JP5176312B2 - Battery pack and manufacturing method thereof - Google Patents

Description

  The present invention relates to an assembled battery in which a plurality of batteries are stacked and connected in series and / or in parallel, and a manufacturing method thereof.

  A battery module formed by laminating a plurality of flat batteries in which a power generation element is sealed in a sheet-shaped exterior member and plate-like electrode tabs (electrode terminals) connected to the power generation element are led out of the exterior member It has been known. In such a battery module, a clip-shaped connection terminal (connection clip) is connected to each electrode tab of a plurality of stacked flat batteries, and the voltage of each flat battery is detected by detecting the voltage of each flat battery. A control device (external device) for controlling output power and capacity is provided (see Patent Document 1). Note that the battery module is a kind of battery pack because it includes a plurality of electrically connected flat batteries.

The electrode tab of the flat battery constituting the battery module is usually a thin plate of about 0.5 mm and has low rigidity, and it is difficult to connect the clip-shaped voltage detection connector as it is. Therefore, in Patent Document 1, a voltage detection terminal member having a higher rigidity than that of the electrode tab is connected to the electrode tab, and the voltage detection connector is inserted into the voltage detection terminal member. A structure is employed in which the electrode tab and the connection clip are electrically connected to each other.
JP-A-2005-116440

  By the way, in patent document 1, since it is a structure which electrically connects an electrode tab and a voltage detection connector via a voltage detection terminal member, the number of parts increases, and an electrode tab and a voltage detection terminal member are Since connection work is required, the number of man-hours in the battery module assembly work process is increased, which increases manufacturing costs.

  The present invention was devised in view of the above circumstances, and can reduce the number of parts, simplify the assembly process of the assembled battery, reduce the work man-hours, and reduce the manufacturing cost. It is an object of the present invention to provide an assembled battery and a manufacturing method thereof.

In order to achieve the above object, an assembled battery according to the present invention includes a plurality of thin batteries stacked in the thickness direction of the thin batteries, and plate electrode tabs adjacent to each other in the stacking direction are connected to each other. A battery assembly in which batteries are electrically connected in series and / or in parallel, and the voltage detection connector is inserted into at least one electrode tab of a plurality of adjacent electrode tabs overlapping in the stacking direction. in a direction perpendicular Te, the convex fitting part for fitting insert the voltage detection connector plurality molding, the fitting portion have a shape that is bulged in the stacking direction, fit the voltage detection connector is plug connection, characterized in Rukoto between parts.

In order to achieve the above object, a method for manufacturing an assembled battery according to the present invention includes stacking a plurality of thin batteries in the thickness direction of the thin batteries, connecting plate-like electrode tabs adjacent to each other in the stacking direction, and A method of manufacturing an assembled battery in which a plurality of thin batteries are electrically connected in series and / or in parallel, wherein the plurality of thin batteries are stacked in the thickness direction of the thin batteries, and the adjacent batteries overlap in the stacking direction A step of positioning each other, and forming so that at least one of the electrode tabs adjacent to each other in the laminating direction is expanded in the laminating direction, and orthogonal to the insertion direction of the voltage detection connector on the same electrode tab in a direction, and having a step for multiple forming the convex fitting part for fitting insert the voltage detecting connector, a.

  According to the assembled battery according to the present invention, the electrode tabs are mechanically joined to each other and the electrode tabs are given rigidity by forming convex or concave fitting portions on the electrode tabs that are adjacent to each other. be able to. Since the voltage detection connector is directly connected to the fitting portion having this rigidity, the number of parts can be reduced, the assembly work process of the assembled battery can be simplified, the work man-hour can be reduced, and the manufacturing cost can be reduced. it can.

  According to the method for manufacturing an assembled battery according to the present invention, the electrode tabs are mechanically joined to each other and the electrode tabs are rigidly formed by forming convex or concave fitting portions on the electrode tabs that are adjacent to each other. Can be given. Since the voltage detection connector is directly connected to the fitting portion having this rigidity, the number of parts can be reduced, the assembly work process of the assembled battery can be simplified, the work man-hour can be reduced, and the manufacturing cost can be reduced. it can.

  Embodiments of an assembled battery and a method for manufacturing the same according to the present invention will be described below in detail with reference to the drawings.

  First, the assembled battery according to the present embodiment will be described. FIG. 1 is a perspective view showing an embodiment of an assembled battery according to the present invention. FIG. 2 is a cross-sectional view of the assembled battery taken along line II-II in FIG. 1 when the voltage detection connector is connected. FIG. 3 shows two flat batteries constituting a first example of the assembled battery according to the present embodiment, wherein (A) is an upper perspective view, and (B) and (C) are lower perspective views. FIG. 4 shows two flat batteries constituting a second example of the assembled battery according to the present embodiment, wherein (A) is an upper perspective view, and (B) and (C) are lower perspective views. FIG. 5 shows two flat batteries constituting a third example of the assembled battery according to the present embodiment, and (A) and (B) are upper perspective views. FIG. 6 shows two flat batteries constituting a fourth example of the assembled battery according to the present embodiment, wherein (A) is an upper perspective view, and (B) and (C) are lower perspective views. FIG. 7 shows two flat batteries constituting a fifth example of the assembled battery according to the present embodiment, wherein (A) is an upper perspective view, and (B) and (C) are lower perspective views.

  With reference to FIG. 1 and FIG. 2, the assembled battery 1 of this Embodiment is generally called a battery module, is a unit unit for assembling an in-vehicle assembled battery, and is a flat battery (hereinafter referred to as “single cell”). A cell unit (laminated body) 20 including a plurality of 10 stacked in multiple stages (eight in the illustrated example) is housed in a case 28. The assembled battery 1 includes an uneven fitting portion 21 connected in series to the positive electrode tab 14 and the negative electrode tab 15 of the upper and lower unit cells 10, and is charged and discharged through input / output terminals 23 and 24 led out of the case 28. For this purpose, the single cells 10 in the stacked body 20 are connected in series, and the stacked body 20 is connected to the input / output terminals 23 and 24. The concave-convex fitting portion 21 is a voltage detection terminal portion of the unit cell 10, and the voltage of the unit cell 10 can be detected by connecting a voltage detection connector 26 from the outside. In the laminated body 20, the upper and lower fitting portions 21 are separated by an insulating plate 25 that does not conduct electricity, such as resin, in order to prevent a short circuit. The module case 28 that accommodates the stacked body 20 is formed of a resin or a metal material, and a heat sink 29 for heat dissipation of the stacked body 20 can be disposed in the gap with the stacked body 20.

  3 to 7, the cell 10 is, for example, a flat lithium ion secondary battery, and a laminated power generation element (not shown) in which a positive electrode plate, a negative electrode plate, and a separator are sequentially laminated is laminated. It is sealed with an exterior material 12 such as a film. In the battery 10, one end is electrically connected to the power generation element, and electrode tabs (a positive electrode tab 14 and a negative electrode tab 15) as plate-like electrode terminals are led out from the exterior material 12 to the outside. The electrode tabs 14 and 15 extend on both sides of the battery 10 in the longitudinal direction. For example, the positive electrode tab 14 is formed of aluminum (Al), and the negative electrode tab 15 is formed of copper (Cu). In the battery 10 including the stacked power generation element, it is necessary to apply pressure to the power generation element and hold it in order to maintain the battery performance by keeping the distance between the electrode plates uniform. For this reason, each battery 10 is accommodated in the case 28 so that the power generation element is pressed down.

  In the 1st example of the assembled battery 1 which concerns on this embodiment shown in FIG. 3, the state which joined the upper and lower unit cell 10 in the laminated body 20 in series is shown for convenience of explanation, and the following 2nd is shown. The same applies to the fifth example. In the first example, the fitting part 21 that connects the upper and lower unit cells 10 in series is a cylindrical convex fitting part 21a, which is substantially at the center of one of the electrode tabs 14 and 15 in the longitudinal direction of the battery 10. To position. The cylindrical convex fitting portion 21a functions as a voltage detection terminal portion, and a U-shaped voltage detection connector 26a is connected to the convex fitting portion 21a from the outside so as to sandwich the outer peripheral surface thereof. The voltage of the unit cell 10 can be detected (see FIG. 3C). The voltage detection connector 26a is made of, for example, copper (Cu) having good conductivity, and is the same in the following second to fifth examples.

  In the second example of the assembled battery 1 according to the present embodiment shown in FIG. 4, the fitting portion 21 that connects the upper and lower unit cells 10 in series is a convex fitting portion 21a having a rectangular column shape such as a rectangular column. In the longitudinal direction of the battery 10, the electrode tabs 14 and 15 are located at substantially the center. The rectangular columnar convex fitting portion 21a functions as a voltage detection terminal portion, and a substantially U-shaped voltage detection connector 26b is connected to the convex fitting portion 21a from outside so as to sandwich the outer surface thereof. Thus, the voltage of the unit cell 10 can be detected (see FIG. 4C).

  In the third example of the assembled battery 1 according to this embodiment shown in FIG. 5, the fitting portion 21 that connects the upper and lower unit cells 10 in series is a rectangular concave fitting portion 21 b, and the length of the battery 10 is long. It is located in the approximate center of one electrode tab 14 and 15 of a direction, and the end surface is opening. The rectangular concave fitting portion 21b functions as a voltage detection terminal portion, and the voltage detection of the unit cell 10 can be performed by inserting and connecting a voltage detection connector 26c having a strip-shaped tip from the outside into the concave fitting portion 21b. This is possible (see FIG. 5B).

  In the fourth example of the assembled battery 1 according to this embodiment shown in FIG. 6, the fitting portion 21 that connects the upper and lower unit cells 10 in series is a pair of convex fitting portions 21a in the shape of a rectangular column such as a rectangular column. It is located at two positions in the approximate center of one of the electrode tabs 14 and 15 in the longitudinal direction of the battery 10 with a space therebetween. The rectangular columnar convex fitting portion 21a functions as a voltage detection terminal portion, and the cell 10 is formed by inserting and connecting a voltage detection connector 26d having a strip-shaped tip from the outside between the convex fitting portions 21a. Can be detected (see FIG. 6C).

  In the fifth example of the battery pack 1 according to this embodiment shown in FIG. 7, the fitting part 21 that connects the upper and lower unit cells 10 in series is a pair of cylindrical convex fitting parts 21a. Ten electrode tabs 14 and 15 in one longitudinal direction are positioned at two positions substantially at the center. The columnar convex fitting portion 21a functions as a voltage detection terminal portion, and the cell 10 is formed by inserting and connecting a voltage detection connector 26f having a strip-shaped tip from the outside between the convex fitting portions 21a. Can be detected (see FIG. 7C).

  Next, a method for manufacturing the assembled battery according to the present embodiment will be described. FIG. 8 shows a unit cell constituting the assembled battery according to the present embodiment, where (A) is a top view and (B) is a side view. FIG. 9 is a schematic diagram showing the internal configuration of the unit cell. FIG. 10 is a perspective view showing the assembly process of the assembled battery of this embodiment. FIG. 11 shows the joining process of the assembled battery of this embodiment, (A) is explanatory drawing of the state before joining, (B) is explanatory drawing of a joining state. FIG. 12 is a longitudinal sectional view showing a stacked state of the single cells. FIG. 13 is a schematic view showing one side surface of the assembled battery of the present embodiment. FIG. 14 is an explanatory view showing a spot welding process in the assembly process of the assembled battery of this embodiment. FIG. 15 is an explanatory diagram showing an ultrasonic welding process in the assembly process of the assembled battery of this embodiment. FIG. 16 is an explanatory view showing a laser welding process in the assembly process of the assembled battery of this embodiment. FIG. 17 is an explanatory view showing another structure of the convex fitting portion.

[Single cell manufacturing process]
With reference to FIG. 8 and FIG. 9, the cell 10 arrange | positions the flat laminated electrode 11 as an electric power generation element in the center part of a pair of laminated film 12a, 12b as the exterior material 12, and these laminated films 12a. , 12b so that both surfaces of the laminated electrode 11 are sandwiched, and the peripheral portions of the laminated films 12a, 12b are heat-welded and joined together to seal the electrolyte layer together with the laminated electrodes 11 between the laminated films 12a, 12b.

  The laminated electrode 11 is obtained by sequentially laminating a plurality of positive plates 11a and negative plates 11b with a separator 11c interposed therebetween. Each positive electrode plate 11a is connected to the positive electrode tab 14 via the positive electrode lead 13a, and each negative electrode plate 11b is connected to the negative electrode tab 15 via the negative electrode lead 13b, and the positive electrode tab 14 and the negative electrode tab 15 are laminated. The film 12 a and 12 b are drawn out from the joint portion 12 c and extend to both sides of the unit cell 10 in the longitudinal direction. In addition, in the four corners of the main body of the unit cell 10, positioning through holes 16 in the assembly process of the assembled battery 1 described later are formed.

  For example, the positive electrode tab 14 is made of aluminum (Al) and the negative electrode tab 15 is made of copper (Cu).

[Assembly battery assembly process]
The unit cell 10 configured as described above is assembled as follows.

  Referring to FIG. 10, first, positioning locate pins 30 are passed through through holes 16 located at the four corners of the main body of the unit cell 10, and the negative electrode tab 15 of the unit cell 10 adjacent to the positive electrode tab 14 of one unit cell 10. Two unit cells 10 are stacked so that the two overlap.

  Next, referring to FIG. 11 (A), the pressure rod 40 is placed above the negative electrode tab 15 of the unit cell 10 adjacent to the positive electrode tab 14 of one of the stacked unit cells 10 so that the convex tip 40a faces downward. The receiving rod 41 is arranged below so that the recess 41a faces upward. Then, referring to FIG. 11 (B), by sandwiching two overlapping electrode tabs 14 and 15 with rods 40 and 41, the overlapping positive electrode tab 14 and negative electrode tab 15 are caulked at the same time to form a convex shape or A concave fitting portion 21 is formed. In addition, as long as the positive electrode tab 14 and the negative electrode tab 15 which overlapped can be shape | molded simultaneously, you may employ | adopt other shaping | molding methods other than crimping, such as press work. By this step, the two unit cells 10 stacked are mechanically joined via the negative electrode tab 15 of the unit cell 10 adjacent to the positive electrode tab 14 of one unit cell 10 and are electrically joined in series. And the fitting portion 21 is formed. Four sets are produced in the same manner using the two connected unit cells 10 as subassemblies.

  Referring to FIG. 12, the four subassemblies are positioned by locating pins 30 corresponding to the thickness of eight unit cells, with electrode tabs 14 and 15 having fitting portions 21 sandwiched in the same direction with insulating plate 25 interposed therebetween. (See FIG. 10). Subsequently, the electrode tabs 14 and 15 on the opposite side of the already-fitted fitting portion 21 are joined. However, since the eight electrode tabs 14 and 15 are stacked at the same time, two pieces are easily joined together. Therefore, the electrode tabs that are not to be joined are bent upward or downward, and are joined by sandwiching the second and third electrode tabs 14 and 15 with the rods 40 and 41 in a stacked state. To do. The fourth and fifth sheets, and the sixth and seventh sheets are joined in the same manner, and the positive input / output terminal 23 of the battery pack 1 is connected to the first tab 14 and the negative input / output terminal 24 is connected to the eighth tab 15. Are joined by rods 40 and 41, and the insulating plate 25 is inserted between the upper and lower joints. Finally, a heat sink 29 made of aluminum for cooling is attached to the top and bottom of the laminate 20 and housed in a case 28 of the assembled battery, whereby the assembled battery 1 is completed.

  Referring to FIG. 13, the case 28 of the assembled battery 1 is open in both longitudinal directions. By fitting a connector housing (not shown) into both openings 31, the protrusions of the tabs 14 and 15 are formed. The voltage detection connector 26 can be connected from the outside to the fitting part 21 having a shape or a concave shape, whereby the voltage of each unit cell 10 can be detected.

  In addition, as shown in FIG. 14, after the step of forming the convex or concave fitting portion 21 by sandwiching the two electrode tabs 14 and 15 by the rods 40 and 41 (see FIG. 11B), It is possible to improve the bonding strength of the fitting portion 21 by applying current to the fitting portion bottom surface 22 by the welding electrodes 42 and 43 of the resistance spot welder, thereby improving the electric bonding performance. improves. Moreover, since it welds to the fitting part 21 which carried out the crimping process, positioning of a welding part is easy and it can weld to a large current part. In addition, the bottom surface 22 of the fitting portion is ultrasonically bonded by the horn 44 and the anvil 45 of the ultrasonic welder shown in FIG. 15, or the laser is applied from the laser condenser 46 of the laser welder shown in FIG. It is also possible to emit light 47 and perform laser welding.

  Even if the positive electrode tab 14 and the negative electrode tab 15 are dissimilar metals, mechanical joining is possible by forming the convex or concave fitting portion 21 by sandwiching the two tabs 14 and 15 with the rods 40 and 41. However, if the surfaces of the positive electrode tab 14 and the negative electrode tab 15 are coated with highly conductive metal plating such as nickel (Ni), the welding effect of resistance spot welding, ultrasonic welding and laser welding is improved. Can be made.

  In the above description, the positive electrode tab 14 and the negative electrode tab 15 are overlapped, and the two overlapping tabs 14 and 15 are sandwiched by the rods 40 and 41 at the same time to form the convex or concave fitting portion 21. However, the present invention is not limited to this, and as shown in FIG. 17, only one electrode 15 (or 14) is molded by the rods 40 and 41 to form a convex fitting portion 21 a, and resistance The electrode tab 15 (or 14) having the fitting portion 21a may be welded to the other flat electrode tab 14 (or 15) at the peripheral portion 32 of the fitting portion 21a by spot welding or the like. Thus, even when the convex fitting portions 21a are formed on the tabs 14 and 15, the voltage detection connector 26 can be connected to the outer surface of the fitting portion 21a (FIGS. 3 and 3). 4).

  Since the assembled battery 1 configured as described above is joined in a mechanically fitted state by forming fitting portions 21 on the electrode tabs 14 and 15 of the unit cells 10 that are stacked and adjacent to each other. Even the thin tabs 14 and 15 of about 5 mm can ensure rigidity. Therefore, voltage detection is not performed on the fitting portions formed on the electrode tabs 14 and 15 without connecting a voltage detection terminal member having rigidity higher than that of the tabs 14 and 15 as a separate part to the electrode tabs 14 and 15 as in the prior art. The connector 26 can be directly connected. Therefore, the number of parts can be reduced, the assembly work process can be simplified and the number of work steps can be reduced, so that the manufacturing cost can be reduced. Moreover, it becomes a simple structure by reducing the number of parts, and the assembled battery 1 can be reduced in size.

It is a perspective view which shows one Embodiment of the assembled battery which concerns on this invention. It is sectional drawing which follows the II-II line | wire of FIG. The two flat batteries which comprise the 1st example of the assembled battery which concerns on this embodiment are shown, (A) is an upper perspective view, (B) and (C) are lower perspective views. The two flat batteries which comprise the 2nd example of the assembled battery which concerns on this embodiment are shown, (A) is an upper perspective view, (B) and (C) are lower perspective views. The two flat batteries which comprise the 3rd example of the assembled battery which concerns on this embodiment are shown, (A) and (B) are upper perspective views. The two flat batteries which comprise the 4th example of the assembled battery which concerns on this embodiment are shown, (A) is an upper perspective view, (B) and (C) are lower perspective views. The two flat batteries which comprise the 5th example of the assembled battery which concerns on this embodiment are shown, (A) is an upper perspective view, (B) and (C) are lower perspective views. The single battery which comprises the assembled battery which concerns on this embodiment is shown, (A) is a top view, (B) is a side view. It is a schematic diagram which shows the internal structure of a cell. It is a perspective view which shows the assembly process of the assembled battery of this embodiment. The joining process of the assembled battery of this embodiment is shown, (A) is explanatory drawing of the state before joining, (B) is explanatory drawing of a joining state. It is a longitudinal cross-sectional view which shows the lamination | stacking state of a cell. It is a schematic diagram which shows one side of the assembled battery of this embodiment. It is explanatory drawing which shows the spot welding process in the assembly process of the assembled battery of this embodiment. It is explanatory drawing which shows the ultrasonic welding process in the assembly process of the assembled battery of this embodiment. It is explanatory drawing which shows the laser welding process in the assembly process of the assembled battery of this embodiment. It is explanatory drawing which shows the other structure of a convex fitting part.

Explanation of symbols

1 battery pack,
10 Flat battery (single cell),
14 positive tab,
15 negative electrode tab,
21 (21a, 21b, 21c) fitting part,
26 (26a, 26b, 26c, 26d, 26f) Voltage detection connector.

Claims (3)

A plurality of thin batteries are stacked in the thickness direction of the thin batteries, plate-like electrode tabs adjacent to each other in the stacking direction are connected, and the plurality of thin batteries are electrically connected in series and / or in parallel. An assembled battery,
A convex shape for inserting and fitting the voltage detection connector into a direction perpendicular to the insertion direction of the voltage detection connector to at least one electrode tab of a plurality of electrode tabs that are adjacent to each other in the stacking direction. battery pack engaging portion and a plurality molding, the fitting portion have a shape that is bulged in the stacking direction, the voltage detecting connector is plug connection between these fitting portions, characterized in Rukoto of . A plurality of thin batteries are stacked in the thickness direction of the thin batteries, plate-like electrode tabs adjacent to each other in the stacking direction are connected, and the plurality of thin batteries are electrically connected in series and / or in parallel. A method for manufacturing an assembled battery, comprising:
Laminating a plurality of thin batteries in the thickness direction of the thin batteries, and positioning adjacent batteries overlapping in the stacking direction;
The voltage detection is performed in a direction perpendicular to the insertion direction of the voltage detection connector on the same electrode tab by forming so that at least one of the electrode tabs adjacent to each other in the stacking direction is expanded in the stacking direction. method of manufacturing a battery pack, characterized in that it comprises the steps of: a plurality shaping the convex fitting part for fitting insert the use connectors, the. The method for producing an assembled battery according to claim 2 , further comprising a step of welding and joining the fitting portion after the forming step of the fitting portion.

Images