Battery cell and battery pack including same

Abstract

A battery cell according to an embodiment of the present invention comprises: an electrode stack in which stacked are a plurality of bipolar electrodes, each having a form in which a negative electrode active material layer and a positive electrode active material layer are respectively coated on both surfaces of a metal current collector; a battery case in which the electrode stack is accommodated; and an exterior member which surrounds a protrusion extending from the outer circumferential surface of the battery case toward the outside of the battery case, wherein the exterior member presses the protrusion in the thickness direction of the protrusion.

Description

Battery cell and battery pack including the same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0192310 filed December 20, 2024 and Korean Patent Application No. 10-2025-0145194 filed October 2, 2025, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of this specification.

[0003] The present invention relates to a battery cell and a battery pack including the same, and more specifically, to a battery cell and a battery pack including the same comprising a battery case in which an electrode stack including a bipolar electrode is accommodated; and a packaging structure comprising an outer member mounted along the outer surface of the same.

[0004] Recently, as the application areas of lithium-ion batteries have rapidly expanded to include not only power supply for electronic devices such as electrical, electronic, telecommunications, and computers, but also power storage for large-area devices such as automobiles and power storage systems, there is a growing demand for high-capacity, high-output, and high-stability secondary batteries.

[0005] The electrodes used in such secondary batteries can be classified into monopolar electrodes, in which an active material with the same polarity is coated on both sides of a current collector, and bipolar electrodes, in which an active material with different polarities is coated on both sides of a current collector.

[0006] Secondary batteries utilizing monopolar electrodes have connection points that link the electrodes, and thus their output may be degraded due to the electrical resistance of these connections. Furthermore, secondary batteries with monopolar electrodes can cause various issues regarding cell safety due to temperature rise caused by Joule heating. Additionally, there is a problem of poor space efficiency because battery components for heat dissipation structures, thermal monitoring, and wiring occupy a significant amount of space within the battery pack.

[0007] In contrast, secondary batteries using bipolar electrodes stack electrodes without having connection points, thereby minimizing electrode contact resistance. Consequently, secondary batteries using bipolar electrodes offer excellent output performance and good space efficiency due to simplified structure and components; thus, energy density and output density per unit volume can be significantly improved compared to conventional lithium-ion batteries.

[0008] Accordingly, secondary batteries applying bipolar electrodes of various structures are currently being developed.

[0009] The problem to be solved by the present invention relates to a battery cell comprising a battery case in which an electrode stack including a bipolar electrode is accommodated; and a packaging structure comprising an outer member mounted along the outer surface of the same, and a battery pack including the same.

[0010] The problems that the present invention aims to solve are not limited to those described above, and problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from this specification and the attached drawings.

[0011] A battery cell according to one embodiment of the present invention comprises: an electrode stack having a plurality of bipolar electrodes, each having a negative active material layer and a positive active material layer coated on both sides of a metal current collector; a battery case accommodating the electrode stack; and an outer casing member covering a protrusion extending from the outer surface of the battery case toward the outside of the battery case, wherein the outer casing member presses the protrusion in the thickness direction of the protrusion.

[0012] The battery case may include a lower metal located on the lower surface of the electrode stack and covering the lower part of the electrode stack, and an upper metal located on the upper surface of the electrode stack and covering the upper part of the electrode stack.

[0013] The lower metal includes a lower housing portion in which the electrode stack is accommodated and a lower protrusion protruding outward from the outer surface of the lower housing portion, and the upper metal includes an upper housing portion in which the electrode stack is accommodated and an upper protrusion protruding outward from the outer surface of the upper housing portion, and the protrusion may be a portion in which the lower protrusion and the upper protrusion face each other.

[0014] The portions where the upper protrusion and the lower protrusion face each other may be sealed.

[0015] It may further include a buffer member extending along the space between the lower protrusion and the upper protrusion.

[0016] The above-described exterior member has a first receiving groove formed along the longitudinal direction of the protrusion, and the protrusion can be fitted into the first receiving groove of the exterior member.

[0017] It includes at least one fixing member that fixes the exterior member and the protrusion to each other, and the fixing member may extend from the exterior member to the protrusion.

[0018] The above at least one fixing member includes a pair of fixing members extending from the upper and lower surfaces of the exterior member to the protrusion, and the at least one fixing member includes a plurality of pairs of fixing members, and the plurality of pairs of fixing members may be spaced apart from each other along the upper and lower surfaces of the exterior member.

[0019] In the above pair of fixed members, one fixed member may have a relatively smaller fastening torque compared to the other fixed member.

[0020] The above exterior member may have at least one through hole formed therein into which the fixing member can be inserted.

[0021] The above-described exterior member includes a pair of first exterior members that each cover both sides of the electrode laminate with respect to the stacking direction of the electrode laminate, and a pair of second exterior members that each cover the front and rear surfaces of the electrode laminate with respect to the stacking direction of the electrode laminate, and the pair of first exterior members and the pair of second exterior members may be combined with each other.

[0022] The above pair of first exterior members and the above pair of second exterior members each include a fitting portion formed at one end and a second receiving groove formed at the other end based on the longitudinal direction, and the fitting portion of the first exterior member is fitted into the second receiving groove of the second exterior member, and the fitting portion of the second exterior member can be fitted into the second receiving groove of the first exterior member.

[0023] The above electrode laminate may further include an electrolyte that impregnates the electrode laminate inside the battery case, wherein the bipolar electrode and the separator are sequentially laminated multiple times.

[0024] The above electrode stack may have the bipolar electrode and solid electrolyte sequentially stacked multiple times.

[0025] The electrode stack further includes a pair of single-sided cathodes and single-sided anodes, each disposed at the outermost edge based on the stacking direction, wherein the single-sided cathode has a single-sided cathode active material layer formed on one surface of a cathode current collector, and the single-sided anode has a single-sided anode active material layer formed on one surface of an anode current collector.

[0026] The separator may be disposed between the above-mentioned single-sided cathode, the above-mentioned single-sided anode, and the above-mentioned bipolar electrode, respectively.

[0027] The negative current collector included in the above-mentioned single-sided negative electrode and the positive current collector included in the above-mentioned single-sided positive electrode can each come into contact with the battery case.

[0028] A battery pack according to another embodiment of the present invention may include the battery cell described above.

[0029] FIG. 1 is a cross-sectional view of a battery cell according to one embodiment of the present invention.

[0030] Figure 2 is a cross-sectional view of an electrode assembly included in the battery cell of Figure 1.

[0031] Figure 3 is a cross-sectional view showing that the upper and lower parts of a battery case are combined with the electrode assembly of Figure 2.

[0032] FIG. 4 is a cross-sectional view showing that an outer casing member is attached to both ends of the upper and lower portions of a battery case coupled to the electrode assembly of FIG. 3.

[0033] FIG. 5 is a cross-sectional view showing that a fixing member is joined in a state where the electrode assembly, battery case, and outer casing member of FIG. 4 are joined.

[0034] Figure 6 is a top view of the battery cell of Figure 1.

[0035] FIG. 7 shows an outer casing member included in the battery cell of FIG. 1, and is a drawing showing the state in which the first outer casing member and the second outer casing member are combined with each other.

[0036] FIGS. 8 to 10 are perspective views showing the first exterior member of FIG. 7.

[0037] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0038] To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0039] Furthermore, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and thus the present invention is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, for convenience of explanation, the thickness of some layers and regions has been exaggerated in the drawings.

[0040] Furthermore, throughout the specification, when a part is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0041] Additionally, throughout the specification, "planar" means when the subject part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the subject part is viewed from the side.

[0042] Hereinafter, a battery cell according to an embodiment of the present invention will be described.

[0043] FIG. 1 is a cross-sectional view of a battery cell according to one embodiment of the present invention. FIG. 2 is a cross-sectional view of an electrode assembly included in the battery cell of FIG. 1.

[0044] Referring to FIG. 1 and FIG. 2, a battery cell (100) according to one embodiment of the present invention comprises: an electrode stack (110) in which a plurality of bipolar electrodes (111) are stacked, wherein a negative active material layer (111b) and a positive active material layer (111c) are respectively coated on both sides of a metal current collector (111a); and a battery case (120) that accommodates the electrode stack (110).

[0045] More specifically, in the electrode stack (110), the bipolar electrode (111) is formed such that a negative active material layer (111b) and a positive active material layer (111c) are respectively coated on both sides of a metal current collector (111a), which can be referred to as a unit cell. Here, the bipolar electrode (111) may refer to a structure in which the negative active material layer (111b) and the positive active material layer (111c) are connected in series with the metal current collector (111a) in between. As an example, as shown in FIGS. 1 and 2, the bipolar electrode (111) may have a negative active material layer (111b) coated on the lower surface of the metal current collector (111a) and a positive active material layer (111c) coated on the upper surface of the metal current collector (111a). However, the arrangement of the negative active material layer (111b) and the positive active material layer (111c) is not limited thereto, and the opposite case may also be included in this embodiment.

[0046] The metal current collector (111a) is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. For example, the metal current collector (111a) may be copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., or an aluminum-cadmium alloy. More specifically, it may be an Al current collector or a Cu current collector. Here, the Al current collector or the Cu current collector may be made of Al or Cu, and the concept includes the inclusion of other metal materials in addition to the impurity content.

[0047] Regardless of the type, the metal current collector (111a) may have a thickness of 3 μm or more to 500 μm or less, and may also have fine irregularities formed on the surface of the current collector to increase adhesion to the positive active material layer and the negative active material layer. As an example, the metal current collector (111a) may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0048] The negative electrode active material layer (111b) may include a negative electrode active material commonly used in lithium secondary batteries, a binder, a conductive material, and other additives as described above.

[0049] The positive active material layer (111c) may include a positive active material commonly used in lithium secondary batteries, a binder, a conductive material, and other additives as described above.

[0050] Accordingly, in the battery cell (100) according to the present embodiment, the bipolar electrode (111) is connected in series as itself, and compared to the structure in which electrode current collectors (111a) are welded together to form an electrode tab, there is an advantage that the electrical connection structure is structurally simplified.

[0051] Additionally, as shown in FIGS. 1 and 2, the electrode stack (110) may further include a pair of single-sided cathodes (117) and single-sided anodes (119) respectively disposed at the outermost edge with respect to the stacking direction. Here, the single-sided cathode (117) may have a single-sided cathode active material layer (117b) formed on one side of a cathode current collector (117a), and the single-sided anode (119) may have a single-sided anode active material layer (119b) formed on one side of an anode current collector (119a). Additionally, in the electrode stack (110), a separator (115) may be disposed between the single-sided cathode (117) and the single-sided anode (119) and the bipolar electrode (111).

[0052] For example, as shown in FIGS. 1 and 2, a single-sided cathode (117) may be disposed on the outermost upper side of the electrode stack (110), and a single-sided anode (119) may be disposed on the outermost lower side of the electrode stack (110). However, the arrangement of the single-sided cathode (117) and the single-sided anode (119) is not limited thereto and may be changed according to the arrangement of the cathode active material layer (111b) and the anode active material layer (111c) included in the bipolar electrode (111).

[0053] As shown in FIG. 1, the electrode stack (110) can have a negative current collector (117a) included in the single-sided negative electrode (117) and a positive current collector (119a) included in the single-sided positive electrode (119) each in contact with the battery case (120). More specifically, the single-sided negative electrode (117) is positioned on the outermost upper side of the electrode stack (110), and the negative current collector (117a) included in the single-sided negative electrode (117) can be in contact with the upper side of the battery case (120). Additionally, the single-sided positive electrode (119) is positioned on the outermost lower side of the electrode stack (110), and the positive current collector (119a) included in the single-sided positive electrode (119) can be in contact with the lower side of the battery case (120).

[0054] The negative current collector (117a) and the positive current collector (119a) are not particularly limited as long as they each have high conductivity without causing chemical changes in the battery. For example, the negative current collector (117a) and the positive current collector (119a) may be made of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel with a surface treated with carbon, nickel, titanium, silver, etc., or an aluminum-cadmium alloy. More specifically, the negative current collector (117a) may be a Cu current collector, and the positive current collector (119a) may be an Al current collector. Here, the Al current collector or the Cu current collector may be made of Al or Cu, and the concept includes the inclusion of other metal materials in addition to the impurity content.

[0055] The cross-sectional negative electrode active material layer (117b) may include a negative electrode active material commonly used in lithium secondary batteries, a binder, a conductive material, and other additives as described above.

[0056] The cross-sectional positive active material layer (119b) may include a positive active material typically used in lithium secondary batteries, a binder, a conductive material, and other additives as described above.

[0057] Accordingly, in the battery cell (100) according to the present embodiment, a single-sided negative electrode (117) and a single-sided positive electrode (119) are respectively arranged at the outermost edge of the electrode stack (110), and the negative current collector (117a) and the positive current collector (119a) can perform the role of an electrode tab, thus having the advantage that a separate electrode tab is not required. In addition, since the front surface of the negative current collector (117a) and the positive current collector (119a) becomes a passage for electron movement, there is an advantage that it is more effective in terms of resistance than conventional electrode tabs.

[0058] Referring to FIG. 1, in a battery cell (100) according to the present embodiment, the electrode stack (110) may have a bipolar electrode (111) and a separator (115) sequentially stacked multiple times, and may further include an electrolyte (110e) that impregnates the electrode stack (110) inside a battery case (120). Here, the separator (115) can be used without special limitations as long as it is a separator typically used in a lithium secondary battery, and it is particularly desirable that it has low resistance to ion movement of the electrolyte and excellent electrolyte absorption capability.

[0059] Here, the electrolyte (110e) may be a liquid electrolyte or a gel-type electrolyte commonly used in lithium secondary batteries. The gel-type electrolyte comprises a lithium salt and a non-aqueous organic solvent and at least one polymerizable compound selected from the group consisting of a polymerizable monomer, oligomer, or copolymer having a polymerizable unsaturated functional group, and at least some of the polymerizable unsaturated functional group may be hardened.

[0060] In other words, the gel-type electrolyte may be a gel electrolyte composition that is cured by heat or light, comprising a lithium salt, a non-aqueous organic solvent, and at least one polymerizable compound selected from the group consisting of polymerizable monomers, oligomers, or copolymers having polymerizable unsaturated functional groups. Here, the lithium salt may be used in the same or similar way as that typically used in lithium secondary batteries. The lithium salt may be used as a medium for transferring ions within the lithium battery.

[0061] As another example, unlike the electrode stack (110) described above, the electrode stack (110) according to the present embodiment has the separator replaced by a solid electrolyte (115), and the electrode stack (110) may have a bipolar electrode (111) and a solid electrolyte (115) stacked sequentially multiple times. In this case, the electrolyte (110e) may be omitted.

[0062] The above solid electrolyte may be an organic solid electrolyte or an inorganic solid electrolyte.

[0063] The above organic solid electrolyte may be, for example, a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, a polymer containing an ionic dissociator, etc.

[0064] The above inorganic solid electrolyte may be, for example, a Li nitride, halide, sulfate, sulfide-based solid electrolyte, or an oxide solid electrolyte.

[0065] As the above inorganic solid electrolyte, for example, nitrides, halides, sulfates of Li such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, Li3PO4-Li2S-SiS2, etc., may be used, or sulfide-based solid electrolytes or oxide solid electrolytes may be used.

[0066] The above sulfide-based solid electrolyte is a Li2S-P2S5 system (Li7P3S 11 , Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2 (Li 13 GeP3S 16 , Li 10 GeP2S 12 etc.), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x Examples include, but are not limited to, combinations thereof.

[0067] The above oxide-based solid electrolyte is an LLTO-based compound, Li6La2CaTa2O 12, Li6La2ANb2O 12 (A is Ca or Sr), Li2Nd3TeS b O 12 , Li3BO 2.5 N 0.5 , Li9SiAlO8, LAGP-based compounds, LATP-based compounds, Li 1+x Ti 2-x Al x Si y (PO4) 3-y (where, 0≤x≤1, 0≤y≤1), LiAl x Zr 2-x (PO4)3(where, 0≤x≤1), LiTi x Zr 2-x It may include any one selected from the group consisting of (PO4)3 (wherein, 0≤x≤1), LISICON-based compounds, LIPON-based compounds, perovskite-based compounds, Nasicon-based compounds, LLZO-based compounds, and LLZMO-based compounds, or two or more of these.

[0068] Accordingly, in the battery cell (100) according to the present embodiment, as the electrolyte (110e) includes a gel or solid form electrolyte, the fluidity of the electrolyte (110e) can be minimized, and an ionic short between bipolar electrodes (111) or an electronic short between metal current collectors (111a) caused by the fluidity of the electrolyte (110e) can be effectively prevented.

[0069] Figure 3 is a cross-sectional view showing that the upper and lower parts of a battery case are combined with the electrode assembly of Figure 2.

[0070] Referring to FIG. 1 and FIG. 3, in a battery cell (100) according to the present embodiment, the battery case (120) may include a lower metal (121) located on the lower surface of the electrode stack (110) and covering the lower part of the electrode stack (110), and an upper metal (125) located on the upper surface of the electrode stack (110) and covering the upper part of the electrode stack (110). For example, as shown in FIG. 3, the battery cell (100) according to the present embodiment may have a structure in which the upper metal (125) is assembled on the upper part of the electrode stack (110) while the electrode stack (110) is accommodated in the lower metal (121).

[0071] In the electrode stack (110), the negative current collector (117a) included in the single-sided negative electrode (117) and the positive current collector (119a) included in the single-sided positive electrode (119) can each come into contact with the lower metal (121) and the upper metal (125) included in the battery case (120). For example, as shown in FIG. 1, in the electrode stack (110), the negative current collector (117a) included in the single-sided negative electrode (117) can come into contact with the upper metal (125), and the positive current collector (119a) included in the single-sided positive electrode (119) can come into contact with the lower metal (121).

[0072] Accordingly, in the battery cell (100) according to the present embodiment, the electrode stack (110) and the battery case (120) can be connected in series as they are, and there is an advantage that a separate electrical connection structure is not required.

[0073] For example, the lower metal (121) and the upper metal (125) are not specifically limited as long as they are metal materials that have high conductivity without causing chemical changes in the battery. For example, the lower metal (121) and the upper metal (125) may be made of aluminum, SUS (Steel Use Stainless), etc. Additionally, regardless of their type, the lower metal (121) and the upper metal (125) may have a thickness of 0.1 mm (0.1 T) or more and 0.3 mm (0.3 T) or less in terms of manufacturing process and cost.

[0074] Referring to FIGS. 1 and 3, in a battery case (120), the lower metal (121) may include a lower storage portion (121p) in which an electrode stack (110) can be accommodated and a lower protrusion (121s) protruding outward from the outer surface of the lower storage portion (121p) toward the battery case (120), and the upper metal (125) may include an upper storage portion (125p) in which an electrode stack (110) can be accommodated and an upper protrusion (125s) protruding outward from the outer surface of the upper storage portion (125p) toward the battery case (120).

[0075] Here, the protrusions (121s, 125s) may be a portion where the lower protrusion (121s) of the lower metal (121) and the upper protrusion (125s) of the upper metal (125) face each other. In other words, the protrusions (121s, 125s) may be formed as a part of the battery case (120), with the portion where the lower protrusion (121s) and the upper protrusion (125s) face each other being sealed. At this time, when a predetermined temperature and pressure are applied while the lower protrusion (121s) and the upper protrusion (125s) are in contact with each other, the space between the lower protrusion (121s) and the upper protrusion (125s) can be sealed from the external environment of the battery case (120).

[0076] However, the shape of the battery case (120) included in the battery cell (100) according to the present embodiment is not limited to this, and various shapes of the battery case (120) may be applied. For example, unlike FIGS. 1 and FIGS. 3, the battery case (120) may be in a form in which the upper storage portion (125p) of the upper metal (125) is omitted, and a structure in which the upper metal (125) in the form of a flat plate covers the lower metal (121) may also be included in the present embodiment.

[0077] For example, as shown in FIG. 3, the battery cell (100) according to the present embodiment may accommodate an electrode stack (110) in the lower storage portion (121p) of the lower metal (121) while a cushioning member (130) is placed on the lower protrusion (121s) of the lower metal (121). Subsequently, an upper metal (125) is assembled on the upper portion of the electrode stack (110), so that the upper protrusion (125p) comes into contact with the cushioning member (130).

[0078] The battery cell (110) according to the present embodiment may further include a cushioning member (130) extending along the space between the lower protrusion (121s) of the lower metal (121) and the upper protrusion (125s) of the upper metal (125). Here, it is preferable that the cushioning member (130) be in the form of a pad sized to cover the entire area between the lower protrusion (121s) and the upper protrusion (125s).

[0079] The cushioning member (130) is not particularly limited as long as it is made of a material that has elasticity, which ensures insulation performance between the first outer surface (121s) of the lower metal (121) and the second outer surface (125s) of the upper metal (125), while allowing for some degree of compression during the process of joining the outer surface member (140) described later. For example, the cushioning member (130) may be a silicone pad, a polymer elastomer pad, a porous pad such as a nonwoven fabric, etc.

[0080] Accordingly, in the battery cell (100) according to the present embodiment, since a buffer member (130) is additionally disposed between the lower protrusion (121s) and the upper protrusion (125s), sufficient insulation performance between the lower metal (121) and the upper metal (125) can be secured, and there is an advantage that compression is possible during the process of combining the outer member (140) described later, thereby allowing the upper and lower parts of the electrode stack (110) to be pressed to a predetermined pressure.

[0081] As such, the battery cell (100) according to the present embodiment has the advantage that contact between the components of the electrode stack (110) can be stably maintained during the contraction / expansion of the electrode stack (110) due to charging / discharging of the battery cell (100) as the upper and lower parts of the electrode stack (110) are pressed with a predetermined pressure.

[0082] FIG. 4 is a cross-sectional view showing that an outer casing member is attached to both upper and lower ends of a battery case coupled to the electrode assembly of FIG. 3. FIG. 5 is a cross-sectional view showing that a fixing member is attached in a state where the electrode assembly, battery case, and outer casing member of FIG. 4 are coupled.

[0083] Referring to FIG. 1 and FIG. 4, the battery cell (100) according to the present embodiment includes an outer member (140) that wraps along protrusions (121s, 125s) extending from the outer surface of the battery case (120) toward the outside of the battery case (120). Here, the outer member (140) can press the protrusions (121s, 125s) in the thickness direction (z-axis direction) of the protrusions (121s, 125s).

[0084] More specifically, in the battery cell (100) according to the present embodiment, the inner surface of the outer member (140) may cover the outer surface of the protrusions (121s, 125s). In other words, the protrusions (121s, 125s) may be inserted into the inner surface of the outer member (140). Here, the outer member (140) may be a structure that covers the entire protrusions (121s, 125s) formed on the outer circumference of the battery case (120). In addition, the inner surface of the outer member (140) may be in close contact with the outer surface of the storage portion (121p, 125p) of the battery case (120).

[0085] For example, the exterior member (140) has a first receiving groove (140d) formed along the longitudinal direction of the protrusions (121s, 125s), and the protrusions (121s, 125s) can be fitted into the first receiving groove (140d) of the exterior member (140). Here, the first receiving groove (140d) may refer to a portion that is recessed from the outer surface of the exterior member (140) toward the center of the exterior member (140).

[0086] The first receiving groove (140d) may be formed to be equal to or greater than the length and thickness of the protrusions (121s, 125s). Here, if a cushioning member (130) is additionally inserted between the lower protrusion (121s) and the upper protrusion (125s), the first receiving groove (140d) may be formed to be equal to or greater than the length and thickness of the protrusions (121s, 125s) and the cushioning member (130).

[0087] More specifically, in the battery cell (100) according to the present embodiment, the first receiving groove (140d) and the protrusions (121s, 125s) included in the outer member (140) can be joined in close contact with each other. In other words, it may be preferable that the size of the recessed first receiving groove (140d) included in the outer member (140) and the size of the protrusions (121s, 125s) protruding are the same.

[0088] It may be preferable that the length of the first receiving groove (140d) included in the outer member (140) being recessed in the opposite direction toward the protrusion (121s, 125s) be equal to the length of the protrusion (121s, 125s) being protruded toward the first receiving groove (140d).

[0089] The height of the first receiving groove (140d) included in the outer member (140) may preferably be equal to or greater than the thickness of the protrusions (121s, 125s). Here, the thickness of the protrusions (121s, 125s) may be the sum of the thickness of the lower protrusion (121s) and the thickness of the upper protrusion (125s). If a cushioning member (130) is additionally inserted between the lower protrusion (121s) and the upper protrusion (125s), the thickness of the protrusions (121s, 125s) may be the sum of the thickness of the lower protrusion (121s), the thickness of the upper protrusion (125s), and the thickness of the cushioning member (130).

[0090] Although not illustrated in FIGS. 1 and 4, an adhesive layer may be additionally formed between the first receiving groove (140d) and the protrusions (121s, 125s) included in the outer member (140). For example, the adhesive layer may be made of a polymer adhesive such as polyvinylidene fluoride (PVDF), epoxy-based, polyol-based, or acrylate-based adhesives, or a hot melt adhesive such as polypropylene (PP), polyethylene (PE), or polyolefin-based adhesives.

[0091] As such, the battery cell (100) according to the present embodiment has the advantage that, as an adhesive layer is additionally formed between the first receiving groove (140d) and the protrusions (121s, 125s) included in the outer member (140), the space between the first receiving groove (140d) and the protrusions (121s, 125s) can be more sealed, and the electrode laminate (110) can be more stably fixed to the outer member (140).

[0092] The outer member (140) may be made of any type of polymer, and it is more preferable that it be a polymer with good thermal stability and mechanical strength. For example, the outer member (140) may be made of a polymer material such as high-density polyethylene (HDPE), polypropylene (PP), or polyethylene terephthalate (PET). As another example, a coating layer such as a moisture-proof material may be additionally formed on the outer surface of the outer member (140).

[0093] Accordingly, in the battery cell (100) according to the present embodiment, the outer member (140) can fix the lower protrusion (121s) and the upper protrusion (125s) so that the lower metal (121) and the upper metal (125) can be stably fixed to each other. That is, by pressing the electrode stack in the vertical direction, there is an advantage in that contact between the components of the electrode stack is stably maintained even during charging and discharging.

[0094] In addition, the outer member (140) can seal the space between the lower protrusion (121s) and the upper protrusion (125s) while preventing the lower protrusion (121s) and the upper protrusion (125s) from being exposed to the outside, making it easy to handle the battery cell during the process and effectively preventing foreign substances such as moisture from penetrating into the battery cell (100) from the outside of the battery cell (100).

[0095] Referring to FIGS. 1 and 5, the battery cell (100) according to the present embodiment further includes at least one fixing member (150) that fixes the outer member (140) and the protrusions (121s, 125s) to each other. More specifically, the fixing member (150) may extend from the outer member (140) to the protrusions (121s, 125s). In other words, the fixing member (140) may extend from the outer member (140) to the first receiving groove (140d). That is, the fixing member (150) is inserted into the outer member (140), and the fixing member (150) may have a length sufficient to press and / or fix the protrusions (121s, 125s) inserted into the first receiving groove (140d).

[0096] The fixing member (150) may be made of an insulating material to prevent short circuits. For example, the fixing member (150) may be a bolt made of plastic material, or a bolt made of metal material including a hose-shaped tube that is insulated on the outside.

[0097] For example, as shown in FIGS. 1 and FIGS. 5, at least one fixing member (150) may include a pair of fixing members (150) extending from the upper and lower surfaces of the outer member (140) to the protrusions (121s, 125s). In other words, at least one fixing member (150) may include a pair of fixing members (150) extending from the upper and lower surfaces of the outer member (140) to the first receiving groove (140d). Additionally, at least one fixing member (150) may include a plurality of pairs of fixing members (150), and a plurality of pairs of fixing members (150) may be spaced apart from each other along the upper and lower surfaces of the outer member (140).

[0098] For example, in a pair of fixing members (150) extending from the upper and lower surfaces of the outer member (140) to the protrusions (121s, 125s), one fixing member (150) may be connected to the outer member (140) such that the fastening torque is relatively smaller than that of the other fixing member (150). In this way, the portion of the outer member (140) where the fixing member (150) with the relatively smaller fastening torque is located may be able to induce the discharge of gases and / or flames that occur during abnormal phenomena such as thermal runaway inside the battery cell (100).

[0099] Accordingly, in the battery cell (100) according to the present embodiment, the outer member (140) can more stably fix the lower protrusion (121s) and the upper protrusion (125s) through the fixing member (150), thereby firmly fixing the lower metal (121) and the upper metal (125) to each other. That is, by pressing the electrode stack in the vertical direction, there is an advantage in that the contact between the components of the electrode stack is maintained more stably even during charging and discharging.

[0100] In addition, the outer member (140) can effectively seal the space between the lower protrusion (121s) and the upper protrusion (125s) through the fixing member (150) while preventing the lower protrusion (121s) and the upper protrusion (125s) from being exposed to the outside, making it easier to handle the battery cell during the process and more effectively preventing foreign substances such as moisture from penetrating into the battery cell (100) from the outside of the battery cell (100).

[0101]

[0102] FIG. 6 is a top view of the battery cell of FIG. 1. FIG. 7 shows an outer casing member included in the battery cell of FIG. 1, and is a drawing showing the state in which the first outer casing member and the second outer casing member are combined with each other. FIG. 8 to 10 are perspective views showing the first outer casing member of FIG. 7.

[0103] Referring to FIGS. 1, 6 and 7, in a battery cell (100) according to the present embodiment, the outer member (140) may include a pair of first outer members (141) that each cover both sides of the electrode stack (110) with respect to the stacking direction of the electrode stack (110), and a pair of second outer members (145) that each cover the front and rear surfaces of the electrode stack (110) with respect to the stacking direction of the electrode stack (110).

[0104] Here, a pair of first exterior members (141) and a pair of second exterior members (145) may be joined together. For example, as shown in FIG. 6, one end of one of the first exterior members (141) of the pair of first exterior members (141) may be joined to the other end of one of the second exterior members (145) of the pair of second exterior members (145). Additionally, one end of one of the second exterior members (145) of the pair of second exterior members (145) may be joined to the other end of the other first exterior member (141) of the pair of first exterior members (141). Additionally, one end of the other first exterior member (141) of the pair of first exterior members (141) may be joined to the other end of the other second exterior member (145) of the pair of second exterior members (145). One end of the other second exterior member (145) of the pair of second exterior members (145) may be connected to the other end of one of the first exterior members (141) of the pair of first exterior members (141).

[0105] Referring to FIG. 7, a pair of first exterior members (141) and a pair of second exterior members (145) may each include a fitting portion (141b, 145b) formed at one end and a second receiving groove (141c, 145c) formed at the other end, respectively, based on the longitudinal direction. At this time, as described above, the fitting portion (145b) of one second exterior member (145) may be fitted into the second receiving groove (141c) of one first exterior member (141). Additionally, although omitted in FIG. 7, the fitting portion (141b) of one first exterior member (141) may also be fitted into the second receiving groove (145c) of the other second exterior member (145). Additionally, although omitted in FIG. 7, the fitting portion (145b) of another second outer member (145) can also be fitted into the second receiving groove (141c) of another first outer member (141). Additionally, although omitted in FIG. 7, the fitting portion (141b) of another first outer member (141) can also be fitted into the second receiving groove (145c) of one second outer member (145).

[0106] In the following description, the first exterior member (141) is described as the basis, but the second exterior member (145) can be described in the same way.

[0107] Referring to FIGS. 8 to 10, in a battery cell (100) according to the present embodiment, the first outer member (141) may include a first main body part (141a), a first fitting part (141b), a first receiving groove (141d), and a second receiving groove (141c).

[0108] Here, the first fitting portion (141b) is formed at one end of the first main body portion (141a) and may protrude outward from the first main body portion (141a). Additionally, the first receiving groove (141d) may be formed by being recessed or etched to a certain thickness on the inner surface of the first main body portion (141a) that contacts the storage portion (121p, 125p), and may extend along the length direction of the first main body portion (141a). Additionally, the second receiving groove (141c) is formed at the other end of the first main body portion (141a), and the other end of the first main body portion (141a) may be formed by being recessed or etched to a certain thickness. In particular, the second receiving groove (141c) may have a size corresponding to that of the first fitting portion (141b).

[0109] In addition, the first outer member (141) may have at least one first through hole (141h) formed on the outer surface of the outer member (141) into which a fixing member (150) can be inserted. Here, the first through hole (141h) may extend from the outer surface of the outer member (141) to the first receiving groove (141d). For example, as shown in FIG. 10, the at least one through hole (141h) may include a plurality of pairs of through holes (141h) each arranged on the same vertical line on the upper and lower surfaces of the outer member (141), and the plurality of pairs of through holes (141h) may be spaced apart from each other on the upper and lower surfaces of the outer member (141).

[0110] Accordingly, in the battery cell (100) according to the present embodiment, the connection between the first outer member (141) and the second outer member (145) is relatively easy, so the outer member (140) has the advantage of having a packaging structure with improved ease of assembly and productivity.

[0111]

[0112] A battery pack according to another embodiment of the present invention may include the battery cell described above. Meanwhile, the battery pack according to the present embodiment may be formed by directly packaging one or more of the battery cells described above within a pack case, or by manufacturing the battery cells in units of battery modules and then packaging them within a pack case.

[0113] The battery pack described above can be applied to various devices. While such devices may include means of transportation such as electric bicycles, electric vehicles, and hybrid vehicles, the present invention is not limited thereto and can be applied to various devices capable of using the battery pack, and this also falls within the scope of the present invention.

[0114] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

[0115] [Explanation of the symbol]

[0116] 100: Battery cell

[0117] 110: Electrode laminate

[0118] 115: Electrolyte

[0119] 120: Battery case

[0120] 130: Buffer member

[0121] 140: Exterior parts

[0122] 150: Fixing member

[0123] According to the embodiments, the battery cell of the present invention and the battery pack including the same include a battery case made of a metal material that accommodates an electrode stack including a bipolar electrode, and has the advantage that the battery case itself can perform the role of an electrode tab.

[0124] In addition, the battery cell and battery pack including the same according to the present invention include a packaging structure composed of an outer member mounted along the outer surface of a battery case, which has the advantage of stably maintaining contact between the components of the electrode stack even during charging and discharging by pressing the electrode stack in the vertical direction.

[0125] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the accompanying drawings.

Claims

An electrode laminate having a plurality of bipolar electrodes stacked such that a negative active material layer and a positive active material layer are respectively coated on both sides of a metal current collector; A battery case accommodating the above electrode stack; and It includes an outer member that encloses a protrusion extending from the outer surface of the battery case in the direction of the outer direction of the battery case, and The above-described outer member is a battery cell that presses the protrusion in the thickness direction of the protrusion. In paragraph 1, The above battery case is, A lower metal located on the lower surface of the electrode laminate and surrounding the lower part of the electrode laminate, and A battery cell comprising an upper metal located on the upper surface of the electrode stack and surrounding the upper portion of the electrode stack. In paragraph 2, The lower metal includes a lower housing portion in which the electrode stack is accommodated and a lower protrusion portion protruding outwardly from the outer surface of the lower housing portion toward the battery case. The upper metal includes an upper housing portion in which the electrode stack is accommodated and an upper protrusion portion protruding outwardly from the outer surface of the upper housing portion toward the battery case. The above protrusion is a battery cell in which the lower protrusion and the upper protrusion face each other. In Paragraph 3, A battery cell in which the portions facing each other, the upper protrusion and the lower protrusion, are sealed. In Paragraph 3, A battery cell further comprising a buffer member extending along the space between the lower protrusion and the upper protrusion. In paragraph 1, The above exterior member has a first receiving groove formed therein that extends along the longitudinal direction of the protrusion, and The above protrusion is a battery cell that is fitted into the first receiving groove of the above outer member. In paragraph 1, It includes at least one fixing member that fixes the above-mentioned exterior member and the above-mentioned protrusion to each other, and The above-mentioned fixed member is a battery cell extending from the above-mentioned outer member to the above-mentioned protrusion. In Paragraph 7, The above at least one fixing member includes a pair of fixing members extending from the upper and lower surfaces of the outer member to the protrusion, and A battery cell in which at least one fixing member comprises a plurality of pairs of fixing members, and the plurality of pairs of fixing members are spaced apart from each other along the upper and lower surfaces of the outer member. In paragraph 8, In the above pair of fixed members, one fixed member is a battery cell having a relatively smaller fastening torque compared to the other fixed member. In Paragraph 7, The above-described outer member is a battery cell having at least one through hole formed in the outer member into which the fixing member can be inserted. In paragraph 1, The above exterior member is, A pair of first outer members each covering both sides of the electrode laminate based on the stacking direction of the electrode laminate, and It includes a pair of second outer members that cover the front and rear surfaces of the electrode laminate, respectively, based on the stacking direction of the electrode laminate, and A battery cell in which the above pair of first outer casing members and the above pair of second outer casing members are combined with each other. In Paragraph 11, The above pair of first exterior members and the above pair of second exterior members each include a fitting part formed at one end and a second receiving groove formed at the other end, respectively, based on the longitudinal direction. The fitting portion of the first outer member is fitted into the second receiving groove of the second outer member, and The fitting portion of the second outer member is a battery cell that is fitted and coupled to the second receiving groove of the first outer member. In paragraph 1, The above electrode stack has the bipolar electrode and separator sequentially stacked multiple times, and A battery cell further comprising an electrolyte impregnating the electrode laminate inside the battery case. In paragraph 1, The above electrode stack is a battery cell in which the above bipolar electrode and solid electrolyte are sequentially stacked multiple times. In paragraph 1, The above electrode stack further includes a pair of single-sided cathodes and single-sided anodes, each disposed at the outermost edge based on the stacking direction, and The above-described single-sided cathode has a single-sided cathode active material layer formed on one surface of a cathode current collector, and The above-described single-sided positive is a battery cell in which a single-sided positive active material layer is formed on one side of a positive current collector. In Paragraph 15, A battery cell in which the separator is disposed between the above-mentioned single-sided cathode, the above-mentioned single-sided anode, and the above-mentioned bipolar electrode, respectively. In Paragraph 15, A battery cell in which the negative current collector included in the above-mentioned cross-section negative electrode and the positive current collector included in the above-mentioned cross-section positive electrode each come into contact with the battery case. A battery pack comprising the battery cell of claim 1.

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