JPH0523414U - Battery structure - Google Patents

Abstract

(57) [Summary] [Structure] Either one of the tab members attached to the sheet-shaped positive and negative electrodes is welded to the inside of the open end of the metal battery can (5), and the tab members (4 ) Has a convex flexure in the battery structure. Further, a battery structure is characterized in that a spacer for preventing the movement of the battery contents is arranged in the space portion on the opening end side of the metal battery can, and the tab member has a convex bend. [Effect] It is possible to provide a battery in which the tab member is not broken even when a shock is applied by dropping the battery.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to the structure of a battery. More specifically, the sheet-shaped positive and negative electrodes are arranged to face each other via a separator so that electric energy can be taken out through a tab member attached to the positive and negative electrodes. The present invention relates to a battery structure in which the battery contents are sealed in a metal battery can.

[0002]

[Prior Art]

 In a battery with positive and negative electrodes facing each other with a separator in between, the output characteristics of the battery are generally proportional to the area of the positive and negative electrodes facing each other, so in order to extract a large current, keep that area as wide as possible. There is a need. Especially in the case of non-aqueous batteries, it is necessary to secure a larger area because the conductivity of the electrolyte solution used is relatively low, so that a large area can be obtained efficiently for the electrodes. A sheet-shaped electrode formed by attaching an active material is used. In such a conventional battery, a metal tab member is usually attached to the positive and negative electrodes in order to take out the electric energy converted through the active material to the outside through the current collector. The positive and negative tab members are welded to a metal battery can and a can lid, respectively, and then sealed.

Although there are various places to weld these tab members to the battery can, the tab member is attached to the battery can open end for the purpose of reducing the volume of the battery can or simplifying the welding work of the tab member to the battery can. A method of welding to the side wall portion directly above the inner electrode is adopted. FIG. 3 shows an example of the structure of a conventional battery having such a structure. However, in the conventional battery configured as described above, the length of the tab member from the electrode to the weld is made as short as possible for the purpose of simplifying the internal structure. When a shock is applied to a battery having this conventional battery structure, for example, by accidentally dropping it, the battery contents move due to the shock, and the tab member is compressed and pulled to cut the tab member. As a result, the current cannot be taken out, and the battery will not function. For this reason, a spacer is placed in the space inside the battery to prevent the movement of the battery contents, but the spacer alone has not been able to achieve a sufficient effect.

[0004]

[Problems to be solved by the device]

 An object of the present invention is to provide a battery structure in which the tab member does not break even when an impact such as a drop occurs, focusing on such a conventional problem.

[0005]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention arranges sheet-like positive and negative electrodes facing each other through a separator, and allows electric energy to be taken out through a tab member attached to the positive and negative electrodes. In a battery structure in which the battery contents are sealed in a metal battery can, one of the tab members attached to the positive and negative electrodes is welded to the inside of the open end of the metal battery can, and the The tab member is characterized by having a convex bend.

Further, the present invention is characterized in that a spacer for preventing movement of battery contents is arranged in a space portion on the opening end side of a metal battery can, and the tab member has a convex bend. Is. According to the present invention, one of the tab members is welded to the inside of the open end of the metal battery can, and the tab member is provided with a convex bend so that the battery is accidentally dropped, for example. Even if a shock is applied to the tab member, the tab member is not subjected to compression or tension, so that it is possible to provide a battery structure in which the tab member does not break. Here, the convex flexure means that the tab member attached to the electrode is not connected to the metal battery can by the straight line that is the shortest length to the welding point, but the battery contents due to a shock such as a drop in the middle. Deflection provided to absorb the compressive and tensile forces applied to the tab member due to the movement of an object, and the convex shape means the shape of the bend formed by temporarily bending the tab member toward the center of the battery can. Represent If there is a fold in this bending portion, when a compressive or tensile force is applied to the tab material, the force is concentrated at the fold and the tab is cut at this portion. Therefore, it is necessary that the bend has no folds.

Further, a spacer for preventing the movement of the battery contents is arranged in the space on the opening end side of the metal battery can, and the tab member is provided with a convex bend so that the battery contents The amount of movement of the tab member can be reduced, and the force of compression and pulling on the tab member can be further reduced, which is more effective for preventing the tab member from being cut. The method of welding the tab member and the metal battery can includes, for example, a resistance welding method and an ultrasonic welding method, but is not particularly limited. Although the tab member and the metal battery can may be directly welded to each other when they are welded, as a method of increasing the welding strength, a metal plate made of a material that is easily welded to the metal battery can is welded to the welded portion of the tab member. It is also possible to adopt a method of welding this portion to a metal battery can after attaching the.

[0008]

【Example】

 Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings, but the present invention is not limited to the following embodiments.

[0009]

Embodiment 1 FIG. 1 is an abbreviated view showing a cross section of a battery composed of a pair of positive and negative electrodes as a basic configuration example of the present invention. Here, the positive electrode sheet 1 and the negative electrode sheet 2 are arranged to face each other with the separator 3 interposed therebetween. The negative tab member 4 is welded to the side wall portion inside the open end of the metal battery can 5 with a convex bend.

The inventor actually made a prototype battery and conducted an experiment. For these batteries, as a positive electrode, a suspension was prepared by adding an equal amount of a 5% solution of polyvinylidene fluoride in DMF to a compound prepared by adding 5% of a carbon-based conductive additive to the active material LiCoO ₂ . Then, this was uniformly attached to an aluminum foil at 300 g / m ² , and for the negative electrode, the same amount of a 5% DMF solution of polyvinylidene fluoride was added to a carbonaceous material having an average particle size of 10 μm as an active material. In addition, a suspension was prepared, which was uniformly attached to a copper foil at 150 g / m ² and used. These were impregnated with a 0.6 mol / l propylene carbonate solution of LiClO ₄ and sealed in a battery can.

The area of the electrode was 40 × 300 mm, a 100 μm thick aluminum foil was used for the positive electrode tab member, and a 100 μm thick copper foil was used for the negative electrode tab member. The width of each tab member was 4 mm. A Nomex paper tape having a width of 6 mm was attached to both surfaces of the positive electrode tab member for the purpose of insulation. The negative electrode tab member was processed so as to have a convex bend, and the tip of the tab member was welded to the inside of the open end of the metal battery can (SUS304 or SUS305). Diameter 16. A battery can with a height of 5 mm and a height of 50 mm was dropped onto the concrete floor 5 times from a height of 1.2 m. Then, the battery can was opened and examined for changes in the tab member inside. The results are shown in Table 1. It can be seen that the battery having such a battery structure has no fear of the tab member being cut off by an impact such as dropping.

[0012]

[Embodiment 2] FIG. 2 shows an embodiment in which a spencer for preventing the movement of the battery contents is arranged in the space on the open end side of the metal battery can, which has a convex bend. 6 is a perspective view of a portion where the tab member 4 is welded to a side wall portion inside the opening end of the metal battery can 5. FIG. Here, a spacer 6 for preventing the movement of the battery contents is arranged in the space on the opening end side of the metal battery can 5, and the tab member is provided with a convex bend to open the metal battery can 5 It is welded to the side wall inside the end. In addition to the first embodiment, the inventor of the present invention arranged a polyethylene spacer having a thickness of 5 mm on the battery can opening end side except for the bending part of the negative electrode tab member as shown in FIG. The tab member was processed so as to have a convex bend, and the tip of the tab member was welded to the inside of the open end of the metal battery can. The battery thus prototyped was dropped in the same manner as in Example 1 to examine the change in the tab member inside the battery. The results are shown in Table 1. In this way, by disposing a spacer to prevent the movement of the battery contents in the space on the open end side of the battery can and providing the tab member with a convex bend, the tab member is cut due to an impact such as a drop. Can be prevented more effectively.

[0013]

Example 3 For the negative electrode, a carbonaceous material having an average particle size of 10 μm was added as an active material in the same amount as a 5% solution of polyvinylidene fluoride in DMF to obtain a suspension, which was uniformly applied to a nickel foil at 150 g / m ² . The battery was assembled in the same manner as in Example 1 except that a nickel foil having a thickness of 100 μm was used for the negative electrode tab member, and dropped to examine the change of the tab member inside the battery. .. The results are shown in Table 1.

[0014]

[Comparative example]

 The negative electrode tab member of Comparative Example 1 was the same as that of Example 2 except that it was directly welded to the metal battery can without any bending as shown in FIG. The battery thus prototyped was dropped in the same manner as in Example 1 to examine the change in the tab member inside the battery. The results are shown in Table 1.

As is apparent from Table 1, in the structure of the battery of Comparative Example 1, the tab member is easily cut by the impact of falling, whereas in the structure of the battery of the present invention, the tab member is not cut. You can see that it can be provided.

[0016]

[Table 1]

[0017]

[Effect of the device]

 The present invention can provide a battery structure in which the tab member does not break even when a shock is applied by accidentally dropping the battery.

[Brief description of drawings]

FIG. 1 is a partially omitted sectional view of a battery showing an example of the present invention.

FIG. 2 is a partially omitted perspective view of a battery can open end showing an example of a case where a spencer for preventing movement of battery contents is arranged in a space of an open end side of a metal battery can of the present invention. is there.

FIG. 3 is a partially omitted sectional view showing an example of a conventional battery.

[Explanation of symbols]

 1 ... Positive electrode sheet 2 ... Negative electrode sheet 3 ... Separator 4 ... Tab member 5 ... Metal battery can 6 ... ·spacer

Claims (1)

[Scope of utility model registration request] 1. A metal battery in which sheet-shaped positive and negative electrodes are arranged to face each other with a separator interposed therebetween, and electric energy can be taken out through a tab member attached to the positive and negative electrodes. In the structure of a battery sealed in a can, one of the tab members attached to the positive and negative electrodes is welded to the inside of the open end of the metal battery can, and the tab member has a convex bend. Battery structure characterized by