Unit battery cell equipped with cover member and secondary battery comprising same

Abstract

A secondary battery includes a unit battery cell including an electrode assembly provided with a tab bundle and having an arcuate portion, and a cover member located in the vicinity of the arcuate portion of the electrode assembly. The cover member includes a pair of first surfaces parallel to upper and lower surfaces of the electrode assembly, a pair of second surfaces parallel to both side surfaces of the electrode assembly, a third surface connecting the pair of first surfaces and the pair of second surfaces, and a sealing member connecting the pair of first surfaces and the pair of second surfaces. The sealing member is disposed in an internal space formed by the pair of first surfaces, the pair of second surfaces, and the one third surface, and is in contact with the arcuate portion of the electrode assembly. The third surface is provided with a through hole, and the lug plate bundle passes through the through hole.

Description

Technical Field

[0001] This application is based on and claims the benefit of priority from Korean Patent Application Nos. 10-2023-0071471 and 10-2023-0180156, filed on June 2, 2023 and December 12, 2023, respectively, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein in their entirety by reference.

[0002] The present disclosure relates to a unit cell equipped with a cover member and a secondary battery including the unit cell. Background Art

[0003] Due to air pollution caused by the use of fossil fuels and the development of alternative energy sources due to energy depletion, the demand for secondary batteries capable of storing generated electrical energy is increasing.

[0004] Due to the increase in the use and complexity of mobile devices and the development of electric vehicles, the required capacity of secondary batteries used as energy sources for various electronic devices that are indispensable to modern society is constantly increasing. In order to meet user needs, a plurality of battery cells are provided in a device with a relatively small size, while for a device with a relatively large size (such as a vehicle, etc.), a battery module in which a plurality of battery cells are electrically connected or a battery pack provided with a plurality of battery modules is used.

[0005] Such a battery cell is manufactured in various structures to improve battery cell performance (for example, see Korean Patent Laid-Open Publication No. 10-2018-0109478). Summary of the invention

[0006] Technical issues

[0007] The present disclosure provides a unit battery cell equipped with a cap member, which can minimize lithium by-products generated during charging and discharging by uniformly controlling pressure applied to each position of an electrode assembly, and a secondary battery including the unit battery cell.

[0008] Technical Solution

[0009] A secondary battery according to the present disclosure includes a unit battery cell and a cover member 200, the unit battery cell includes an electrode assembly 100, the electrode assembly is provided with a tab bundle 110 and an arc portion 130 is formed at the end of the electrode assembly in the direction where the tab bundle 110 is located, and the cover member is provided near the arc portion 130 of the electrode assembly 100. The cover member 200 includes a pair of first surfaces 210 parallel to the upper surface and the lower surface of the electrode assembly 100, a pair of second surfaces 220 parallel to both side surfaces of the electrode assembly 100, a third surface 230 connecting the pair of first surfaces 210 and the pair of second surfaces 220, and a close contact member (or adhesive member) 240, the close contact member is provided in the internal space formed by the pair of first surfaces 210, the pair of second surfaces 220 and the third surface 230 and contacts the arc portion 130 of the electrode assembly 100. The third surface 230 is provided with a through hole 231, and the tab bundle 110 passes through the through hole.

[0010] In the secondary battery of the present disclosure, the close contact member 240 is provided with a first space S1 for gas capture.

[0011] In the secondary battery of the present disclosure, the first space S1 has a slit shape formed in the longitudinal direction of the close contact member 240 .

[0012] In the secondary battery of the present disclosure, a first space S1 for gas capture is provided between the third surface 230 and the close contact member 240 .

[0013] The cover member 200 is made of at least one of an insulating rubber material and a chemical-resistant plastic material.

[0014] The cover member 200 is styrene-butadiene rubber or acrylonitrile-butadiene rubber.

[0015] In the secondary battery of the present disclosure, the unit battery cell further includes a case 300 for accommodating the electrode assembly 100 in a state where the cover member 200 is provided.

[0016] In the secondary battery of the present disclosure, a plurality of unit battery cells are stacked with the second space S2 provided between the electrode assemblies 100 .

[0017] Fixing members A are interposed between the first surfaces 210 to enable the unit battery cells to be fixed to each other.

[0018] The fixing member A is an adhesive.

[0019] In the secondary battery of the present disclosure, the secondary battery is a battery module or a battery pack.

[0020] In the secondary battery of the present disclosure, a plurality of unit battery cells are stacked.

[0021] In addition, a secondary battery according to the present disclosure includes a unit battery cell including an electrode assembly 100, the electrode assembly is provided with a tab bundle 110 and an arc portion 130 is formed at an end portion in a direction where the tab bundle 110 of the electrode assembly is located, a housing 300 for accommodating the electrode assembly 100, and a cover member 200 provided near an outer end of the housing 300. The cover member 200 includes a pair of first surfaces 210, a pair of second surfaces 220, and a third surface 230, the pair of first surfaces are parallel to the upper surface and the lower surface of the housing 300, the pair of second surfaces are parallel to both side surfaces of the housing 300, and the third surface connects the pair of first surfaces 210 and the pair of second surfaces 220. The third surface 230 includes a through hole 231, through which the tab bundle 110 or the electrode lead 120 extending from the electrode assembly 100 passes.

[0022] In the secondary battery of the present disclosure, the cover member includes a close contact member which is disposed in the internal space formed by the pair of first surfaces, the pair of second surfaces, and the one third surface and is in close contact with the end surface of the case.

[0023] The housing is a soft package for lithium secondary batteries.

[0024] The electrode assembly is the basic structure of a lithium secondary battery, and the electrode assembly includes at least a positive electrode, a negative electrode and a separator.

[0025] In addition, in the secondary battery of the present disclosure, the unit battery cells are stacked in plural, and the third space S3 is provided between the electrode assemblies 100 .

[0026] Fixing members A are interposed between the first surfaces 210 to fix the unit battery cells to each other.

[0027] Beneficial Effects

[0028] As described above, the secondary battery according to the present disclosure has the advantage that by including the cap member near the end of the electrode assembly, pressure applied to all surfaces of the electrode assembly can be uniformly controlled, which can minimize lithium byproducts generated during charging and discharging of the secondary battery.

[0029] The cover member included in the secondary battery according to the present disclosure is advantageous in that it has a space and can function as a pocket for exhausting gas.

[0030] The cover member included in the secondary battery according to the present disclosure can clearly indicate the outer boundaries of the pouch-type unit battery cells, allowing accurate stacking, which has an advantage of reducing product defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is an exploded perspective view of a battery cell according to the prior art.

[0032] Figure 2 is an exploded perspective view of a unit battery cell according to a first embodiment of the present disclosure.

[0033] Figure 3 yes Figure 2 A cross-sectional view of a unit battery cell shown in FIG.

[0034] Figure 4 A perspective view showing a first modified example of a cover member mounted on a unit battery cell according to the first embodiment of the present disclosure.

[0035] Figure 5 yes Figure 4 A cross-sectional view of the cover member shown in FIG.

[0036] Figure 6 is a perspective view showing a second modified example of the cover member mounted on the unit battery cell according to the first embodiment of the present disclosure.

[0037] Figure 7 yes Figure 6 A cross-sectional view of the cover member shown in FIG.

[0038] Figure 8 is a first example of a cross-sectional view of a secondary battery showing a state in which unit battery cells are stacked according to the first embodiment of the present disclosure.

[0039] Fig. 9 is a second example of a cross-sectional view of a secondary battery showing a state in which unit battery cells are stacked according to a second modified example of the first embodiment of the present disclosure.

[0040] Fig.10 is a third example of a cross-sectional view of the secondary battery showing a state in which the unit battery cells are stacked according to the first embodiment of the present disclosure.

[0041] Fig.11 is an exploded perspective view of a unit battery cell according to a second embodiment of the present disclosure.

[0042] Fig.12 is a cross-sectional view of a secondary battery showing a state in which unit battery cells are stacked according to a second embodiment of the present disclosure.

[0043] Fig.13 is a perspective view of a unit battery cell according to a third embodiment of the present disclosure.

[0044] In some of the drawings, corresponding parts are given the same reference numerals. It will be understood by those skilled in the art that the drawings simply and clearly depict elements and are not necessarily drawn to scale. For example, to facilitate understanding of the various embodiments, the sizes of some elements shown in the drawings may be exaggerated compared to other elements. In addition, elements of known technology that are useful or necessary in commercially feasible embodiments may not generally be depicted so as not to interfere with the spirit of the various embodiments of the present disclosure. DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present disclosure that can be easily implemented by a person skilled in the art will be described in detail with reference to the accompanying drawings. However, when explaining the working principle of the embodiments of the present disclosure in detail, if it is determined that a detailed description of the related known functions or structures may unnecessarily obscure the main points of the present disclosure, the detailed description will be omitted.

[0046] In addition, throughout the drawings, the same reference numerals are used for components that perform similar functions and actions. Throughout the specification, when a component is said to be connected to another component, this includes not only the case where a component is directly connected to another component, but also the case where a component is indirectly connected to another component through another element in the middle. In addition, unless otherwise specifically stated, the inclusion of a certain component does not mean the exclusion of other components, but means that other components may be further included.

[0047] Figure 1 is an exploded perspective view of a battery cell according to the prior art. Figure 1 As shown, the battery cell includes a shell 10, an electrode assembly 20, an electrode lead 30 and an insulating film 40. A accommodating portion is formed in the shell 10, and the electrode assembly 20 is accommodated in the accommodating portion of the shell 10. One side of the electrode lead 30 is connected to an electrode sheet formed on the electrode assembly 20 and the other side extends outward from the shell 10. The insulating film 40 is located at the portion where the electrode sheet and the electrode lead 30 are in contact.

[0048] In the manufacturing process of a battery cell, for example, when coating an electrode active material, a sliding portion where the thickness of the active material at the end of the electrode is relatively thin compared to the thickness of the active material at the center portion thereof inevitably occurs due to the fluidity of the slurry.

[0049] Secondary batteries need to be frequently charged and discharged, and the slip portion causes a difference in pressure applied to the electrode assembly, which also causes the generation of lithium byproducts.

[0050] In view of the defects caused by the slip portion of a secondary battery, the present disclosure provides a secondary battery in which a cover member is arranged near the end of an electrode assembly, so that the pressure applied to all surfaces of the electrode assembly can be equally controlled and the lithium by-products generated during the charging and discharging process of the secondary battery can be minimized.

[0051] Hereinafter, a unit battery cell equipped with a cover member and a secondary battery including the unit battery cell according to the present disclosure will be described with reference to the accompanying drawings.

[0052] Figure 2 is an exploded perspective view of a unit battery cell according to a first embodiment of the present disclosure. Figure 3 yes Figure 2 A cross-sectional view of a unit battery cell shown in FIG.

[0053] Reference Figure 2 and Figure 3 , the unit battery cell according to the first embodiment of the present disclosure includes an electrode assembly 100 , a cover member 200 , and a case 300 .

[0054] According to an embodiment, the electrode assembly 100 can be formed by a jelly-roll type electrode assembly, a stack-type electrode assembly, a stack-and-folding type electrode assembly, or a lamination-and-stack type electrode assembly, wherein the wound electrode assembly is wound after inserting a separator between a positive electrode and a negative electrode having a long sheet shape; the stack-type electrode assembly includes a plurality of unit battery cells, and the unit battery cells have a structure in which a positive electrode and a negative electrode having a rectangular shape are stacked with a separator inserted between the positive electrode and the negative electrode; the unit battery cells in the stack-folding type electrode assembly are wound by a long separation film; and the unit battery cells in the lamination-and-stack type electrode assembly are stacked with a separator inserted between the unit battery cells and attached to each other.

[0055] For example, the negative electrode is prepared by applying slurry in which a negative electrode active material and a binder are mixed to a negative electrode collector.

[0056] As the negative electrode active material, for example, carbon such as hard carbon or graphite carbon; metal composite oxides such as Li x Fe 2 O 3 (0≤x≤1), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me' y O z(Me: Mn, Fe, Pb or Ge; Me': Al, B, P, Si, elements of Groups 1, 2 and 3 of the Periodic Table or halogens; 0 < x ≤ 1, 1 ≤ y ≤ 3 and 1 ≤ z ≤ 8); lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SnO, SnO 2 、PbO, PbO 2 、Pb 2 O 3 、Pb 3 O 4 、Sb 2 O 3 、Sb 2 O 4 、Sb 2 O 5 、GeO, GeO 2 、Bi 2 O 3 、Bi 2 O 4 和Bi 2 O 5 ;导电聚合物,诸如聚乙炔;Li-Co-Ni基材料;单独的Si、SiO或SiO 2 或其混合物的Si基材料。

[0057] The positive electrode is manufactured by coating a paste mixed with a positive electrode active material and a binder onto a positive electrode current collector.

[0058] In addition, the positive electrode active material may include layered compounds such as: lithium cobalt oxide (LiCoO 2 ), or lithium nickel oxide (LiNiO 2 ), or a compound substituted with one or more transition metals; lithium manganese oxide represented by the chemical formula Li 1+x Mn 2-x O 4 (where x is from 0 to 0.33): LiMnO 3 、LiMn 2 O 3 或LiMnO 2 ;锂铜氧化物(Li 2 CuO 2 ); vanadium oxides such as LiV 3 O 8 、V 2 O 5 和Cu 2 V 2 O 7 ;由化学式LiNi 1-x M x O 2(wherein M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x is 0.01 to 0.3) represented by Ni-site lithium nickel oxide; 2-x M x O 2 (wherein M is Co, Ni, Fe, Cr, Zn or Ta, and x is 0.01 to 0.1) represented by a lithium manganese composite oxide, or Li 2 Mn 3 MO 8 (wherein M is Fe, Co, Ni, Cu or Zn); LiMn wherein part of Li is replaced by alkaline earth metal ions 2 O 4 ; disulfide compounds; and Fe 2 (MoO 4 ) 3 .

[0059] Meanwhile, the negative electrode collector and the positive electrode collector are composed of a portion coated with a slurry mixed with an active material and an uncoated portion not coated with the slurry. The uncoated portion is cut, for example, a separate conductive member is connected to the uncoated portion by ultrasonic welding to form an electrode sheet, and the electrode sheets are gathered together to form a tab bundle 110.

[0060] A pair of electrode leads 120 including a positive electrode lead and a negative electrode lead are electrically connected to a tab bundle 110 including a positive electrode sheet and a negative electrode sheet of the electrode assembly 100 , respectively, and are exposed to the outside of the case 300 .

[0061] At the end of the electrode assembly in the direction where the tab bundle 110 is located, a load is reduced due to the fluidity of the active material in a slurry state, resulting in a slip phenomenon, which forms an arc portion 130 having a specific curvature.

[0062] The cover member 200 according to an embodiment of the present disclosure is configured to cover the arc portion 130 of the electrode assembly 100, for example, the arc portion 130 located at the end in the direction where the tab bundle 110 of the electrode assembly is located, so that the pressure transmitted to all surfaces of the electrode assembly 100 is uniform regardless of its position. Meanwhile, the above-mentioned electrode assembly 100 may be a basic structure of a lithium secondary battery, which includes at least one positive electrode, one negative electrode, and one separator.

[0063] The cover member 200 includes a first surface 210 , a second surface 220 , a third surface 230 , and a contact member 240 .

[0064] For example, the first surface 210 of the cover member 200 is formed by a pair of first surfaces 210, and is respectively set to be parallel to the upper surface and the lower surface of the end portion with the full length direction (Y axis) of the electrode assembly 100 as the reference. The second surface 220 of the cover member 200 is formed by a pair of second surfaces 220, and is respectively set to be parallel to the two side surfaces of the end portion with the full width direction (X axis) of the electrode assembly 100 as the reference. The third surface 230 is set to be parallel to the thickness direction (Z axis) of the electrode assembly 100, and is connected to the pair of first surfaces 210 and the pair of second surfaces 220.

[0065] In summary, the cover member 200 has a hexahedral shape, the interior of which is hollow and one side is opened by the first surface 210 , the second surface 220 , and the third surface 230 .

[0066] The third surface 230 is provided with a through hole 231 which is cut into a certain width so that the tab bundle 110 of the electrode assembly 100 passes through the through hole 231 and protrudes outward.

[0067] According to the embodiment, the close contact member 240 of the cover member 200 is disposed in the inner space formed by the first surface 210, the second surface 220 and the third surface 230 of the cover member 200, and is configured to be in close contact with all side surfaces of the arc portion 130 of the electrode assembly 100. Therefore, one surface of the close contact member 240 of the cover member 200 is formed in the same shape as the arc portion 130 to accommodate the arc portion 130 of the electrode assembly 100, and the remaining surfaces of the close contact member 240 are formed to be in contact with the first surface 210, the second surface 220 and the third surface 230 of the cover member 200.

[0068] Since the cover member 200 configured by the first surface 210 , the second surface 220 , the third surface 230 and the contact member 240 covers the vicinity of the end of the electrode assembly 100 , the cover member 200 may be made of one or more of an insulating rubber material and a chemical-resistant plastic material.

[0069] For example, the insulating rubber material may be styrene-butadiene rubber or nitrile rubber, but is not limited thereto if the insulating rubber material can perform the same function.

[0070] In addition, for example, the chemical-resistant plastic material may include one or more of polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET), and polyolefin, but is not limited thereto if the chemical-resistant plastic material is a material capable of performing the same function.

[0071] Meanwhile, since the cover member 200 is installed at the end of the electrode assembly 100 and then accommodated in the case 300, there is no need to use a separate adhesive member to fix the cover member 200. However, when an adhesive is applied to the inner surface of the adhesive member 240, the adhesive member 240 can be more firmly fixed to the arc portion 130.

[0072] The cap member 200 having the above-described configuration is disposed on the arc portion 130 of the electrode assembly 100 , and thus may reduce deviation in pressure occurring at each position of the electrode assembly 100 , thereby minimizing lithium byproducts that may be generated during charging and discharging of the secondary battery.

[0073] The case 300 may be composed of an upper case and a lower case, and provided with a pocket-shaped receiving portion to receive the electrode assembly 100 in a state where the cover member 200 is mounted.

[0074] The housing 300 forms a receiving portion using a laminate sheet formed of an outer resin layer, a metal layer, and an inner resin layer.

[0075] The outer resin layer is located outside the shell 300, and the outer resin layer can be formed using a heat-resistant polymer with excellent tensile strength, moisture resistance, and air permeation resistance to protect the electrode assembly 100 and ensure heat resistance and chemical resistance, for example, using nylon or polyethylene terephthalate.

[0076] The metal layer in contact with the outer resin layer corresponds to a barrier layer that prevents moisture or various gases from penetrating into the battery from the outside, and the material for the metal layer may be a lightweight aluminum film having excellent formability.

[0077] Furthermore, since the inner resin layer is in direct contact with the electrode assembly 100 , it should have anti-electrolysis performance and insulation performance and have excellent sealing performance for sealing from the outside (eg, a sealing area where the inner layers are thermally bonded to each other).

[0078] The material of the inner resin layer can be selected from polyolefin resins such as polypropylene, polyethylene, polyethylene acrylic acid or polybutylene, polyurethane resins and polyimide resins with excellent chemical resistance and good sealing properties, so polypropylene with excellent chemical resistance and excellent mechanical properties (such as tensile strength, rigidity, surface hardness and impact resistance) can be used.

[0079] exist Figure 2 In the battery cell of the present invention, although the receiving portion is provided in both the upper shell and the lower shell and four sealing surfaces for sealing the upper shell and the lower shell are provided, the receiving portion may be provided only in the upper shell or the lower shell. In addition, three sealing surfaces may be constructed by connecting one surface of the upper shell and one surface of the lower shell to each other.

[0080] In addition, a pair of electrode tabs is shown located in two directions, but this is only an example. The unit battery cell may be a unidirectional unit battery cell in which a pair of electrode tabs are located in the same direction, and in this case, two through holes may be formed in the surface of the cover member 200 .

[0081] Figure 4 is a perspective view showing a first modified example of the cover member mounted on the unit battery cell according to the first embodiment of the present disclosure, Figure 5 yes Figure 4 A cross-sectional view of the cover member shown in FIG.

[0082] Reference Figure 4 and Figure 5 , since the first modified example of the cover member is Figure 2 and Figure 3 The cover member of the first embodiment described in is similar except that the shape of a part thereof is different, so only the configuration different from the first embodiment will be described.

[0083] The cover member 200 according to the first modified example is formed so that the third surface 230 and the close contact member 240 are spaced apart by a certain distance to form a first space S1 between the third surface 230 and the close contact member 240. The first space S1 can be used as a space for capturing gas generated during the charge and discharge process of the secondary battery, which has the advantages of reducing the deviation of the pressure applied to the electrode assembly and delaying or preventing the case breakage due to gas expansion.

[0084] Figure 6 is a perspective view showing a second modified example of the cover member 200 mounted on the unit battery cell according to the first embodiment of the present disclosure, Figure 7 yes Figure 6 A cross-sectional view of the cover member shown in FIG.

[0085] Reference Figure 6 and Figure 7 , since the second modified example of the cover member 200 is Figure 2 and Figure 3 The cover member of the first embodiment described in is similar except that the shape of a part thereof is different, so only the configuration different from the first embodiment will be described.

[0086] The first space S1 is provided in the close contact member 240 of the cover member 200 according to the second modified example. For example, the first space S1 having a slit shape along the length direction of the close contact member 240 is provided, so that the deviation of the pressure applied to the electrode assembly can be reduced while providing a function of capturing the gas generated during the charging and discharging process of the secondary battery.

[0087] Figure 8 is a first example of a cross-sectional view of a secondary battery showing a state in which unit battery cells are stacked according to the first embodiment of the present disclosure.

[0088] Reference Figure 8 , refer to Figure 2 and Figure 3 The described plurality of unit battery cells may be stacked to form a battery module or a battery pack.

[0089] Since the cover member 200 is accommodated together in the housing 300 , the overall thickness of each unit battery cell is uniform and the outer boundaries of the unit battery cells are clear, facilitating a stacking process of a battery module or a battery pack.

[0090] Fig. 9 2 is a second example of a cross-sectional view of a secondary battery showing a state in which unit battery cells are stacked according to a second modified example of the first embodiment of the present disclosure. Figure 6 and Figure 7 The plurality of unit battery cells described above can be stacked to form a battery module or battery pack. Fig. 9 In the stacked structure of the unit battery cells of the second modified example shown in FIG. Figure 6 and Figure 7 The cover member 200 described in the embodiment of the present invention is, for example, provided with a cover member 200 in the form of a first space S1 having a slit shape along the length direction of the close contact member 240. Figure 8 Similar to the case in, the deviation of the pressure applied to the electrode assembly can be reduced while providing a function of capturing gas generated during the charge and discharge process of the secondary battery.

[0091] Fig.10 is a third example of a cross-sectional view of the secondary battery showing a state in which the unit battery cells are stacked according to the first embodiment of the present disclosure.

[0092] The secondary battery of the third example is a battery module or a battery pack including a plurality of unit battery cells stacked therein, wherein Figure 2 and Figure 3 The cover member 200 of the first embodiment described in is mounted on the electrode assembly 100, and the case 300 surrounds the plurality of unit battery cells.

[0093] Where the cover members 200 are in close contact with each other between the first surfaces of the cover members 200 , a fixing member A such as an adhesive may be interposed to fix the unit battery cells disposed adjacent to each other.

[0094] In the case of the secondary battery according to the third example described above, due to the thickness of the cover member 200 , the second space S2 is formed between the unit battery cells, and thus may be used as a buffer space when expansion occurs and as a gas capture space.

[0095] Furthermore, a plurality of unit battery cells including each of the electrode assembly 100 and the cover member 200 are accommodated in one case 300 , and thus it is possible to reduce manufacturing costs and improve energy density due to a reduction in overall weight.

[0096] Although not shown in the drawings, a battery module or a battery pack may also be formed by stacking a plurality of unit battery cells in which the cover member 200 according to the first modified example or the second modified example is mounted on the electrode assembly.

[0097] Fig.11 is an exploded perspective view of a unit battery cell according to a second embodiment of the present disclosure. Fig.12 is a cross-sectional view of a secondary battery showing a state in which unit battery cells are stacked according to a second embodiment of the present disclosure.

[0098] Since the unit battery cell according to the second embodiment of the present disclosure is Figure 2 and Figure 3 The unit battery cells according to the first embodiment described in are similar except for the position of the cover member 200, so the description of the same configuration will be omitted.

[0099] In the unit battery cell of the second embodiment, the cover member 200 is located near the outer end of the case 300. Here, according to one embodiment, the case 300 may be a pouch for a lithium secondary battery.

[0100] The cover member 200 includes a first surface 210, a second surface 220, a third surface 230, and a close contact member 240. For example, the first surface 210 of the cover member 200 is formed by a pair of first surfaces 210, and is respectively set to be parallel to the upper surface and the lower surface of the end of the shell 300 with the full length direction (Y axis) of the shell 300 as a reference. The second surface 220 of the cover member 200 is formed by a pair of second surfaces 220, and is respectively set to be parallel to the two side surfaces of the end with the full width direction (X axis) of the shell 300 as a reference, and the third surface 230 of the cover member 200 is set to be parallel to the thickness direction (Z axis) of the shell 300 and connected to the pair of first surfaces 210 and the pair of second surfaces 220.

[0101] In summary, the cover member 200 has a hexahedral shape, the interior of which is hollow and one side of which is opened by the first surface 210 , the second surface 220 , and the third surface 230 .

[0102] The third surface 230 of the cover member 200 is provided with a through hole 231 which is cut into a certain width so that the tab bundle 110 or the electrode lead 120 of the electrode assembly 100 passes through the through hole 231 and protrudes outward.

[0103] The close contact member 240 of the cover member 200 is disposed in the internal space formed by the first surface 210, the second surface 220, and the third surface 230, and is in close contact with all surfaces of the end of the housing 300. Therefore, one surface of the close contact member 240 is formed in the same shape as the end of the housing 300, and the remaining surfaces of the close contact member 240 are formed to contact the first surface 210, the second surface 220, and the third surface 230.

[0104] When a battery module or a battery pack is formed by stacking a plurality of unit battery cells having the cover member 200 mounted near the outer end of the case 300 , a third space S3 is formed between the unit battery cells due to the thickness of the cover member 200 .

[0105] The third space S3 may serve as a buffer space when expansion occurs, and as an insulating layer to minimize heat transfer between the unit battery cells.

[0106] Where the cover members 200 are in close contact with each other between the first surfaces of the cover members 200 , a fixing member A such as an adhesive may be interposed to fix the unit battery cells disposed adjacent to each other.

[0107] Fig.13 2 is a perspective view of a unit battery cell according to a third embodiment of the present disclosure. The unit battery cell according to the third embodiment of the present disclosure has the same structure as that of the first embodiment except for the structure of the cover member 200. Fig.11 The structure is similar to the structure of the unit battery cell of the second embodiment described in.

[0108] In the unit battery cell according to the third embodiment, a pair of cover members 200 are provided to closely contact both outer ends of the case 300 , respectively, and one or more connecting members 400 may be provided to connect portions of the pair of cover members 200 to each other.

[0109] The connecting member 400 is configured to connect the pair of cover members 200 to each other, thereby preventing the cover members 200 from being separated from each other. The connecting member 400 may be made of the same material as the cover member 200, and is not particularly limited to a tape, a clip, a hook, or an adhesive, as long as it can connect the pair of cover members 200 to each other.

[0110] Although the above has been described with reference to the embodiments of the present disclosure, it will be understood by those of ordinary skill in the art or those of ordinary skill in the art with ordinary knowledge in the art that various modifications and changes may be made to the present disclosure without departing from the scope of the ideas and techniques of the present invention as set forth in the patent claims to be described below. Therefore, the technical scope of the present disclosure is not limited to the contents described in the specific embodiments of the specification, but should be defined by the patent claims.

[0111] (Explanation of Reference Numerals)

[0112] 100: Electrode assembly

[0113] 110: Lug bundle

[0114] 120: Electrode lead

[0115] 130: Arc

[0116] 200: Cover member

[0117] 210: First surface

[0118] 220: Second surface

[0119] 230: third surface 231: through hole

[0120] 240: Closely connected components

[0121] 300: Shell

[0122] 400: Connecting components

[0123] A: Fixed components

[0124] S: Space

[0125] S1: First Space

[0126] S2: Second Space

[0127] S3: The Third Space

Claims

1. A secondary battery comprising: A unit battery cell comprises an electrode assembly and a cover member, wherein the electrode assembly is provided with a tab bundle and an arc portion is formed at an end portion of the electrode assembly in a direction where the tab bundle is located, and the cover member is located near the arc portion of the electrode assembly, wherein the cover member comprises a pair of first surfaces, a pair of second surfaces, a third surface and a close contact member, the pair of first surfaces are parallel to the upper surface and the lower surface of the electrode assembly, the pair of second surfaces are parallel to the two side surfaces of the electrode assembly, the third surface connects the pair of first surfaces and the pair of second surfaces, the close contact member is arranged in an internal space formed by the pair of first surfaces, the pair of second surfaces and the third surface and contacts the arc-shaped portion of the electrode assembly, and The third surface is provided with a through hole, and the wiring sheet bundle passes through the through hole.

2. The secondary battery according to claim 1, wherein The close contact member is provided with a first space for gas capture.

3. The secondary battery according to claim 2, wherein: The first space has a slit shape formed in the longitudinal direction of the close contact member.

4. The secondary battery according to claim 1, wherein A first space for gas capture is provided between the third surface and the close contact member.

5. The secondary battery according to claim 1, wherein The cover member is made of at least one of an insulating rubber material and a chemical-resistant plastic material.

6. The secondary battery according to claim 5, wherein The cover member is made of styrene-butadiene rubber or nitrile-butadiene rubber.

7. The secondary battery according to claim 1, wherein The unit battery cell further includes a case for accommodating the electrode assembly in a state where the cover member is provided.

8. The secondary battery according to claim 1, wherein The unit battery cells are stacked in plurality, and a second space is provided between the electrode assemblies.

9. The secondary battery according to claim 8, wherein A fixing member is interposed between the first surfaces of the cover members so that the unit battery cells can be fixed to each other.

10. The secondary battery according to claim 9, wherein The fixing member is an adhesive.

11. The secondary battery according to claim 10, wherein The secondary battery is a battery module or a battery pack.

12. The secondary battery according to claim 7, wherein A plurality of the unit battery cells are stacked.

13. A secondary battery comprising: A unit battery cell comprises an electrode assembly, a shell and a cover member, wherein the electrode assembly is provided with a tab bundle and an arc portion is formed at an end of the electrode assembly in a direction where the tab bundle is located, the shell is used to accommodate the electrode assembly, and the cover member is provided near an outer end of the shell, wherein the cover member comprises a pair of first surfaces, a pair of second surfaces and a third surface, the pair of first surfaces are parallel to the upper surface and the lower surface of the shell, the pair of second surfaces are parallel to the two side surfaces of the shell, the third surface connects the pair of first surfaces and the pair of second surfaces, and The third surface has a through hole, and the tab bundle or electrode lead extending from the electrode assembly passes through the through hole.

14. The secondary battery according to claim 13, wherein The cover member includes a close contact member that is provided in an internal space formed by the pair of first surfaces, the pair of second surfaces, and the one third surface and that is in close contact with an end surface of the housing.

15. The secondary battery according to claim 14, wherein The shell is a soft package for a secondary lithium battery.

16. The secondary battery according to claim 13, wherein The electrode assembly is the basic structure of a lithium secondary battery, and the electrode assembly includes at least a positive electrode, a negative electrode and a separator.

17. The secondary battery according to claim 13, wherein The unit battery cells are stacked in plurality, and a third space is provided between the electrode assemblies.

18. The secondary battery according to claim 17, wherein A fixing member is interposed between the first surfaces so that the unit battery cells can be fixed to each other.

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