KR-102963972-B1 - Battery cell, and battery pack and vehicle comprising the same and manufacturing method comprising the same

KR102963972B1KR 102963972 B1KR102963972 B1KR 102963972B1KR-102963972-B1

Abstract

The present invention relates to a battery cell capable of preventing damage caused by welding heat, a battery pack including the same, an automobile, and a method for manufacturing the same. The battery cell comprises a can having an open end on one side, an electrode assembly accommodated inside the can, a current collector plate electrically connected to the electrode assembly, a cap covering the open end, and a welded portion in which the can and the cap are joined by welding. The can comprises a beading portion pressed inwardly along the circumference near the open end on the side of the can and a clamping portion folded inwardly along the circumference of the open end on the side of the can to wrap around and secure the edge of the cap. The invention provides a battery cell, a battery pack including the same, an automobile, and a method for manufacturing the same.

Inventors

박경훈
이제준

Assignees

주식회사 엘지에너지솔루션

Dates

Publication Date: 20260512
Application Date: 20241008
Priority Date: 20231222

Claims (20)

As a battery cell, A can having an open end on one side; An electrode assembly accommodated inside the above can; A current collector plate electrically connected to the above electrode assembly; A cap covering the above-mentioned open end; and The above can and the above cap include a welded portion joined by welding, The above can is, A beading portion pressed inward along the circumference near the open end on the side of the above can; and It is provided with a clamping portion that is bent inward along the circumference of the open end on the side of the can and wraps around and secures the edge of the cap. The above current collector plate is, It includes a direction changer bent inward, and A battery cell characterized in that the above-mentioned direction changing part is interposed between the upper surface of the cap and the lower surface of the bent area of the clamping part.
In Article 1, The above beading part is, A lower inclined depression formed to face downwards as it moves inward; and A battery cell characterized by including an upper inclined recess that is connected to the lower inclined recess and is formed to face upward as it extends inward.
In Article 2, The above beading part is, A battery cell characterized by the fact that the lower inclined depression and the upper inclined depression form a certain angle, so that the whole has an inclined shape.
In Article 1, The above current collector plate is, It includes an outward extension formed to face upward as it moves outward, and A battery cell characterized in that the above-mentioned outward extension portion contacts the above-mentioned beading portion.
In Article 1, The above current collector plate is, A battery cell characterized by including a can connecting portion interposed between the edge of the cap and the clamping portion.
In Article 5, The above can connection part is, A battery cell characterized by having a ring shape or a closed-loop shape.
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In Article 1, The above-mentioned direction changing unit is, A battery cell characterized in that at least some area extends further inward than the folded area of the clamping portion.
In Article 1, The above welded part is, A battery cell characterized by seam welding in the bent area or outermost area of the above-mentioned clamping portion.
In Article 1, The above welded part is, A battery cell characterized by being welded together with at least a portion of the above-mentioned current collector plate.
In Article 1, The above welded part is, A first weld portion welded along the end of the bent area of the above-mentioned clamping portion; and A battery cell characterized by including at least one of a second weld portion welded along the vicinity of the end of the bent region of the above-mentioned clamping portion.
In Article 1, The above welded part is, A battery cell characterized by being provided in multiple units, each having a different penetration depth.
In Article 1, The above welded part is, A battery cell comprising multiple units, wherein at least one has a closed-curve welded shape.
In Article 1, The above welded part is, A battery cell characterized by the welding position or penetration depth varying according to the shape of the current collector plate.
A battery pack characterized by including a battery cell according to any one of claims 6 and 8 through 14 within claim 1.
A vehicle equipped with at least one of the battery packs according to claim 15.
As a method for manufacturing a battery cell, A step of housing an electrode assembly connected to a current collector plate in a can; Step of beading the side of the above can; A step of inserting a cap into the open end of the above can; A step of sealing the open end of the can by clamping it so that the edge region of the above-mentioned collector plate is bent radially inward and interposed between the upper surface of the cap and the can; and A method for manufacturing a battery cell, characterized by including the step of double-sealing by welding the area where the upper part of the cap and the can overlap.
In Article 17, The above method for manufacturing the battery cell is, A method for manufacturing a battery cell, characterized by including a step of injecting an electrolyte into the interior of the can before or after the beading process step.
In Article 17, The above double sealing step is, A method for manufacturing a battery cell characterized by welding the above-mentioned collector plate, the above-mentioned cap, and the above-mentioned can together.
In any one of paragraphs 17 through 19, The above double sealing step is, A method for manufacturing a battery cell characterized by seam welding in which the penetration depths in multiple welding areas are the same or different.

Description

Battery cell, battery pack including the same, vehicle and manufacturing method including the same The present invention relates to a battery cell, a battery pack including the same, an automobile, and a method for manufacturing the same. More specifically, the invention relates to a battery cell capable of preventing damage caused by welding heat, a battery pack including the same, an automobile, and a method for manufacturing the same. Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product groups, are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by electric sources. These secondary batteries are attracting attention as a new energy source for enhancing eco-friendliness and energy efficiency, not only for the primary advantage of drastically reducing the use of fossil fuels but also because they generate no by-products from energy use. Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells, or unit battery cells, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, multiple battery cells are connected in series to form a battery pack. Additionally, depending on the charge/discharge capacity required for the battery pack, multiple battery cells are connected in parallel to form a battery pack. Accordingly, the number of battery cells included in the battery pack can be varied depending on the required output voltage or charge/discharge capacity. Meanwhile, the process of manufacturing a battery cell using a cylindrical can comprises the steps of deep drawing a metal sheet to form a circular bottom portion and a circular tubular side wall member connected thereto, housing an electrode assembly inside, and then covering the open end of the side wall member with a cap to finish it. At this time, a current collector plate is provided at the end of the axial ends of the electrode assembly facing the open end, which contacts the electrode tab of the electrode assembly and is electrically connected thereto. The current collector plate is connected to the cap or the side wall member by means such as welding so as to be electrically connected by contacting the cap or the side wall member. In other words, in the process of welding the aforementioned collector plate to the cap or side wall member, the collector plate must maintain a state of close contact with the cap or side wall member. However, generally, to achieve this, a jig is required to bring the collector plate and the cap or the collector plate and the side wall member into close contact, and in addition, a mask is required to expose the weld area. At this time, in order to bring the collector plate into close contact with the cap or side wall member through the mask or jig, a space must be provided inside the can to accommodate the mask or jig. However, since this space remains empty after the mask or jig is removed, there was a problem in that the internal volume of the can could not be utilized efficiently. Accordingly, a method was studied to perform welding while the cap is forcibly pressed into the collector plate or can without a mask or jig. However, this welding method is also cumbersome in that it requires tack welding to temporarily secure the parts to be welded prior to the actual welding process. Furthermore, if part tolerances or assembly errors occur, a problem arises where the welding laser beam is directly irradiated into the interior of the can due to tolerances in the connection points between the can, collector plate, and cap, thereby damaging the electrode assembly. In particular, in order to weld the side wall member of the can, the cap, and the current collector plate all at once, a large amount of thermal energy must be generated to melt all the contact areas between them. Such excessive welding heat can be transferred to the separator of the electrode assembly, and this has become a factor that can cause deterioration such as melting or pore closing of the separator, or decomposition. Furthermore, in order to seal the edges of the can and the cap by welding, electrolyte or other substances must not remain in the welded area. Accordingly, an additional process must be added to thoroughly clean the area where welding will take place after the electrolyte is injected. To avoid the inconvenience of this cleaning process, a method of injecting the electrolyte after sealing the can and the cap could be considered. However, this method also had the problem of incurring the inconvenience of having to seal the can opening with the cap, inject the electrolyte through a separate injection port, and then seal the injection port again. Therefore, the need for research on a batt