Secondary battery

Abstract

To provide a secondary battery in which the influence of an external force on a current collector tab can be suppressed.SOLUTION: A secondary battery 10 includes an electrode assembly 100, a tubular member 210, a pair of sealing bodies 510 and 610, a first external terminal 520, a second external terminal 620, and a spacer 40 disposed inside the tubular member 210. The electrode assembly 100 has a first end portion 101 located on one side in a parallel direction parallel to a cylindrical axis direction and a second end portion 102 located on the other side in the parallel direction. The first end portion 101 is provided with one or more first current collector tabs electrically connected to the first external terminal 520, and the second end portion 102 is provided with one or more second current collector tabs electrically connected to the second external terminal 620. The spacer 40 includes a first member 41 provided between the one sealing body 510 and the first end portion 101, and a second member 42 provided between the other sealing body 610 and the second end portion 102.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a secondary battery, and more particularly to a secondary battery mounted on a vehicle. [Background technology]

[0002] As a conventional secondary battery, JP 2021-044082 A (Patent Document 1) discloses a configuration in which an electrode body with a current collecting tab provided at the upper end of the electrode body is housed in a case, and an impact absorbing member is disposed between the electrode body and the case. The case is composed of a main body that opens upward and a sealing body that closes the opening of the main body. The impact absorbing member is formed in a cylindrical bag shape with a bottom that opens upward, and is provided so as to surround the electrode body around an axis parallel to the vertical direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-044082 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, secondary batteries are required to have a low profile and a high capacity. In order to meet such requirements, it is conceivable to reduce the height of the electrode body and make it horizontally long. In such a case, it is conceivable to house the electrode body in a cylindrical member that opens on both sides in the horizontal direction, and to close the openings of the cylindrical member on both sides in the horizontal direction with a pair of sealing bodies provided with external terminals.

[0005] When the secondary battery is mounted on a vehicle, the electrode body may move laterally (in the axial direction of the cylindrical member) due to vibrations of the vehicle, etc. In such a case, if no measures are taken, the current collecting tab located on the opposite side to the direction of movement of the electrode body will be pulled. This may cause the current collecting tab to break or the electrical connection between the current collecting tab and the external terminal to be disconnected.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a secondary battery capable of suppressing the effect of external forces on a current collecting tab. [Means for solving the problem]

[0007] A secondary battery according to the present disclosure includes an electrode body, a cylindrical member that houses the electrode body, a pair of sealing bodies that close a pair of openings provided on both sides of the cylindrical member in the cylindrical axis direction, a first external terminal provided on one of the pair of sealing bodies, a second external terminal provided on the other of the pair of sealing bodies, and a spacer disposed inside the cylindrical member. The electrode body has a first end located on one side of a parallel direction parallel to the cylindrical axis direction and a second end located on the other side of the parallel direction. The first end is provided with one or more first current collecting tabs electrically connected to the first external terminal. The second end is provided with one or more second current collecting tabs electrically connected to the second external terminal. The spacer includes a first member provided between the one sealing body and the first end, and a second member provided between the other sealing body and the second end.

[0008] According to the above configuration, spacers are disposed between both ends of the electrode body and the pair of sealing bodies. This allows the spacers to exert a resistance in the opposite direction to an external force that moves the electrode body in a direction parallel to the cylindrical axis direction. This makes it possible to suppress movement of the electrode body and to suppress one of the first and second current collecting tabs from being pulled due to the movement of the electrode body. As a result, it is possible to suppress the effect of external forces on the current collecting tabs due to vibrations, etc.

[0009] In the secondary battery according to the present disclosure, the spacer may be elastic. According to the above configuration, an elastic force can be applied to the electrode body in addition to a resistive force, which further suppresses movement of the electrode body and further suppresses the effect of external forces, such as vibrations, on the current collecting tabs.

[0010] The secondary battery according to the present disclosure may further include a first conductive member including a first opposing portion facing the first end in the parallel direction and connected to the first external terminal, and a second conductive member including a second opposing portion facing the second end in the parallel direction and connected to the second external terminal. The one or more first current collecting tabs may be folded back in a cross direction crossing the parallel direction to include a portion facing the parallel direction with a first gap, and a tip side of the one or more first current collecting tabs may be connected to the first opposing portion. The one or more second current collecting tabs may be folded back in the cross direction to include a portion facing the parallel direction with a second gap, and a tip side of the one or more second current collecting tabs may be connected to the second opposing portion. The first member may be disposed in the first gap. The second member may be disposed in the second gap.

[0011] According to the above configuration, when a tensile force acts on one side of the first current collecting tab and the second current collecting tab in the moving direction of the electrode body as the electrode body moves in a direction parallel to the cylindrical axis direction, the spacer can apply a resistance to the tensile force to the connection part between the first current collecting tab and the first opposing part, or the connection part between the second current collecting tab and the second opposing part, thereby more suitably suppressing the effect of external forces on the current collecting tabs due to vibrations, etc. Effect of the Invention

[0012] According to the present disclosure, a secondary battery capable of suppressing the effect of external forces on a current collecting tab can be provided. [Brief description of the drawings]

[0013] [Figure 1] 1 is a perspective view of a secondary battery according to an embodiment; [Diagram 2] 1 is an exploded perspective view of a secondary battery according to an embodiment; [Diagram 3] 3 is a cross-sectional view of the secondary battery taken along line III-III shown in FIG. [Figure 4] 4 is a cross-sectional view of the secondary battery taken along line IV-IV shown in FIG. [Diagram 5]4 is a cross-sectional view of the secondary battery taken along line VV shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, 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 characters in the drawings, and the description thereof will not be repeated.

[0015] Fig. 1 is a perspective view of a secondary battery according to an embodiment. Fig. 2 is an exploded perspective view of the secondary battery according to an embodiment. Fig. 3 is a cross-sectional view of the secondary battery taken along line III-III shown in Fig. 1. A secondary battery 10 according to an embodiment will be described with reference to Figs. 1 to 3.

[0016] As shown in Figures 1 to 3, the secondary battery 10 of embodiment 1 includes an electrode body 100, a housing 200, a negative electrode member 520 as one external terminal, a positive electrode member 620 as the other external terminal, and a spacer 40.

[0017] The electrode body 100 has a first end 101 located on one side of the width direction W of the housing 200, and a second end 102 located on the other side of the width direction W. The width direction W is a direction parallel to the cylindrical axis direction of the cylindrical member 210 described later. The first end 101 is provided with a plurality of negative electrode tabs 110N as one or more first current collecting tabs. The second end 102 is provided with a plurality of positive electrode tabs 110P as one or more second current collecting tabs. The negative electrode tab 110N and the positive electrode tab 110P may be singular. A detailed configuration of the electrode body 100 will be described later with reference to FIG. 4.

[0018] The housing 200 has a rectangular parallelepiped shape with a thickness in a thickness direction T that is smaller than its width in a width direction W and its height in a height direction H. The thickness direction T is parallel to a side-by-side direction in which a positive electrode 110 (see FIG. 4) and a negative electrode 120 (see FIG. 4) described below are arranged side by side. The width direction W is perpendicular to the thickness direction T. The height direction H is perpendicular to the thickness direction T and the height direction H. 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.

[0019] The housing 200 accommodates the electrode assembly 100 and an electrolyte (not shown) therein. The housing 200 includes a cylindrical member 210 for accommodating the electrode assembly 100, and a first sealing body 510 and a second sealing body 610 as a pair of sealing bodies.

[0020] The cylindrical member 210 has a pair of openings provided on both sides in the cylindrical axis direction. The pair of openings includes a first opening 215 and a second opening 216. 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 cylindrical member 210 is made of a metal such as aluminum.

[0021] A spacer 40 is disposed inside the cylindrical member 210. The spacer 40 is made of, for example, an insulating member. The spacer 40 may have elasticity. The spacer 40 includes a first member 41 and a second member 42, which will be described later. The spacer 40 (each of the first member 41 and the second member 42) may be made of a polyethylene or polypropylene foam, styrene rubber, ethylene-propylene rubber, or the like. The first member 41 and the second member 42 may have, for example, a leaf spring shape.

[0022] 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, for example, laser welding or the like.

[0023] The second sealing body 610 closes 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, for example, laser welding or the like.

[0024] Each of the first sealing body 510 and the second sealing body 610 is provided with a pressure release valve 222 and a liquid injection port 224. The pressure release valve 222 is provided so as to break when the internal pressure of the housing 200 reaches or exceeds a predetermined pressure. When the pressure release valve 222 breaks, gas within the housing 200 is discharged to the outside of the housing 200, and the internal pressure within the housing 200 decreases.

[0025] The liquid inlet 224 is sealed by a sealing member 225. The liquid inlet 224 is a through hole for injecting an electrolyte into the housing 200 in the manufacturing process of the secondary battery 10. The liquid inlet 224 is sealed by a sealing member 225. The sealing member 225 is a member that seals the liquid inlet 224 after the electrolyte is injected into the housing 200. The sealing member 225 may be, for example, a gas-permeable membrane 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 housing 200, the gas can be discharged through the gas-permeable membrane. This saves the trouble of providing a separate gas vent. In addition, the gas-permeable membrane can prevent the electrolyte from leaking to the outside of the housing 200. The sealing member 225 is not limited to a gas-permeable membrane, and a resin member, a metal member, or the like can be appropriately adopted.

[0026] The first sealing body 510 is provided with a negative electrode member 520, and the second sealing body 610 is provided with a positive electrode member 620.

[0027] 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.

[0028] Negative electrode terminal plate 521 is formed in a substantially rectangular parallelepiped shape. Negative electrode terminal plate 521 is held by insulating plate 522. Insulating plate 522 is fixed to the outer surface of first sealing body 510. Insulating plate 522 insulates first sealing body 510 from negative electrode terminal plate 521. Each of negative electrode terminal plate 521 and insulating plate 522 is provided with a through hole for inserting first coupling portion 532, which will be described later.

[0029] 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 has a positive electrode terminal plate 621 and a terminal block 622.

[0030] The positive electrode terminal plate 621 is formed in a rectangular parallelepiped shape and is made of a metal such as aluminum.

[0031] The terminal block 622 is formed in a rectangular parallelepiped shape. The terminal block 622 is made of a metal (such as iron) different from the metal constituting the positive electrode 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 electrode terminal plate 621 is fixed to the terminal block 622 by welding or the like. The cylindrical member 210 and the second sealing body 610 are electrically connected to the positive electrode terminal plate 621 via the terminal block 622, and are charged with the same polarity as the positive electrode terminal plate 621. Each of the positive electrode terminal plate 621 and the terminal block 622 has a through hole formed therein for inserting a second connecting portion 632 described later.

[0032] An insulating plate may be disposed between the positive electrode component 620 and the second sealing body 610, so that the positive electrode component 620 and the second sealing body 610 are electrically insulated from each other. In this case, an insulating plate may be disposed instead of the terminal block 622, or an insulating plate may be disposed between the terminal block 622 and the second sealing body 610.

[0033] The secondary battery 10 further includes a first conductive member 530 and an insulator 560 on the negative electrode member 520 side.

[0034] The first conductive member 530 connects the negative electrode tabs 110N and the negative electrode terminal plate 521. The negative electrode tabs 110N are connected to the first conductive member 530 in a bundled state by ultrasonic welding or the like. The first conductive member 530 has, for example, a first opposing portion 531 and a first connecting portion 532. The first opposing portion 531 has a plate-like shape. The first opposing portion 531 is approximately parallel to the inner surface of the first sealing body 510. The first opposing portion 531 faces the first end portion 101 of the electrode body 100 in the width direction W. The first connecting portion 532 extends along a direction parallel to the first direction. The first connecting portion 532 has, for example, a cylindrical shape. The tip end of first connecting portion 532 passes through first sealing body 510 , insulating plate 522 and negative electrode terminal plate 521 , and is crimped to negative electrode terminal plate 521 .

[0035] The insulator 560 is disposed between the first opposing portion 531 and the first sealing body 510, and is insulated from the first opposing portion 531 and the first sealing body 510. The insulator 560 includes a portion that covers the periphery of the base end side of the first connecting portion 532, and a portion that is located between the first opposing portion 531 and the inner surface of the first sealing body 510.

[0036] The negative electrode member 520, the first sealing member 510, the first conductive member 530 and the insulator 560 are assembled together to form the first lid assembly 50.

[0037] The first lid assembly 50 is fixed to the cylindrical member 210 by attaching the first sealing body 510 to the first opening 215 with the multiple negative electrode tabs 110N and the first conductive member 530 fixed by welding or the like.

[0038] The secondary battery 10 further includes a second conductive member 630 and an insulator 660 on the positive electrode member 620 side.

[0039] The second conductive member 630 connects the positive electrode tabs 110P and the positive electrode terminal plate 621. The positive electrode tabs 110P are connected to the second conductive member 630 in a bundled state by ultrasonic welding or the like. The second conductive member 630 includes a second opposing portion 631 and a second connecting portion 632. The second opposing portion 631 has a plate-like shape. The second opposing portion 631 is approximately parallel to the inner surface of the second sealing body 610. The second opposing portion 631 faces the second end 102 of the electrode body 100 in the width direction W. The second connecting portion 632 extends along a direction parallel to the first direction. The second connecting portion 632 has, for example, a cylindrical shape. The tip portion of the second connecting portion 632 penetrates the second sealing body 610, the terminal block 622, and the positive electrode terminal plate 621, and is crimped to the positive electrode terminal plate 621.

[0040] The insulator 660 is disposed between the second facing portion 631 and the second sealing body 610, and is insulated from the second facing portion 631 and the second sealing body 610. The insulator 660 includes a portion that covers the periphery of the base end side of the second connecting portion 632, and a portion that is located between the second facing portion 631 and the inner surface of the second sealing body 610.

[0041] The positive electrode member 620, the second sealing body 610, the second conductive member 630 and the insulator 660 are assembled together to form the second lid assembly 60.

[0042] The second lid assembly 60 is fixed to the cylindrical member 210 by attaching the second sealing body 610 to the second opening 216 with the multiple positive electrode tabs 110P and the second conductive member 630 fixed by welding or the like.

[0043] Fig. 4 is a cross-sectional view of the secondary battery taken along line IV-IV shown in Fig. 1. A detailed configuration of the electrode body of the secondary battery will be described with reference to Fig. 4. For convenience, Fig. 4 omits the case 200 of the secondary battery 10 and shows only the electrode body 100. With reference to Fig. 4, the electrode body 100 will be described in detail.

[0044] 4, the electrode assembly 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.

[0045] Each negative electrode 120 is formed in a rectangular shape with the length direction being the width direction W and the width direction being the height direction H. Each negative electrode 120 has 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. As shown in Fig. 4, 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.

[0046] Each positive electrode 110 is formed in a rectangular shape with the width direction W as the long side and the height direction H as the short side. Each positive electrode 110 has a positive electrode current collector foil 112 and a positive electrode active material layer 114 provided on both sides of the positive electrode current collector foil 112 in the thickness direction T. The positive electrode current collector foil 112 has 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.

[0047] The separator 130 provides insulation between the positive electrode 110 and the negative electrode 120. The separator 130 is made of an insulating material and has minute voids that allow ions to pass through. The separator 130 is formed in a zigzag shape.

[0048] The separator 130 has a rectangular shape before being folded in a zigzag shape. The separator 130 is disposed between the positive electrode 110 and the negative electrode 120 while being folded in a zigzag shape. The separator 130 has a plurality of interposed portions 132a, a plurality of first folded portions 132b, a plurality of second folded portions 132c, and an outermost covering portion 132d.

[0049] Each interposed portion 132a is interposed between the positive electrode 110 and the negative electrode 120 adjacent to each other in the thickness direction T. In other words, each interposed portion 132a has a function of insulating the positive electrode 110 and the negative electrode 120 from each other. Each interposed portion 132a is formed of a rectangular region.

[0050] Each first folded portion 132b connects one side end portion in the height direction H of adjacent intermediate portions 132a in the thickness direction T so that the positive electrode 110 is located therebetween. The first folded portion 132b is disposed on one side (upper) of the positive electrode 110 in the height direction H.

[0051] Each second folded portion 132c connects the other end portions in the height direction H of the intervening portions 132a adjacent to each other in the thickness direction T so that the negative electrode 120 is located therebetween. The second folded portion 132c is disposed on the other side (lower) of the negative electrode 120 in the height direction H.

[0052] The outermost covering portion 132d covers all the first folded portions 132b and all the second folded portions 132c together. More specifically, the outermost covering portion 132d covers all the positive electrodes 110, all the negative electrodes 120, all the intervening portions 132a, all the first folded portions 132b, and all the second folded portions 132c together while being wound around a central axis parallel to the width direction W. The end 132e of the outermost covering portion 132d is set in a range that does not overlap the positive electrode active material layer 114 and the negative electrode active material layer 124 in the thickness direction T. In this embodiment, the end 132e of the outermost covering portion 132d is provided below each positive electrode 110 and each negative electrode 120. The peripheral surfaces and bottom surfaces of the multiple positive electrodes 110, the multiple negative electrodes 120, and the separator 130 may be covered with an insulating film (not shown).

[0053] Fig. 5 is a cross-sectional view of the secondary battery taken along line VV shown in Fig. 3. With reference to Fig. 5, a detailed description will be given of a connection mode of the first member 41 and the second member 42 constituting the spacer 40, as well as the multiple negative electrode tabs 110N and the multiple positive electrode tabs 110P.

[0054] The multiple negative electrode tabs 110N are folded back in a direction intersecting the width direction W so as to include portions facing each other in the width direction W with a first gap G1 therebetween, and their tip ends are connected to the first opposing portion 531. The tip end side of the negative electrode tab 110N is the side opposite to the side on which the first end 101 is located. The multiple negative electrode tabs 110N are folded back in a substantially U-shape.

[0055] The multiple positive electrode tabs 110P are folded back in a direction intersecting the width direction W so as to include portions that face each other in the width direction W with a second gap G2 therebetween, and their tip ends are connected to the second opposing portion 631. The tip end side of the positive electrode tab 110P is the side opposite to the side on which the second end 102 is located. The multiple positive electrode tabs 110P are folded back in a substantially U-shape.

[0056] The first member 41 is disposed between the first sealing body 510 and the first end 101 of the electrode body 100. Specifically, it is disposed in the first gap G1. The second member 42 is disposed between the second sealing body 610 and the second end 102 of the electrode body 100. Specifically, it is disposed in the second gap G2.

[0057] As described above, by providing the first member 41 and the second member 42 as the spacer 40, when an external force is applied to the electrode body 100 due to vibration or the like, which moves the electrode body 100 in a direction parallel to the cylindrical axis direction (width direction W), a resistance force can be applied by the first member 41 or the second member 42 in the direction opposite to the movement direction of the electrode body 100. This suppresses the movement of the electrode body 100, and suppresses one of the negative electrode tab 110N and the positive electrode tab 110P from being pulled due to the movement of the electrode body 100. As a result, the effect of the external force on the electrode body 100 due to vibration or the like can be suppressed.

[0058] Furthermore, since the first member 41 and the second member 42 have elasticity, an elastic force in addition to the above-mentioned resistance force can be applied to the electrode body 100. This further suppresses the movement of the electrode body 100, and further suppresses the effect of external forces on the current collecting tabs due to vibrations or the like.

[0059] In addition, by disposing the first member 41 and the second member 42 in the first gap G1 and the second gap G2, respectively, as described above, when a tensile force acts on one side of the negative electrode tab 110N and the positive electrode tab 110P in the movement direction of the electrode body 100 due to vibration or the like, the first member 41 and the second member 42 can apply a resistance to the tensile force to the connection portion between the negative electrode tab 110N and the first opposing portion 531, or the connection portion between the positive electrode tab 110P and the second opposing portion 631. This makes it possible to more suitably suppress the effect of an external force on the current collecting tab due to vibration or the like.

[0060] The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0061] 10 secondary battery, 40 spacer, 41 first member, 42 second member, 50 first lid assembly, 60 second lid assembly, 100 electrode body, 101 first end, 102 second end, 110 positive electrode, 110N negative electrode tab, 110P positive electrode tab, 112 positive electrode current collector foil, 114 positive electrode active material layer, 120 negative electrode, 122 negative electrode current collector foil, 124 negative electrode active material layer, 130 separator, 132a intermediate portion, 132b first folded portion, 132c second folded portion, 132d outermost coating portion, 132e end, 200 housing, 210 cylindrical member, 215 first opening, 216 second opening, 222 pressure release valve, 224 liquid port, 225 sealing member, 510 first sealing body, 520 Negative electrode member, 521 negative electrode terminal plate, 522 insulating plate, 530 first conductive member, 531 first opposing portion, 532 first connecting portion, 560 insulator, 610 second sealing body, 620 positive electrode member, 621 positive electrode terminal plate, 622 terminal block, 630 second conductive member, 631 second opposing portion, 632 second connecting portion, 660 insulator, G1 first gap, G2 second gap, H height direction, T thickness direction, W width direction.

Claims

1. An electrode body; A cylindrical member for accommodating the electrode assembly; a pair of sealing bodies that close a pair of openings provided on both sides of the cylindrical member in a cylindrical axis direction; a first external terminal provided on one of the pair of sealing bodies; a second external terminal provided on the other of the pair of sealing bodies; a spacer disposed inside the cylindrical member, the electrode body has a first end portion located on one side in a parallel direction parallel to the cylindrical axis direction and a second end portion located on the other side in the parallel direction, the first end portion is provided with one or more first current collecting tabs electrically connected to the first external terminal; the second end portion is provided with one or more second current collecting tabs electrically connected to the second external terminal; The spacer includes a first member provided between the one sealing body and the first end, and a second member provided between the other sealing body and the second end.

2. The secondary battery according to claim 1 , wherein the spacer has elasticity.

3. a first conductive member including a first opposing portion facing the first end portion in the parallel direction and connected to the first external terminal; a second conductive member including a second opposing portion facing the second end portion in the parallel direction and connected to the second external terminal, the one or more first current collecting tabs are folded back in a cross direction crossing the parallel direction to include portions facing each other in the parallel direction with a first gap therebetween, and a tip end side of the first current collecting tabs is connected to the first opposing portion; the one or more second current collecting tabs are folded back in the intersecting direction to include portions facing each other in the parallel direction with a second gap therebetween, and a tip end side of the one or more second current collecting tabs is connected to the second opposing portion; The first member is disposed in the first gap, The secondary battery according to claim 1 , wherein the second member is disposed in the second gap.

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