JPH1064576A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a short-circuit between positive and negative electrodes and dropping of active substance caused by deformation of an electrode group by providing a member for fixing a power generation element inside a battery container and providing on this member, a shock absorbing material having elasticity and electrolyte- resistant property. SOLUTION: A negative pole 2, a separator 3, and a positive pole 4 are stored in a battery container 1. An insulating fixing member is provided in contact with a container lid 5 and a shock absorbing material 11. The fixing member 10 is manufactured by processing polyethylene or polypropylene or the like and the shock damping material 11 is manufactured in such a way that a plate of foamed polyurethane or the like of about 5mm thickness is cut in the longitudinal dimension identical to the thickness in laminate direction of electrode group in which a negative pole 2 and a positive pole 4 are laminated via a separator 3 and cut in lateral direction storable between a positive pole collector terminal 7 and a negative pole collector terminal 6. In the case of the material 11, for instance, a bag having a three dimensional network structure of foamed polyurethane, foamed nylon, or the like in which rare gas such as argon or the like poured and tightly sealed may be pointed out. This material 11 has electrolyte-resistant property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery having an insulating fixing member for fixing a power generating element in a battery container.

[0002]

2. Description of the Related Art Generally, in a cylindrical secondary battery, a step is formed on a side wall of a battery container for two purposes, that is, for fixing an electrode and for caulking by installing a container lid at an opening of a battery can. Have been. On the other hand, in the case of a rectangular battery, such a stepping process is difficult, and welding is generally used to make the opening of the battery can and the lid of the container closely contact each other. Therefore, in particular, in the case of a prismatic battery, in order to fix the electrode group, a fixing member provided integrally with the lid in the battery is pressed while bending the upper part of the separator, as proposed in JP-A-62-229669. It is desirable to install so as to press the upper part. This is considered to be somewhat effective in preventing a short circuit between terminals having different polarities, such as a lead storage battery or a rectangular alkaline storage battery, in which the positive and negative connection conductors (terminals) are arranged in the same direction of the electrode group.

[0003]

In a nickel-cadmium battery, a nickel-hydrogen battery and the like, which are the mainstream of conventional secondary batteries, the positive electrode has an electrode thickness of 0.6 to 0.7 mm, and the negative electrode has an electrode thickness of 0.6 to 0.7 mm. Is about 0.5 mm. Similarly, in a lead storage battery, which has been the mainstream of the conventional secondary battery, the electrode thickness is 1.4 to 1.8 mm for the positive electrode and 1.3 for the negative electrode.
１．５1.5 mm. The electrode group composed of the positive and negative electrodes and the separator is unlikely to be deformed so as to affect the battery characteristics with respect to the contact with the fixing member or the load due to the weight of the electrode group itself as conventionally used. . On the other hand, in non-aqueous electrolyte batteries such as lithium ion secondary batteries, the ionic conductivity of the electrolyte is lower than that of the above lead storage batteries and alkaline storage batteries. And the internal resistance is reduced. Therefore, the positive electrode is 0.02 mm
Is filled with an active material mixture, and the electrode thickness is about 0.2 mm. The negative electrode is 0.02-0.03 m
m of copper foil is filled with the active material mixture, and the electrode thickness is 0.15 m
m to about 0.2 mm, and both the positive and negative electrodes are composed of very thin electrodes compared to the electrodes of alkaline storage batteries and lead storage batteries. Therefore, the electrode group composed of the positive and negative electrodes and the separator is easily deformed due to the collision with the fixing member or the insulating member or the load of the electrode group itself, and the short circuit between the positive and negative electrodes and the drop of the active material mixture are easily caused. There was a point. The problem to be solved by the present invention is to provide a battery capable of reducing a short circuit between a positive electrode and a negative electrode due to deformation of an electrode group and a fall of an active material even for a low-strength electrode group represented by a lithium ion secondary battery. To provide.

[0004]

In order to solve the above-mentioned problems, a power generating element of the present invention is housed in a battery container 1 and the power generating element is fixed in the battery container 1 by an insulating fixing member 10. The battery according to the present invention is characterized in that the insulating fixing member 10 has an elasticity at a portion in contact with the power generation element and a buffer material 11 which is resistant to an electrolytic solution. The above configuration is particularly effective for a prismatic battery formed by laminating electrodes, but is also applicable to a cylindrical battery. The above configuration is particularly effective for a lithium ion battery or the like using a low-strength electrode. Specific examples of the cushioning material 11 include a three-dimensional network structure such as foamed polyurethane and foamed nylon, rubber such as butyl rubber, silicone rubber, and acrylic rubber, and a rare gas such as argon, nitrogen, or the like in a polyolefin bag. There are a type in which gas such as dry air is injected and sealed, and a type in which a three-dimensional network structure is packed in a polyolefin bag. These have elasticity. An electrolyte-resistant one may be selected from these depending on the battery used. The power generation element in this specification includes an electrode group including the positive electrode 4, the negative electrode 2, and the separator 3, an electrolytic solution, and an electrode current collecting terminal.

After the electrode group is housed in the main body of the rectangular battery container 1, the buffer material is filled with the buffer material 11 so as to be in contact with the electrode group. Thereafter, the insulating fixing member 10 is set on the cushioning material 11. As described above, the electrode group and the insulating fixing member 10
By providing the cushioning material 11 between them, the electrode group can avoid direct contact with the insulating fixing member 10, or the load of the electrode group itself is applied in the installation direction of the cushioning material 11. Since the load on the electrode group at the time can be reduced, it is possible to secure a stable battery capacity without causing a short circuit between the positive and negative electrodes due to deformation of the electrode group and falling off of the active material,
A stable charge / discharge cycle life for secondary batteries can be ensured.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a partial sectional view of a prismatic battery which is an example of the present invention. Reference numeral 1 denotes a battery container, in which a negative electrode 2, a separator 3, and a positive electrode 4 are housed.
The negative electrode 2 is a material in which a carbon material and a binder are held on a copper foil, and is provided with a porous separator 3 made of polyethylene.
A positive electrode 4 holding LiCoO ₂ , a conductive agent, and a binder on an aluminum foil is alternately laminated to form an electrode group. Reference numeral 5 denotes a battery container lid, which is welded at the opening and the peripheral edge of the battery container 1. Reference numeral 6 denotes a negative electrode current collecting terminal provided above the negative electrode 2, and is connected to the negative electrode terminal 8.
Reference numeral 7 denotes a positive electrode current collecting terminal provided above the positive electrode 4 and is connected to the positive electrode terminal 9. The negative electrode terminal 8 and the positive electrode terminal 9 are insulated from the battery container lid 5. Reference numeral 10 denotes an insulating fixing member manufactured by processing polyethylene or polypropylene. Reference numeral 11 denotes a cushioning material, which has the same length as the thickness in the stacking direction of an electrode group in which a 5 mm-thick foamed polyurethane plate is stacked with a negative electrode and a positive electrode with a separator interposed therebetween. It is cut to a width that fits between the terminals 6. The insulating fixing member 10 includes the container lid 5 and the cushioning material 1.
1 and the cushioning material 11 is an insulating fixing member 10
And the electrode group.

FIG. 2 is a partial sectional view of a prismatic battery as another example of the present invention. The battery case 1, the negative electrode 2, the separator 3, the positive electrode 4, the negative current collecting terminal 6, the positive current collecting terminal 7, the negative terminal 8, and the positive terminal 9 are arranged in the same manner as in FIG.
11 is a cushioning material, and the insulating fixing member 10 is
And the cushioning material 11, and the cushioning material 11 is in contact with the insulating fixing member 10 and the electrode group. 1 and 2, LiPF ₆ (solute) is used as a mixed solvent of ethylene carbonate and dimethyl carbonate as an electrolytic solution. This is housed in the container 1.

[0008]

EXAMPLE A battery having the structure shown in FIG. 2 (Example 1) and the batteries of Examples 2 to 4 and Comparative Example 1 described below were manufactured to demonstrate the effectiveness of the present invention. . (Production of Battery of Example 2) A battery was produced under the same conditions as in Example 1 except that a butyl rubber plate was used instead of the foamed polyurethane plate as the cushioning material.

(Preparation of Battery of Example 3) A battery was prepared under the same conditions as in Example 1 except that a polyethylene bag sealed by injecting dry air was used instead of a foamed polyurethane plate as a cushioning material.

(Fabrication of Battery of Example 4) A battery was fabricated under the same conditions as in Example 1 except that the cushioning material was a polyethylene bag packed with foamed nylon instead of the foamed polyurethane plate.

(Preparation of Battery of Comparative Example 1) A battery was prepared under the same conditions as in Example 1 except that no buffer was provided between the insulating fixing member and the electrode group. It was arranged between the battery container lid and the electrode group. However, in this case, the thickness of the insulating fixing member was increased by the thickness of the buffer material by 5 mm.

(Experiment) The batteries prepared in Examples 1 to 4 and Comparative Example 1 were vibrated for 1 minute at an amplitude of 1 cm and a frequency of 1.6 / sec, and a test for confirming the short circuit of the batteries was performed. After the test for confirming the short circuit, the battery was disassembled to check for electrode deformation.
Table 1 shows the results.

[0013]

[Table 1]

From Table 1, Examples 1 to 4 did not cause an internal short circuit and did not deform the electrode, whereas Comparative Example 1 caused an internal short circuit and the electrode was deformed. For this reason, by providing a cushioning material between the insulating fixing member and the electrode group, the positive and negative electrodes due to the deformation of the electrode group can be used even for a low-strength electrode group represented by a lithium ion secondary battery. It can be seen that a short circuit between them and the falling off of the active material can be reduced or suppressed. To be able to reduce or suppress the falling off of the active material means to obtain a stable battery capacity and, in the case of a secondary battery, a stable charge / discharge cycle life. In the case of a lithium ion secondary battery, if there is a short circuit, there is a risk of explosion. According to the present invention, the short circuit can be suppressed and the safety can be improved.

In this embodiment, a prismatic lithium ion secondary battery is used. However, the present invention is not limited to this, and can be applied to other battery shapes and battery systems. In the first embodiment, the foamed polyurethane plate is used as the cushioning material. However, another three-dimensional network structure having electrolytic resistance and elasticity may be used. In the second embodiment, a butyl rubber plate is used as a buffer. However, another rubber having an electrolytic solution resistance and elasticity can be applied. In the case of a battery using an organic solvent as an electrolyte such as a lithium ion secondary battery, there are silicon rubber, acrylic rubber, and the like. In the third embodiment, a polyethylene bag sealed by injecting dry air is used as a buffer, but another gas may be used, or a bag of another polyolefin such as polypropylene may be used. For lithium ion secondary batteries,
In the unlikely event that gas leaks from the bag, a rare gas such as argon, neon, or krypton, which is an inert gas that does not react with lithium, can be used. Further, in Example 4, a polyethylene bag packed with foamed nylon was used as the cushioning material. However, other materials than nylon can be used as long as the cushioning material has elasticity.

[0016]

According to the present invention, it is possible to provide a battery which can reduce a short circuit between the positive electrode and the negative electrode and a fall of the active material due to the deformation of the electrode group even for the electrode group having low strength. Further, this effect is particularly remarkable in a battery including a low-strength electrode group represented by a lithium ion secondary battery. For this reason, the short circuit between the positive and negative electrodes due to the deformation of the electrode group can be prevented, and the safety is improved.Also, without causing the active material mixture to fall off, securing a stable battery capacity and a stable It is possible to secure the charge / discharge cycle life.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view of a prismatic battery as an example of the present invention.

FIG. 2 is a partially cutaway view of a prismatic battery as another example of the present invention.

[Explanation of symbols]

 1. Battery container 2. Negative electrode 3. Separator 4. Positive electrode 5. Battery container lid 6. 6. Negative electrode current collector terminal 7. Positive current collector terminal Negative electrode terminal 9. Positive electrode terminal 10. 10. Insulating fixing member Cushioning material

Claims (8)

[Claims] 1. A battery in which a power generating element is housed in a battery container and the power generating element is fixed in the battery container by an insulating fixing member, wherein the insulating fixing member is in contact with the power generating element. A battery having a portion having elasticity and a buffer material which is resistant to an electrolytic solution. 2. The battery according to claim 1, wherein the battery container is rectangular. 3. The battery according to claim 1, wherein the battery is a lithium ion secondary battery. 4. The cushioning material is a three-dimensional network structure.
The battery according to any one of claims 1 to 3. 5. The battery according to claim 1, wherein the cushioning material is made of rubber. 6. The battery according to claim 1, wherein the cushioning material is formed by injecting gas into a polyolefin bag and sealing the bag. 7. The battery according to claim 6, wherein the gas is a rare gas, a nitrogen gas, or dry air. 8. The battery according to claim 1, wherein the cushioning material is a polyolefin bag packed with a three-dimensional network structure.