JP2008103109A - Nonaqueous electrolyte cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte cell and a method of manufacturing the nonaqueous electrolyte cell capable of suppressing increase of an internal resistance even under a low temperature environment to improve heavy load characteristics, by enhancing the current collection effect. <P>SOLUTION: In this nonaqueous electrolyte cell 10 and the method of the nonaqueous electrolyte cell, the nonaqueous electrolyte cell is provided with a negative electrode can 11, a negative electrode pellet 12 made of lithium or lithium aluminum alloy, an aluminum foil 13 disposed on a positive electrode side-negative surface of the negative electrode pellet 12, a positive electrode pellet 15 mainly made of β manganese dioxide, a positive electrode can 17, and a separator 14 disposed between the negative electrode pellet 12 and the positive electrode pellet 15. The negative electrode pellet 12 and the positive electrode pellet 15 are encapsulated, together with nonaqueous electrolyte, in a cell case comprising the negative electrode can 11 and the positive electrode can 17. A positive electrode ring 16, which is L-shaped in half section, closely contacting an inner surface of the positive electrode pellet 15 is weld-bonded to an inside of the positive electrode can 17 by resistant welding or laser welding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-aqueous electrolyte battery, and more particularly to a coin-type non-aqueous electrolyte battery and a method for manufacturing a non-aqueous electrolyte battery that are optimal for power sources of various portable electric devices.

  As an example of a non-aqueous electrolyte battery, as shown in FIG. 3, a positive electrode can 51 also serving as a positive electrode terminal made of nickel-plated stainless steel, and a positive electrode pellet obtained by pressure-molding a mixture mainly composed of manganese dioxide 52, a separator 53 made of polypropylene nonwoven fabric, a negative electrode pellet 54 using lithium as a negative electrode active material, a negative electrode can 55 also serving as a negative electrode terminal made of nickel-plated stainless steel, a polypropylene 56 gasket, There is known a nonaqueous electrolyte battery 50 including a cylindrical positive electrode ring 57 made of stainless steel having a predetermined thickness, in which the inner diameter of the positive electrode ring 57 is 102% to 110% of the outer diameter of the positive electrode pellet 52 ( For example, see Patent Document 1).

JP-A-9-204920

  However, in the conventional non-aqueous electrolyte battery 50 disclosed in Patent Document 1, a difference in the amount of electrolyte injected is prevented, and leakage of the electrolyte is prevented to suppress variation in discharge capacity. Although it is possible, when it swells at a high temperature, the conduction resistance increases and the current collecting effect may be insufficient.

  In recent years, lithium batteries and the like have been used as driving power sources, and demand for heavy load characteristics at low temperatures has increased. Lithium batteries generally have a normal operating temperature range of −20 ° C. to 60 ° C., but in particular, when used in a system for sensing vehicle tire pressure, −40 ° C. to 120 ° C. Thus, heavy load characteristics in a wide temperature range from low temperature to high temperature are being demanded.

  In a heavy load pulse test at a low temperature of a lithium manganese battery, since the electrolyte reaches a point near the freezing point at a low temperature of −40 ° C., the conductivity of ions is significantly reduced, and the positive electrode can which collects the current of the battery There has been a problem that the heavy load pulse characteristics at a low temperature are remarkably deteriorated due to a decrease in the contact of the positive electrode ring and the positive electrode pellet.

  Furthermore, as a part to improve the adverse effect of reducing current collection due to battery swelling during high-temperature storage, the positive electrode pellet and the positive electrode ring are integrally molded, and the positive electrode can has an elastic plate material. There are a method of welding the positive electrode can by resistance welding or laser, and a method of improving the current collecting property by applying a conductive paint mainly made of carbon to the positive electrode can. These methods can suppress the increase in internal resistance by maintaining the contact of the current collector even if the battery size changes at low and high temperatures, but both increase the number of parts and the current collection effect is insufficient. There were some problems.

  The present invention has been made in view of the above-described problems, and its object is to dramatically increase the current collecting effect, thereby suppressing an increase in internal resistance even in a low temperature environment and significantly improving heavy load characteristics. An object of the present invention is to provide a non-aqueous electrolyte battery and a method for manufacturing the non-aqueous electrolyte battery.

In order to achieve the above object, a nonaqueous electrolyte battery according to the present invention includes a negative electrode can, a negative electrode pellet using lithium or a lithium aluminum alloy, and an aluminum foil disposed on the positive electrode side negative electrode surface of the negative electrode pellet, The positive electrode pellet, which is a positive electrode current collector mainly composed of baked β-manganese dioxide, the positive electrode can, and the separator disposed between the negative electrode pellet and the positive electrode pellet are arranged to face each other, and the negative electrode pellet And the positive electrode pellet is a non-aqueous electrolyte battery enclosed and assembled in a battery case made of the negative electrode can and the positive electrode can together with a non-aqueous electrolyte,
An L-shaped positive electrode ring, which is integrally formed with the positive electrode can and the positive electrode pellet, is fixed in close contact with the inner surface of the positive electrode pellet, and the positive electrode can and the positive electrode ring are bonded by resistance welding or It is characterized by being welded from the inside of the positive electrode can by laser welding.

  According to the non-aqueous electrolyte battery having the above configuration, the positive electrode can and the positive electrode ring integrally formed with the positive electrode pellet are fixed in close contact with the inner surface of the positive electrode pellet, and the positive electrode can and the positive electrode ring are bonded by resistance welding or laser welding. Since it is welded from the inside of the positive electrode can, the side surfaces of the positive electrode pellet and the positive electrode ring are reduced in diameter and fixed closely. Thereby, even if it swells at high temperature, the current collection effect of the positive electrode when lithium is ion-implanted from the negative electrode to the positive electrode can be dramatically improved. Since the battery internal resistance does not increase even after the cycle, good results can be obtained in the heavy load pulse characteristics.

  In addition, the ratio of the outer diameter of the positive electrode pellet in close contact with the positive electrode ring described above / the inner diameter of the positive electrode ring is 1.0 to 1.10.

  According to the non-aqueous electrolyte battery having the above configuration, the ratio of the outer diameter of the positive electrode pellet to the inner diameter of the positive electrode ring is 1.0 to 1.10. Therefore, even after a heat cycle of −40 ° C. to 120 ° C., the battery internal resistance does not increase, and good results can be obtained in the heavy load pulse characteristics.

  Moreover, the outer diameter of the negative electrode pellet described above is smaller than the outer diameter of the positive electrode pellet.

  According to the non-aqueous electrolyte battery having the above configuration, when the positive electrode can containing the positive electrode pellet and the negative electrode can containing the negative electrode pellet are assembled, the outer diameter of the negative electrode pellet is larger than the outer diameter of the positive electrode pellet. Since it is small, it is easy to position the negative electrode can with respect to the positive electrode can, so that the assembly workability can be improved.

In addition, the method for producing a nonaqueous electrolyte battery according to the present invention includes a negative electrode can, a negative electrode pellet using lithium or a lithium aluminum alloy, and an aluminum foil disposed on a negative electrode surface of the negative electrode pellet. A positive electrode pellet that is a positive electrode current collector mainly composed of β-manganese dioxide, a positive electrode can, and a separator disposed between the negative electrode pellet and the positive electrode pellet, the negative electrode pellet and the positive electrode A method for producing a non-aqueous electrolyte battery in which a pellet is enclosed in a battery case composed of the negative electrode can and the positive electrode can together with a non-aqueous electrolyte,
An L-shaped positive electrode ring integrally formed with the positive electrode can and the positive electrode pellet is fixed in close contact with the inner surface of the positive electrode pellet, and the positive electrode can and the positive electrode ring are resistance welded or laser welded. It was characterized by welding from the inside of the positive electrode can.

  According to the method for manufacturing a non-aqueous electrolyte battery having the above-described configuration, the positive electrode can and the positive electrode ring integrally molded with the positive electrode pellet are fixed in close contact with the inner surface of the positive electrode pellet, and the positive electrode can and the positive electrode ring are resistance-welded or Since it is welded from the inside of the positive electrode can by laser welding, the side surfaces of the positive electrode pellet and the positive electrode ring are reduced in diameter and are fixed closely. Thereby, even if it swells at high temperature, the current collection effect of the positive electrode when lithium is ion-implanted from the negative electrode to the positive electrode can be dramatically improved. Since the battery internal resistance does not increase even after the cycle, good results can be obtained in the heavy load pulse characteristics.

  According to the non-aqueous electrolyte battery of the present invention, the current collecting effect is remarkably enhanced, so that the increase in internal resistance can be suppressed even in a low temperature environment, and the heavy load characteristics can be remarkably improved. And the manufacturing method of a nonaqueous electrolyte battery can be provided.

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

  FIG. 1 is a cross-sectional view of a nonaqueous electrolyte battery according to an embodiment of the present invention, FIG. 2 is a single cross-sectional view of a positive electrode pellet of the nonaqueous electrolyte battery shown in FIG. 1, and Table 1 is an example of the present invention. The result table of the heat cycle pulse condition test from low temperature to high temperature, Table 2 is an example of the present invention, and is a measurement result table of the battery internal resistance after 50 heat cycles.

  As shown in FIG. 1, a nonaqueous electrolyte battery 10 according to an embodiment of the present invention includes a negative electrode can 11, a negative electrode pellet 12, an aluminum foil 13, a separator 14, a positive electrode pellet 15, and a positive electrode ring 16. And a coin-type lithium battery comprising a positive electrode can 17 and a sealing gasket 18.

  The negative electrode can 11 is formed in a lenticular cylindrical shape using nickel-plated stainless steel.

  The negative electrode pellet 12 is formed into a disk shape using lithium (Li) or a lithium aluminum alloy, and is pressure-bonded to the negative electrode can 11. The outer diameter D1 of the negative electrode pellet 12 is smaller than the outer diameter D2 of the positive electrode pellet 15. More specifically, D1 / D2 = 95 to 85% is desirable. This is because in the discharge reaction, lithium ionized from the negative electrode is efficiently transferred when it is inserted into the positive electrode.

  The aluminum foil 13 is sandwiched between the negative electrode pellet 12 and the separator 14 and is disposed on the positive electrode side negative electrode surface of the negative electrode pellet 12.

  The separator 14 is a non-woven fabric made of polypropylene (PP), and is disposed between the aluminum foil 13 and the positive electrode pellet 15 via a sealing gasket 18.

  The positive electrode pellet 15 is a positive electrode current collector mainly composed of baked β-manganese dioxide, and is formed into a disk shape.

  The positive electrode ring 16 is a substantially cylindrical metal ring having an L shape in a semi-sectional view, and is fixed in close contact with the inner surface of the positive electrode pellet 15 on the positive electrode can 17 side of the positive electrode pellet 15. From the inner side, it has the welding part 19 welded to the positive electrode can 17 by laser welding. Resistance welding may be used instead of laser welding.

  The positive electrode can 17 is formed into a bottomed cylindrical shape using nickel-plated stainless steel (SUS).

  The sealing gasket 18 is formed in an annular shape using a polymer material such as plastics, and the outer edge portion is sandwiched between the outer periphery of the negative electrode can 11 and the inner periphery of the outer periphery of the positive electrode can 17. The part is disposed in contact with the separator 14.

  As shown in FIG. 2, the ratio between the outer diameter D3 of the positive electrode pellet 15 and the inner diameter d1 of the positive electrode ring 16 is set to D3 / d1 = 1.0 to 1.10.

  Next, a method for manufacturing the nonaqueous electrolyte battery 10 will be described.

  First, 89 parts by weight of β manganese dioxide, 9 parts by weight of graphite, and 2 parts by weight of polytetrafluoroethylene (PTFE) that have been heat-treated at a predetermined temperature for a predetermined time as a positive electrode are homogeneously mixed and preformed, and then a predetermined average particle size is obtained. A positive electrode pellet 15 is manufactured by filling a predetermined weight of the aluminum foil 13 on a preformed positive electrode pellet base material and press-molding it.

  Then, the positive electrode ring 16 is closely fixed to the inner surface of the positive electrode pellet 15 on the positive electrode can 17 side of the positive electrode pellet 15.

  Further, as the negative electrode, lithium or a lithium aluminum alloy is punched into a predetermined outer diameter, a predetermined height, and a predetermined weight to manufacture the negative electrode pellet 12. At this time, the outer diameter D1 of the negative electrode pellet 12 is smaller than the outer diameter D2 of the positive electrode pellet 15.

  Next, the negative electrode pellet 12 is pressure-bonded and fixed to the negative electrode can 11, the separator 14 is stacked thereon, the sealing gasket 18 is placed on the upper part via the separator 14, and the nonaqueous electrolyte is dropped from above.

  Then, on the separator 14, the anti-positive electrode ring 16 side of the positive electrode pellet 15 is placed, and the positive electrode can 17 is placed thereon. Therefore, a laser welder is disposed opposite to the inner surface side of the positive electrode can 17 at the contact portion between the positive electrode ring 16 and the positive electrode can 17, and this laser welder is used to contact the positive electrode ring 16 and the positive electrode can 17. By irradiating laser light from the inside of the positive electrode can 17, the positive electrode ring 16 is welded to the positive electrode can 17.

  Subsequently, the outer edge portion of the positive electrode can 17 is crimped and fixed to the outer edge portion side of the negative electrode can 11 via the sealing gasket 18, thereby completing the manufacture of the nonaqueous electrolyte battery 10.

  Next, examples carried out to verify the effect of the nonaqueous electrolyte battery 10 of the present invention will be described.

  As shown in Table 1, as Comparative Example 1, a negative electrode active material was prepared by storing a disc-shaped negative electrode pellet having a diameter of φ20 mm in a negative electrode can and cutting it to a thickness of 15 μm and actually measuring an outer diameter of φ15.0 mm in diameter. Crimped to. The outer diameter of the negative electrode active material at this time is smaller than the outer diameter of the positive electrode. Next, a mix obtained by mixing conductive material mainly composed of baked electrolytic manganese dioxide (β manganese dioxide) and graphite, 2.0% binder mainly composed of PTFE, and distilled water was prepared.

  Furthermore, the positive electrode pellet which heat-processed at 150 degreeC and evaporated and dried water was shape | molded in the shape of a pellet, and after making it by integrally forming with a positive electrode ring, it accommodated in the stainless steel positive electrode can. At this time, the ratio of positive electrode ring inner diameter / closed positive electrode pellet outer diameter is 0.90. A flat micrometer was used for the measurement of the outer diameter (measurement of the outer diameter of the cylinder). Furthermore, the inner diameter of the positive ring (inner diameter measurement of the hole) was measured using an inner micrometer. As this measuring method, a micrometer specified in JISB7502 or a measuring instrument of the same or higher system is used.

The negative electrode pellet and the positive electrode pellet are arranged in a direction through a separator having a basis weight of 50 g / m ² and a thickness of 300 μm made of polypropylene, and the stainless steel positive electrode can and the stainless steel negative electrode can are passed through a sealing gasket made of polypropylene. Sealed by mating. In the non-aqueous electrolyte, lithium perchlorate (0.5 mol / L) was used as a solute, and propylene carbonate and dimethoxyethane (volume ratio 5: 5) were used as solvents. With these configurations, a coin-type lithium battery having a battery outer diameter of 24 mm and a total height of 5.0 mm was produced.

  As Comparative Example 2, a positive electrode can and a positive electrode ring produced in the same manner as in Comparative Example 1 were welded by a laser welding machine. Other than this, a coin-type lithium battery having a battery outer diameter of 24 mm and a total height of 5.0 mm was produced in the same manner as in Comparative Example 1.

  As Example 1, it was fabricated by integrally molding with a stainless steel positive electrode ring, and then housed in a stainless steel positive electrode can. The ratio of the positive electrode ring inner diameter / closed positive electrode pellet outer diameter at this time is 1.00. Except for this, a coin-type lithium battery having a battery outer diameter of φ24 mm and a total height of 5.0 mm was manufactured in the same manner as in Comparative Example 2.

  As Example 2, it was fabricated by integrally molding with a stainless steel positive electrode ring, and then housed in a stainless steel positive electrode can. At this time, the ratio of positive electrode ring inner diameter / closed positive electrode pellet outer diameter is 1.05. Except for this, a coin-type lithium battery having a battery outer diameter of φ24 mm and a total height of 5.0 mm was manufactured in the same manner as in Comparative Example 2.

  As Example 3, it was fabricated by integrally molding with a stainless steel positive electrode ring, and then housed in a stainless steel positive electrode can. The ratio of the positive electrode ring inner diameter / closed positive electrode pellet outer diameter at this time is 1.10. Except for this, a coin-type lithium battery having a battery outer diameter of φ24 mm and a total height of 5.0 mm was manufactured in the same manner as in Comparative Example 2.

  As Example 4, it was fabricated by integrally molding with a stainless steel positive electrode ring, and then housed in a stainless steel positive electrode can. The ratio of positive electrode ring inner diameter / closed pellet outer diameter at this time is 1.15. Except for this, a coin-type lithium battery having a battery outer diameter of 24 mm and a total height of 5.0 mm was produced in the same manner as in Comparative Example 3.

  And the heat cycle pulse condition test from low temperature to high temperature was implemented. The test condition was that the temperature was lowered from 23 ° C. to −40 ° C. over 1 hour, the temperature was kept constant at −40 ° C. for 1 hour, and then a pulse test of 11 mA and 10 msec was performed. Thereafter, the temperature is increased from −40 ° C. to 120 ° C. over 1 hour, 120 ° C. is kept constant for 1 hour, and then returned to room temperature of 23 ° C. over 1 hour. The battery internal resistance after 50 cycles of this test was measured.

  As is apparent from Table 1, the pulse closing circuit voltage results after 10 days at −40 to 120 ° C. heat cycle (80 cycles) indicate that the electronic devices can generally operate in Comparative Examples 1 and 2 and Example 4. It cannot be used because it interrupts the closed circuit voltage of 2.0V. On the other hand, regarding Examples 1, 2, and 3, it can be seen that a closed circuit voltage of 2.0 V or more can be sufficiently secured.

  Then, as shown in Table 2, in order to verify the further effect of the nonaqueous electrolyte battery 10 of the present invention, the battery internal resistance after 50 heat cycles in Table 1 was measured.

  As is apparent from Table 2, in Examples 1 to 3, the increase in internal resistance was about 3Ω in the amount of change even in the heat cycle test finished batteries, and about 8Ω in other Comparative Examples 1 and 2 and Example 4. It can be seen that the difference is significant compared to the above increase.

  This is because the positive electrode ring 16 in which the nonaqueous electrolyte battery 10 of the present invention is integrally formed with the positive electrode can 17 and the positive electrode pellet 15 that is a positive electrode current collector is welded and fixed to the inner surface of the positive electrode pellet 15. Since the electrical contact that is the conduction between the positive electrode ring 16 and the positive electrode can 17 is remarkably stabilized by welding the can 17 and the positive electrode ring 16 by laser welding or resistance welding, a temperature of −40 ° C. to 120 ° C. It can be confirmed that a large voltage drop is unlikely to occur with a heavy load pulse even after a heat cycle in change. In particular, the increase in internal resistance of Comparative Example 1 without laser welding is significant.

  As described above, according to the nonaqueous electrolyte battery 10 and the nonaqueous electrolyte battery manufacturing method, the positive electrode can 17 and the positive electrode ring 16 integrally formed with the positive electrode pellet 15 are brought into close contact with the inner surface of the positive electrode pellet 15. Since the positive electrode can 17 and the positive electrode ring 16 are welded from the inside of the positive electrode can 17 by laser welding, the side surfaces of the positive electrode pellet 15 and the positive electrode ring 16 are reduced in diameter and are fixed firmly. Thereby, even if the nonaqueous electrolyte battery 10 swells at a high temperature, the current collection effect of the positive electrode when lithium is ion-implanted from the negative electrode to the positive electrode can be dramatically improved. Since the battery internal resistance does not increase even after a heat cycle of 40 ° C. to 120 ° C., good results can be obtained in the heavy load pulse characteristics.

  Moreover, according to the nonaqueous electrolyte battery 10, the ratio of the outer diameter D3 of the positive electrode pellet 15 / the inner diameter d1 of the positive electrode ring 16 is D3 / d1 = 1.0 to 1.10. Since the effect can be dramatically improved, the battery internal resistance does not increase even after a heat cycle of −40 ° C. to 120 ° C., and good results can be obtained in the heavy load pulse characteristics.

  In addition, according to the nonaqueous electrolyte battery 10, when the positive electrode can 17 containing the positive electrode pellet 15 and the negative electrode can 11 containing the negative electrode pellet 12 are assembled, the outer diameter of the negative electrode pellet 12 is the positive electrode pellet. Since the negative electrode can 11 can be easily positioned with respect to the positive electrode can 17, it is possible to improve the assembly workability.

  In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

It is sectional drawing of the nonaqueous electrolyte battery of one Embodiment of this invention. FIG. 2 is a single sectional view of a positive electrode pellet of the nonaqueous electrolyte battery shown in FIG. 1. It is sectional drawing of the conventional nonaqueous electrolyte battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Nonaqueous electrolyte battery 11 Negative electrode can 12 Negative electrode pellet 13 Aluminum foil 14 Separator 15 Positive electrode pellet 16 Positive electrode ring 17 Positive electrode can 19 Welding part

Claims (4)

A negative electrode can,
Negative electrode pellets using lithium or lithium aluminum alloy;
An aluminum foil disposed on the negative electrode surface of the negative electrode pellet,
A positive electrode pellet, which is a positive electrode current collector mainly composed of baked β-manganese dioxide;
A positive electrode can,
The negative electrode pellet and the positive electrode pellet are placed opposite to each other with a separator disposed between the negative electrode pellet and the positive electrode pellet, and enclosed in a battery case including the negative electrode can and the positive electrode can together with a non-aqueous electrolyte. Non-aqueous electrolyte battery,
An L-shaped positive electrode ring, which is integrally formed with the positive electrode can and the positive electrode pellet, is fixed in close contact with the inner surface of the positive electrode pellet, and the positive electrode can and the positive electrode ring are bonded by resistance welding or A nonaqueous electrolyte battery characterized by being welded from the inside of the positive electrode can by laser welding.   2. The nonaqueous electrolyte battery according to claim 1, wherein a ratio of an outer diameter of the positive electrode pellet in close contact with the positive electrode ring to an inner diameter of the positive electrode ring is 1.0 to 1.10.   The nonaqueous electrolyte battery according to claim 1, wherein an outer diameter of the negative electrode pellet is smaller than an outer diameter of the positive electrode pellet. A negative electrode can,
Negative electrode pellets using lithium or lithium aluminum alloy;
An aluminum foil disposed on the negative electrode surface of the negative electrode pellet,
A positive electrode pellet, which is a positive electrode current collector mainly composed of baked β-manganese dioxide;
A positive electrode can,
The negative electrode pellet and the positive electrode pellet are placed opposite to each other with a separator disposed between the negative electrode pellet and the positive electrode pellet, and enclosed in a battery case including the negative electrode can and the positive electrode can together with a non-aqueous electrolyte. A method for producing a non-aqueous electrolyte battery comprising:
An L-shaped positive electrode ring integrally formed with the positive electrode can and the positive electrode pellet is fixed in close contact with the inner surface of the positive electrode pellet, and the positive electrode can and the positive electrode ring are resistance welded or laser welded. A method for producing a non-aqueous electrolyte battery, wherein the non-aqueous electrolyte battery is welded from the inside of the positive electrode can.

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