Secondary batteries

Abstract

To provide a secondary battery, equipped with a collector, which has a structure for maintaining the insulation quality between a tab group and a sealing plate.SOLUTION: A secondary battery comprises: an outer package 1 which houses an electrode body 3; an external terminal 10 which is provided outside a sealing plate 2 for sealing an opening of the outer package; a connection member 11, provided inside the sealing plate, which is connected to the external terminal; an insulation member 14 which is provided between the sealing plate and the connection member; and a collector 12, disposed inside the sealing plate, which is connected to the connection member and is also connected to a tab group 40a made up of a plurality of collector tabs extending from the electrode body. The tab group has a projecting portion where at least part of the collector tabs projects from the collector in the longitudinal direction of the sealing plate. The insulation member has an extension part 14c which extends at least between the projecting portion and the sealing plate, along the longitudinal direction of the sealing plate.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] This disclosure relates to secondary batteries.

Background Art

[0002] As a current collecting structure of a secondary battery in which an electrode body is housed in an exterior body, a structure is known in which a current collecting tab extending from the electrode body to the sealing plate side of the exterior body is connected to an external terminal via a current collector.

[0003] In such a current collecting structure, Patent Document 1 discloses a configuration in which a positive electrode plate and a negative electrode plate are wound flatly via a separator as an electrode body. The positive electrode plate and the negative electrode body are each formed in a strip shape, and a plurality of positive and negative current collecting tabs are formed at a predetermined interval at one end in the width direction. When the positive electrode plate and the negative electrode plate are wound to form an electrode body, the plurality of positive and negative current collecting tabs are laminated at predetermined positions to form a tab group. The positive and negative tab groups are each bundled and connected to positive and negative current collectors, and further, the current collectors are connected to external terminals, thereby constituting a current collecting structure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above current collecting structure, an insulating member is disposed between the current collector and the sealing plate in order to electrically insulate the current collector connected to the external terminal from the sealing plate.

[0006] Incidentally, to increase the output of the secondary battery, it is effective to widen the width of the current-collecting tabs in the longitudinal direction of the sealing plate. Widening the width of the current-collecting tabs also widens the area of ​​the current collector to which the tab groups are connected. As a result, the tab groups are positioned closer to the ends of the current collector in the longitudinal direction.

[0007] On the other hand, multiple current-collecting tabs are pre-formed at predetermined intervals on one end of the positive and negative electrode plates so that they can be stacked in predetermined positions when the electrode body is constructed by winding the positive and negative electrode plates in a flattened shape. However, due to variations in the thickness of the electrode plates, the curvature of the wound electrode plates, and the direction of pressure when the wound electrode body is pressed in a flattened shape, they may be stacked off-center from their predetermined positions.

[0008] In this manner, when multiple current-collecting tabs are misaligned and the group of tabs is connected to the current collector, some of the current-collecting tabs may protrude from the current collector in the longitudinal direction of the sealing plate. As a result, the protruding portions of the current-collecting tabs may come into contact with the sealing plate, potentially leading to a loss of insulation between the group of tabs and the sealing plate. [Means for solving the problem]

[0009] The secondary battery according to this disclosure comprises an electrode body having a positive electrode plate and a negative electrode plate, an outer casing having an opening and housing the electrode body, and a sealing plate that seals the opening. A current collector is positioned inside the sealing plate and connected to a group of tabs consisting of multiple current-collecting tabs extending from the positive and negative electrode plates, An insulating member provided between the sealing plate and the current collector and 、 The tab group comprises, at least some of the current-collecting tabs having an overhang that extends from the current collector in the longitudinal direction of the sealing plate, and the insulating member has an extended portion that extends along the longitudinal direction of the sealing plate, at least between the overhang and the sealing plate. The sealing plate has injection holes that penetrate through the thickness of the sealing plate. The current collector has an edge at the end in the longitudinal direction. and in a position that does not block the injection port. A notch is formed, and the joint between the tab group and the current collector overlaps with the notch and the sealing plate in the short direction. [Effects of the Invention]

[0010] According to this disclosure, it is possible to provide a secondary battery equipped with a current collector, in which a group of tabs consisting of multiple current-collecting tabs maintains insulation between the tabs and the sealing plate. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic perspective view showing the configuration of a secondary battery in one embodiment of the present disclosure. [Figure 2] Figure 2 is a cross-sectional view along the line II-II in Figure 1. [Figure 3A] Figure 3A is a plan view of the positive electrode plate. [Figure 3B] Figure 3B is a plan view of the negative electrode plate. [Figure 4A] Figure 4A is a top view of the electrode body. [Figure 4B] Figure 4B is a side view of the electrode body. [Figure 4C] Figure 4C is a front view of the electrode body. [Figure 5] Figure 5 is an exploded perspective view of the components of a secondary battery, excluding the outer casing and electrodes. [Figure 6] Figure 6 is an exploded perspective view of the components of a secondary battery, excluding the outer casing and electrodes. [Figure 7] Figure 7 is a plan view showing the positive electrode tab group and the negative electrode tab group connected to the positive electrode current collector and the negative electrode current collector. [Figure 8] Figure 8 is a plan view showing the sealing plate with the positive external terminal, negative external terminal, positive connector, and negative connector assembled. [Figure 9] Figure 9 is a plan view showing the positive electrode current collector and negative electrode current collector in the state shown in Figure 7, connected to the positive electrode connecting member and negative electrode connecting member in the state shown in Figure 8. [Figure 10] Figure 10 is a plan view showing an enlarged view of the positive electrode side in Figure 9. [Figure 11] Figure 11 is a side view of Figure 9, showing an enlarged view of the positive electrode side. [Figure 12] Figure 12 is a perspective view of Figure 9, taken from the bottom of the sealing plate.

Best Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. Note that the present disclosure is not limited to the following embodiments, and appropriate modifications can be made without departing from the scope in which the effects of the present disclosure are achieved.

[0013] FIG. 1 is a perspective view schematically showing the configuration of a secondary battery in an embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.

[0014] As shown in FIGS. 1 and 2, the secondary battery 100 in the present embodiment includes an exterior body 1 having an opening and accommodating an electrode body 3, and a sealing plate 2 sealing the opening of the exterior body 1. The exterior body 1 and the sealing plate 2 are made of, for example, aluminum or an aluminum alloy. A positive electrode external terminal 10 and a negative electrode external terminal 20 are provided on the outside of the sealing plate 2. The electrode body 3 has a structure in which a positive electrode plate and a negative electrode plate are wound flatly via a separator. In the present embodiment, the longitudinal direction of the sealing plate 2 refers to the direction indicated by arrow A in FIG. 1.

[0015] Inside the sealing plate 2, a positive electrode connection member 11 and a negative electrode connection member 21 respectively connected to the positive electrode external terminal 10 and the negative electrode external terminal 20 are provided. Further, inside the sealing plate 2, a positive electrode current collector 12 and a negative electrode current collector 22 respectively connected to the positive electrode connection member 11 and the negative electrode connection member 21 are provided.

[0016] The electrode body 3 has a positive electrode tab group 40a and a negative electrode tab group 50a each composed of a plurality of current collector tabs respectively connected to the positive electrode plate and the negative electrode plate at the end on the sealing plate 2 side. The positive electrode tab group 40a and the negative electrode tab group 50a are respectively connected to the positive electrode current collector 12 and the negative electrode current collector 22.

[0017] The positive electrode external terminal 10, the positive electrode connecting member 11, and the positive electrode current collector 12 are made of, for example, aluminum or an aluminum alloy. The negative electrode external terminal 20, the negative electrode connecting member 21, and the negative electrode current collector 22 are made of, for example, copper or a copper alloy.

[0018] Upper insulating members 13 and 23 are positioned between the positive external terminal 10 and the negative external terminal 20 and the sealing plate 2, respectively. In addition, insulating members 14 and 24 are positioned between the positive connecting member 11 and the negative connecting member 21 and the sealing plate 2, respectively. As a result, the positive external terminal 10, the negative external terminal 20, and the positive connecting member 11 and the negative connecting member 21 are electrically insulated from the sealing plate 2.

[0019] The sealing plate 2 is provided with an injection hole (not shown) for injecting electrolyte, and the injection hole is sealed with a sealing member 30. The sealing plate 2 is provided with a gas discharge valve 31, and when the pressure inside the outer casing 1 exceeds a predetermined value, the gas inside the outer casing 1 is discharged to the outside through the ruptured gas discharge valve 31. An insulating electrode holder 6 is positioned between the outer casing 1 and the electrode body 3.

[0020] Next, with reference to Figures 3A to 9, the assembly method of the secondary battery in this embodiment and the details of each component will be explained.

[0021] Figure 3A is a plan view of the positive electrode plate 4. The positive electrode plate 4 has a configuration in which a positive electrode mixture layer containing positive electrode active material is formed on both sides of the positive electrode core. Multiple positive electrode current collector tabs 4a protrude from the edge of the positive electrode plate 4 at predetermined intervals. The positive electrode current collector tabs 4a may be part of the positive electrode core or other components. The positive electrode core is made of, for example, aluminum foil or aluminum alloy foil. The positive electrode active material is made of, for example, a lithium transition metal composite oxide.

[0022] Figure 3B is a plan view of the negative electrode plate 5. The negative electrode plate 5 has a configuration in which a negative electrode mixture layer containing negative electrode active material is formed on both sides of the negative electrode core. Multiple negative electrode current collector tabs 5a protrude from the edge of the negative electrode plate 5 at predetermined intervals. The negative electrode current collector tabs 5a may be part of the negative electrode core or other components. The negative electrode core is made of, for example, copper foil or copper alloy foil. The negative electrode active material is made of, for example, a carbon material or a material containing silicon.

[0023] Figures 4A to 4C show an electrode body 3 constructed by winding a positive electrode plate 4 and a negative electrode plate 5 in a flattened shape with a separator in between. Here, Figure 4A is a top view of the electrode body 3, Figure 4B is a side view of the electrode body 3, and Figure 4C is a front view of the electrode body 3.

[0024] As shown in Figures 4A to 4C, a group of positive electrode tabs 40a and a group of negative electrode tabs 50a extend from the ends of the electrode body 3. The group of positive electrode tabs 40a and the group of negative electrode tabs 50a are formed when the electrode body 3 is constructed by winding the positive electrode plate 4 and the negative electrode plate 5 in a flattened shape, and multiple positive electrode current collector tabs 4a and multiple negative electrode current collector tabs 5a are stacked at predetermined positions. The ends of the group of positive electrode tabs 40a and the group of negative electrode tabs 50a are bundled together and connected to the positive electrode current collector 12 and the negative electrode current collector 22, which will be described later.

[0025] Figures 5 and 6 are exploded perspective views of the components of the secondary battery, excluding the outer casing 1 and the electrode body 3. Here, Figure 5 is an exploded perspective view seen from above the sealing plate 2, and Figure 6 is an exploded perspective view seen from below the sealing plate 2. In the following, the components of the positive electrode side will be described, but the components of the negative electrode side have basically the same configuration.

[0026] As shown in Figures 5 and 6, the positive electrode external terminal 10 and the upper insulating member 13 are positioned on the upper side of the sealing plate 2. The insulating member 14, the positive electrode connecting member 11, and the positive electrode current collector 12 are positioned on the lower side of the sealing plate 2.

[0027] The positive electrode external terminal 10 has a cylindrical projection 10a. The upper insulating member 13, sealing plate 2, insulating member 14, and positive electrode connecting member 11 are provided with through holes 13a, 2a, 14a, and 11a, respectively, which pass through the projection 10a of the positive electrode external terminal 10.

[0028] The sealing plate 2 has an injection hole 2b for injecting electrolyte and a gas discharge valve 31 for discharging gas from inside the outer casing 1. The insulating member 14 is provided with an opening 14b in a position that does not block the injection hole 2b.

[0029] The positive electrode current collector 12 has a first connection region 12a connected to the positive electrode tab group 40a and a second connection region 12b connected to the positive electrode connecting member 11, along the longitudinal direction of the sealing plate 2. The positive electrode current collector 12 also has a stepped portion 12c between the first connection region 12a and the second connection region 12b, with the first connection region 12a located closer to the sealing plate 2 than the second connection region 12b. The positive electrode current collector 12 is provided with a notch 12d in a position that does not block the liquid injection hole 2b.

[0030] Furthermore, since the insulating member 24 and the negative electrode current collector 22 are not positioned to block the liquid injection hole 2b, they do not have portions corresponding to the opening 14b and notch 12d provided in the insulating member 14 and the positive electrode current collector 12.

[0031] Figure 7 is a plan view showing the positive electrode tab groups 40a, 40b and negative electrode tab groups 50a, 50b, which are provided on two electrode bodies 3a and 3b with the same configuration, respectively, connected to the positive electrode current collector 12 and the negative electrode current collector 22.

[0032] Specifically, as shown in Figure 7, the two electrode bodies 3a and 3b are arranged so that the positive electrode tab groups 40a and 40b and the negative electrode tab groups 50a and 50b face each other. The positive electrode tab groups 40a and 40b and the negative electrode tab groups 50a and 50b are then placed on the first connection region 12a of the positive electrode current collector 12 and the first connection region 22a of the negative electrode current collector 22, and the positive electrode tab groups 40a and 40b and the negative electrode tab groups 50a and 50b are welded to the positive electrode current collector 12 and the negative electrode current collector 22 at the welding locations 60 and 70. Welding can be performed using, for example, ultrasonic welding, resistance welding, laser welding, etc.

[0033] The two electrode bodies 3a and 3b are housed in the outer casing 1 with the positive electrode tab groups 40a and 40b and the negative electrode tab groups 50a and 50b bent so that the electrode bodies 3a and 3b are arranged in parallel to each other.

[0034] Figure 8 is a plan view of the sealing plate 2 as seen from below, showing the sealing plate 2 with the positive external terminal 10, negative external terminal 20, positive connecting member 11, and negative connecting member 21 assembled on it.

[0035] Specifically, as shown in Figures 5 and 6, the upper insulating member 13, the sealing plate 2, the insulating member 14, and the positive electrode connecting member 11 are arranged so that the positions of the through holes 13a, 2a, 14a, and 11a provided in each are aligned. Then, the protruding portion 10a of the positive electrode external terminal 10 is inserted into the through holes 13a, 2a, 14a, and 11a, and the tip of the protruding portion 10a is crimped onto the positive electrode connecting member 11 to fix the positive electrode external terminal 10 and the positive electrode connecting member 11 to the sealing plate 2. In addition, the positive electrode external terminal 10 and the positive electrode connecting member 11 may be further welded at the crimped portion.

[0036] The insulating member 14 has a recess 14d, and the positive electrode connecting member 11 is fitted into the recess 14d. A portion of the recess 14d is exposed from the positive electrode connecting member 11, and the positive electrode current collector 12, which will be described later, is fitted into this exposed portion.

[0037] Figure 9 is a plan view showing the positive electrode current collector 12 and negative electrode current collector 22, as shown in Figure 7, connected to the positive electrode connecting member 11 and negative electrode connecting member 21, as shown in Figure 8.

[0038] As shown in Figure 9, the positive electrode current collector 12 is welded to the positive electrode connecting member 11 at the second connection region 12b, with the first connection region 12a fitted into the recess 14d of the insulating member 14. The welding can be performed using, for example, laser welding.

[0039] Incidentally, as shown in Figures 3A, 3B, and 4A to 4C, multiple positive electrode current collector tabs 4a and negative electrode current collector tabs 5a are formed in advance at predetermined intervals on one end of the positive electrode plate 4 and negative electrode plate 5 so that they are stacked at predetermined positions when the electrode body 3 is constructed by winding the positive electrode plate 4 and negative electrode plate 5 in a flattened shape. However, due to variations in the thickness of the positive electrode plate 4 and negative electrode plate 5, the curvature of the electrode body 3, and the pressing direction when pressing the wound electrode body 3 in a flattened shape, they may be stacked off-center from the predetermined positions.

[0040] Figure 10 is a plan view showing an enlarged view of the positive electrode side in Figure 9. Note that electrodes 3a and 3b are omitted in Figure 10.

[0041] As shown in Figure 10, the multiple positive electrode current collector tabs 4a and 4b that make up the positive electrode tab groups 40a and 40b (three are shown in Figure 10) are stacked offset from each other in the longitudinal direction of the sealing plate 2. Therefore, at least some of the positive electrode current collector tabs 4a and 4b of the positive electrode tab groups 40a and 40b have portions that protrude from the positive electrode current collector 12 (first connection region 12a) in the longitudinal direction of the sealing plate 2 (protruding portions).

[0042] In particular, if the width of the positive electrode current collector tabs 4a and 4b in the longitudinal direction of the sealing plate 2 is widened in order to increase the output of the secondary battery, the first connection region 12a of the positive electrode current collector 12 to which the positive electrode tab groups 40a and 40b are connected will also widen. As a result, the positive electrode tab groups 40a and 40b are positioned closer to the ends of the positive electrode current collector in the longitudinal direction, so the protruding portions of the positive electrode tab groups 40a and 40b will increase. Also, if the joint portions 60, 60 between the positive electrode current collector 12 and the positive electrode tab groups 40a and 40b are located on the end side of the positive electrode current collector 12 in the first connection region 12a, rather than on the stepped portion 12c, the protruding portions of the positive electrode tab groups 40a and 40b will increase.

[0043] In this embodiment, the insulating member 14 has an extended portion 14c that extends between the protruding portions of the positive electrode tab groups 40a and 40b and the sealing plate 2 in the longitudinal direction of the sealing plate 2. Therefore, the extended portion 14c also protrudes from the positive electrode current collector 12 in the longitudinal direction of the sealing plate 2.

[0044] According to this embodiment, by providing an extended portion 14c on the insulating member 14, it is possible to prevent the protruding portions of the positive electrode tab groups 40a and 40b from coming into contact with the sealing plate 2. This makes it possible to provide a secondary battery with a structure that maintains insulation between the positive electrode tab groups 40a and 40b and the sealing plate 2. In particular, even if the width of the positive electrode current collecting tabs 4a and 4b in the longitudinal direction of the sealing plate 2 is widened, it is possible to prevent the protruding portions of the positive electrode tab groups 40a and 40b from coming into contact with the sealing plate 2, thus making it possible to provide a secondary battery with high output and a structure that maintains insulation between the positive electrode tab groups 40a and 40b and the sealing plate 2.

[0045] In this embodiment, the insulating member 24 on the negative electrode side also has a similar configuration, so it is possible to provide a secondary battery with a structure that maintains insulation between the negative electrode tab groups 50a and 50b and the sealing plate 2.

[0046] Figures 11 and 12 are a side view and a perspective view of the sealing plate 2 viewed from below, respectively, as shown in Figure 9, with the positive electrode side enlarged. Note that in Figures 10 and 11, the electrode bodies 3a and 3b, the positive electrode tab groups 40a and 40b, and the negative electrode tab groups 50a and 50b are omitted.

[0047] As shown in Figures 11 and 12, the positive electrode current collector 12 is welded to the positive electrode connecting member 11 with a first connection region 12a to which the positive electrode tab groups 40a and 40b are connected fitted into a recess 14d of the insulating member 14. The surface of the first connection region 12a on the electrode body 3a and 3b side and the surface of the extended portion 14c of the insulating member 14 on the electrode body 3a and 3b side are on the same plane. This prevents unnecessary load from being placed on the positive electrode current collector tabs 4a and 4b even if they are positioned across the positive electrode current collector 12 (first connection region 12a) and the insulating member 14 (extended portion 14c).

[0048] Furthermore, as shown in Figures 11 and 12, a gap S is provided between the sealing plate 2 and the extended portion 14c. This makes it possible to reduce the weight and cost of the insulating member 14.

[0049] Furthermore, in this embodiment, as shown in Figure 2, the first connection region 12a of the positive electrode current collector 12 is located closer to the sealing plate 2 than the second connection region 12b. This allows the sealing plate 2 side end of the electrode body 3 to be brought closer to the sealing plate 2. As a result, the capacity of the secondary battery can be increased.

[0050] Although this disclosure has been described above with reference to preferred embodiments, this description is not limiting, and various modifications are, of course, possible.

[0051] For example, in the above embodiment, the positive external terminal 10 and the positive connecting member 11 are made of separate components, but they may be integrally formed from the same component. Similarly, the negative external terminal 20 and the negative connecting member 21 are made of separate components, but they may be integrally formed from the same component.

[0052] Furthermore, in the above embodiment, electrode bodies 3a and 3b were used in which a positive electrode plate 4 and a negative electrode plate 5 were wound around each other with a separator in between. However, a structure in which multiple positive and negative electrode plates are stacked with separators in between may also be used. This is because, even in an electrode body with a stacked structure, the multiple current-collecting tabs provided on each positive and negative electrode plate are stacked in a offset manner from each other, and some of them may protrude from the positive and negative current-collecting bodies.

[0053] Furthermore, although the above embodiment describes an example in which two electrode bodies 3a and 3b are housed in the outer casing 1, there may be only one electrode body, or three or more electrode bodies may be used.

[0054] The secondary battery in this embodiment is not particularly limited in type and can be applied to, for example, non-aqueous electrolyte secondary batteries such as lithium-ion secondary batteries. [Explanation of symbols]

[0055] 1. Exterior 2 Sealing plate 2b Liquid injection hole 3, 3a, 3b electrode body 4 Positive plate 4a, 4b Positive electrode current collector tab 5. Negative plate 5a, 5b Negative electrode current collector tab 6 Electrode holder 10 Positive external terminal 10a protrusion 11 Positive electrode connecting member 12 Positive electrode current collector 12a First connection area 12b Second connection area 12c Step section 12d Notch 13, 23 Upper insulating member 13a, 2a, 14a, 11a through hole 14, 24 Insulating material 14b opening 14c extension 14d recess 20 Negative external terminal 21 Negative electrode connecting member 22 Negative electrode current collector 22a First connection area 30 Sealing member 31 Gas discharge valve 40a, 40b Positive electrode tab group 50a, 50b Negative Electrode Tab Group 60, 70 welding points 100 Secondary battery

Claims

1. An electrode body comprising a positive electrode plate and a negative electrode plate, An outer casing having an opening and housing the electrode body, A sealing plate that seals the aforementioned opening, A current collector is positioned inside the sealing plate and connected to a group of tabs consisting of multiple current-collecting tabs extending from the positive electrode plate and the negative electrode plate, An insulating member provided between the sealing plate and the current collector, A secondary battery equipped with, The group of tabs has, at least some of the current-collecting tabs having an overhang that extends from the current collector in the longitudinal direction of the sealing plate, The insulating member has an extended portion that extends along the longitudinal direction of the sealing plate, at least between the protruding portion and the sealing plate, The sealing plate has an injection hole that penetrates through it in the thickness direction of the sealing plate. The current collector has a notch formed at the edge at the end in the longitudinal direction, in a position that does not block the liquid injection hole. A secondary battery in which the joint between the tab group and the current collector overlaps the notch and the sealing plate in the short-side direction.

2. The secondary battery according to claim 1, wherein the electrode-side surface of the current collector to which the tab group is connected and the electrode-side surface of the extending portion of the insulating member are the same surface.

3. A secondary battery according to claim 1, wherein a gap is provided between the sealing plate and the extended portion.

4. The secondary battery according to claim 1, wherein the electrode body has a structure in which the positive electrode plate and the negative electrode plate are wound around a separator.

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