Battery cell

Abstract

Provided is a battery cell comprising: a case forming an internal space; an electrode assembly including a plurality of electrode plates and a plurality of separators, and accommodated in the inner space; a current collector electrically connected to the plurality of electrode plates; a cap plate coupled to at least one side of the case; an electrode terminal installed on the cap plate; and a connector electrically connecting the electrode terminal and the current collector, wherein the current collector and the connector are in surface contact with each other by means of a plurality of protrusions provided on at least one of the current collector and the connector.

Description

battery cell

[0001] The present disclosure relates to a secondary battery cell capable of being charged and discharged.

[0002] Demand for secondary battery cells as an energy source has been rapidly increasing recently.

[0003] A secondary battery cell is a battery that can be repeatedly charged and discharged because the interconversion between chemical energy and electrical energy is reversible.

[0004] A secondary battery cell may include an electrode assembly in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are repeatedly laminated, a case that accommodates the electrode assembly, and a cap plate assembly that covers the case. The cap plate assembly may include a cap plate that covers the case and an electrode terminal that is electrically connected to the electrode assembly. A plurality of electrode tabs of the electrode assembly may be electrically connected to a current collector, and the current collector may be electrically connected to the cap plate assembly.

[0005]

[0006] In conventional battery cells, a current collector and multiple electrode tabs are joined by welding, and the current collector and cap plate assembly are joined by welding. Therefore, conventional battery cells have the problem of requiring numerous welding processes, which increases the likelihood of defects occurring during the welding process. In particular, in conventional battery cells, the current collector and cap plate assembly must be welded to ensure electrical connection between the electrode assembly and the electrode terminal. However, since the connectors of the current collector and cap plate assembly must be welded while the electrode assembly is housed in a case, the welding process is not only difficult, but also increases the likelihood of welding defects.

[0007] According to an aspect of the present disclosure, a battery cell can be provided that can easily implement electrical connection between a current collector and an electrode terminal.

[0008] In addition, according to one aspect of the present disclosure, a battery cell can be provided in which the contact area between the entire body and the connector can be increased.

[0009] The battery cell of the present disclosure can be widely applied in green technology fields such as electric vehicles, battery charging stations, and other battery-powered solar and wind power generation. Furthermore, the battery cell of the present disclosure can be used in eco-friendly electric vehicles, hybrid vehicles, and other vehicles that aim to prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0010]

[0011] A battery cell according to the present disclosure comprises: a case forming an internal space; an electrode assembly including a plurality of electrode plates and a plurality of separators, the electrode assembly being accommodated in the internal space; a current collector electrically connected to the plurality of electrode plates; a cap plate coupled to at least one side of the case; an electrode terminal installed on the cap plate; and a connector electrically connecting the electrode terminal and the current collector; wherein the current collector and the connector can be in surface contact through a plurality of protrusions provided on at least one of the current collector and the connector.

[0012] In embodiments, the first surface of the collector is in surface contact with the second surface of the connector, and the plurality of protrusions may be provided on either the first surface or the second surface.

[0013] In embodiments, the first side or the second side may include a plurality of coupling holes or a plurality of coupling grooves that contact the plurality of protrusions.

[0014] In embodiments, the plurality of protrusions may be in surface contact with the plurality of coupling holes or the plurality of coupling grooves.

[0015] In embodiments, the plurality of protrusions may be engaged and coupled with the plurality of coupling holes or the plurality of coupling grooves.

[0016] In embodiments, the plurality of protrusions may have a slope that narrows in width in the direction of engagement with the plurality of coupling holes or the plurality of coupling holes.

[0017] In embodiments, the connector and the collector can be in surface contact while being pressed by elastic force.

[0018] In embodiments, the connector may include an inner connecting member that contacts the current collector and an elastic connecting member that elastically presses the inner connecting member toward the current collector. In addition, the connector may further include a terminal connecting member that is connected to the electrode terminal, and the elastic connecting member may be positioned between the terminal connecting member and the inner connecting member.

[0019] In embodiments, at least some of the connectors may be positioned to penetrate through a through hole formed in the cap plate, and at least some of the elastic connecting members may be positioned inside the through hole.

[0020] In embodiments, the elastic connecting member may include at least one coil spring or at least one plate spring.

[0021] In embodiments, the inner connecting member includes a body that contacts the elastic connecting member, and a contact member that is connected to the body and makes surface contact with the current collector, and a cross-sectional area of ​​the contact member may have a value greater than the cross-sectional area of ​​the body.

[0022] In embodiments, the contact area between the contact member and the collector may have a value greater than the cross-sectional area of ​​the body.

[0023] In embodiments, the current collector is welded to a plurality of electrode tabs extending from the plurality of electrode plates, and the current collector and the connector can be brought into close contact by elastic pressure.

[0024] In embodiments, at least some of the connectors may be fixedly fitted into through holes formed in the cap plate.

[0025] A battery cell according to one embodiment of the present disclosure further includes: an insulating member disposed on at least one of both sides of the cap plate for electrical insulation of the cap plate; and a sealing member sealing between the cap plate and the connector within the through hole; wherein the connector can be electrically connected to the current collector by penetrating the cap plate, the insulating member, and the sealing member.

[0026] According to another aspect of the present disclosure, a battery cell comprises: a case forming an internal space; an electrode assembly including a plurality of electrode plates and a plurality of separators, the electrode assembly being accommodated in the internal space; a current collector electrically connected to the plurality of electrode plates; a cap plate coupled to at least one side of the case; an electrode terminal installed on the cap plate; and a connector electrically connecting the electrode terminal and the current collector; wherein the current collector and the connector may have a plurality of protruding and recessed shapes that are interlocked with each other on opposite surfaces.

[0027]

[0028] According to one embodiment of the present disclosure, electrical connection between a current collector and an electrode terminal can be easily achieved. For example, since the current collector and connector can be electrically connected by contact, welding between the current collector and the connector is not necessary. Therefore, compared to conventional techniques that require welding between the current collector and the connector, defects caused by welding can be reduced or minimized.

[0029] In addition, according to one embodiment of the present disclosure, since the current collector and the connector are in contact by elastic pressure, an electrical connection between the current collector and the electrode terminal can be stably maintained even without welding.

[0030] And, according to one embodiment of the present disclosure, the contact area between the current collector and the connector is increased, and accordingly, the electrical resistance between the current collector and the connector is reduced and the current flow can be smooth.

[0031]

[0032] Figure 1 is a perspective view of a battery cell according to one embodiment.

[0033] Figure 2 is an exploded perspective view of the battery cell illustrated in Figure 1.

[0034] Figure 3 is a cross-sectional view along line I-I' of Figure 1.

[0035] Fig. 4 is a schematic diagram for explaining the joint structure of the cap plate assembly and the collector illustrated in Fig. 3.

[0036] Fig. 5 is a perspective view of an inner connecting member and a collector according to one embodiment.

[0037] Figures 6 (a), 6 (b), 7 (a) and 7 (b) are cross-sectional views taken along line II-II' of Figure 5, showing various examples of a bonding structure between a contact member and a current collector.

[0038] Fig. 8 is a perspective view showing another embodiment of the inner connecting member and the collector shown in Fig. 5.

[0039] Fig. 9 is a perspective view showing another embodiment of the inner connecting member and the collector shown in Fig. 5.

[0040] Fig. 10 (a) and Fig. 10 (b) are cross-sectional views taken along line III-III' of Fig. 9, showing various examples of a bonding structure between a contact member and a current collector.

[0041] Figures 11(a), 11(b), and 11(c) are cross-sectional views showing various embodiments of the bonding structure between the contact member and the current collector.

[0042] Fig. 12 is a schematic diagram for explaining the joint structure of a cap plate assembly and a collector according to another embodiment.

[0043] Fig. 13 is a perspective view of a battery cell according to another embodiment.

[0044]

[0045] In the following description, the term "connected" between a component and another component means not only that the components are "directly connected," but also that they are "indirectly connected" with other components in between. Furthermore, the term "including" a component means that, unless otherwise specifically stated, it does not exclude other components, but rather may include other components.

[0046] Additionally, terms including ordinal numbers, such as "first," "second," etc., used herein may be used to describe various components; however, these components are not limited by these terms, and these terms are used only to distinguish one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0047] Hereinafter, the present disclosure will be described in detail with reference to the attached drawings. However, these are merely illustrative and the present disclosure is not limited to the specific embodiments illustrated by the drawings. It should be noted that in the attached drawings, identical components are represented by identical reference numerals, where possible. Furthermore, detailed descriptions of well-known functions and structures that may obscure the gist of the present disclosure will be omitted. For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted, and the sizes of each component do not fully reflect the actual size.

[0048]

[0049] FIG. 1 is a perspective view of a battery cell (100) according to one embodiment, and FIG. 2 is an exploded perspective view of the battery cell (100) illustrated in FIG. 1.

[0050] According to one embodiment, a battery cell (100) may be configured as a secondary battery. In this specification, the battery cell (100) is described as a square battery cell as an example, but the shape of the battery cell (100) is not limited to a hexahedral structure.

[0051] The battery cell (100) may include a case (110) and a cap plate assembly (140).

[0052] The case (110) may form the exterior of the battery cell (100) and may be formed of aluminum or a material including aluminum. However, the material of the case (110) is not limited thereto. In addition, the battery cell (100) of the square type may have a case (110) that is flat and has the shape of an angular hexahedron. An internal space may be formed in the case (110), and an opening (111) may be formed in at least one side of the case (110).

[0053] An electrode assembly (120) and an electrolyte may be accommodated in the internal space of the case (110). The electrode assembly (120) may include a plurality of electrode plates and a plurality of separators. The electrode plates may include a positive electrode plate and a negative electrode plate. The separator may be composed of an insulator interposed between the negative electrode plate and the positive electrode plate. The electrode assembly (120) may be composed of a stack type in which negative electrode plates, positive electrode plates, and separators are alternately stacked, or a jelly roll type in which stacked negative electrode plates, positive electrode plates, and separators are rolled together.

[0054] The negative electrode plate and the positive electrode plate may each have a structure in which a negative electrode active material or a positive electrode active material is coated on a foil. For example, the negative electrode plate may be formed by coating graphite or the like on a copper or nickel foil, and the positive electrode plate may be formed by coating a transition metal oxide active material on an aluminum foil.

[0055] The electrode assembly (120) may include an electrode tab (121) connected to an electrode plate. The electrode tab (121) may include a negative tab (121a) connected to a negative electrode plate, and a positive tab (121b in FIG. 3) connected to a positive electrode plate. The negative electrode plate and the positive electrode plate may each include a non-coated portion in which a negative electrode active material or a positive electrode active material is not coated on a foil. The non-coated portions of the negative electrode plates may be connected to each other to form a negative electrode tab (121a), and the non-coated portions of the positive electrode plates may be connected to each other to form a positive electrode tab (121b).

[0056] The electrode tab (121) may be connected to a current collector (130). The negative tab (121a) and the positive tab (121b) may each be connected to the current collector (130). The current collector (130) may be electrically connected to a plurality of electrode plates through a plurality of electrode tabs (121). The current collector (130) may be joined to the plurality of electrode tabs (121) by welding. Laser welding may be used for welding the current collector (130) and the plurality of electrode tabs (121), but the type of welding is not limited thereto.

[0057] The cap plate assembly (140) can be coupled to the opening (111) of the case (110). For example, the battery cell (100) can have a double-ended tab structure in which electrode tabs (121) are arranged at each of the two ends of the case (110). When the battery cell (100) has a double-ended tab structure, the cap plate assembly (140) can be coupled to each of the two sides of the case (110) in the longitudinal direction (X). The cap plate assembly (140) can include a first cap plate assembly (140a) coupled to the opening (111) on one side of the case (110) in the longitudinal direction (X), and a second cap plate assembly (140b) coupled to the opening (111) on the other side in the longitudinal direction (X). In this specification, a battery cell (100) having a double-end tab structure in which a cap plate assembly (140) is coupled to each of the longitudinal (X) sides of a case (110) is described, but the structure of the cap plate assembly (140) is not limited thereto. For example, as illustrated in FIG. 13, a battery cell (100a) may also include one cap plate assembly (140).

[0058] The cap plate assembly (140) may include a cap plate (141) covering the opening (111), an electrode terminal (142) installed on the outer surface of the cap plate (141), and a connector (145) electrically connecting the electrode terminal (142) to the electrode tab (121).

[0059] A venting part (150) may be coupled to the case (110). The venting part (150) may be coupled to a coupling hole (112) formed in the case (110). The venting part (150) may also be coupled to a cap plate (141). The venting part (150) closes the coupling hole (112) and may be fixed to the case (110) by welding. The venting part (150) may be configured to discharge gas, etc. generated inside the case (110). For example, the venting part (150) may be configured to be broken when the internal pressure of the case (110) increases due to gas, etc. The installation position and number of the venting parts (150) may be variously changed.

[0060] A cap (160) that closes the electrolyte injection port (141d in FIG. 3) after injecting the electrolyte into the internal space of the case (110) may be installed on the cap plate (141).

[0061]

[0062] FIG. 3 is a cross-sectional view taken along line I-I' of FIG. 1, and FIG. 4 is a schematic diagram for explaining the joint structure of the cap plate assembly (140) and the current collector (130) illustrated in FIG. 3.

[0063] Referring to FIGS. 3 and 4, the battery cell (100) may have a structure in which an electrode assembly (120) is accommodated in the internal space of a case (110) and a cap plate assembly (140) is coupled to both sides of the case (110). The cap plate assembly (140) may be electrically connected to the electrode plate of the electrode assembly (120).

[0064] When the battery cell (100) has a double-ended tab structure, the electrode assembly (120) may have electrode tabs (121) arranged on each side in the longitudinal direction (X). The negative tab (121a) may be positioned on one side of the electrode assembly (120) in the longitudinal direction (X), and the positive tab (121b) may be positioned on the other side of the electrode assembly (120) in the longitudinal direction (X).

[0065] The positive electrode tab (121b) and the negative electrode tab (121a) may each be electrically connected to a current collector (130). The current collector (130) may be fixed to the positive electrode tab (121b) and the negative electrode tab (121a) by laser welding or the like. The shape, structure, and welding connection of the current collector (130) and the electrode tab (121) are known in various forms, and therefore, a detailed description thereof will be omitted.

[0066] The cap plate assembly (140) may include a first cap plate assembly (140a) coupled to one side of the case (110) in the longitudinal direction (X) and a second cap plate assembly (140b) coupled to the other side in the longitudinal direction (X).

[0067] The first cap plate assembly (140a) can be electrically connected to the negative tab (121a), and the second cap plate assembly (140b) can be electrically connected to the positive tab (121b). Among the components of the first and second cap plate assemblies (140a, 140b), components that are made of a conductive material can be charged negatively or positively. The first cap plate assembly (140a) can include components that are charged negatively, and the second cap plate assembly (140b) can include components that are charged positively.

[0068] The cap plate assembly (140) may include a cap plate (141), an electrode terminal (142), and a connector (145). In addition, the cap plate assembly (140) may additionally include an insulating member (143) and a sealing member (144).

[0069] The cap plate (141) can be coupled to at least one side of the case (110). The cap plate (141) is a component that is directly coupled to the case (110) in the cap plate assembly (140). The cap plate (141) can be welded to the case (110) while covering the opening (111 of FIG. 2) of the case (110). Laser welding can be performed along the edge of the cap plate (141) to couple the cap plate (141) and the case (110).

[0070] An electrolyte injection port (141d) may be formed in the cap plate (141) after the electrolyte is injected into the internal space of the case (110). The electrolyte injection port (141d) may be sealed by a stopper (160) after the electrolyte is injected. The stopper (160) may have a structure that is detachable from the cap plate (141) or may have a structure that is fixed by welding after being assembled to the cap plate (141).

[0071] The electrode terminal (142) may be disposed on the outer portion of the cap plate (141) so as to be exposed to the outside of the cap plate (141). The electrode terminal (142) may have a plate shape, but is not limited thereto. The electrode terminal (142) may supply electricity to the electrode assembly (120) disposed inside the case (110) or receive electricity from the electrode assembly (120) and transmit it to the outside. The electrode terminal (142) may be electrically connected to the negative electrode tab (121a) or the positive electrode tab (121b) and may be charged to a negative or positive electrode. The electrode terminal (142) may be formed of a conductive material. For example, the electrode terminal (142) connected to the positive electrode tab (121b) may be formed of aluminum or a material including aluminum, and the electrode terminal (142) connected to the negative electrode tab (121a) may be formed of copper or a material including copper. However, the material of the electrode tab (121) is not limited to this.

[0072] A connector (145) can connect an electrode terminal (142) and an electrode tab (121). The connector (145) can be formed of an electrically conductive material. The connector (145) can be electrically connected to the electrode tab (121) through a current collector (130) coupled to the electrode tab (121). At least a portion of the connector (145) can pass through a through hole (141c) formed in the cap plate (141).

[0073] The connector (145) may include an inner connecting member (146) connected to the current collector (130) and a terminal connecting member (148) connected to the electrode terminal (142). The inner connecting member (146) may be arranged in a direction toward the electrode assembly (120) so as to be in contact with the current collector (130). A portion of the inner connecting member (146) that is in contact with the current collector (130) may have a shape and cross-sectional area corresponding to those of the current collector (130). In the present specification, the electrode terminal (142) and the terminal connecting member (148) are illustrated as having a separate structure, but the electrode terminal (142) and the terminal connecting member (148) may also be formed integrally.

[0074] The connector (145) and the current collector (130) can be in surface contact while being pressed by elastic force. For this purpose, the connector (145) may include an elastic connecting member (149) that provides elastic force. The elastic connecting member (149) can elastically press the inner connecting member (146) that is in contact with the current collector (130) toward the current collector (130). The elastic connecting member (149) may be arranged between the terminal connecting member (148) and the inner connecting member (146). The connector (145) and the current collector (130) can be brought into close contact by the elastic pressing force of the elastic connecting member (149). Therefore, even if the connector (145) and the current collector (130) are not welded, the connector (145) and the current collector (130) can be in stable contact, and a stable electrical connection between the connector (145) and the current collector (130) is possible. The elastic connecting member (149) may include at least one coil spring (149a). However, the elastic connecting member (149) may be modified into various forms as long as it can provide elasticity. For example, the elastic connecting member (149) may also include at least one plate spring (149b of FIG. 12).

[0075] An insulating member (143) may be placed on at least one of both sides of the cap plate (141) to electrically insulate the cap plate (141). The insulating member (143) may perform electrical insulation in at least one of the following: between the cap plate (141) and the connector (145), between the cap plate (141) and the electrode terminal (142), and between the cap plate (141) and the current collector (130) or the electrode assembly (120).

[0076] The insulating member (143) may include a first insulating member (143a) that electrically insulates between the inner connecting member (146) of the connector (145) and the inner surface of the cap plate (141), and a second insulating member (143b) that electrically insulates between the outer surface of the cap plate (141) and the electrode terminal (142). The first insulating member (143a) may be installed in a mounting groove (141a) formed on the inner surface of the cap plate (141), and the second insulating member (143b) may be installed in a mounting groove (141b) formed on the outer surface of the cap plate (141).

[0077] However, it is also possible that the second insulating member (143b) is not disposed on either the first cap plate assembly (140a) or the second cap plate assembly (140b). In this case, the electrode terminal (142) and the case (110) may be charged positively or negatively. For example, if the second insulating member (143b) is not disposed on the second cap plate assembly (140b) to which the positive tab (121b) is connected, the electrode terminal (142) may be charged positively.

[0078] The cap plate assembly (140) may include a sealing member (144) installed inside the through hole (141c). The sealing member (144) may seal between the cap plate (141) and the connector (145) inside the through hole (141c). The sealing member (144) may prevent an electrolyte contained in the internal space of the case (110) or a gas generated inside the case (110) from being discharged to the outside through the cap plate assembly (140). The sealing member (144) may have a shape that surrounds at least a portion of the connector (145). At least a portion of the connector (145) may be installed to penetrate the inside of the sealing member (144).

[0079] The sealing member (144) may be formed of an elastic and insulating material. The sealing member (144) may electrically insulate between the cap plate (141) and the connector (145) inside the through hole (141c). In FIGS. 3 and 4 , the sealing member (144) is illustrated as having a shape disposed between the first insulating member (143a) and the second insulating member (143b) inside the through hole (141c), but the shape of the sealing member (144) may be variously changed. In addition, the sealing member (144) may be provided separately from the first insulating member (143a) and the second insulating member (143b), but may also be formed integrally with the first insulating member (143a) or the second insulating member (143b).

[0080] The connector (145) can be electrically connected to the current collector (130) by penetrating the cap plate (141), the insulating member (143), and the sealing member (144). When the electrode terminal (142) and the terminal connecting member (148) have separate structures, the terminal connecting member (148) of the connector (145) can have a structure that penetrates the electrode terminal (142).

[0081] The cap plate assembly (140) can be formed by assembling a connector (145) while arranging a sealing member (144) and an insulating member (143) on the cap plate (141). At least some of the connectors (145) can be assembled to the cap plate (141) or the like in a manner of passing through a through-hole (141c). The inner connecting member (146) of the connector (145) can be inserted into the through-hole (141c) on the inner surface of the cap plate (141). The terminal connecting member (148) can be inserted into the through-hole (141c) on the outer surface of the cap plate (141). At this time, the elastic connecting member (149) can be arranged inside the through-hole (141c).

[0082] The inner connecting member (146) of the connector (145) may be arranged between the cap plate (141) and the current collector (130). When the cap plate (141) is coupled to the case (110), the inner connecting member (146) of the connector (145) may be supported by the current collector (130) welded to the electrode tab (121). When the terminal connecting member (148) is pushed into the through hole (141c) while the elastic connecting member (149) is arranged inside the through hole (141c), the elastic connecting member (149) may be compressed. Accordingly, the elastic force of the elastic connecting member (149) is transmitted to the inner connecting member (146), and the inner connecting member (146) may provide an elastic pressing force to the current collector (130). The inner connecting member (146) and the current collector (130) can be brought into close contact by the elastic pressure of the elastic connecting member (149).

[0083] At least some of the connectors (145) may be fixed in a state of being fitted into the through hole (141c). For example, the terminal connecting member (148) may be maintained in a state of being fixed to the cap plate (141) so that the elastic force of the elastic connecting member (149) may be transmitted to the inner connecting member (146). The terminal connecting member (148) may be fixed to the electrode terminal (142) or may be formed integrally with the electrode terminal (142). The electrode terminal (142) may be fixed to the cap plate (141) via the terminal connecting member (148).

[0084] The terminal connecting member (148) may be force-fitted into the through-hole (141c). However, the method of fixing the terminal connecting member (148) to the cap plate assembly (140) is not limited thereto. For example, the terminal connecting member (148) may be fixed in a state of being fitted into the through-hole (141c) by a known connecting method such as a rivet connection, a screw connection, a welding connection, a force-fit, or a combination thereof. The inner connecting member (146) may be arranged in a movable state within the through-hole (141c) by the elastic force of the elastic connecting member (149).

[0085] The electrode assembly (120) can maintain a fixed position without moving inside the case (110) by the elastic pressing force applied to the elastic connecting member (149). When the first cap plate assembly (140a) and the second cap plate assembly (140b) are respectively arranged at both ends in the longitudinal direction (X) of the electrode assembly (120), the electrode assembly (120) can maintain a constant position by the elastic pressing force of the elastic connecting members (149) respectively arranged in the first cap plate assembly (140a) and the second cap plate assembly (140b). The force applied by the elastic connecting members (149) to the current collector (130) and / or the electrode assembly (120) can be set in consideration of the elastic coefficient, shape, number, etc. of the elastic connecting members (149).

[0086]

[0087] Next, the joint structure of the inner connecting member (146) and the current collector (130) will be described with reference to FIGS. 5 to 11.

[0088] FIG. 5 is a perspective view of an inner connecting member (146) and a current collector (130) according to one embodiment, and FIGS. 6 (a), 6 (b), 7 (a), and 7 (b) are cross-sectional views taken along line II-II' of FIG. 5, showing various embodiments of a joint structure between a contact member (147) of the inner connecting member (146) and a current collector (130).

[0089] Referring to FIG. 5 together with FIGS. 3 and 4, the inner connecting member (146) may include a body (146a) at least part of which is installed in the through hole (141c), and a contact member (147) connected to the body (146a) and in contact with the current collector (130). One side of the body (146a) may be in contact with an elastic connecting member (149) installed inside the through hole (141c), and the other side of the body (146a) may be exposed to the outside of the through hole (141c). As an example, the body (146a) may have a cylindrical shape, but the shape of the body (146a) is not limited thereto.

[0090] The contact member (147) is connected to the other side of the body (146a) and can come into contact with the current collector (130). The contact member (147) can make surface contact with the current collector (130) while being pressed by the elastic force of the elastic connecting member (149). In addition, the contact member (147) of the connector (145) can be brought into close contact with the current collector (130) by the elastic force of the elastic connecting member (149). The contact member (147) can have a shape and a cross-sectional area that are substantially the same as the shape and cross-sectional area of ​​the current collector (130).

[0091] In order to increase the contact area between the contact member (147) and the current collector (130), the cross-sectional area of ​​the contact member (147) may have a larger value than the cross-sectional area of ​​the body (146a). That is, the contact member (147) may have a shape with an enlarged cross-sectional area compared to the body (146a). In addition, the contact area between the contact member (147) and the current collector (130) may have a larger value than the cross-sectional area of ​​the body (146a). In this way, since the cross-sectional area of ​​the contact member (147) and the contact area between the contact member (147) and the current collector (130) are increased, the electrical resistance between the current collector (130) and the connector (145) may be reduced and the current flow may be made smooth.

[0092] It can be configured to make surface contact through a plurality of protrusions provided on at least one of the collector (130) and the connector (145).

[0093] The current collector (130) has a tab connection portion (131) formed on one side to be connected to an electrode tab (121 in FIG. 3) and a first surface (132a) facing a connector (145) on the other side. A first contact portion (132b) may be formed on the first surface (132a) of the current collector (130). The contact member (147) of the inner connection member (146) has a second surface (147a) facing the current collector (130). A second contact portion (147b) may be formed on the second surface (147a) of the inner connection member (146). The first surface (132a) of the current collector (130) and the second surface (147a) of the connector (145) may be in surface contact.

[0094] At least one of the first contact portion (132b) and the second contact portion (147b) may include a plurality of protrusions. For example, as illustrated in FIGS. 5, 6(a), 6(b), 7(a), and 7(b), the first contact portion (132b) may include a plurality of protrusions. The second contact portion (147b) may include a plurality of coupling holes that contact the plurality of protrusions. The first contact portion (132b) and the second contact portion (147b) may contact each other. To increase the contact area, the first contact portion (132b) and the second contact portion (147b) may be in surface contact with each other. When the first contact portion (132b) includes a plurality of protrusions and the second contact portion (147b) includes a plurality of coupling holes, each protrusion may be in surface contact with each coupling hole.

[0095] The current collector (130) and the connector (145) may have a plurality of interlocking shapes on their opposing surfaces. That is, the first contact portion (132b) of the current collector (130) and the second contact portion (147b) of the connector (145) may have shapes that interlock with each other. For example, the first contact portion (132b) and the second contact portion (147b) may have shapes that interlock with each other.

[0096] In Fig. 5, the first contact portion (132b) and the second contact portion (147b) are illustrated as having a rectangular shape, but the shapes of the first contact portion (132b) and the second contact portion (147b) can be changed to various shapes such as polygons and circles.

[0097] As shown in (a) of FIG. 6, (b) of FIG. 6, (a) of FIG. 7, and (b) of FIG. 7, the first contact portion (132b) formed on the first surface (132a) of the current collector (130) may be formed as a protrusion, and the second contact portion (147b) formed on the second surface (147a) of the contact member (147) may be formed as a coupling hole that couples with the protrusion.

[0098] As illustrated in (a) of FIG. 6 and (a) of FIG. 7, the tab connection portion (131) of the current collector (130) may be formed in a flat shape. In this case, welding between the tab connection portion (131) of the current collector (130) and the electrode tab (121) can be performed smoothly.

[0099] In contrast, as illustrated in (b) of FIG. 6 and (b) of FIG. 7, the current collector (130) may be configured to have a generally constant thickness. In the embodiments illustrated in (b) of FIG. 6 and (b) of FIG. 7, the current collector (130) may be easily manufactured by a press process. In this case, a groove (131a) may be formed in the tab connection portion (131) of the current collector (130).

[0100] As illustrated in (a) and (b) of FIG. 7, the first contact portion (132b) and the second contact portion (147b) may have inclined surfaces. That is, the first contact portion (132b) formed of a protrusion may have an incline whose width becomes narrower in the direction in which it is coupled with the second contact portion (147b) formed of a coupling hole. Conversely, the second contact portion (147b) formed of a coupling hole may have an incline whose width becomes wider in the direction toward the first contact portion (132b). In this way, the inclined surfaces of the first contact portion (132b) and the second contact portion (147b) may perform a guide function when the first contact portion (132b) and the second contact portion (147b) are coupled. Therefore, when the inclined surfaces are formed, the coupling between the contact member (147) of the inner connecting member (146) and the current collector (130) may be facilitated.

[0101]

[0102] FIG. 8 is a perspective view showing another embodiment of the inner connecting member (146) and the collector (130) shown in FIG. 5.

[0103] Referring to Fig. 8, the first contact portion (132b) of the current collector (130) may include a plurality of circular protrusions, and the second contact portion (147b) of the contact member (147) may include a plurality of circular coupling holes. In addition, the embodiment of Fig. 8 has a configuration in which the number of protrusions and coupling holes is smaller than that of the embodiment of Fig. 5. In this way, the first contact portion (132b) of the current collector (130) and the second contact portion (147b) of the contact member (147) may be changed to have various shapes and numbers.

[0104]

[0105] FIG. 9 is a perspective view showing another embodiment of the inner connecting member (146) and the current collector (130) shown in FIG. 5, and FIG. 10 (a) and FIG. 10 (b) are cross-sectional views taken along line III-III' of FIG. 9, showing various embodiments of the bonding structure between the contact member (147) of the inner connecting member (146) and the current collector (130).

[0106] The embodiments illustrated in FIGS. 5 to 8 have a configuration in which the protrusion is coupled with the coupling hole, whereas the embodiments illustrated in FIGS. 9 to 10 (b) have a configuration in which the protrusion is coupled with the coupling groove.

[0107] As illustrated in FIG. 9, FIG. 10 (a) and FIG. 10 (b), the first contact portion (132b) formed on the first surface (132a) of the current collector (130) may be formed as a protrusion, and the second contact portion (147b) formed on the second surface (147a) of the contact member (147) may be formed as a coupling groove that couples with the protrusion. When either the first contact portion (132b) or the second contact portion (147b) is formed as a coupling groove, the contact area between the first contact portion (132b) and the second contact portion (147b) may be increased compared to when the first contact portion (132b) and the second contact portion (147b) are formed as coupling holes. When the contact area between the contact member (147) and the current collector (130) is increased in this way, the electrical resistance between the current collector (130) and the connector (145) may be reduced, and the current flow may be facilitated.

[0108] The first contact portion (132b) and the second contact portion (147b) may have inclined surfaces. That is, the first contact portion (132b) formed of a protrusion may have an inclined surface that narrows in a direction in which it is coupled with the second contact portion (147b) formed of a coupling groove. Conversely, the second contact portion (147b) formed of a coupling groove may have an inclined surface that widens in a direction toward the first contact portion (132b). In this way, the inclined surfaces of the first contact portion (132b) and the second contact portion (147b) may perform a guide function when the first contact portion (132b) and the second contact portion (147b) are coupled. Therefore, when the inclined surfaces are formed, the coupling between the contact member (147) of the inner connecting member (146) and the current collector (130) may be facilitated.

[0109] As illustrated in (a) of Fig. 10, the tab connection portion (131) of the current collector (130) may be formed in a flat surface. In this case, welding between the electrode tab (121) and the tab connection portion (131) of the current collector (130) can be performed smoothly.

[0110] In contrast, as illustrated in (b) of FIG. 10, the current collector (130) may be configured to have a generally constant thickness. In the embodiment illustrated in (b) of FIG. 10, the current collector (130) may be easily manufactured by a press process. In this case, a groove (131a) may be formed in the tab connection portion (131) of the current collector (130).

[0111]

[0112] Figures 11(a), 11(b), and 11(c) are cross-sectional views illustrating various embodiments of the bonding structure between the contact member (147) of the inner connecting member (146) and the current collector (130).

[0113] The embodiments of FIGS. 5 to 10 have a configuration in which the first contact portion (132b) of the current collector (130) includes a plurality of protrusions and the second contact portion (147b) of the inner connecting member (146) has a coupling hole or a coupling groove, but the embodiment of FIG. 11 differs in that the second contact portion (147b) of the inner connecting member (146) includes a plurality of protrusions and the first contact portion (132b) of the current collector (130) has a coupling hole or a coupling groove. In this way, the positions of the protrusions and the coupling holes or coupling grooves coupled thereto can be interchanged.

[0114] As shown in (a) and (b) of FIG. 11, the second contact portion (147b) formed on the second surface (147a) of the contact member (147) may be formed as a protrusion, and the first contact portion (132b) formed on the first surface (132a) of the current collector (130) may be formed as a coupling hole that couples with the protrusion.

[0115] As illustrated in (b) of FIG. 11, the first contact portion (132b) and the second contact portion (147b) may have inclined surfaces. That is, the second contact portion (147b) formed of a protrusion may have an inclined surface that narrows in a direction in which it is coupled with the first contact portion (132b) formed of a coupling hole. Conversely, the first contact portion (132b) formed of a coupling hole may have an inclined surface that widens in a direction toward the second contact portion (147b). In this way, the inclined surfaces of the first contact portion (132b) and the second contact portion (147b) may perform a guide function when the first contact portion (132b) and the second contact portion (147b) are coupled. Therefore, when the inclined surfaces are formed, the coupling between the contact member (147) of the inner connecting member (146) and the current collector (130) may be facilitated.

[0116] As illustrated in (c) of FIG. 11, the first contact portion (132b) and the second contact portion (147b) may have inclined surfaces. The second contact portion (147b) formed of a protrusion may have an inclined surface that narrows in a direction in which it is coupled with the first contact portion (132b) formed of a coupling groove. Conversely, the first contact portion (132b) formed of a coupling groove may have an inclined surface that widens in a direction toward the second contact portion (147b). In this way, the inclined surfaces of the first contact portion (132b) and the second contact portion (147b) may perform a guide function when the first contact portion (132b) and the second contact portion (147b) are coupled. Therefore, when the inclined surfaces are formed, the coupling between the contact member (147) of the inner connecting member (146) and the current collector (130) may be facilitated.

[0117]

[0118] Fig. 12 is a schematic diagram for explaining the joint structure of a cap plate assembly (140) and a collector (130) according to another embodiment.

[0119] The embodiment illustrated in FIG. 5 has a configuration in which the elastic connecting member (149) includes at least one coil spring (149a), whereas the embodiment illustrated in FIG. 12 has a configuration in which the elastic connecting member (149) includes at least one plate spring (149b).

[0120]

[0121] When the elastic connecting member (149) includes at least one plate spring (149b), the contact area between the elastic connecting member (149) and the terminal connecting member (148), and between the elastic connecting member (149) and the inner connecting member (146) is increased compared to the coil spring (149a), so that the current flow can be made smooth.

[0122] Although Fig. 12 illustrates that the cross-section of the plate spring (149b) has a roughly rectangular shape, the cross-section of the plate spring (149b) may also have a shape such as a diamond or an oval so that the plate spring (149b) can be easily deformed when pressurized.

[0123]

[0124] Fig. 13 is a perspective view of a battery cell (100a) according to another embodiment.

[0125] The battery cell (100a) illustrated in FIG. 13 illustrates a configuration in which one cap plate assembly (140) is installed on one side of the case (110). In this case, a plurality of electrode terminals (142) may be arranged on the cap plate (141). The plurality of electrode terminals (142) may be electrically connected to the electrode tabs (121 of FIG. 3) of the electrode assembly (120) via connectors (145), respectively. The plurality of electrode terminals (142) may be charged to positive and negative poles, respectively. A stopper (160) for sealing an electrolyte injection port (141d of FIG. 3) and a venting portion (150) for releasing gas inside the case (110) to the outside of the case (110) may be arranged on the cap plate (141).

[0126] The configuration of the cap plate assembly (140) described with reference to FIGS. 1 to 12 can also be applied to the embodiment of FIG. 13.

[0127]

[0128] Although the embodiments have been described in detail above, the scope of the present disclosure is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible within a scope that does not depart from the technical spirit of the present invention described in the claims.

[0129] For example, the above-described embodiments may be implemented by deleting some of the components, and the embodiments may be implemented in combination with each other.

[0130]

[0131] [Explanation of symbols]

[0132] 100... battery cells

[0133] 110... case

[0134] 120... electrode assembly

[0135] 121... Electrode tab

[0136] 130... current collector

[0137] 132a... Page 1

[0138] 132b... first contact

[0139] 140... Cap plate assembly

[0140] 140a... 1st cap plate assembly

[0141] 140b... Second cap plate assembly

[0142] 141... cap plate

[0143] 142... electrode terminal

[0144] 143... Insulating material

[0145] 144... sealing member

[0146] 145... connector

[0147] 146... inner connecting member

[0148] 146a... body

[0149] 147... Absence of contact

[0150] 147a... Page 2

[0151] 147b... Second contact

[0152] 148... terminal connecting member

[0153] 149... Elastic connecting member

[0154] 149a... coil spring

[0155] 149b... leaf spring

[0156] 150... venting department

[0157] 160... plug

Claims

1. Case forming the internal space; An electrode assembly including a plurality of electrode plates and a plurality of separators, and accommodated in the internal space; A current collector electrically connected to the plurality of electrode plates; A cap plate coupled to at least one side of the case; An electrode terminal (electrode termina1) installed on the above cap plate; and A connector that electrically connects the electrode terminal and the current collector; Includes, A battery cell in which the above-mentioned collector and the above-mentioned connector are in surface contact through a plurality of protrusions provided on at least one of the above-mentioned collector and the above-mentioned connector.

2. In paragraph 1, The first surface of the above-mentioned collector is in surface contact with the second surface of the above-mentioned connector, A battery cell wherein the plurality of protrusions are provided on one of the first surface and the second surface.

3. In paragraph 2, A battery cell wherein the first side or the second side includes a plurality of coupling holes or a plurality of coupling grooves that come into contact with the plurality of protrusions.

4. In paragraph 3, A battery cell in which the plurality of protrusions are in surface contact with the plurality of joining holes or the plurality of joining grooves.

5. In paragraph 3, A battery cell in which the plurality of protrusions are interlocked with the plurality of coupling holes or the plurality of coupling grooves.

6. In paragraph 3, A battery cell in which the plurality of protrusions have a slope that narrows in the direction in which they are combined with the plurality of coupling holes or the plurality of coupling holes.

7. In paragraph 1, A battery cell in which the connector and the collector are in surface contact while being pressed by elastic force.

8. In paragraph 7, A battery cell wherein the connector includes an inner connecting member that contacts the current collector and an elastic connecting member that elastically presses the inner connecting member toward the current collector.

9. In paragraph 8, The above connector additionally includes a terminal connecting member connected to the electrode terminal, A battery cell in which the elastic connecting member is positioned between the terminal connecting member and the inner connecting member.

10. In paragraph 8, At least some of the above connectors are arranged to penetrate through the through holes formed in the cap plate, A battery cell wherein at least some of the elastic connecting members are positioned inside the through hole.

11. In paragraph 8, A battery cell wherein the elastic connecting member comprises at least one coil spring or at least one plate spring.

12. In paragraph 8, The inner connecting member includes a body that contacts the elastic connecting member, and a contact member that is connected to the body and makes surface contact with the collector, A battery cell in which the cross-sectional area of ​​the above contact member has a value greater than the cross-sectional area of ​​the body.

13. In paragraph 12, A battery cell in which the contact area between the contact member and the current collector has a value greater than the cross-sectional area of ​​the body.

14. In paragraph 7, The above-mentioned collector is welded to a plurality of electrode tabs extending from the plurality of electrode plates, The above-mentioned battery cell and the above-mentioned connector are in close contact with each other by elastic pressure.

15. In paragraph 1, A battery cell wherein at least some of the above connectors are fixed in a state of being fitted into a through hole formed in the cap plate.

16. In paragraph 15, An insulating member disposed on at least one of both sides of the cap plate for electrical insulation of the cap plate; and A sealing member that seals between the cap plate and the connector inside the through hole; In addition, it includes: The above connector is a battery cell that is electrically connected to the current collector by penetrating the cap plate, the insulating member, and the sealing member.

17. Case forming the internal space; An electrode assembly including a plurality of electrode plates and a plurality of separators, and accommodated in the internal space; A current collector electrically connected to the plurality of electrode plates; A cap plate coupled to at least one side of the case; Electrode terminals installed on the above cap plate; and A connector that electrically connects the electrode terminal and the current collector; Includes, A battery cell having a plurality of protruding shapes that are interlocked with each other on opposite surfaces of the above-mentioned collector and the above-mentioned connector.

Images