JP2009259581A - Battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery module capable of preventing itself from deformation due to expansion of laminated batteries. <P>SOLUTION: In the battery module 1 having a laminated battery in which laminate cells each enveloping an electrode, an active material, an electrolyte or the like sealed in a laminating film are connected in series or in parallel and laminated, belt-like circular frame bodies 2 are arranged at one or a plurality of places at a center part of the laminated battery. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a battery module in which a plurality of batteries sealed with a laminate film are stacked and assembled.

  In recent years, batteries used in mobile terminals such as mobile phones and laptop computers are required to be light and have a high capacity, and battery elements such as electrodes and electrolytes using a laminate film having a relatively high degree of freedom. Laminate batteries that are sealed have come to be adopted. Laminate batteries are easy to have a structure of multiple battery packs and battery modules by laminating a plurality of them, and they are increasingly used in devices that require a large current, such as bicycles, power tools, and automobiles. is doing.

  FIG. 3 is a perspective view of a laminated battery. As shown in FIG. 3, the laminated battery has battery elements such as electrodes, active materials, and electrolytes stored in a laminated film, and the positive electrode tab 11 and the negative electrode tab 12 are drawn out to thermally bond the laminated film and surround the battery element. A heat-welded portion 13 is formed on the laminated battery 10.

  When an abnormal operation such as overcharging is performed on the laminate battery 10, in a secondary battery such as a lithium ion secondary battery, the electrolyte is vaporized inside the laminate battery and the laminate film expands. When multiple laminated batteries are stacked and connected, and abnormalities such as overcharge and overdischarge occur, the protective circuit that functions to shut down the current fails, and the laminate battery itself operates abnormally. There is a problem that the battery module is deformed because the laminated battery in the module is similarly expanded.

  Patent Document 1 describes a technique that has a sharp protrusion on the inner surface of a case containing a lithium secondary battery in order to allow the gas to escape easily when the laminate film expands due to gas generation from the unit cell. ing. Further, in Patent Document 2, even if expansion occurs due to gas generation inside the laminate battery, the case has a protrusion, and the protrusion leads from the tip to the outside of the case in order to break the laminate and release the gas to the outside. Techniques having through holes are described. FIG. 4 is a schematic diagram showing the relationship between a conventional laminated battery and a case. Conventionally, as shown in FIG. 4, a protrusion shape 14 a is provided on the inner surface of the outer case 14, and when the laminate battery 15 expands, the protrusion shape 14 a breaks the laminate film and vents the internal gas to solve the above problem. Was.

Japanese Patent Laid-Open No. 10-208720 JP 2003-168410 A

  In a battery module having a laminated battery in which laminated batteries are connected in series or in parallel, a method in which a protrusion shape is provided on the inner surface of the outer case, the battery that can be reliably broken when the battery expands has a protrusion shape. It will be limited to the laminated battery of the adjacent or projection-shaped reach | attainment range. Therefore, even if only the laminated battery within the reach of the protrusion shape escapes, if the other laminated battery expands, the possibility of deformation due to expansion of the battery module as a whole cannot be eliminated.

  In addition, when the battery continues to expand without releasing the gas generated inside each laminated battery in the battery module, the outer case is deformed by the expanded laminated battery and becomes a fan shape with the connecting portion of the positive electrode or negative electrode tab as a fulcrum. If opened, the battery tabs may come into contact with each other and a short circuit may occur.

  The present invention focuses on the above problems, and an object of the present invention is to provide a battery module capable of preventing deformation due to expansion of a laminated battery.

  In order to solve the above-mentioned problems, the battery module of the present invention has a laminated battery in which laminated batteries enclosed in battery elements such as electrodes, active materials, and electrolytes and sealed with a laminated film are connected in series or in parallel. The battery module is characterized in that a belt-like annular frame is arranged at least at one place in the center of the laminated battery.

  The belt-like annular frame is preferably made of at least one material selected from resin resins such as nylon, polyethylene, polypropylene, and fluororesin, or metal materials such as nickel and stainless steel. Furthermore, it is preferable to have an insulating resin plate on the upper and lower surfaces of the laminated battery and an insulating adhesive tape on the side surface.

  According to the present invention, some abnormality such as overcharge occurs in the battery module, the electrolyte inside the laminated battery is vaporized and the laminated battery expands, and the expanded laminated battery is suppressed and pressed by the belt-shaped annular frame, Parts that are structurally weak, such as the heat-welded part of the laminate film, can not withstand the suppression and break, and if the laminate battery used has a gas leak valve, it will operate and the gas accumulated inside will be released The Since the laminated battery breaks in order from the one that can no longer withstand the pressure or the gas leak valve operates, the laminated battery itself in the battery module does not expand greatly, and the expanded laminated battery deforms the outer case. It is possible to eliminate the possibility that the connected battery tab opens in a fan shape with the fulcrum as a fulcrum and the battery tabs come into contact with each other to cause a short circuit, and deformation and short circuit as a battery module can be prevented.

  Further, according to the present invention, it is not necessary to provide a protruding shape on the exterior case, and the assembly itself can be performed without a large man-hour because only the belt-like annular frame is attached.

  Furthermore, it is not necessary to provide a measure for giving strength against the swelling of the battery module in the thickness or fitting shape of the outer case, and there is an effect that the width of the outer case design is widened.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the battery module of the present invention, and FIG. 2 is an exploded perspective view showing the embodiment of the battery module of the present invention. FIG. 3 is a perspective view of a laminated battery.

  The laminated battery encloses battery elements such as electrodes, active materials, and electrolytes, and is sealed with a laminate film. As shown in FIG. 3, the positive electrode tab 11 and the negative electrode tab 12 are drawn from the same side and laminated around the laminated battery 10. The heat welding part 13 of the film is formed. The positive electrode tab and the negative electrode tab do not necessarily have to be drawn from the same side, and may be drawn from the opposite side. As a laminated battery, for example, there is a lithium ion secondary battery.

  Single laminated batteries are stacked, for example, one by one with their front and back alternating, and are joined in series by welding the positive and negative tabs of adjacent laminated batteries. In the case of parallel connection, the front and back surfaces can be stacked in the same direction. An insulating plate (not shown) formed of an insulating material such as polycarbonate is disposed between adjacent laminated batteries, and is adhered to the battery with a double-sided tape.

  Next, as shown in FIG. 2, an L-shaped tab 6 is disposed and welded between two battery tabs to be connected, that is, a positive electrode tab and a negative electrode tab. The L-shaped tab 6 disposed between the two battery tabs is obtained by soldering an electric wire serving as the signal line 3 that senses the voltage of each battery. Also, the battery tab connected to the main output wire, the L-shaped tab 6 to which the main output wire 4 and the signal line 3 are soldered are resistance-welded to each. Above and below the connected battery tabs, tab spacers 5 made of rubber sponge or the like having an insulating role are arranged. A battery protection plate 7 formed of an insulating resin material such as polycarbonate is bonded to the upper and lower sides of a laminated battery to which a predetermined number of laminated batteries are connected, and adhesive tapes 8 and 9 are attached around the side surface to attach the laminated battery. Is insulated and fixed.

  Next, as shown in FIG. 1, the laminated battery is passed through the belt-like annular frame 2, the belt-like annular frame is disposed at the center, and is housed in an outer case (not shown) to form a battery module. Here, the annular frame is formed by forming a metal annular body such as nickel or stainless steel, or a metal strip connected annularly by resistance welding, laser welding, ultrasonic welding or the like, or nylon, polyethylene It is assumed that it is molded from a resin material such as polypropylene or fluororesin. The corner portion 2a of the belt-shaped annular frame 2 is formed in advance so that the assembled laminated battery can be easily passed through and inserted into the outer case. Further, the number of the annular frames is not necessarily one, and a plurality of annular frames may be arranged. Further, the annular frame body does not need to be in close contact with the laminated battery during normal arrangement, and may be in close contact when the laminated battery slightly expands, and further expansion may be suppressed.

  Next, the present invention will be specifically described with reference to examples.

(Example 1)
The laminate battery uses lithium manganate as a positive electrode active material, graphite as a negative electrode active material, and LiPF ₆ dissolved in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) as an electrolyte solution. Was used which was sealed with a laminate film as shown in FIG. 1 drawn out from the same side, length 158 mm × width 82 mm × thickness 5.6 mm. Six of the laminated batteries were stacked in series with the front and back alternating. An L-shaped tab is disposed and welded between the positive electrode tab and the negative electrode tab. The L-shaped tab is soldered to an electric wire serving as a signal line for sensing the voltage of each battery, and the L-shaped tab to which the main output electric wire and the signal line are soldered is resistance-welded to each. A tab spacer made of a rubber sponge having a length of 20 mm, a width of 30 mm, and a thickness of 2 mm is adhered to the upper and lower sides of the tab after resistance welding so that the tab is not exposed with a double-sided tape. A polycarbonate plate of 160 × 80 mm × 0.15 mm was placed between the laminated batteries and connected with a double-sided tape to obtain a laminated battery. A battery protection plate made of polycarbonate of 160 mm × 82 mm × 0.5 mm was adhered to the top and bottom of the laminated battery with a double-sided tape, and an adhesive tape was attached around the side surface to insulate and fix the laminated battery. At this time, the laminated battery was 160.2 mm × 82.1 mm × 36.5 mm.

  In the central part of this laminated battery, a band-shaped annular frame body obtained by processing an annular nickel material having a width of 10 mm × thickness 0.2 mm so that the inner dimension is 84 mm × 38.5 mm was arranged at two locations at intervals of 30 mm. Thereafter, the battery module was housed in an exterior case made of polycarbonate.

(Example 2)
A laminated battery was produced in the same manner as in Example 1. A band-shaped annular frame body obtained by processing an annular nickel material having a width of 13 mm × thickness of 0.3 mm so that the inner dimension is 84 mm × 38.5 mm was disposed at the center of the laminated battery. Thereafter, the battery module was housed in an exterior case made of polycarbonate.

(Example 3)
A laminated battery was produced in the same manner as in Example 1. Two strip-shaped annular frames formed by injection-molding polycarbonate so as to have a width of 15 mm, a thickness of 2 mm, and an inner dimension of 84 mm × 38.5 mm were arranged at 30 mm intervals in the center of the laminated battery. Thereafter, the battery module was housed in an exterior case made of polycarbonate.

(Comparative example)
A laminated battery was produced in the same manner as in Example 1, and housed in an outer case made of polycarbonate to obtain a battery module.

  When the overcharge test of 44V, 7A was performed directly without passing the protective circuit through the main output wires of the battery modules of Examples 1, 2, and 3 and Comparative Example, in Examples 1, 2, and 3, the laminated film heat welded portion Was broken, gas was released, and the outer case was not deformed, whereas in the comparative example, the laminate battery expanded and the outer case was deformed.

The perspective view which shows embodiment of the battery module of this invention. The disassembled perspective view which shows embodiment of the battery module of this invention. The perspective view of a laminate battery. The schematic diagram which shows the relationship between the conventional laminated battery and a case.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery module 2 Annular frame 2a Corner part 3 Signal line 4 Main output electric wire 5 Tab spacer 6 L-shaped tab 7 Battery protective plate 8, 9 Adhesive tape 10 Laminated battery 11 Positive electrode tab 12 Negative electrode tab 13 Thermal welding part 14 Exterior case 14a Protrusion shape 15 Laminated battery

Claims (3)

  In a battery module having a laminated battery in which battery elements such as electrodes, active materials, electrolytes, etc. are enclosed and sealed with a laminate film are connected in series or in parallel, a band-like ring is formed at the center of the laminated battery. A battery module, wherein the frame body is arranged at one place or a plurality of places.   2. The belt-like annular frame body is made of at least one material selected from resin materials such as nylon, polyethylene, polypropylene, and fluororesin, or metal materials such as nickel material and stainless steel material. The battery module as described.   3. The battery module according to claim 1, further comprising an insulating resin plate on an upper surface and a lower surface of the laminated battery, and an insulating adhesive tape on a side surface.

Images