery and the chemical reaction during high-temperature aging is reached. Since the self-heating of the battery can cause deterioration of the battery performance, in order to control the self-heating of the battery, the battery is cooled to a suitable temperature by blowing air to the battery or the like.

[0007] FIG. 1 is a top view of a conventional battery tray for accommodating a plurality of conventional cylindrical batteries. Referring to FIG. 1, the conventional battery tray 10 is provided with pockets 12 for accommodating a plurality of batteries at a constant pitch. The pockets 12 are formed at a constant pitch in the X direction (horizontal direction) and the Y direction (vertical direction), respectively, and the batteries are each accommodated in the pockets 12.

[0008] A partition wall 11 is installed in the battery tray 10, and a square pocket 12 is formed so as to be surrounded on all sides by the partition wall 11. And an insertion hole 13 into which a charge and discharge terminal is inserted is formed at the bottom, and the charge and discharge terminal is electrically connected to the battery accommodated inside the tray through the insertion hole so that charge and discharge can be performed under the conditions necessary for activation in a state where the battery is accommodated in the tray.

[0009] On the other hand, in order to activate a plurality of batteries, the battery tray performs an activation step in a state where a plurality of trays in which the batteries are accommodated are stacked. In such a case, the conventional battery tray structure has poor heat flow and may cause uneven cooling depending on the position where the battery is accommodated.

[0010] Therefore, the actual situation is that there is a need for technological development of a battery tray that can improve the heat flow between the central part and the outer part of the tray and the heat flow between the upper part and the lower part when the trays are stacked. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] The present invention is for solving the problems of the above prior art, and provides a battery tray with a novel structure that can improve the heat flow of the tray and improve the temperature deviation due to the storage position of the battery.

Means for Solving the Problems

[0012] The battery tray according to an embodiment of the present invention is a battery tray for storing a plurality of batteries in a battery manufacturing process, and a plurality of insertion holes into which charge and discharge terminals are inserted and a plurality of heat release holes for air flow are formed at the bottom of a housing in which the batteries are accommodated.

[0013] The battery tray according to an embodiment of the present invention includes partition walls that form a plurality of rectangular pockets (Pockets) for storing the batteries one by one.

[0014] In one embodiment of the present invention, one insertion hole is formed at the bottom of each pocket.

[0015] In one embodiment of the present invention, the insertion hole is formed at the center of the bottom of the pocket.

[0016] In one embodiment of the present invention, the heat release hole is formed on the outer periphery thereof with the insertion hole as the center.

[0017] In one embodiment of the present invention, 2 to 5 heat release holes are formed on the outer periphery of each insertion hole.

[0018] In one embodiment of the present invention, the diameter of the heat release hole is 3 mm to 12 mm.

[0019] In one embodiment of the present invention, the housing includes a bottom and side walls that are vertically extended from four corner portions of the bottom and have a predetermined height.

[0020] In one embodiment of the present invention, a plurality of side wall heat release holes are formed in the side wall.

[0021] The battery tray according to an embodiment of the present invention has a structure in which a plurality of battery trays can be stacked vertically.

[0022] The battery tray according to an embodiment of the present invention has an open upper surface side, and the pocket is configured such that a cylindrical battery can be stored in the pocket in an upright state.

[0023] The method for manufacturing a battery according to the present invention includes storing a plurality of batteries in the battery tray and performing an activation process.

Advantages of the Invention

[0024] The battery tray of the present invention is provided with heat release holes at the bottom, and the hot air generated from the battery flows smoothly through the heat release holes. Therefore, even if there is a difference due to the center or outer contour of the tray at the position where the battery is stored, the temperature deviation is reduced.

[0025] In addition, in the conventional tray, the heat flow in the central portion is poor, the cooling efficiency for the battery stored in the portion is reduced, and there is an effect of improving the problem that the deterioration of the battery may be caused.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Best Mode for Carrying Out the Invention

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of the present invention based on the principle that the inventor can appropriately define the concept of the terms in order to explain his own invention in the best way.

[0028] Therefore, the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Thus, there can be various equivalents and modifications that can replace them at the time of this application.

[0029] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 2 to 4.

[0030] FIG. 2 is a perspective view of a battery tray according to an embodiment of the present invention, FIG. 3 is a top view of the battery tray according to an embodiment of the present invention and an enlarged view of a part thereof, and FIG. 4 is a drawing showing a state in which battery trays are stacked according to an embodiment of the present invention.

[0031] Referring to FIGS. 2 to 4, the battery tray 100 has a housing 110 for accommodating batteries formed in a regular square shape with an open upper surface, and a plurality of batteries can be stored in an upright state therein. In the battery tray 100, a plurality of insertion holes 120 into which charge and discharge terminals are inserted and a plurality of heat release holes 130 for air flow are formed at the bottom of the housing 110.

[0032] The heat release holes allow the hot air generated by the battery to flow easily from the central part of the tray to the outer part. When the trays are stacked, the hot air can flow easily from the lower part to the upper part of the tray stack. Therefore, the battery tray of the present invention smooths the heat flow of the hot air released from the battery during the activation step, reducing the temperature deviation between the batteries depending on the position where the batteries are housed. In the conventional tray structure, in the case of a battery housed in the center of the tray, the hot air would remain without moving to the outer part, and the battery would not be properly cooled, resulting in possible deterioration of the performance of the battery. However, such problems can also be improved.

[0033] The battery tray 100 is provided with a plurality of pockets 140 for housing a plurality of batteries at a constant pitch. These pockets 140 are formed at a constant pitch in the X direction (lateral direction) and the Y direction (longitudinal direction), respectively, and one battery is housed in each of these pockets 140.

[0034] A partition wall 150 is installed in the battery tray 100, and a rectangular pocket 140 is formed so as to be surrounded on all sides by this partition wall 150. The partition wall 150 is formed along the lateral direction (X direction) and the longitudinal direction (Y direction) of the battery tray.

[0035] The pocket 140 is configured to maintain the cylindrical battery in an upright state. In other words, the pocket is configured such that a cylindrical battery can be housed therein in an upright state. The cylindrical battery is placed upright on the bottom of the pocket.

[0036] One insertion hole is provided at the center of the bottom of each of the pockets 140, and the charge and discharge terminals of the battery are inserted into this insertion hole.

[0037] The heat release holes 130 are formed at the bottom of the tray to smooth the flow of the hot air generated by the battery during the activation process. The heat release holes are formed on the outer periphery thereof with the insertion holes as the center, and 2 to 5 heat release holes are formed on the outer periphery of each insertion hole.

[0038] The diameter of the heat release holes is 3 mm to 12 mm, preferably 4 mm to 10 mm, and more preferably 5 mm to 9 mm. The larger the diameter of the heat release holes, the smoother the air flow in the tray can be, which is advantageous in terms of heat flow. However, if the diameter of the heat release holes is too large, the rigidity of the battery tray may become weak. Therefore, it is preferable that the diameter of the heat release holes is within the above range.

[0039] On the other hand, at the bottom of one pocket, in order to make the air flow move uniformly, as shown in FIG. 3, the heat release holes are arranged around each of the four vertices at the bottom of the pocket.

[0040] The housing 110 houses a plurality of batteries therein and includes a bottom portion and side walls 112 that extend vertically (in the upright direction of the battery) from the four corner portions of the bottom portion and have a predetermined height.

[0041] The bottom portion is a portion where the lower surface of the battery housed inside the housing abuts, and is rectangular. On the left side in the vertical direction, the right side in the vertical direction, the left side in the horizontal direction, and the right side in the horizontal direction, which are the four outer sides of the bottom portion, side walls extending in the vertical direction are respectively installed.

[0042] On the side walls 112, a plurality of side wall heat release holes 160 are formed to smooth the heat flow of the tray in the same manner as the bottom portion. Such 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 at a certain interval from each other. By forming heat release holes in the side walls as well, the hot air generated from the battery can flow through the side portions of the tray, which is more effective for achieving the object of the present invention.

[0043] Referring to FIG. 4, the battery tray of the present invention has a structure in which a plurality of battery trays can be stacked in the vertical direction.

[0044] The height of the side wall is higher than that 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 can be 50% to 95% of the side wall height.

[0045] Such a battery tray can be manufactured by injection molding of industrial thermoplastic plastics such as engineering plastics. After the cavity of the mold for manufacturing the battery tray is shaped to take into account the partition wall, insertion holes and heat release holes of the present invention, injection molding is performed, and a battery tray with the partition wall, insertion holes and heat release holes formed can be integrally manufactured.

[0046] On the other hand, 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.

[0047] The activation process may include a process of initially charging the battery at SOC 20% to 60%, a process of aging the battery, and a process of fully charging and fully discharging the battery so that the battery after the assembly of the battery can be used. Since the specific content of the activation process is by a known method, further description is omitted.

[0048] Since the heat flow of the battery tray of the present invention is improved, when the activation process is performed with the battery stored in the battery tray of the present invention during the battery activation process, the temperature deviation due to the battery storage position is reduced, and the temperature rise rate and the cooling rate are made uniform, resulting in an epoch-making improvement in the capacity deviation.

[0049] 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 pocket 240 is formed so as to be surrounded by the partition wall 250 on all sides. The partition wall 250 is formed along the diagonal direction of the battery tray 200. The embodiment shown in FIG. 5 has a different pocket arrangement compared to the pockets of the embodiments shown in FIGS. 2 to 3. That is, the battery tray of the embodiment shown in FIG. 5 is configured in a shape in which the pockets are rotated by 45°, that is, in a form in which the pockets are in contact with each other face to face along the diagonal direction of the battery tray 200, reducing the space to be discarded (improving the space utilization efficiency) and enabling more batteries to be stored.

[0050] Referring to FIG. 5, the lowermost pocket in the leftmost column is in contact with the lower side in the horizontal direction, and the uppermost pocket in the next column on the right is in contact with the upper side in the horizontal direction. Thus, when comparing two adjacent columns, the pockets are arranged alternately in a zigzag pattern such that one column is in contact with the lower side in the horizontal direction and the other column is in contact with the upper side in the horizontal direction. That is, instead of simply arranging a plurality of columns of pockets vertically side by side so that the corners of the pockets meet each other, a plurality of columns are arranged horizontally, and one column is attached to the lower side and the adjacent column is attached to the upper side without any empty space. As a result, more pockets can be arranged in the battery tray without any discarded space, and more pockets can be arranged within the same area.

[0051] Hereinafter, the present invention will be described in more detail through examples and the like. However, the configurations described in the examples described in this specification are only one embodiment of the present invention and do not represent all of the technical ideas of the present invention. Therefore, there may be various equivalents and modifications that can replace them at the time of this application.

[0052] [Example 1] A battery tray as shown in FIGS. 2 to 3 (with an outer size of 540 mm × 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, there is one insertion hole for inserting a charge and discharge terminal and heat release holes with a diameter of 5.6 mm are formed around the four vertex portions respectively.

[0053] [Example 2] A battery tray was prepared by changing the diameter of the heat release holes in the battery tray of Example 1 to 7.0 mm.

[0054] [Example 3] A battery tray was prepared by changing the diameter of the heat release holes in the battery tray of Example 1 to 8.4 mm.

[0055] [Comparative Example] A battery tray was prepared by eliminating the heat release holes from the battery tray of Example 1.

[0056] [Experimental Example 1: Temperature Measurement] Cylindrical batteries with a diameter of 21.45 mm were stored in each pocket of the battery tray of Example 2. With the trays storing the batteries stacked in 5 layers, initial charging and high-temperature aging were performed on the batteries.

[0057] Thereafter, in an atmosphere with a temperature of 25°C, the ambient temperatures at the central part and the outer part of the three trays in the center of the tray stack were measured over time, and the results are shown in FIG. 6.

[0058] The same experiment as described above was also performed on the battery tray of the comparative example, and the results are shown in FIG. 7.

[0059] Referring to FIGS. 6 and 7, in both the trays according to Example 2 and the comparative example, due to the self-heating of the batteries, the temperature around them rises, so the temperature at the temperature measurement site shows an increasing trend in the initial stage.

[0060] In the tray of Example 2, it was shown that the temperature of the central part of the three layers rose to a maximum of 72°C, the temperature of the outer part of the three layers rose to a maximum of 67°C, and the maximum temperature deviation between the central part and the outer part was 5°C. And it was shown that the outer part where the heat flow was advantageous reached temperature equilibrium after about 6 hours, and the central part where the heat flow was relatively disadvantageous took about 8 hours to reach temperature equilibrium.

[0061] In the tray of the comparative example, it was shown that the temperature deviation between the central part of the three layers and the outer part of the three layers was about 20°C when about 4 hours had elapsed, and about 10°C when about 17 hours had elapsed. It can be confirmed that the temperature deviation between the central part and the outer part is larger compared to the tray of Example 2. Also, it has been shown that the central part where the heat flow is relatively disadvantageous continues to have a temperature rising tendency even when 17 hours have elapsed, and it can be confirmed that the heat flow in the central part of the tray is poor.

[0062] [Experimental Example 2: Measurement of Heat Fluidity] For the trays of Examples 1 to 3, DT_max was measured, and the results are shown in Table 1. DT_max means the maximum temperature difference over the entire volume of the tray, and the smaller the DT_max, the more advantageous it is for heat flow.

[0063]

Table 1

[0064] Referring to Table 1, it can be confirmed that the larger the diameter of the heat release hole, the smaller the DT_max value, which is advantageous for heat flow.

[0065] As described above, the present invention has been described with reference to the limited examples and drawings, but the present invention is not limited thereto. Of course, various modifications and variations are possible within the equivalent scope of the technical idea of the present invention and the claims described below by those having ordinary knowledge in the technical field to which the present invention belongs.

Explanation of Reference Numerals

[0066] 10, 100, 200: Battery tray 110: Housing 112: Side wall 13, 120: Insertion hole 130: Heat release hole 12, 140, 240: Pocket 11, 150, 250: Partition wall 160: Side wall heat release hole

Claims

1. In a battery manufacturing process, a battery tray for accommodating a plurality of batteries, wherein a plurality of insertion holes for inserting charge and discharge terminals and a plurality of heat release holes for air flow are formed at the bottom of the housing of the battery tray before the batteries are accommodated.

2. The battery tray according to Claim 1, including partition walls forming a plurality of rectangular pockets for accommodating one battery at a time.

3. The battery tray according to Claim 2, wherein one insertion hole is formed at the bottom of each of the pockets.

4. The battery tray according to Claim 3, wherein the insertion hole is formed at the center of the bottom of the pocket.

5. The battery tray according to Claim 1, wherein the heat release holes are formed on the outer periphery thereof with the insertion hole as the center.

6. The battery tray according to Claim 5, wherein 2 to 5 heat release holes are formed on the outer periphery of each of the insertion holes.

7. The battery tray according to Claim 1, wherein the diameter of the heat release holes is 3 mm to 12 mm.

8. The housing The battery tray according to Claim 1, including a bottom and side walls vertically extending from four corner portions of the bottom and having a predetermined height.

9. The battery tray according to Claim 8, wherein a plurality of side wall heat release holes are formed on the side walls.

10. The battery tray according to Claim 8, wherein the battery tray has a structure in which a plurality of battery trays are stacked in the vertical direction.

11. The battery tray has an open upper surface side, The battery tray according to Claim 2, wherein the pockets are adapted to accommodate cylindrical batteries in an upright state therein.

12. A method for manufacturing a battery, which comprises accommodating a plurality of batteries in the battery tray according to any one of Claims 1 to 11 and performing an activation process.

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