JP4945993B2 - Non-aqueous electrolyte battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte battery using an electrode plate formed by holding a positive electrode mixture mainly composed of fluorocarbon as a positive electrode on a metal core.

  Non-aqueous electrolyte batteries using lithium metal or lithium alloy for the negative electrode have a high energy density and can be reduced in size and weight, so they can be used in various applications such as main power supplies for various electronic devices and power supplies for memory backup. Is used. In particular, a non-aqueous electrolyte primary battery using fluorocarbon as a positive electrode has excellent long-term reliability, and has been used as a main power source for devices that require long-term reliability such as a gas microcomputer meter. In such a battery used for a long period of time, it is necessary not only to avoid heat generation due to the internal short circuit of the battery, but also to prevent the discharge capacity from being consumed due to a slight internal short circuit.

  On the other hand, in order to cope with the high loads associated with the higher functionality of equipment, as a means to increase the reaction area, the positive electrode mixture is held on a metal core, etc. The electrode group is formed by laminating with a negative electrode plate that is also formed into a long shape through a coil and winding it in a spiral shape. However, in the battery configured in this way, the metal positive electrode core burr generated on the cut end face of the positive electrode plate during the processing of the positive electrode plate penetrates the separator and contacts the negative electrode to cause an internal short circuit. It was easy to cause.

  Therefore, in Patent Document 1, the width of one electrode plate is made smaller than the width of the other electrode plate, and the core material of the narrow electrode plate is made smaller than the electrode plate, and burrs may be generated. It has been proposed to improve the reliability by configuring so that the cut end faces of the two bipolar plates do not oppose as much as possible. At this time, when the width of the negative electrode plate is smaller than the width of the positive electrode plate, the negative electrode plate is prevented from facing the end face of the positive electrode plate as much as possible to prevent internal short circuit due to the burr of the positive electrode core material. Furthermore, even if the cut end face of the positive electrode plate faces the negative electrode plate due to misalignment or the meandering of the electrode plate, the burr of the positive electrode core material does not touch the core material of the negative electrode plate, and the negative electrode active material in the contact portion However, if it is consumed by a local short-circuit reaction, this contact can be easily eliminated and only a slight internal short-circuit can be achieved.

In addition, when the width of the positive electrode plate is smaller than the width of the negative electrode plate, the positive electrode core material is made smaller than the positive electrode plate, and the cutting burr of the positive electrode core material is exposed from the cut end surface of the positive electrode plate so as to penetrate the separator. No internal short circuit occurs with the negative electrode plate.
Japanese Patent Publication No.53-32851

  However, if the width of the negative electrode plate is smaller than the width of the positive electrode plate, the burr on the cut end face of the positive electrode plate faces the negative electrode plate due to the displacement in the width direction or the meandering of the electrode plate when the electrode plate group is configured. In some cases, burrs on the cut end face may cause an internal short circuit between the opposing negative electrode plate that penetrates the separator. In Patent Document 1, it is possible to limit the internal short circuit to a very small amount. However, in a battery used for a long period of time, it is necessary to prevent the discharge capacity from being consumed due to the small internal short circuit.

  Further, when the width of the positive electrode plate is smaller than the width of the negative electrode plate, the positive electrode core material is made smaller than the positive electrode plate, and the cutting burr of the positive electrode core material is not exposed from the cut end face of the positive electrode plate. However, if the positive electrode mixture on the end face of the positive electrode plate is missing, the positive electrode core material is exposed, and there is a problem that an internal short circuit occurs between the negative electrode plate that penetrates the separator and opposes.

  In order to solve the above problems, in the present invention, in a nonaqueous electrolyte battery having a positive electrode having carbon fluoride and a negative electrode having lithium metal or a lithium alloy, the positive electrode active material containing fluorocarbon is made of a metal core. The width of the positive electrode plate formed by filling or coating the material into a sheet shape is larger than the width of the negative electrode plate formed by cutting a lithium metal or lithium alloy foil into a predetermined dimension, and the core material of the positive electrode plate The width is smaller than the width of the positive electrode plate, and the blending ratio of the binder contained in the positive electrode is 13 or more by weight ratio when the fluorocarbon is 100.

  Even if the cut end surface of the positive electrode plate is opposed to the negative electrode plate due to the displacement in the width direction during the configuration of the electrode plate group or the meandering of the electrode plate, the positive electrode core material is not exposed from the cut end surface of the positive electrode plate, The positive electrode mixture on the end face of the positive electrode plate does not cause an internal short circuit with the negative electrode plate that the metal positive electrode core material penetrates the separator and faces the negative electrode plate. Thus, a sufficient binding force without chipping is obtained, so that the positive electrode core material is not exposed and an internal short circuit does not occur between the negative electrode plate that penetrates the separator and opposes.

  According to the configuration of the present invention, even when the cut end surface of the positive electrode plate faces the negative electrode plate due to displacement in the width direction when the electrode plate group is configured, meandering of the electrode plate, or the like, the positive electrode core material is the cut end surface of the positive electrode plate. In addition, since the positive electrode mixture on the end face of the positive electrode plate is not lost, the burrs of the metal positive electrode core material penetrate through the separator and do not cause an internal short circuit with the opposing negative electrode plate. A highly reliable battery is obtained.

  The present invention relates to a nonaqueous electrolyte battery having carbon fluoride as a positive electrode and lithium metal or a lithium alloy as a negative electrode, and filling or coating a metal core with a positive electrode active material containing carbon fluoride. The width of the positive electrode plate formed in a sheet shape is larger than the width of the negative electrode plate obtained by cutting a lithium metal or lithium alloy foil into a predetermined dimension, and the core material width of the positive electrode plate is smaller than the positive electrode plate width. Further, the blending ratio of the binder contained in the positive electrode is 13 or more in a weight ratio when the fluorocarbon is 100, the displacement in the width direction during the construction of the electrode plate group, and the electrode plate Even if the cut end surface of the positive electrode plate faces the negative electrode plate due to meandering of the metal plate, the positive electrode core material is not exposed from the cut end surface of the positive electrode plate, and the positive electrode mixture on the positive electrode plate end surface is not lost. The positive electrode core burr made of metal penetrates the separator and faces it. That reliable battery does not occur an internal short circuit between the negative electrode plate in which it is obtained.

  If the blending ratio of the binder is increased too much, the battery capacity is reduced.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of the positive electrode plate 1 of the present invention. The positive electrode mixture 2 is mainly composed of fluorocarbon, and the weight ratio when the blending ratio of the binder is 100 is 13 or more. It is as. The positive electrode mixture 2 is filled and coated on the positive electrode core material 3 and formed into a sheet shape, and then cut into predetermined dimensions. As the positive electrode core material 3, a metal foil such as SUS, aluminum and titanium, a lath metal, a punching metal, or the like is mainly used.

Here, the cut end face of the positive electrode core material 3 is not exposed than the cut end face of the positive electrode plate 1 (= the cut end face of the positive electrode mixture 2). That is, the width of the positive electrode core material 3 is smaller than the width of the positive electrode plate 1. In this method, the positive electrode plate 1 is once cut into a single plate, and further rolled to a predetermined size so that the positive electrode mixture 2 extends so as to cover the cut end surface of the metal positive electrode core material 3. There is a technique in which the positive electrode plate 1 in which the cut end face of the material 3 is not exposed from the cut end face of the positive electrode mixture 2 is available. Further, by using a thermal fusing such as a laser when cutting the positive electrode plate 1 to a predetermined size, the metal positive electrode core material 3 is melted at the end face and becomes spherical due to surface tension at the time of cutting, and is not a sharp burr. There is a method of obtaining the positive electrode plate 1 which is shorter than the cut size and in which the cut end face of the positive electrode core material 3 is not exposed from the cut end face of the positive electrode mixture 2.

  The positive electrode current collector 4 is electrically fixed to the positive electrode core material 3.

  FIG. 2 shows an example of the negative electrode plate 5. The negative electrode active material 6 is lithium metal or a lithium alloy such as Li—Al, Li—Si, Li—Sn, and Li—Pb. The negative electrode plate 5 is cut so that the width of the negative electrode plate 5 is smaller than the width of the positive electrode plate 1. Yes. Since these negative electrode active materials 6 are metals or alloys, they do not require a metal core material for imparting conductivity, and at the same time, since they are soft metals, burrs generated during cutting break through the separator and cause internal leakage. It will not cause The negative electrode current collector 7 is electrically fixed to the negative electrode active material 6 that also serves as a core material.

Example 1
(1) Preparation of positive electrode The positive electrode uses carbon fluoride as an active material, acetylene black as a conductive agent, and polytetrafluoroethylene dispersion (solid content 60%) as a binder, and these are 100: The positive electrode mixture 2 was obtained by mixing at a ratio of 10:13 (solid content). The positive electrode mixture 2 was filled and molded into the positive electrode core material 3 made of SUS444 lath metal welded with the positive electrode current collector 4 made of SUS444 thin plate, and then cut into a single plate having a width of 22.5 mm and a length of 199.5 mm. Thereafter, rolling was performed to obtain a positive electrode plate 1 having a thickness of 0.3 mm, a width of 23 mm, and a length of 200 mm, in which the cut end surface of the positive electrode core material 3 was not exposed from the cut end surface of the positive electrode mixture 2. This was used after being dried at 110 ° C. for 12 hours.

(2) Production of Negative Electrode A negative electrode active material 6 is made of a metal lithium foil having a thickness of 0.16 mm, cut into a width of 21 mm and a length of 220 mm, and a negative electrode current collector 7 made of a nickel metal plate is pressure-bonded. It was.

(3) Production of Separator As a separator, a 0.06 mm thick polyethylene non-woven fabric was cut into a width of 25 mm and a length of 560 mm.

(4) Preparation of non-aqueous electrolyte As the non-aqueous electrolyte, lithium borofluoride (LiBF ₄ ) was dissolved as a solute in γ-butyllactone as a solvent to give a non-aqueous electrolyte.

(5) Production of Cylindrical Nonaqueous Electrolyte Primary Battery A cylindrical nonaqueous electrolyte battery having an outer diameter of φ17 mm and a height of 33.5 mm was produced using the positive electrode, the negative electrode, the separator, and the nonaqueous electrolyte. A cross-sectional view thereof is shown in FIG.

  After the positive electrode plate 1 and the negative electrode plate 5 are laminated via the separator 8 and wound into a spiral shape to form an electrode plate group in a case 9 that also serves as a negative electrode terminal, the negative electrode current collector 7 The case 9 was resistance welded. After the positive electrode current collector 4 and the sealing plate 10 were resistance-welded, 3 g of nonaqueous electrolyte was injected to seal the sealing plate 10 and the case 9 via the gasket 11.

  When the electrode plate group was configured, the cut end surface of the positive electrode plate 1 was configured to face the negative electrode plate 5. Thereby, when the metal burr | flash which generate | occur | produces in the cut end surface of the positive electrode core material 3 is exposed to the cut end surface of the positive electrode plate 1, it becomes easy to raise | generate an internal short circuit, and it becomes easy to understand the effect of this invention.

  Thus, a cylindrical non-aqueous electrolyte primary battery of Example 1 of the present invention was produced.

(Example 2)
Cylindrical non-same as in Example 1 except that it was prepared using the positive electrode plate 1 using the positive electrode mixture 2 in which the weight ratio of the binder was 20 (solid content) with respect to the fluorocarbon 100. A water electrolyte primary battery was produced as the battery of Example 2.

(Comparative Example 1)
A cylinder similar to that in Example 1 is used except that the positive electrode plate 1 in which the cut end face of the positive electrode core material 3 is exposed from the cut end face of the positive electrode mixture 2 is not used when the positive electrode plate 1 is rolled. A non-aqueous electrolyte primary battery was produced and used as the battery of Comparative Example 1.

(Comparative Example 2)
The same non-cylindrical shape as in Example 1 except that the positive electrode plate 1 using the positive electrode mixture 2 in which the blending ratio of the binder was 7 (solid content) with respect to the fluorocarbon 100 was 7 by weight. A water electrolyte primary battery was produced and used as a battery of Comparative Example 2.

(Comparative Example 3)
The same non-cylindrical shape as in Example 1 except that it was prepared using the positive electrode plate 1 using the positive electrode mixture 2 in which the blending ratio of the binder was 10 (solid content) with respect to the fluorocarbon 100 by weight. A water electrolyte primary battery was produced and used as the battery of Comparative Example 3.

<< Evaluation of Cylindrical Nonaqueous Electrolyte Primary Battery >>
The batteries of Example 1, Example 2 and Comparative Examples 1 to 3 produced as described above were subjected to UN-Test 3 vibration test as defined in the UN Transport Regulations, and the fluctuation of the open circuit voltage before and after that was measured. . The results are shown in Table 1.

As is clear from the comparison between Example 1 and Comparative Example 1 in Table 1, the battery of Example 1 does not experience a decrease in open circuit voltage before and after the vibration test as compared with the battery of Comparative Example 1, and is reliable. It can be seen that is improved.

  In the battery of Comparative Example 1, the width of the positive electrode core material 3 is equal to the width of the positive electrode plate 1, and the cut end surface of the positive electrode core material 3 is exposed from the cut end surface of the positive electrode mixture 2. In this test configured to face the plate 5, the cut end surface burr of the metal positive electrode core material 3 penetrated the separator 8 and contacted the negative electrode plate 5 to cause an internal short circuit. On the other hand, in the battery of Example 1, the positive electrode plate 1 is cut once into a single plate and then rolled to a predetermined size so that the positive electrode mixture 2 covers the cut end surface of the metal positive electrode core material 3. Therefore, it is considered that the cut end face of the positive electrode core material 3 was not exposed from the cut end face of the positive electrode mixture 2 and an internal short circuit did not occur.

  Similarly, in the battery of Example 1 of the present invention, the open circuit voltage drop before and after the vibration test does not occur and the reliability is improved as compared with the batteries of Comparative Example 2 and Comparative Example 3. .

  In the batteries of Comparative Example 2 and Comparative Example 3, when the positive electrode plate 1 was produced, the positive electrode mixture 2 was once cut into a single plate and then rolled to a predetermined size, whereby the positive electrode mixture 2 was cut into a cut end surface of the metal positive electrode core material 3. Therefore, the cut end face of the positive electrode core material 3 is not exposed from the cut end face of the positive electrode mixture 2, and the rate of occurrence of the open circuit voltage drop is lower than that of the battery of Comparative Example 1. However, since the blending ratio of the binder is as small as 7 and 10 respectively with respect to the fluorocarbon 100, sufficient binding force cannot be obtained, and the positive electrode mixture 2 is chipped at the end face of the positive electrode plate 1, As a result, the cut end face of the positive electrode core material 3 is exposed, leading to an internal short circuit. On the other hand, in the battery of Example 1, the compounding ratio of the binder was 13 with respect to the fluorocarbon 100, a sufficient binding force was obtained, the chipping of the positive electrode mixture 2 did not occur, and the positive electrode core material 3 This is probably because the cut end face was not exposed.

  Further, in both the batteries of Examples 1 and 2, there was no open circuit voltage drop after the vibration test, and if the blending ratio of the binder was 13 or more with respect to the fluorocarbon 100, a sufficient binding force was obtained and the reliability was improved. It can be seen that sex is secured.

  The positive electrode according to the present invention is formed by holding a positive electrode mixture mainly composed of fluorocarbon as a positive electrode on a metal core, and using a lithium metal or an alloy thereof as a negative electrode, and laminating with a separator. A non-aqueous electrolyte primary battery having a group of electrodes wound in a spiral shape is used when the cut end surface of the positive electrode plate faces the negative electrode plate due to deviation in the width direction during the configuration of the electrode plate group, meandering of the electrode plate, etc. However, since the positive electrode core material is not exposed from the cut end face of the positive electrode plate, a highly reliable battery in which the burrs of the metal core material penetrate the separator and do not cause an internal short circuit with the opposing negative electrode plate is obtained. Therefore, its industrial value is very large.

Plan view of the positive electrode plate of the present invention Plan view of the negative electrode plate of the present invention Sectional view of the battery of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Positive electrode mixture 3 Positive electrode core material 4 Positive electrode collector 5 Negative electrode plate 6 Negative electrode active material 7 Negative electrode collector 8 Separator 9 Case 10 Sealing plate 11 Gasket

Claims (1)

In a non-aqueous electrolyte battery having carbon fluoride in the positive electrode and lithium metal or lithium alloy in the negative electrode, a positive electrode active material containing fluorocarbon is filled or applied to a metal core material into a sheet shape The width of the formed positive electrode plate is larger than the width of the negative electrode plate obtained by cutting a lithium metal or lithium alloy foil into a predetermined dimension, the core material width of the positive electrode plate is smaller than the positive electrode plate width, and the positive electrode A non-aqueous electrolyte battery characterized in that the blending ratio of the binder contained therein is 13 or more by weight ratio when the fluorocarbon is 100.