KR-20260066525-A - Battery cell and battery pack

Abstract

A battery cell according to one embodiment of the present invention is characterized by comprising: an electrode assembly; a battery case for accommodating the electrode assembly; and a cushioning member disposed on the inner surface of the battery case and disposed along the circumferential direction of the electrode assembly. The battery cell according to the present embodiment has the effect of preventing electrode disconnection and separator tearing.

Inventors

• 손민진

Assignees

• 주식회사 엘지에너지솔루션

Dates

Publication Date

20260512

Application Date

20241104

Claims (13)

1. Electrode assembly; A battery case for accommodating the above electrode assembly; and A buffer member disposed on the inner surface of the battery case and disposed along the circumferential direction of the electrode assembly; A battery cell containing
2. In paragraph 1, The above buffer member is a battery cell comprising an outer layer and an inner layer disposed on the outer layer.
3. In paragraph 2, The above outer layer is disposed on the inner surface of the battery case, and The inner layer is a battery cell positioned on the outer layer toward the electrode assembly.
4. In paragraph 3, The above inner layer is an elastic layer, which is a battery cell.
5. In paragraph 4, The above inner layer is an elastically restorable battery cell.
6. In paragraph 4, The above outer layer is a rigid layer, which is a battery cell.
7. In paragraph 2, The above buffering member is a battery cell that is a buffering film.
8. In paragraph 1, The above electrode assembly is a battery cell that is a jelly roll electrode assembly.
9. In paragraph 8, The above electrode assembly is a battery cell formed by winding a first electrode, a separator, and a second electrode.
10. In paragraph 8, The above battery case is a cylindrical can battery cell.
11. In paragraph 1, The height of the above buffer member is greater than that of the above electrode assembly, in a battery cell.
12. A battery pack comprising a plurality of battery cells according to claim 1.
13. An automobile including a battery pack pursuant to Paragraph 12.

Description

Battery cell and battery pack The present invention relates to a battery cell and a battery pack, and more specifically, to a battery cell and a battery pack capable of preventing electrode disconnection and separator tearing in a cylindrical battery cell. Unlike primary batteries, which cannot be recharged, secondary batteries refer to batteries capable of charging and discharging, and are applied not only to portable devices but also to electric vehicles (EVs) and hybrid electric vehicles (HEVs) driven by electric power sources. 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 4.6V. Therefore, if a higher output voltage is required, a battery pack is formed by connecting multiple battery cells in series. Additionally, a battery pack is formed by connecting multiple battery cells in parallel depending on the charge/discharge capacity required for the 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. When configuring a battery pack by connecting multiple battery cells in series or parallel, it is common practice to first configure a battery module consisting of at least one battery cell, preferably multiple battery cells, and then use at least one such battery module and add other components to form a battery pack. Here, a battery module refers to a component in which multiple battery cells are connected in series or parallel, and a battery pack may refer to a component in which multiple battery modules are connected in series or parallel to increase capacity and output. Battery cells are classified into pouch type, cylindrical type, prismatic type, etc., depending on the shape of the battery case. Among these, cylindrical cells offer excellent safety as they primarily utilize a metal case with a cylindrical structure. They also have the advantage of high energy density by housing a jelly-roll type electrode assembly inside the case, and make it easy to configure a large-capacity power storage device by connecting multiple cells in series or parallel. The electrode assembly, housed in a cylindrical case, is a rechargeable power generation device composed of a stacked structure of an anode, a separator, and a cathode, and is classified into jellyroll, stack, and stack/folding types. The jellyroll type is formed by winding a separator between long sheet-shaped anodes and cathodes coated with active material; the stack type is formed by sequentially stacking multiple anodes and cathodes of a predetermined size with a separator in between; and the stack/folding type is a composite structure of the jellyroll and stack types. Among these, the jellyroll electrode assembly has the advantages of being easy to manufacture and having a high energy density per unit weight. The jelly roll electrode assembly is in the form of a wound structure with a separator interposed between an anode and a cathode, each coated with an active material, and an anode tab protruding from the upper part of the electrode assembly is disposed on the anode, and a cathode tab protruding from the lower part of the electrode assembly can be disposed on the cathode. Currently, Si-based materials are used as high-capacity anode materials for lithium-ion batteries, but large volume expansion causes electrode degradation, which in turn leads to a decline in cell performance and is directly related to cell safety. Due to the expansion of the electrode, significant pressure is generated on the electrode inside the cylindrical cell, and there are vulnerable areas depending on the jellyroll step. These vulnerable areas can lead to electrode disconnection and separator tearing. FIG. 1 is a drawing illustrating a cylindrical battery cell in one embodiment of the present invention, and FIG. 2 is a drawing for explaining the structure of a cylindrical battery cell in an embodiment of the present invention, and FIG. 3 is a drawing illustrating an electrode assembly in an embodiment of the present invention, and FIG. 4 is a drawing illustrating the appearance of an electrode assembly before it is wound in an embodiment of the present invention, and FIG. 5 is a drawing for explaining the wound form of an electrode assembly in one embodiment of the present invention, and FIG. 6 is a cross-sectional view of a cylindrical battery cell in one embodiment of the present invention, and FIG. 7 is a cross-sectional view of a cylindrical battery cell in one embodiment of the present invention, and FIG. 8 is a partial detail view of FIG. 7, and FIG. 9 is a drawing illustrating a battery pack in an embodiment of the present invention, and FIG. 10 is a drawing illustrating an electric vehicle equipped with a b