JP2009016122A - Laminated secondary battery and battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated secondary battery which has a structure made by sheathing a battery element composed of a tabular positive electrode and a negative electrode laminated via a separator with a laminated outer sheath material to seal the battery element, and causes no connection trouble even when superposed to make up a battery pack. <P>SOLUTION: The battery element of an approximately oblong plane shape made by laminating the positive electrode and the negative electrode via the separator is sheathed with the laminated material, and a positive tab 14 and a negative tab 15 are extended out from opposite sides to form the laminated secondary battery. The positive tab 14 and the negative tab 15 are each disposed to be offset to the center line 11 of each tab-extension side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laminated secondary battery and an assembled battery, and more particularly to a laminated secondary battery and an assembled battery having a structure in which battery cells can be efficiently connected to each other.

  A laminated secondary battery has a structure in which a laminated body obtained by laminating a sheet-like positive electrode and a negative electrode on a current collector made of metal foil or the like through a separator is covered with an exterior material and sealed. Composed.

  A laminated element in which a battery element having a substantially rectangular planar shape in which a positive electrode and a negative electrode are laminated via a separator is covered with a laminate material (metal composite film), and the positive electrode tab and the negative electrode tab are drawn out from opposite sides. A secondary battery is described in Patent Document 1. Also, Patent Document 2 describes an example of an assembled battery in which stacked secondary batteries are combined.

  FIG. 5 is a plan view of a conventional laminated secondary battery covered with a film such as a laminate material, and FIG. 6 is a perspective view of the assembled battery in which the conventional laminated secondary batteries are stacked. FIG. 4 is a perspective view of an assembled battery in which conventional stacked secondary batteries are arranged side by side. As shown in FIG. 5, the conventional stacked secondary battery includes a positive electrode tab 54 and a negative electrode tab 55 from opposite sides of the exterior material having a substantially rectangular planar shape, here, from the center of the short side 53 of the exterior material. It is the structure pulled out oppositely. When the stacked secondary batteries are stacked and connected in series as an assembled battery, as shown in FIG. 6, the positive electrode tabs 54 and the negative electrode tabs 55 of the stacked secondary battery are alternately disposed to form a pair of positive electrodes. It is necessary to connect the tab 54 and the negative electrode tab 55. In this case, since the positive electrode tab 54 or the negative electrode tab 55 that should not be connected are adjacent to each other, there is a possibility of contact. Become. For this reason, as shown in FIG. 7, it is possible to form a battery pack by arranging stacked batteries side by side.

JP 2004-79481 A JP 2003-162989 A

  A laminated type secondary battery packaged with a film such as a laminate material has a structure in which only one of the positive and negative electrode tabs is drawn from one side of the exterior material for ease of the manufacturing process. When the stacked secondary batteries having such a structure are stacked to form an assembled battery, particularly when connected in series, two positive and negative electrode tabs are connected to each other. Because there is a positive and negative electrode tab, there is a high possibility that the tabs will contact each other, and there is a problem that it does not become the original connection state, and there was a problem in miniaturization if connecting side by side to avoid it . That is, there has been a demand for a technique that allows easy connection even when stacked secondary batteries are stacked.

  The present invention has been made to solve such problems, and the technical problem thereof is a laminated type having a structure in which a battery element in which a plate-like positive electrode and a negative electrode are laminated via a separator is covered with a laminate outer packaging material and sealed. An object of the present invention is to provide a stacked secondary battery that does not cause a problem in connection even when a secondary battery is stacked to form an assembled battery.

  In order to solve the above-described problems, the laminated secondary battery of the present invention includes a battery element having a substantially rectangular planar shape in which a positive electrode and a negative electrode are stacked with a separator interposed between them, and a positive electrode tab and a negative electrode tab are provided. In the stacked secondary battery drawn out from the opposite sides, the positive electrode tab and the negative electrode tab are arranged so as to be removed from the center line in the respective extraction sides.

  In the multilayer secondary battery of the present invention, preferably, the width of the positive electrode tab and the width of the negative electrode tab are not less than 1/6 and not more than 2/5 of the length of the lead-out side. The tab may be disposed on the same side with respect to the center line of the lead-out side, and the positive electrode tab and the negative electrode tab may be disposed on different sides with respect to the center line of the lead-out side. Furthermore, the assembled battery of the present invention is characterized in that a plurality of the stacked secondary batteries are stacked and electrically connected. The assembled battery of the present invention includes a stacked secondary battery in which the positive electrode tab and the negative electrode tab are arranged on the same side with respect to the center line of the lead-out side, and the positive electrode tab and the negative electrode tab are the center line of the lead-out side. On the other hand, the laminated secondary batteries arranged on different sides are alternately laminated.

  According to the laminated secondary battery of the present invention, when the laminated secondary battery is a stacked assembled battery, the positive electrode tab and the negative electrode tab that are not connected are removed from the center line of the lead-out side and arranged in opposite directions. Thus, it is possible to provide a stacked secondary battery capable of avoiding contact with adjacent upper and lower positive and negative electrode tabs and efficiently producing an assembled battery.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a plan view of the multilayer secondary battery according to the first embodiment of the present invention.

  As shown in FIG. 1, the stacked secondary battery according to the first embodiment of the present invention has a positive electrode tab 14 and a negative electrode tab 15 each having a short side 13 from an opposing short side 13 of a packaging material having a rectangular planar shape. Are disposed in the same direction with respect to the center line. Here, the positive and negative electrode tabs are drawn from the short side, but may be drawn from the long side. Further, the width of the positive electrode tab and the width of the negative electrode tab are preferably from 1/6 to 2/5 of the length of the lead-out side. If it is less than 1/6, the tab area becomes small and the resistance of the tab becomes high. In particular, when a large current is taken out, there is a high possibility that the load becomes a cause of heat generation. When the number of cells exceeds 2/5, it is not preferable to stack the cells in a stacked manner because the possibility that the cells come into contact with the terminals on the opposite poles of the stacked cells and the cell becomes short-circuited is increased.

  Next, the manufacture of the stacked secondary battery according to the first embodiment of the present invention will be described. FIG. 3 is a diagram for explaining a process in the middle of manufacturing the stacked secondary battery according to the first embodiment of the present invention. FIG. 3 (a) is a front view of a battery element in which a positive electrode and a negative electrode are stacked via a separator. FIG. 3 (b) is a perspective view of a laminate material.

  The positive electrode 6 is obtained by forming a positive electrode active material on a positive electrode current collector made of, for example, a strip-shaped aluminum foil having a thickness of 20 μm. For example, to a positive electrode active material made of lithium cobaltate, a binder prepared from PVDF and a conductive agent made of acetylene black were added to prepare a slurry to be applied to both surfaces on the positive electrode current collector, The positive electrode is formed by drying and rolling with a roll press. The negative electrode 7 is a product in which a negative electrode active material is formed on a negative electrode current collector made of, for example, a copper foil having a thickness of 10 μm. For example, a negative electrode active material made of graphite powder is applied to both sides of a negative electrode current collector with a preparation prepared so as to form a slurry together with a binder made of PVDF, dried, and rolled by a roll press to roll the negative electrode. It is formed. A predetermined number of sheets are laminated between the positive electrode 6 and the negative electrode 7 with a separator 8 made of, for example, a polyethylene non-woven fabric, to produce a battery element. Further, the positive electrode tab and the negative electrode tab are connected to the positive electrode current collector and the negative electrode current collector, for example, by welding. At that time, the positive electrode tab and the negative electrode tab are drawn out from the opposite sides, removed from the center line in each of the drawn sides, and arranged on the same side with respect to the center line. Next, in order to store the battery element in the exterior film 9a made of an aluminum laminate film having a three-layer structure of nylon / aluminum / polypropylene, for example, a storage portion by drawing is provided so that the polypropylene side is concave. The battery element is housed in the battery element housing portion of the exterior film 9a, the battery element is covered with the other exterior film 9b, the joint portions are overlapped, and the three sides around the exterior films 9a and 9b are fused by heat fusion. To do. An electrolyte solution is poured into the battery element storage portion from one side that is not fused. After pouring, the film is sealed with a heat-sealing machine in a vacuum to produce a film-type laminated secondary battery.

  FIG. 2 is a plan view of the stacked secondary battery according to the second embodiment of the present invention. In the multilayer secondary battery according to the first embodiment of the present invention, the positive electrode tab and the negative electrode tab are arranged in the same direction with respect to the center line of the lead-out side, but the multilayer secondary battery according to the second embodiment of the present invention. In the secondary battery, when the positive electrode tab and the negative electrode tab are connected to the positive electrode current collector and the negative electrode current collector, the positive electrode tab 24 and the negative electrode tab 25 are arranged on different sides with respect to the center line as shown in FIG.

  Next, the assembled battery of the present invention will be described. 4A and 4B are diagrams for explaining the assembled battery of the present invention. FIG. 4A is a perspective view and FIG. 4B is a side view. As an assembled battery, for example, a case where four stacked secondary batteries are stacked and connected in series will be described. The stacked secondary battery according to the first embodiment of the present invention manufactured as described above, that is, the positive electrode tab and the negative electrode tab arranged in the same direction with respect to the center line of the lead-out side and the second embodiment of the present invention The stacked secondary battery of the embodiment, ie, the positive electrode tab and the negative electrode tab arranged in different directions with respect to the center line of the lead-out side are alternately overlapped, and the positive electrode tab 44 of the uppermost stacked secondary battery and 2 from above The negative electrode tab 45 of the second stacked secondary battery is arranged and connected so as to overlap, and the negative electrode tab 45 of the uppermost stacked secondary battery and the positive electrode tab 44 of the second stacked secondary battery from the top are pulled out. It arrange | positions so that it may be on the opposite side with respect to the centerline 41 of a line, and may not contact. Further, the positive electrode tab 44 of the second stacked secondary battery from the top and the negative electrode tab 45 of the third stacked secondary battery from the top are arranged and connected so as to overlap, and the second stacked secondary battery from the top. The negative electrode tab 45 and the positive electrode tab 44 of the third stacked secondary battery from the top are arranged so as not to contact each other with respect to the center line 41 of the lead-out side. For the third and fourth stacked secondary batteries from the top, an assembled battery is assembled by arranging and connecting the positive electrode tab and the negative electrode tab in the same concept as described above. The assembly of the assembled battery described here is an example, and in the present invention, the positive electrode tab and the negative electrode tab are arranged off the center line of the drawer side, and only the positive and negative electrode tabs that need to be connected are connected. Any form that does not contact is acceptable.

Example 1
Next, the laminated secondary battery of Example 1 of the present invention will be described in detail. The structure of the stacked secondary battery of Example 1 is the same as that of FIG. A battery element was produced by a known method, connected so that the positive electrode tab and the negative electrode tab were pulled out facing each other, and then covered with a laminate material. Here, the battery element has a length of 100 mm, a width of 60 mm, and a thickness of 13 mm, and the laminated secondary battery after the exterior has a length of 150 mm, a width of 80 mm, and a thickness of 15 mm. As shown in FIG. 1, the positive electrode tab 14 and the negative electrode tab 15 are drawn oppositely from the short side of the exterior material, and the positive electrode tab is 15 mm wide and 0.2 mm thick and is 10 mm away from the center line 11 of the short side 13 of the external material. The negative electrode tab was arranged in the same direction as the positive electrode tab with a width of 15 mm, a thickness of 0.2 mm, and a distance of 10 mm from the center line 11 of the short side 13 of the exterior material.

(Example 2)
Next, the laminated secondary battery of Example 2 of the present invention will be described. The structure of the stacked secondary battery of Example 2 is the same as that of FIG. As shown in FIG. 2, the positive electrode tab 24 and the negative electrode tab 25 are arranged 10 mm apart from the center line 21 of the short side 23 of the exterior material, and the negative electrode tab is 15 mm wide and 0.2 mm thick, It was produced in the same manner as in Example 1 except that it was separated from the center line 21 by 10 mm and arranged in a different direction from the positive electrode tab.

(Example 3)
Next, an assembled battery of Example 3 of the present invention will be described. The structure of the assembled battery of Example 3 is the same as that of FIG. 4 already described. As described above, the stacked secondary battery in which the positive electrode tab 44 and the negative electrode tab 45 are arranged on the same side with respect to the center line of the drawer side manufactured in Example 1, and the center line of the drawer side manufactured in Example 2 are used. On the other hand, four stacked secondary batteries having positive electrode tabs 44 and negative electrode tabs 45 arranged on different sides were alternately stacked. The positive electrode tab 44 of the uppermost stacked secondary battery and the negative electrode tab 45 of the second stacked battery are connected, and the positive tab 44 and the third stacked film of the second stacked secondary battery are connected. The negative electrode tab 45 of the type secondary battery is connected, and the positive electrode tab 44 of the third-stage stacked secondary battery and the negative electrode tab 45 of the fourth-stage (lowermost) stacked secondary battery are connected in series. A connected assembled battery was produced. In the assembled battery thus produced, the positive electrode tab and the negative electrode tab are drawn out of the center line of the drawer side, and contact each other tab that is not joined by joining the positive and negative electrode tabs adjacent to each other vertically. As a result, an assembled battery connected in series could be easily produced.

1 is a plan view of a stacked secondary battery according to a first embodiment of the present invention. The top view of the laminated type secondary battery of 2nd embodiment of this invention. FIG. 3A is a front view of a battery element in which a positive electrode and a negative electrode are stacked via a separator, and FIG. 3A is a diagram illustrating a process in the middle of manufacturing the stacked secondary battery according to the first embodiment of the present invention. b) is a perspective view of a laminate material. The figure explaining the assembled battery of this invention, Fig.4 (a) is a perspective view, FIG.4 (b) is a side view. The top view of the laminated type secondary battery coat | covered with films, such as the conventional laminate material. The perspective view of the assembled battery which piled up the conventional laminated type secondary battery. The perspective view of the assembled battery which arranged the conventional laminated type secondary battery side by side.

Explanation of symbols

11, 21, 41, 51 Center line 12, 22, 52 (exterior material) long side 13, 23, 53 (exterior material) short side 14, 24, 44, 54 Positive electrode tab 15, 25, 45, 55 Negative electrode Tab 6 Positive electrode 7 Negative electrode 8 Separator 9a, 9b Exterior film

Claims (6)

  In a stacked secondary battery in which a battery element having a substantially rectangular planar shape in which a positive electrode and a negative electrode are stacked via a separator is covered with a laminate, and the positive electrode tab and the negative electrode tab are drawn from opposite sides, the positive electrode A laminated secondary battery, wherein the tab and the negative electrode tab are arranged away from the center line of each of the lead sides.   2. The stacked secondary battery according to claim 1, wherein a width of the positive electrode tab and a width of the negative electrode tab are 1/6 or more and 2/5 or less of a length of the lead-out side.   The multilayer secondary battery according to claim 1, wherein the positive electrode tab and the negative electrode tab are arranged on the same side with respect to a center line of the lead-out side.   The stacked secondary battery according to claim 1, wherein the positive electrode tab and the negative electrode tab are arranged on different sides with respect to a center line of the lead-out side.   A battery pack comprising a plurality of the stacked secondary batteries according to claim 1, which are stacked and electrically connected.   An assembled battery, wherein the stacked secondary battery according to claim 3 and the stacked secondary battery according to claim 4 are alternately stacked.

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