Secondary batteries

Abstract

To provide a magnetic disk device that can improve recording quality.SOLUTION: According to an embodiment, a secondary battery comprises: an outer container 12 that has a lid body 14; an electrode body 30 that has a collector tab 32a, and is stored in the outer container; an output terminal 20 that is provided on the lid body; and a lead 40A that is provided between the electrode body and the lid body inside the outer container, and electrically connects the collector tab and the output terminal to each other. The output terminal has a connection part 20c that is exposed to the outside of the lid body and can connect a connection member, and an exposed part 20E that is exposed to the outside of the lid body, and through holes 23 that are formed in the exposed part, and the exposed part is joined to the lead.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a secondary battery. [Background technology]

[0002] High-energy-density secondary batteries, such as lithium-ion secondary batteries, are widely used as power sources for electronic devices and electric vehicles. Such secondary batteries are constructed by housing an electrode assembly having a positive electrode and a negative electrode in a rectangular outer container. A positive electrode output terminal and a negative electrode output terminal are provided on the lid of the outer container. The positive electrode output terminal and the negative electrode output terminal are connected to the positive electrode and the negative electrode of the electrode assembly, respectively, via a positive electrode lead and a negative electrode lead provided inside the outer container. In the secondary battery described above, it is required to connect the output terminal provided on the lid and the lead of the electrode body with high positional accuracy. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 5-90813 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-197048 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the embodiments of the present invention is to provide a secondary battery that can improve the accuracy of connection between the output terminals and the leads and improve the reliability. [Means for solving the problem]

[0005] According to an embodiment, a secondary battery includes an outer container having a lid, an electrode assembly having a current collecting tab and housed in the outer container, an output terminal provided on the lid, and a lead provided inside the outer container between the electrode assembly and the lid and electrically connecting the current collecting tab and the output terminal. The output terminal has a connection portion exposed to the outside of the lid and capable of connecting a connection member, an exposed portion exposed to the outside of the lid, and a through hole formed in the exposed portion, and the exposed portion is joined to the lead. The lead has a base portion having an abutment surface facing the lid body, and a spring-like abutment portion that protrudes from the base portion toward the lid body and abuts against the exposed portion of the output terminal. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view showing the appearance of a secondary battery according to a first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of an outer container and an electrode assembly of the secondary battery. [Figure 3A] FIG. 3A is a perspective view showing one end of the lid. [Figure 3B] FIG. 3B is a perspective view of an output terminal. [Figure 4] FIG. 4 is an exploded perspective view showing an electrode body, leads, and insulating spacers of the secondary battery. [Figure 5] FIG. 5 is a perspective view of the lead as seen from above. [Figure 6] FIG. 6 is a perspective view of the lead as seen from the rear surface side. [Figure 7] FIG. 7 is a perspective view showing an engagement state between the lead and the outer container. [Figure 8] 8 is a cross-sectional view of an output terminal portion of the secondary battery taken along line AA in FIG. [Figure 9] 9 is a cross-sectional view of the secondary battery taken along line BB in FIG. [Figure 10] FIG. 10 is a plan view schematically showing a secondary battery according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, a secondary battery according to an embodiment of the present invention will be described with reference to the drawings. The disclosure is merely an example, and appropriate modifications that are easily conceivable by those skilled in the art while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment for the sake of clarity, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings may be designated by the same reference numerals, and detailed descriptions may be appropriately simplified or omitted.

[0008] (First embodiment) The secondary battery according to the first embodiment will be described in detail. FIG. 1 is a perspective view showing the appearance of a secondary battery according to a first embodiment. As shown in the figure, the secondary battery 10 is, for example, a non-aqueous electrolyte secondary battery such as a lithium ion battery, and includes a substantially rectangular outer container 12 and an electrode assembly 30 (described below) housed together with a non-aqueous electrolyte solution in the outer container 12. The outer container 12 is, for example, an outer can (battery case) made of synthetic resin.

[0009] The outer container 12 has a container body 16 with an open top end and a rectangular plate-shaped lid 18 that is welded or glued to the container body 16 to close the opening of the container body 16, forming an airtight interior. The lid 14 is provided with a pair of output terminals, a positive terminal 20 and a negative terminal 21, and an injection port. The injection port is sealed with a disk-shaped sealing lid 25. Here, the longitudinal direction of the lid 14 and the container body 16 is defined as X, the width direction of the lid 14 and the container body 16 perpendicular to the longitudinal direction X is defined as Y, and the height direction of the container body 16 is defined as Z.

[0010] FIG. 2 is an exploded perspective view of the secondary battery, showing the outer container and the electrode assembly disassembled. 2, the container body 16 has a rectangular long side wall 16a, a rectangular long side wall 16b that faces the long side wall 16a in parallel with and spaced apart from the long side wall 16a, a pair of opposing short side walls 16c, and a bottom wall 16d. A rectangular upper opening 17 is defined by the upper edges of the pair of long side walls 16a, 16b and the upper edges of the pair of short side walls 16c. A plurality of recesses (notches) P1, P2 are formed in the upper edges of the long side walls 16a, 16b, respectively. The recesses P1, P2 extend in the longitudinal direction X and open to the upper end surfaces and inner surfaces of the long side walls 16a, 16b, respectively. For example, the length of the recess P1 in the longitudinal direction X is longer than the length of the recess P2 in the longitudinal direction X. The recesses P1, P2 are spaced apart in the longitudinal direction X. Ends of leads 40A, 40B, which will be described later, are placed in the recesses P1, P2.

[0011] The lid 14 is formed in the shape of a rectangular plate large enough to cover the upper opening 17. The outer peripheral edge of the lower surface of the lid 14 is welded or glued to the upper end surface of the container body 16, and the lid 14 is fixed to the container body 16 in a state in which the upper opening 17 is closed. Rectangular openings OP1 and OP2 are formed at both ends of the lid 14 in the longitudinal direction X. The openings OP1 and OP2 each penetrate the lid 14 in the thickness direction. A positive electrode terminal 20 is embedded in one end of the lid 14 in the longitudinal direction X. A portion of the positive electrode terminal 20 is exposed to the upper surface 14a and the lower surface 14b of the lid 14 through the opening OP1. Another portion (connection portion) 20c of the positive electrode terminal 20 is exposed to the upper surface of the lid 14 and is positioned alongside the opening OP1 in the longitudinal direction X. A negative electrode terminal 21 is embedded in the other end of the lid 14 in the longitudinal direction X. A portion of the negative electrode terminal 21 is exposed to the upper surface 14a and the lower surface 14b of the lid 14 through the opening OP2. Another portion (connection portion) 20c of the negative electrode terminal 21 is exposed to the upper surface of the lid 14 and is positioned alongside the opening OP2 in the longitudinal direction X. An electrolyte injection port 29 is provided at approximately the center of the lid 14 in the longitudinal direction X. The injection port 29 penetrates the lid 14 in the thickness direction and opens on the top and bottom surfaces of the lid 14. After the electrolyte is injected into the outer container 12 through the injection port 29, the injection port 29 is sealed with the sealing lid 25.

[0012] The positive electrode terminal 20 and the negative electrode terminal 21 will now be described. FIG. 3A is an enlarged perspective view of one end of the lid, and FIG. 3B is a perspective view of the positive terminal, which is an output terminal. As shown in FIG. 3B, the positive terminal 20 has a rectangular plate-shaped first layer 20a and a rectangular plate-shaped second layer 20b laminated on one end of the first layer 20a in the longitudinal direction X. The first layer 20a has two positioning holes 23. The two holes 23 are formed to penetrate the first layer 20a in the height direction Z and open to the upper and lower surfaces of the first layer 20a. The two holes 23 are arranged side by side in the longitudinal direction X. The second layer 20b has integrally therewith a rectangular protrusion (connection portion) 20c that protrudes from its upper surface in the height direction Z. The first layer 20a is formed of a conductive metal, such as titanium (Ti) or zinc (Zn), which is the same as the material forming the leads described below. The second layer 20b is formed of a metal material different from that of the first layer 20a, such as aluminum or zinc. The material forming the second layer 20b is selected depending on the material forming the connection member (bus bar) joined to the connection portion 20c of the second layer 20b. For example, if the connection member is formed of aluminum, the second layer 20b is also formed of aluminum. Furthermore, if the connection member is formed of the same metal material as the leads, such as titanium, the second layer 20b is formed integrally with the first layer 20a using titanium. The other negative electrode terminal 21 is formed to have the same configuration and dimensions as the positive electrode terminal 20 described above.

[0013] As shown in FIG. 3A, the positive electrode terminal 20 is attached to the lid 14 while being embedded in one end of the lid 14. The first layer 20a is embedded in approximately the center of the thickness of the lid 14 and is disposed parallel to the upper surface (outer surface) 14a and the lower surface 14b of the lid 14. The first layer 20a extends in the longitudinal direction X across the opening OP1. A central portion (exposed portion) 20E of the first layer 20a, which includes two through-holes 23, is exposed to the upper surface 14a and the lower surface 14b of the lid 14 through the opening OP1 of the lid 14. The second layer 20b is embedded in the lid 14, and only the upper surface of the connection portion 20c is exposed on the upper surface 14a of the lid 14. The upper surface of the connection portion 20c is formed flat and is located approximately flush with the upper surface 14a of the lid 14. The connection portion 20c is located alongside the opening OP1 in the longitudinal direction X, and is located on the negative electrode terminal 21 side of the opening OP1. 2, the negative electrode terminal 21 is embedded in the other end of the lid 14 in the longitudinal direction X. The exposed portion of the first layer is exposed on the upper surface of the lid 14 through the opening OP2, and the connecting portion 20c of the second layer is exposed on the upper surface of the lid 14.

[0014] FIG. 4 is an exploded perspective view of the secondary battery showing the leads and insulating spacers. 2 and 4, the electrode assembly 30 housed in the outer container 12 is configured, for example, by stacking a plurality of sheet-like positive electrode plates and a plurality of sheet-like negative electrode plates alternately with separators sandwiched between them. That is, in this embodiment, the electrode assembly 30 is a so-called stacked electrode assembly. The positive electrode plate has a rectangular plate-shaped positive electrode current collector, a positive electrode active material layer formed on at least one surface of the current collector, and a strip-shaped positive electrode current collector tab 32a extending from one end of the positive electrode current collector in the height direction Z. The negative electrode plate has a rectangular plate-shaped negative electrode current collector, a negative electrode active material layer formed on at least one surface of the current collector, and a strip-shaped negative electrode current collector tab 32b extending from one end of the negative electrode current collector in the height direction Z. An electrically insulating separator is sandwiched between the positive electrode plate and the negative electrode plate to electrically insulate them. The current collectors and current collecting tabs of the positive and negative electrode plates are formed, for example, from a metal foil having a thickness of about 5 to 50 μm. The material of the metal foil can vary depending on the type of active material used in the positive and negative electrodes, but examples of the material that can be used include aluminum, an aluminum alloy, copper, and a copper alloy.

[0015] 4, the positive electrode current collecting tabs 32a extend outward from one end of the electrode assembly (electrode group) 30 and are stacked one on top of the other in the thickness direction of the electrode assembly 30. The extending ends of the positive electrode current collecting tabs 32a may be clamped together by a backup lead (not shown) bent into a U-shape. The positive electrode current collecting tabs 32a are located on one end side of the electrode assembly 30 in the longitudinal direction X. The negative electrode current collecting tabs 32b extend outward from one end of the electrode assembly 30 in the same direction as the positive electrode current collecting tabs 32a, and are stacked one on top of the other in the thickness direction of the electrode assembly 30. The extending ends of the negative electrode current collecting tabs 32b may be clamped together by a backup lead (not shown) bent into a U-shape. The negative electrode current collecting tab 32b is located on the other end side of the electrode assembly 30 in the longitudinal direction X. In this way, the positive electrode current collecting tab 32 a and the negative electrode current collecting tab 32 b extend in the same direction from one end of the electrode body 30 and are positioned apart from each other in the longitudinal direction X of the electrode body 30 . The electrode assembly 30 configured as described above is housed in the container body 16 with one end face of the electrode assembly 30, the positive electrode current collecting tab 32a, and the negative electrode current collecting tab 32b facing the lid 14. One end face of the electrode assembly 30 faces the lid 14 at a predetermined distance.

[0016] As shown in Figures 2 and 4, the secondary battery 10 includes a rectangular frame-shaped insulating member 50, a positive electrode lead 40A, and a negative electrode lead 40B, which are provided in the space between the electrode assembly 30 and the lid 14 inside the outer casing 12. The insulating member 50 is formed into a plate shape from an insulating material such as synthetic resin. In one example, the insulating member 50 is divided into a pair of insulating members 50a and 50b, which are joined together to form a rectangular frame. The insulating member 50 abuts against the inner surface of the casing body 16 and covers the entire periphery of the area between the lid 14 and the end face of the electrode assembly 30. The positive electrode lead 40A is disposed opposite the positive electrode current collector tab 32a between a pair of insulating members 50a, 50b. The positive electrode current collector tab 32a is welded to an extending portion of the positive electrode lead 40A for electrical connection. The positive electrode lead 40A is also connected to the positive electrode terminal 20. As a result, the positive electrode lead 40A electrically connects the positive electrode terminal 20 and the positive electrode current collector tab 32a. The negative electrode lead 40B is disposed opposite the negative electrode current collector tab 32b between the pair of insulating members 50a, 50b. The negative electrode current collector tab 32b is welded to an extending portion of the negative electrode lead 40B for electrical connection. The negative electrode lead 40B is also connected to the negative electrode terminal 21. As a result, the negative electrode lead 40B electrically connects the negative electrode terminal 21 and the negative electrode current collector tab 32b.

[0017] The positive electrode lead 40A and the negative electrode lead 40B will be described in detail below. In this embodiment, the positive electrode lead 40A and the negative electrode lead 40B are formed to have the same shape and the same dimensions. Here, the configuration of the positive electrode lead 40A will be described as a representative. FIG. 5 is a perspective view showing the upper surface side of the positive electrode lead, and FIG. 6 is a perspective view showing the lower surface side of the positive electrode lead. As shown in the figure, the positive electrode lead 40A is formed by bending a conductive metal plate, such as a titanium (Ti) plate. In one example, the positive electrode lead 40A integrally includes a substantially rectangular base portion 41, a pair of rectangular first extension portions 43 extending substantially perpendicularly to the base portion 41 from both ends of one side edge of the base portion 41 extending in the longitudinal direction X, a rectangular second extension portion 45 extending substantially perpendicularly to the base portion 41 from the center of the other side edge of the base portion 41 extending in the longitudinal direction X, a rectangular first engagement protrusion 49 extending a predetermined length from the center of the one side edge in parallel with the base portion 41, and a pair of rectangular second engagement protrusions 48 extending a predetermined length from both ends of the other side edge in parallel with the base portion 41. The pair of first extension portions 43 and second extension portions 45 extend in the same direction in the height direction Z. The first engaging protrusions 49 extend in one direction in the width direction Y, and the second engaging protrusions 48 extend in the opposite direction in the width direction Y to the first engaging protrusions 49.

[0018] Two slits S extending in the longitudinal direction X are formed in the center of the base portion 41. The region of the base portion 41 between the two slits S is pushed out in the height direction Z to form a rectangular abutment portion 47. That is, the abutment portion 47 protrudes upward from the upper surface (abutment surface) 41a of the base portion 41 by approximately the plate thickness. The length in the longitudinal direction X and the width in the width direction Y of the abutment portion 47 are set slightly smaller than the length and width of the opening OP1 (OP2) of the lid 14 described above. Each of the first extending portions 43 has an outer surface that faces and is parallel to the long side wall 16a of the container body 16. Each of the first extending portions 43 has a long hole (engaged portion) 44 extending in the longitudinal direction X formed therethrough. The second extending portion 45 has an outer surface that faces and is parallel to the long side wall 16b of the container body 16. A pair of side edges of the second extending portion 45 extending in the height direction Z are each provided with a recess (engaged portion) 46. The current collecting tab of the electrode body 30 is joined or welded to the inner surface of the second extending portion 45. The negative electrode lead 40B is formed to have the same shape and dimensions as the positive electrode lead 40A described above.

[0019] As shown in FIGS. 2 and 4, the positive electrode lead 40A having the above configuration is disposed between the insulating members 50a and 50b at a position facing the positive electrode terminal 20. The outer surfaces of the pair of first extension portions 43 of the positive electrode lead 40A abut against the inner surface of the insulating member 50a, and the engaging pin 52 provided on the insulating member 50a engages with the elongated hole 44. The outer surface of the second extension portion 45 of the positive electrode lead 40A abuts against the inner surface of the insulating member 50b, and the engaging pin 52 provided on the insulating member 50b engages with the recess 46. As a result, the positive electrode lead 40A is held by the insulating members 50a and 50b while being positioned relative to the insulating member 50. The first engaging protrusion 49 is positioned so as to overlap the upper edge of the insulating member 50a. The pair of second engaging protrusions 48 are positioned so as to overlap the upper edge of the insulating member 50b. The base portion 41 and the abutment portion 47 of the positive electrode lead 40A are positioned in parallel to and facing the inner surface of the lid 14 and the positive electrode terminal 20. The extending end portion of the positive electrode current collecting tab 32a is joined to the inner surface of the second extending portion 45.

[0020] The negative electrode lead 40B is disposed between the insulating members 50a and 50b at a position facing the negative electrode terminal 21. The negative electrode lead 40B is disposed in a direction inverted by 180 degrees relative to the positive electrode lead 40A. The outer surfaces of the pair of first extension portions 43 of the negative electrode lead 40B abut against the inner surface of the insulating member 50b, and the engaging pin 52 provided on the insulating member 50b engages with the elongated hole 44. The outer surface of the second extension portion 45 of the negative electrode lead 40B abuts against the inner surface of the insulating member 50a, and the engaging pin 52 provided on the insulating member 50a engages with the recess 46. As a result, the negative electrode lead 40B is held by the insulating members 50a and 50b while being positioned relative to the insulating member 50a. The first engaging protrusion 49 is positioned so as to overlap the upper edge of the insulating member 50b. The pair of second engaging protrusions 48 is positioned so as to overlap the upper edge of the insulating member 50a. The base portion 41 and the abutment portion 47 of the negative electrode lead 40B are positioned in parallel to and facing the inner surface of the lid 14 and the negative electrode terminal 21. The extending end portion of the negative electrode current collecting tab 32b is joined to the inner surface of the second extending portion 45.

[0021] The insulating members 50a, 50b, which are combined with the positive electrode lead 40A and the negative electrode lead 40B sandwiched therebetween, are attached to the electrode body 30 by adhesive members, for example, two adhesive tapes AP. Each adhesive tape AP is attached to the insulating member 50 in an overlapping manner, with one end attached to the upper part of one surface of the electrode body 30 and the other end attached to the upper part of the other surface of the electrode body 30. As a result, the insulating member 50, the positive electrode lead 40A, and the negative electrode lead 40B are fixed and held in a position where they overlap the upper end surface of the electrode body 30.

[0022] FIG. 7 is a perspective view showing the state in which the positive electrode lead 40A and the container body 16 are engaged with each other. When the electrode assembly 30 and the insulating member 50 are housed in the container body 16, the insulating member 50 is located between the upper opening 17 of the container body 16 and the upper end surface of the electrode assembly 30. The outer peripheral surface of the insulating member 50 is close to and faces the inner surface of the container body 16. 7, the extending end of the first engaging protrusion 49 of the positive electrode lead 40A engages with a recess P1 formed in the upper edge of the long side wall 16a and is supported by the long side wall 16a. The extending end of the pair of second engaging protrusions 48 engages with a pair of recesses P2 formed in the upper edge of the long side wall 16b, respectively, and is supported by the long side wall 16b. In this way, the positive electrode lead 40A is supported by the long side walls 16a and 16b, and is positioned and held at a predetermined position relative to the container body 16. Similarly, the engaging protrusions of the negative electrode lead 40B are engaged with the recesses P1 and P2 of the long side walls 16a and 16b, and the negative electrode lead 40B is positioned and held at a predetermined position relative to the container body 16.

[0023] The internal structure of the assembled secondary battery 10 will now be described. 8 is a cross-sectional view of the secondary battery 10 taken along line AA in FIG. 1, and FIG. 9 is a cross-sectional view of the secondary battery 10 taken along line BB in FIG. 1. As shown, the lid 14 is welded or bonded to the upper end of the container body 16. The base portion 41 of the positive electrode lead 40A faces the inner surface of the lid 14 in parallel. The upper surface of the base portion 41 abuts against the inner surface of the lid 14, and the abutting portion 47 is located within the opening OP1 of the lid 14 and abuts against the lower surface of the positive electrode terminal 20. More specifically, the abutting portion 47 has spring properties that allow it to elastically deform in the height direction Z, and the positive electrode lead 40A is positioned and held in place in the height direction Z relative to the insulating member 50 by the engaging pin 52 and the first and second engaging protrusions 49, 48. Therefore, the contact portion 47 is elastically pressed against the positive electrode terminal 20 , and the upper surface (contact surface) of the contact portion 47 is in close contact with the lower surface of the first layer 20 a of the positive electrode terminal 20 . The positive electrode terminal 20 is welded to the contact portion 47 by, for example, laser welding, and is mechanically and electrically joined to the positive electrode lead 40A. During laser welding, the laser irradiation position is determined by using the through-hole 23 provided in the exposed portion 20E of the positive electrode terminal 20 as a mark. This allows the desired portion of the positive electrode terminal 20 to be accurately welded to the positive electrode lead 40A. Similar to the positive electrode terminal 20, the negative electrode terminal 21 is welded to the contact portion 47 of the negative electrode lead 40B and is mechanically and electrically joined to the negative electrode lead 40B.

[0024] The outer peripheral surface of the insulating member 50 is adjacent to and faces the inner surface of the container body 16 . 7, the extending end of the first engaging protrusion 49 of the positive electrode lead 40A engages with a recess P1 formed in the upper edge of the long side wall 16a and is supported by the long side wall 16a. The extending end of the pair of second engaging protrusions 48 engages with a pair of recesses P2 formed in the upper edges of the long side walls 16b, respectively, and is supported by the side walls 16b. In this way, the positive electrode lead 40A is supported by the long side walls 16a and 16b, and is positioned and held at a predetermined position relative to the container body 16. Similarly, the engaging protrusions of the negative electrode lead 40B are engaged with the recesses P1 and P2 of the long side walls 16a and 16b, and the negative electrode lead 40B is positioned and held at a predetermined position relative to the container body 16.

[0025] 8, the insulating member 50 is disposed between the electrode assembly 30 and the lid 14, and the outer peripheral surface of the insulating member 50 is adjacent to and faces the inner surface of the container body 16. The second extension portion 45 of the positive electrode lead 40A and the second extension portion 45 of the negative electrode lead 40B abut against the inner surfaces of the insulating members 50a and 50b, respectively. The positive electrode current collecting tab 32a is welded to the inner surface of the second extension portion 45, and is welded to the inner surface of the second extension portion 45 of the negative electrode lead 40B. As a result, the electrode body 30 is electrically connected to the positive electrode terminal 20 via the positive electrode current collecting tab 32a and the positive electrode lead 40A, and is further electrically connected to the negative electrode terminal 21 via the negative electrode current collecting tab 32b and the negative electrode lead 40B. The positive electrode terminal 20 and the positive electrode lead 40A do not protrude from the electrode body 30 in the longitudinal direction X, and are positioned so that almost their entirety faces the upper end surface of the electrode body 30 in the height direction Z. Similarly, the negative electrode terminal 21 and the negative electrode lead 40B do not protrude from the electrode body 30 in the longitudinal direction X, and are positioned so that almost their entirety faces the upper end surface of the electrode body 30 in the height direction Z. This makes it possible to reduce the dead space in the outer container 12 and obtain a secondary battery with a high volumetric energy density.

[0026] In the secondary battery 10 configured as described above, the output terminals (positive and negative terminals) have exposed portions 20E that are exposed to the outside through the opening in the lid 14, and these exposed portions 20E are provided with a pair of through-holes 23 that open to the outside of the outer casing. When the lid 14 is molded by embedding the output terminals using insert molding or the like, the through-holes 23 can be used to position the output terminals relative to the mold. This improves the positioning accuracy of the output terminals relative to the lid 14. Furthermore, when welding the output terminal to the electrode lead, the welding position can be determined based on the through hole 23, allowing the desired portion of the output terminal to be accurately welded to the electrode lead, improving welding accuracy. By providing the contact portion 47 of the electrode lead with springiness, the contact portion 47 comes into close contact with the output terminal, improving the reliability of the connection between the electrode lead and the output terminal.

[0027] The positive electrode lead 40A and the negative electrode lead 40B have a plurality of engaging protrusions 48, 49 that protrude in the planar direction of the base portion 41, and these engaging protrusions are engaged with and supported by the upper edge of the side wall of the container body. That is, the positive electrode lead and the negative electrode lead are supported and positioned by the container body. Therefore, even if a load acts on the positive electrode lead 40A and the negative electrode lead 40B when the lid 14 is joined to the container body, the leads can be prevented from shifting position and can be held and fixed in the predetermined position. The positive electrode lead 40A and the negative electrode lead 40B are arranged so that their planar directions are inverted by 180 degrees from each other. In other words, the positive electrode lead 40A and the negative electrode lead 40B are formed and arranged symmetrically with respect to the central axis C (see FIG. 2) of the height direction Z of the secondary battery 10. The pair of leads are symmetrically engaged with the pair of long side walls 16a, 16b of the container body 16. Therefore, the lid 14 can be joined to the pair of long side walls 16a, 16b with equal strength, thereby improving the joining strength of the outer container 12. As described above, according to the first embodiment, a secondary battery can be obtained that can improve the connection accuracy and connection reliability between the output terminals and leads.

[0028] Next, a secondary battery according to another embodiment of the present invention will be described. In the following embodiment, the same parts and components as those in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and their description will be omitted or simplified. The following description will focus on the parts that are different from the first embodiment. (Second embodiment) FIG. 10 is a plan view showing the secondary battery according to the second embodiment with the lid omitted. According to this embodiment, the secondary battery is configured as a battery pack having a plurality of, for example, three, secondary batteries 10A, 10B, and 10C. The container body of the outer container 12 has a pair of opposing long side walls 16a and 16b, a pair of opposing side walls 16C, and two partition walls 16e located between the pair of long side walls 16a and 16b. The long side walls 16a and 16b and the partition walls 16e are aligned parallel to each other and spaced apart in the width direction Y. This forms three storage chambers 55A, 55B, and 55C within the container body 16.

[0029] An electrode body 30A is housed in the housing chamber 55A. A positive electrode lead 40A and a negative electrode lead 40B are arranged on top of the electrode body 30A and are each connected to the current collecting tabs of the electrode body 30A. The electrode body 30A and the positive and negative electrode leads 40A, 40B constitute a secondary battery 10A. The positive electrode lead 40A and the negative electrode lead 40B are arranged in orientations that are 180 degrees opposite to each other in the planar direction. The first engaging protrusion 49 of the positive electrode lead 40A is supported in a recess in the long side wall 16a, and the pair of second engaging protrusions 48 are each supported in a recess in the partition wall 16e. The first engaging protrusion 49 of the negative electrode lead 40B is supported in a recess in the partition wall 16e, and the pair of second engaging protrusions 48 are each supported in a recess in the long side wall 16a.

[0030] The electrode body 30B is housed in the housing chamber 55B. A positive electrode lead 40A and a negative electrode lead 40B are arranged on top of the electrode body 30B and are connected to the current collecting tabs of the electrode body 30B. The electrode body 30B and the positive and negative electrode leads 40A, 40B constitute a secondary battery 10B. The positive electrode lead 40A and the negative electrode lead 40B are arranged in directions that are 180 degrees opposite to each other in the planar direction. The positive electrode lead 40A is arranged alongside the negative electrode lead 40B of the secondary battery 10A in the width direction Y, and is arranged in the same direction as the negative electrode lead 40B of the secondary battery 10A. The negative electrode lead 40B is arranged alongside the positive electrode lead 40A of the secondary battery 10A in the width direction Y, and is arranged in the same direction as the positive electrode lead 40A of the secondary battery 10A. That is, the first engaging protrusion 49 of the positive electrode lead 40A is supported in a recess in the partition wall 16e on the long side wall 16b side, and the pair of second engaging protrusions 48 are each supported in a recess in the partition wall 16e on the long side wall 16a side. The first engaging protrusion 49 of the negative electrode lead 40B is supported in a recess in the partition wall 16e on the long side wall 16a side, and the pair of second engaging protrusions 48 are each supported in a recess in the partition wall 16e on the long side wall 16b side.

[0031] An electrode body 30C is housed in the housing chamber 55C. A positive electrode lead 40A and a negative electrode lead 40B are arranged on top of the electrode body 30C and are each connected to the current collecting tabs of the electrode body 30C. The electrode body 30C and the positive and negative electrode leads 40A, 40B constitute a secondary battery 10C. The positive electrode lead 40A and the negative electrode lead 40B are arranged in directions that are 180 degrees opposite to each other in the planar direction. The positive electrode lead 40A is arranged alongside the negative electrode lead 40B of the secondary battery 10B in the width direction Y, and is arranged in the same direction as the negative electrode lead 40B of the secondary battery 10B. The negative electrode lead 40B is arranged alongside the positive electrode lead 40A of the secondary battery 10B in the width direction Y, and is arranged in the same direction as the positive electrode lead 40A of the secondary battery 10B. That is, the first engaging protrusion 49 of the positive electrode lead 40A is supported in a recess in the partition wall 16e on the long side wall 16b side, and the pair of second engaging protrusions 48 are each supported in a recess in the long side wall 16b. The first engaging protrusion 49 of the negative electrode lead 40B is supported in a recess in the long side wall 16b, and the pair of second engaging protrusions 48 are each supported in a recess in the partition wall 16e on the long side wall 16b side.

[0032] As described above, in the three secondary batteries 10A, 10B, and 10C, the three positive electrode leads 40A are arranged in a staggered pattern in the width direction Y, and the three negative electrode leads 40B are arranged in a staggered pattern in the width direction Y. As a result, the positive electrode leads 40A and the negative electrode leads 40B provided at one end in the longitudinal direction X are arranged alternately while facing the same direction. The negative electrode leads 40B and the positive electrode leads 40A provided at the other end in the longitudinal direction X are arranged alternately while facing the same direction, which is the opposite direction to the three electrode leads. In the second embodiment, the other configurations of the secondary batteries 10A, 10B, and 10C are the same as the configuration of the secondary battery 10 according to the first embodiment.

[0033] According to the second embodiment configured as described above, even in a battery pack having a plurality of secondary batteries, a sufficient bonding area can be secured on the upper end surfaces of the long side walls 16a, 16b and the partition wall 16e, and the bonding strength between the container body and the lid (not shown) can be increased, thereby providing a secondary battery with improved reliability.

[0034] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. In the above-described embodiment, the positive electrode lead and the negative electrode lead have the same shape and configuration, but this is not limited to this and they may be configured with different shapes. The second engaging protrusion of the lead is not limited to a pair, but may be a single one. The electrode body is not limited to a so-called stacked type electrode body formed by stacking multiple electrode plates in the thickness direction, but a so-called wound type electrode body formed by winding electrode plates may also be applied. Furthermore, the forming materials, shapes, sizes, etc. of the elements constituting the secondary battery are not limited to the above-described embodiment and can be variously changed as needed. [Explanation of symbols]

[0035] 10, 10A, 10B, 10C... Secondary battery, 12... Outer container, 14... Lid, 16... Container body, 16a, 16b...long side wall, 20...positive electrode terminal, 21...negative electrode terminal, 20a...first layer, 20b... second layer, 20c... connection portion, 20E... exposed portion, 23... through hole, OP1, OP2... opening, 30...electrode body, 32a, 32b...current collecting tabs, 40A...positive electrode lead, 40B...negative electrode lead, 47...Abutting portion, 48...Second engagement protrusion, 49...First engagement protrusion

Claims

1. an outer container having a lid; an electrode assembly having a current collecting tab and housed in the outer container; an output terminal provided on the cover; a lead provided between the electrode body and the lid body in the outer container, the lead electrically connecting the current collecting tab and the output terminal; the output terminal has a connection portion exposed to the outside of the lid body and to which a connection member can be connected, an exposed portion exposed to the outside of the lid body, and a through-hole formed in the exposed portion, and the exposed portion is joined to the lead, The lead has a base portion having an abutment surface facing the lid body, and a spring-like abutment portion that protrudes from the base portion toward the lid body and abuts against the exposed portion of the output terminal. Secondary battery.

2. 2. The secondary battery of claim 1, wherein the output terminal has a first layer formed of the same metal as the lead and including the exposed portion, and a second layer formed of a metal different from the lead, laminated on the first layer in an area excluding the exposed portion, and including the connection portion.

3. the lead has a first engaging protrusion located on the same plane as the contact surface and protruding from the base portion in a first direction, and a second engaging protrusion located on the same plane as the contact surface and protruding from the base portion in a second direction different from the first direction, The outer container includes a container body having a pair of long side walls opposed to each other at a distance and an opening formed between one end edges of the pair of long side walls, and the lid body is fixed to the one end edges of the pair of long side walls to close the opening, the base portion of the lead is disposed between the pair of long side walls, and the first engaging protrusion and the second engaging protrusion are supported by one end edge of one long side wall and one end edge of the other long side wall, respectively; The secondary battery according to claim 1 .

4. the output terminal includes a positive electrode terminal provided at one end of the lid body and a negative electrode terminal provided at the other end of the lid body, and the leads include a positive electrode lead connected to the positive electrode terminal and a negative electrode lead connected to the negative electrode terminal, The positive electrode lead and the negative electrode lead are such that the orientation of the first engaging protrusion and the second engaging protrusion is The secondary battery according to claim 3 , wherein the first and second electrodes are arranged in symmetrical positions about an axis in the height direction of the container body.

5. The lid has an opening that penetrates the lid in a thickness direction, the output terminal is embedded in the lid and extends across the opening; the exposed portion is exposed to the outer surface and the inner surface of the lid through the opening, The contact portion of the lead projects into the opening and contacts the exposed portion. The secondary battery according to claim 1 .

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