Secondary battery

Abstract

The present disclosure provides a secondary battery capable of suppressing damage to an electrode body. A secondary battery is provided with an electrode body in which one or more negative electrode tabs are formed at a first end and one or more positive electrode tabs are formed at a second end, a case that houses the electrode body, and a negative electrode terminal and a positive electrode terminal provided in the case, the case including a cylindrical main body, a first sealing body, and a second sealing body, the negative electrode terminal being provided in the first sealing body, and the positive electrode terminal being provided in the second sealing body. The positive electrode terminal is provided in the second sealing body, the one or more negative electrode tabs are electrically connected to the negative electrode terminal, the one or more positive electrode tabs are electrically connected to the positive electrode terminal, and the length of one of the one or more negative electrode tabs and the one or more positive electrode tabs is greater than the length of the other of the one or more negative electrode tabs and the one or more positive electrode tabs.

Description

Technical Field

[0001] The present disclosure relates to a secondary battery, and in particular to a secondary battery mounted on a vehicle. Background Art

[0002] As a conventional secondary battery, U.S. Patent Application Publication No. 2022 / 0302533 discloses a structure in which openings of a case body opened on both sides in the longitudinal direction of a case for storing an electrode body are each closed by a cover member provided with an external terminal. Summary of the invention

[0003] In the secondary battery disclosed in U.S. Patent Application Publication No. 2022 / 0302533, the external terminal and the current collector are pre-assembled on the cover member to form a cover assembly, and then the electrode tab provided on the electrode body is fixed to the current collector of the cover assembly. Next, in a state where the electrode tab is fixed to the current collector, the opening of the case body is closed with the cover assembly.

[0004] Specifically, first, the electrode tab (e.g., positive electrode tab) of the electrode body is connected to the current collector of the cap assembly on one side in the long-side direction, and the opening of the case body is closed with the cap assembly. Next, the electrode tab (e.g., negative electrode tab) of the electrode body is connected to the current collector of the cap assembly on the other side in the long-side direction, and the opening of the case body is closed with the cap assembly.

[0005] There is a concern that the electrode tab may be pulled and fixed to the current collector on the other side in the long direction due to the different fixing states of the current collector and the electrode tab on one side in the long direction. In this case, if no measures are taken, the entire electrode body may be pulled and damaged.

[0006] The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a secondary battery capable of suppressing damage to an electrode body.

[0007] The secondary battery disclosed in the present invention comprises: an electrode body, the electrode body having a first end located on one side of the first direction and a second end located on the other side of the first direction, one or more negative electrode tabs formed at the first end, and one or more positive electrode tabs formed at the second end; a shell for accommodating the electrode body; and a negative terminal and a positive terminal disposed on the shell. The shell includes: a main body having a first opening on the one side of the first direction and a second opening on the other side of the first direction, a first sealing body for closing the first opening, and a second sealing body for closing the second opening. The negative terminal is disposed on the first sealing body. The positive terminal is disposed on the second sealing body. The one or more negative electrode tabs are electrically connected to the negative terminal. The one or more positive electrode tabs are electrically connected to the positive terminal. The length of one of the one or more negative electrode tabs and the one or more positive electrode tabs is greater than the length of the other of the one or more negative electrode tabs and the one or more positive electrode tabs.

[0008] According to the above configuration, the electrode tab of one of the positive electrode tab and the negative electrode tab is electrically connected to the external terminal of the positive terminal and the negative terminal, which has the same polarity as the electrode tab of the above one. The electrode tab of the other of the positive electrode tab and the negative electrode tab is electrically connected to the external terminal of the other of the positive terminal and the negative terminal. The external terminal of the above one is provided on the sealing body of one of the first sealing body and the second sealing body. The external terminal of the above other is provided on the sealing body of the other of the first sealing body and the second sealing body. The sealing body of the above one closes the opening of one of the first opening and the second opening. The sealing body of the above other closes the opening of the other of the first opening and the second opening.

[0009] When assembling a secondary battery, the electrode tab of one side is electrically connected to the external terminal of the other side and the opening of the other side of the main body is closed with the sealing body of the other side, while the electrode tab of the other side is electrically connected to the external terminal of the other side and the opening of the other side of the main body is closed with the sealing body of the other side. At this time, as described above, the electrode tab of one side is longer than the electrode tab of the other side. Thus, the sealing body of one side can be assembled to the opening of one side while adjusting the relaxation of the electrode tab of one side. As a result, the force applied to the electrode body can be suppressed, and the damage of the electrode body can be suppressed.

[0010] In the secondary battery according to the present disclosure, one of the one or more negative electrode tabs and the one or more positive electrode tabs may be more relaxed than the other of the one or more negative electrode tabs and the one or more positive electrode tabs.

[0011] According to the above configuration, since one electrode tab is loosened to a greater extent than the other electrode tab, it is possible to more reliably suppress the force applied to the electrode body.

[0012] In the secondary battery based on the above-mentioned present disclosure, the above-mentioned main body has a first wall portion and a second wall portion that are opposite to each other in a second direction orthogonal to the above-mentioned first direction. The above-mentioned first wall portion is located on one side of the above-mentioned second direction. The above-mentioned second wall portion is located on the other side of the above-mentioned second direction. The above-mentioned electrode body has a third end portion located on the above-mentioned one side of the above-mentioned second direction, and a fourth end portion located on the above-mentioned other side of the above-mentioned second direction. In this case, the above-mentioned one or more negative electrode tabs and the above-mentioned one or more positive electrode tabs may also include: a portion that is loosened in a manner closer to the above-mentioned first wall portion than the above-mentioned third end portion, or a portion that is loosened in a manner closer to the above-mentioned second wall portion than the above-mentioned fourth end portion.

[0013] According to the above configuration, a large margin for adjusting the degree of looseness of one electrode tab can be ensured, so that the electrode body can be stably electrically connected to the positive electrode terminal and the negative electrode terminal.

[0014] In the secondary battery based on the present disclosure, the other of the one or more negative electrode tabs and the one or more positive electrode tabs may also be configured not to extend from the third end toward the first wall portion in the second direction and not to extend from the fourth end toward the second wall portion.

[0015] According to the above configuration, the degree of loosening of the other electrode tab can be reduced, and the contact between the other electrode tab and the case can be suppressed.

[0016] The secondary battery according to the present disclosure may further include an insulating member disposed between a slack portion of one of the one or more negative electrode tabs and the one or more positive electrode tabs and the case to insulate the slack portion from the case.

[0017] According to the above configuration, by insulating the slack portion and the case with the insulating member, it is possible to suppress electrical conduction between one electrode tab and the case.

[0018] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a perspective view of the secondary battery according to the first embodiment.

[0020] Figure 2 This is an exploded perspective view of the secondary battery according to the first embodiment.

[0021] Figure 3 It is along Figure 1 A cross-sectional view along line III-III is shown.

[0022] Figure 4 It is along Figure 1 A cross-sectional view taken along line IV-IV is shown.

[0023] Figure 5 It is a cross-sectional view of the secondary battery showing the connection state of the positive electrode tab and the negative electrode tab according to the first embodiment.

[0024] Figure 6 It is a cross-sectional view of a secondary battery showing a connection state between a positive electrode tab and a negative electrode tab according to a second embodiment.

[0025] Figure 7 It is a cross-sectional view of a secondary battery showing a connection state between a positive electrode tab and a negative electrode tab according to a third embodiment. DETAILED DESCRIPTION

[0026] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and their description will not be repeated.

[0027] (Implementation Method 1)

[0028] Figure 1 This is a perspective view of the secondary battery according to the first embodiment. Figure 2 This is an exploded perspective view of the secondary battery according to the first embodiment. Figure 3 It is along Figure 1 A cross-sectional view along line III-III is shown.

[0029] like Figure 1 to Figure 3 As shown, the secondary battery 10 of the first embodiment includes an electrode body 100 , a case 200 , a positive electrode member 620 as a positive electrode terminal, and a negative electrode member 520 as a negative electrode terminal.

[0030] The electrode body 100 has a first end 101 located on one side in a first direction and a second end 102 located on the other side in the first direction. The first direction is a direction parallel to a width direction W described later. A plurality of negative electrode tabs 110N are provided at the first end 101. A plurality of positive electrode tabs 110P are provided at the second end 102.

[0031] The electrode body 100 has a third end 103 located on one side of a second direction orthogonal to the first direction, and a fourth end 104 located on the other side of the second direction. The second direction is a direction parallel to a thickness direction T described later. Figure 4 Will describe later.

[0032] The case 200 has a rectangular parallelepiped shape in which the thickness in the thickness direction T is smaller than the width in the width direction W and the height in the height direction H. The thickness direction T is parallel to the positive electrode 110 (see Figure 4 ) and the negative electrode 120 (refer to Figure 4 ) are arranged in parallel. The width direction W is orthogonal to the thickness direction T. The height direction H is orthogonal to the thickness direction T and the width direction W. The width of the housing 200 in the width direction W is greater than the height of the housing 200 in the height direction H. The width direction W is taken as the long side direction of the housing 200, and the height direction H is taken as the short side direction of the housing 200.

[0033] The case 200 accommodates the electrode assembly 100 and an electrolyte solution (not shown) therein. The case 200 includes a main body 210 , a first sealing body 510 , and a second sealing body 610 .

[0034] The main body 210 has a cylindrical shape with a first opening 215 and a second opening 216 respectively provided on both sides in the width direction W. More specifically, the main body 210 has a quadrangular cylindrical shape with both sides open in the width direction W. The first opening 215 is provided on one side in the width direction W, and the second opening 216 is provided on the other side in the width direction W. The main body 210 is made of a metal such as aluminum.

[0035] The main body 210 includes a first wall 211 and a second wall 212 facing each other in the thickness direction T, and a third wall 213 and a fourth wall 214 facing each other in the height direction H. The areas of the first wall 211 and the second wall 212 are larger than those of the third wall 213 and the fourth wall 214 .

[0036] The first wall portion 211 is arranged opposite to the third end portion 103 of the electrode body 100, and the second wall portion 212 is arranged opposite to the fourth end portion 104 of the electrode body 100. The third wall portion 213 is located on one side (upper side) of the height direction H. The third wall portion 213 connects the ends of the first wall portion 211 and the second wall portion 212 located on one side of the height direction H to each other. The fourth wall portion 214 is located on the other side (lower side) of the height direction H. The fourth wall portion 214 connects the ends of the first wall portion 211 and the second wall portion 212 located on the other side of the height direction H to each other.

[0037] The first sealing body 510 closes the first opening 215. The first sealing body 510 has a flat plate shape. The first sealing body 510 is made of a metal such as aluminum. The first sealing body 510 is fixed to the first opening 215 by laser welding or the like, for example.

[0038] The second sealing body 610 blocks the second opening 216. The second sealing body 610 has a flat plate shape. The second sealing body 610 is made of a metal such as aluminum. The second sealing body 610 is fixed to the second opening 216 by laser welding or the like, for example.

[0039] The first sealing body 510 and the second sealing body 610 are each provided with a pressure release valve 222 and a liquid injection port 224. The pressure release valve 222 is configured to rupture when the internal pressure of the housing 200 reaches a predetermined pressure or more. When the pressure release valve 222 ruptures, the gas in the housing 200 is discharged to the outside of the housing 200, so that the internal pressure in the housing 200 decreases.

[0040] The liquid injection port 224 is sealed by a sealing member 225. The liquid injection port 224 is a through hole for injecting electrolyte into the shell 200 during the manufacturing process of the secondary battery 10. The liquid injection port 224 is sealed by a sealing member 225. The sealing member 225 is a member that seals the liquid injection port 224 after the electrolyte is injected into the shell 200. As the sealing member 225, for example, it can be a vent film that does not allow liquid to pass through but allows gas to pass through. In this case, when the gas generated during charging is discharged to the outside of the shell 200, the gas can be discharged through the vent film. Thus, the trouble of setting up an exhaust port separately is saved. Moreover, the vent film can be used to suppress the leakage of the electrolyte to the outside of the shell 200. Furthermore, the sealing member 225 is not limited to the vent film, and a resin member, a metal member, etc. can be appropriately used.

[0041] The negative electrode member 520 is provided on the first sealing body 510 , and the positive electrode member 620 is provided on the second sealing body 610 .

[0042] The negative electrode member 520 is provided on the outer surface of the first sealing body 510 . The negative electrode member 520 functions as a negative electrode terminal. The negative electrode member 520 includes a negative electrode terminal plate 521 and an insulating plate 522 .

[0043] The negative terminal plate 521 is formed in a substantially rectangular parallelepiped shape. The negative terminal plate 521 is held by an insulating plate 522. The insulating plate 522 is fixed to the outer surface of the first sealing body 510. The insulating plate 522 insulates the first sealing body 510 from the negative terminal plate 521. A through hole for inserting a cylindrical portion 532 described later is provided on each of the negative terminal plate 521 and the insulating plate 522.

[0044] The positive electrode member 620 is provided on the outer surface of the second sealing body 610 . The positive electrode member 620 functions as a positive electrode terminal. The positive electrode member 620 includes a positive electrode terminal plate 621 and a terminal block 622 .

[0045] The positive electrode terminal plate 621 is formed in a rectangular parallelepiped shape and is made of metal such as aluminum.

[0046] The terminal block 622 is formed in a rectangular parallelepiped shape. The terminal block 622 is made of a metal (iron, etc.) different from the metal constituting the positive terminal plate 621. The terminal block 622 is fixed to the outer surface of the second sealing body 610 by welding or the like. The positive terminal plate 621 is fixed to the terminal block 622 by welding or the like. The main body 210 and the second sealing body 610 are electrically connected to the positive terminal plate 621 via the terminal block 622, and are charged with the same polarity as the positive terminal plate 621. A through hole for inserting the cylindrical portion 632 described later is formed on each of the positive terminal plate 621 and the terminal block 622.

[0047] Furthermore, an insulating plate may be disposed between the positive electrode member 620 and the second sealing body 610 to electrically insulate the positive electrode member 620 from the second sealing body 610. In this case, the insulating plate may be disposed instead of the terminal block 622 or between the terminal block 622 and the second sealing body 610.

[0048] The secondary battery 10 further includes a negative electrode side conductive member 530 and an insulator 560 on the negative electrode member 520 side.

[0049] The negative electrode side conductive member 530 connects a plurality of negative electrode tabs 110N and a negative electrode terminal plate 521. The plurality of negative electrode tabs 110N are connected to the negative electrode side conductive member 530 in a bundled state by ultrasonic welding or the like. The negative electrode side conductive member 530 includes a plate-like portion 531 and a cylindrical portion 532. The plate-like portion 531 is substantially parallel to the inner surface of the first sealing body 510. The cylindrical portion 532 extends in a direction parallel to the first direction. The top end of the cylindrical portion 532 penetrates the first sealing body 510, the insulating plate 522 and the negative electrode terminal plate 521, and is riveted to the negative electrode terminal plate 521.

[0050] The insulator 560 is disposed between the plate-shaped portion 531 and the first sealing member 510 to insulate the plate-shaped portion 531 from the first sealing member 510. The insulator 560 includes a portion covering the periphery of the base end side of the cylindrical portion 532 and a portion located between the plate-shaped portion 531 and the inner surface of the first sealing member 510.

[0051] The negative electrode member 520 , the first sealing body 510 , the negative electrode side conductive member 530 , and the insulator 560 described above are assembled to form the first cap assembly 50 .

[0052] With the plurality of negative electrode tabs 110N and the negative electrode-side conductive member 530 fixed by welding or the like, the first sealing body 510 is attached to the first opening 215 , whereby the first cap assembly 50 is fixed to the main body 210 .

[0053] The secondary battery 10 further includes a positive electrode side conductive member 630 and an insulator 660 on the positive electrode member 620 side.

[0054] The positive electrode side conductive member 630 connects a plurality of positive electrode tabs 110P and a positive terminal plate 621. A plurality of positive electrode tabs 110P are connected to the positive electrode side conductive member 630 in a bundled state by ultrasonic welding or the like. The positive electrode side conductive member 630 includes a plate-shaped portion 631 and a cylindrical portion 632. The plate-shaped portion 631 is substantially parallel to the inner surface of the second sealing body 610. The cylindrical portion 632 extends in a direction parallel to the first direction. The top end of the cylindrical portion 632 passes through the second sealing body 610, the terminal block 622 and the positive terminal plate 621, and is riveted to the positive terminal plate 621.

[0055] The insulator 660 is disposed between the plate portion 631 and the second sealing member 610 to insulate the plate portion 631 from the second sealing member 610. The insulator 660 includes a portion covering the periphery of the base end side of the cylindrical portion 632 and a portion located between the plate portion 631 and the inner surface of the second sealing member 610.

[0056] The positive electrode member 620 , the second sealing body 610 , the positive electrode-side conductive member 630 , and the insulator 660 described above are assembled to form the second cap assembly 60 .

[0057] With the plurality of positive electrode tabs 110P and the positive electrode-side conductive member 630 fixed by welding or the like, the second sealing body 610 is attached to the second opening 216 , whereby the second cap assembly 60 is fixed to the main body 210 .

[0058] Figure 4 It is along Figure 1 The cross-sectional view along the line IV-IV is shown. Figure 4 In the figure, for the sake of convenience, the housing 200 of the secondary battery 10 is omitted, and only the electrode body 100 is shown. Figure 4 , the details of the electrode body 100 will be described.

[0059] like Figure 4 As shown, the electrode body 100 includes a plurality of positive electrodes 110 , a plurality of negative electrodes 120 , and a separator 130 . The plurality of positive electrodes 110 and the plurality of negative electrodes 120 are arranged alternately in the thickness direction T while being insulated by the separator 130 .

[0060] Each negative electrode 120 is formed in a rectangular shape with a width direction W as a long side direction and a height direction H as a short side direction. Each negative electrode 120 includes a negative electrode current collector foil 122 and a negative electrode active material layer 124 provided on both sides of the negative electrode current collector foil 122. Figure 4 As shown, the negative electrode current collector foil 122 has a negative electrode tab 110N on which the negative electrode active material layer 124 is not provided. The negative electrode tab 110N protrudes toward one side in the width direction W.

[0061] Each positive electrode 110 is formed into a rectangular shape with the width direction W as the long side direction and the height direction H as the short side direction. Each positive electrode 110 includes a positive electrode collector foil 112 and a positive electrode active material layer 114 provided on both sides of the positive electrode collector foil 112 in the thickness direction T. The positive electrode collector foil 112 includes a positive electrode tab 110P on which the positive electrode active material layer 114 is not provided. The positive electrode tab 110P protrudes toward the other side in the width direction W.

[0062] The separator 130 insulates the positive electrode 110 from the negative electrode 120. The separator 130 is made of an insulating material and has minute gaps that allow ions to pass through. The separator 130 is formed in a hairpin shape.

[0063] The separator 130 has a rectangular shape before being formed into a hairpin shape. The separator 130 is arranged between the positive electrode 110 and the negative electrode 120 while being formed into a hairpin shape. The separator 130 has a plurality of intervening portions 132a, a plurality of first folded portions 132b, a plurality of second folded portions 132c, and an outermost covering portion 132d.

[0064] Each intervening portion 132a is interposed between the positive electrode 110 and the negative electrode 120 adjacent to each other in the thickness direction T. That is, each intervening portion 132a has a function of insulating the positive electrode 110 from the negative electrode 120. Each intervening portion 132a is composed of a rectangular region.

[0065] Each first folded portion 132b connects ends of the intervening portions 132a adjacent to each other in the thickness direction T with the positive electrode 110 therebetween on one side in the height direction H. The first folded portion 132b is disposed on one side in the height direction H of the positive electrode 110 (upper side).

[0066] Each second folded portion 132c connects the other ends of the intervening portion 132a adjacent to each other in the thickness direction T with the negative electrode 120 therebetween. The second folded portion 132c is disposed on the other side (lower side) in the height direction H of the negative electrode 120 .

[0067] The outermost covering portion 132d covers all the first folding portions 132b and all the second folding portions 132c collectively. In more detail, the outermost covering portion 132d covers all the positive electrodes 110, all the negative electrodes 120, all the intervening portions 132a, all the first folding portions 132b, and all the second folding portions 132c collectively while winding around a central axis parallel to the width direction W. The terminal 132e of the outermost covering portion 132d is set in a range that does not overlap with the positive electrode active material layer 114 and the negative electrode active material layer 124 in the thickness direction T. In the present embodiment, the terminal 132e of the outermost covering portion 132d is set at a position lower than each positive electrode 110 and each negative electrode 120. Furthermore, the peripheral surface and bottom surface of multiple positive electrodes 110, multiple negative electrodes 120, and the separator 130 may also be covered with an insulating film (not shown).

[0068] Figure 5 It is a cross-sectional view of the secondary battery showing the connection state of the positive electrode tab and the negative electrode tab according to the first embodiment. Figure 5 It is along Figure 3 A cross-sectional view taken along line VV is shown. [006

[0070] like Figure 5 As shown, each of the plurality of negative electrode tabs 110N is longer than each of the plurality of positive electrode tabs 110P. The plurality of negative electrode tabs 110N have a slack portion 110T. The plurality of negative electrode tabs 110N are more slack than the plurality of positive electrode tabs 110P.

[0071] Any of the plurality of negative electrode tabs 110N includes a loose portion that is closer to the first wall portion 211 than the third end portion 103 of the electrode body 100 .

[0072] The negative electrode tab 110N located on the opposite side (the other side in the second direction) to the bulging direction (the one side in the second direction) of the slack portion 110T among the plurality of negative electrode tabs 110N is bent in a substantially U-shape. Specifically, the negative electrode tab 110N is bent from the one side in the second direction toward the other side in the second direction as it moves from the electrode body 100 toward the first sealing body 510.

[0073] The negative electrode tab 110N located on the bulging direction side among the plurality of negative electrode tabs 110N is bent in a substantially S-shape. Specifically, the negative electrode tab 110N is bent to bulge to the other side in the second direction and then to bulge to one side in the second direction as it approaches the first sealing body 510 from the electrode body 100 .

[0074] On the other hand, the plurality of positive electrode tabs 110P are arranged so that none of them protrudes from the third end 103 toward the first wall portion 211 side in the second direction (thickness direction T), and none of them protrudes from the fourth end 104 toward the second wall portion 212 side. The positive electrode tab 110P located on the other side in the second direction among the plurality of positive electrode tabs 110P is bent into a substantially U-shape so as to temporarily face one side in the second direction and then face the other side in the second direction as it moves from the electrode body 100 toward the second sealing body 610. The positive electrode tab 110P located on one side in the second direction among the plurality of positive electrode tabs 110P is bent so as to face the other side in the second direction as it moves from the electrode body 100 toward the second sealing body 610.

[0075] In this way, the plurality of negative electrode tabs 110N are longer than the plurality of positive electrode tabs 110P. Therefore, after the second cover assembly 60 is assembled to the second opening 216 of the main body 210, when the first cover assembly 50 is assembled to the first opening 215 of the main body 210, the first sealing body 510 can be fixed to the main body 210 while adjusting the degree of slack of the plurality of negative electrode tabs 110N. Thus, when assembling the first cover assembly, it is possible to suppress the situation where the electrode body 100 is pulled toward one side of the first direction (the first opening 215 side) as a whole. As a result, the force applied to the electrode body 100 can be suppressed, and damage to the electrode body 100 can be suppressed.

[0076] Furthermore, the plurality of negative electrode tabs 110N are loosened to a greater extent than the plurality of positive electrode tabs 110P, and thus the force applied to the electrode body 100 can be more reliably suppressed when the first cap assembly 50 is assembled.

[0077] Furthermore, since the plurality of negative electrode tabs 110N include a slack portion closer to the first wall portion 211 than the third end portion 103 , a large margin for adjusting the degree of slack can be ensured. Thus, the electrode body 100 and the external terminal can be electrically connected stably.

[0078] Furthermore, since the plurality of positive electrode tabs 110P do not extend from the third end 103 toward the first wall 211 in the second direction, and do not extend from the fourth end 104 toward the second wall 212, the degree of slack of the positive electrode tabs 110P can be reduced. Thus, the plurality of positive electrode tabs 110P can be prevented from contacting the housing.

[0079] (Implementation Method 2)

[0080] Figure 6 : is a cross-sectional view of a secondary battery showing the connection state of the positive electrode tab and the negative electrode tab of Embodiment 2. Specifically, Figure 6 is the same as above Figure 5 A cross-sectional view of the secondary battery according to the second embodiment at corresponding positions.

[0081] like Figure 6 As shown, the secondary battery 10A of the second embodiment is different from the secondary battery 10 of the first embodiment in that an insulating member 80 is provided. The other structures are substantially the same.

[0082] The insulating member 80 is disposed between the slack portion 110T and the housing 200. The insulating member 80 is disposed between the wall of the main body 210 and the slack portion 110T that faces the slack portion 110T in the second direction. In the present embodiment, the insulating member 80 fills the gap between the slack portion 110T and the first wall portion 211.

[0083] The insulating member 80 has a support surface 81 which is provided along the slack portion 110T and supports the slack portion 110T. The support surface 81 is, for example, a curved surface curved in a U-shape.

[0084] Even when configured as above, the secondary battery 10A according to the second embodiment has substantially the same effects as those of the secondary battery 10 according to the first embodiment.

[0085] Furthermore, by providing the insulating member 80, the plurality of negative electrode tabs 110N can be prevented from contacting and conducting with the case 200. Furthermore, by having the supporting surface 81 of the insulating member 80, the movement of the plurality of negative electrode tabs 110N can be restricted. Thus, the loose portion 110T can be prevented from contacting and conducting with the case 200 unintentionally.

[0086] (Implementation 3)

[0087] Figure 7 : is a cross-sectional view of a secondary battery showing the connection state of the positive electrode tab and the negative electrode tab of Embodiment 3. Specifically, Figure 7 is the same as above Figure 5 A cross-sectional view of the secondary battery according to the third embodiment at corresponding positions.

[0088] like Figure 7 As shown, the secondary battery 10B of the third embodiment is different from the secondary battery 10 of the first embodiment mainly in the shapes of the negative electrode side conductive member 530 and the positive electrode side conductive member 630. The other structures are substantially the same.

[0089] The negative electrode side conductive member 530 has a first extension portion 533 extending in the first direction toward the first end portion 101 of the electrode body 100. The first extension portion 533 is provided at an end portion of the plate-shaped portion 531 located on one side in the second direction. The first extension portion 533 has an outer main surface facing the first wall portion 211 and an inner main surface located on the opposite side of the outer main surface in the second direction.

[0090] The plurality of negative electrode tabs 110N are connected to the inner main surface of the first extension portion 533. The plurality of negative electrode tabs 110N have a bent portion that is bent in a U-shape as a whole. The bent portion is bent in the following manner: as it moves from the electrode body 100 toward the first sealing body 510, it temporarily moves toward the side opposite to the side where the first extension portion 533 is located in the second direction, and then moves toward the side where the first extension portion 533 is located. The slack portion of the plurality of negative electrode tabs 110N is formed by the bent portion.

[0091] The positive electrode side conductive member 630 has a second extension portion 633, and the second extension portion 633 extends along the first direction toward the second end portion 102 of the electrode body 100. The second extension portion 633 is provided at the end of the plate-shaped portion 631 located on one side in the second direction. The second extension portion 633 has an outer main surface facing the first wall portion 211, and an inner main surface located on the opposite side of the outer main surface in the second direction.

[0092] The plurality of negative electrode tabs 110N may be provided so that none of them protrudes from the third end 103 toward the first wall portion 211 and none of them protrudes from the fourth end 104 toward the second wall portion 212 in the second direction (thickness direction T).

[0093] The plurality of positive electrode tabs 110P are connected to the inner main surface of the second extending portion 633. The plurality of positive electrode tabs 110P have less slack than the plurality of negative electrode tabs 110N.

[0094] The plurality of positive electrode tabs 110P may be provided so that none of them protrudes from the third end portion 103 toward the first wall portion 211 in the second direction (thickness direction T) and none of them protrudes from the fourth end portion 104 toward the second wall portion 212 .

[0095] Even when configured as above, the secondary battery 10B according to the third embodiment has substantially the same effects as those of the secondary battery 10 according to the first embodiment.

[0096] Furthermore, in Embodiment 3, the first extension portion 533 and the second extension portion 633 are provided at the ends of the plate-like portions 531 and 631 located on one side in the second direction, but the present invention is not limited thereto. The first extension portion 533 and the second extension portion 633 may also be provided at the ends of the plate-like portions 531 and 631 located on the other side in the second direction.

[0097] (Other Modifications)

[0098] In the above-mentioned embodiments 1 to 3, the case where the plurality of negative electrode tabs 110N are longer than the plurality of positive electrode tabs 110P is illustrated, but it is not limited thereto. The plurality of positive electrode tabs 110P may also be longer than the plurality of negative electrode tabs 110N. In this case, after the first cover assembly 50 is assembled to the first opening 215 of the main body 210, when the second cover assembly 60 is assembled to the second opening 216 of the main body 210, the second sealing body 610 can be fixed to the main body 210 while adjusting the degree of slack of the plurality of positive electrode tabs 110P. Thus, when the second cover assembly 60 is assembled, the force applied to the electrode body 100 can be suppressed, and damage to the electrode body 100 can be suppressed.

[0099] In the above case, the plurality of positive electrode tabs 110P may be loosened to a greater extent than the plurality of negative electrode tabs 110N, and an insulating member 80 similar to that of the second embodiment may be disposed between the loose portions of the plurality of positive electrode tabs 110P and the case 200 .

[0100] In the above-mentioned first and second embodiments, the case where the plurality of negative electrode tabs 110N include a portion that is loosened closer to the first wall portion 211 than the third end portion 103 of the electrode body 100 is exemplified, but the present invention is not limited thereto. The plurality of negative electrode tabs 110N may also include a portion that is loosened closer to the second wall portion 212 than the fourth end portion 104 of the electrode assembly 100. Even in this case, it is possible to ensure a large margin for adjusting the degree of looseness, and the electrode body 100 and the external terminal can be stably electrically connected.

[0101] Although the embodiments of the present invention have been described, it should be considered that the embodiments of the present disclosure are illustrative in all aspects and not restrictive. The scope of the present invention is shown by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

Claims

1. A secondary battery comprising: An electrode body, the electrode body having a first end located on one side in a first direction and a second end located on the other side in the first direction, at least one negative electrode tab being formed at the first end, and at least one positive electrode tab being formed at the second end; a housing for housing the electrode body; and A negative terminal and a positive terminal are provided on the housing, The housing includes: a main body having a first opening on the one side in the first direction and a second opening on the other side in the first direction, a first sealing body for closing the first opening, and a second sealing body for closing the second opening. The negative electrode terminal is provided on the first sealing body, The positive electrode terminal is provided on the second sealing body, The one or more negative electrode tabs are electrically connected to the negative electrode terminal, The one or more positive electrode tabs are electrically connected to the positive electrode terminal, The length of one of the one or more negative electrode tabs and the one or more positive electrode tabs is greater than the length of the other of the one or more negative electrode tabs and the one or more positive electrode tabs. 2 . The secondary battery according to claim 1 , wherein the one of the one or more negative electrode tabs and the one or more positive electrode tabs is more relaxed than the other of the one or more negative electrode tabs and the one or more positive electrode tabs.

3. The secondary battery according to claim 2, The main body has a first wall portion and a second wall portion that are opposed to each other in a second direction orthogonal to the first direction. The first wall portion is located on one side of the second direction, The second wall portion is located on the other side of the second direction, The electrode body has a third end portion located on the one side in the second direction and a fourth end portion located on the other side in the second direction, The one of the one or more negative electrode tabs and the one or more positive electrode tabs includes a portion that is loosened so as to be closer to the first wall portion than the third end portion, or a portion that is loosened so as to be closer to the second wall portion than the fourth end portion.

4. The secondary battery according to claim 3, wherein the other of the one or more negative electrode tabs and the one or more positive electrode tabs is arranged not to extend from the third end portion toward the first wall portion in the second direction, and not to extend from the fourth end portion toward the second wall portion. 5 . The secondary battery according to claim 2 , further comprising an insulating member disposed between the slack portion of the one or more negative electrode tabs and the one or more positive electrode tabs and the case to insulate the slack portion from the case.

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