阅读说明：本技术 非水电解液电池以及非水电解液电池的制造方法 (Nonaqueous electrolyte battery and method for manufacturing nonaqueous electrolyte battery ) 是由 桑村俊行 渊本雄平 于 2021-03-19 设计创作，主要内容包括：本发明的课题在于不在外装罐形成突起地抑制正极的膨胀。对非水电解液电池而言,具有：容器状的外装罐,在一面形成有开口部；筒状的正极,沿上述外装罐的内周面配置,包含正极活性物质；绝缘性且筒状的隔板,配置于上述正极的内侧；负极,配置于上述隔板的内侧,包含负极活性物质；封口板,密封上述外装罐的开口部；以及插入部件,插入上述正极与上述封口板之间,一端面抵接于上述正极的端面并且另一端面抵接于上述封口板,对上述插入部件而言,上述另一端面在与接合于上述外装罐的上述封口板的外周相比接近中央的位置抵接于上述封口板。(The invention aims to restrain the expansion of a positive electrode without forming a protrusion on an outer can. The nonaqueous electrolyte battery comprises: a container-shaped outer can having an opening formed in one surface thereof; a cylindrical positive electrode arranged along an inner peripheral surface of the outer can and containing a positive electrode active material; an insulating cylindrical separator disposed inside the positive electrode; a negative electrode disposed inside the separator and containing a negative electrode active material; a sealing plate for sealing the opening of the outer can; and an insertion member that is inserted between the positive electrode and the sealing plate, one end surface of which abuts against an end surface of the positive electrode and the other end surface of which abuts against the sealing plate, wherein the other end surface of the insertion member abuts against the sealing plate at a position closer to the center than the outer periphery of the sealing plate joined to the outer can.)

1. A nonaqueous electrolyte battery comprising:

a container-shaped outer can having an opening formed in one surface thereof;

a cylindrical positive electrode that is disposed along an inner peripheral surface of the outer can and contains a positive electrode active material;

an insulating cylindrical separator disposed inside the positive electrode;

a negative electrode disposed inside the separator and containing a negative electrode active material;

a sealing plate for sealing an opening of the outer can; and

an insertion member inserted between the positive electrode and the sealing plate, one end surface of the insertion member abutting against an end surface of the positive electrode and the other end surface of the insertion member abutting against the sealing plate,

as far as the insert part is concerned,

the other end surface abuts against the sealing plate at a position closer to the center than the outer periphery of the sealing plate joined to the outer can.

2. The nonaqueous electrolyte battery according to claim 1,

the insertion member has:

a first ring having the one end face;

a second ring having the other end face; and

and a connecting portion connecting the first ring and the second ring.

3. The nonaqueous electrolyte battery according to claim 2,

the coupling portion protrudes laterally of the first ring and has an inclined surface inclined with respect to the one end surface.

4. The nonaqueous electrolyte battery according to claim 2,

the first ring has an inner diameter corresponding to an outer diameter of the separator plate.

5. A method for manufacturing a nonaqueous electrolyte battery, comprising the steps of:

a cylindrical positive electrode containing a positive electrode active material is disposed along the inner peripheral surface of a container-shaped outer can having an opening formed in one surface thereof,

an insulating cylindrical separator having a negative electrode containing a negative electrode active material therein is disposed inside the positive electrode,

an insertion member having one end surface abutting against the end surface of the positive electrode is disposed,

a nonaqueous electrolytic solution is injected into the outer can,

the opening formed in the outer can is sealed by a sealing plate that abuts the other end surface of the insertion member.

Technical Field

The present invention relates to a nonaqueous electrolyte battery and a method for manufacturing a nonaqueous electrolyte battery.

Background

In general, a nonaqueous electrolyte battery such as a cylindrical lithium battery is manufactured by housing a positive electrode, a negative electrode, and the like in an outer can, injecting an electrolyte solution, and sealing an opening of the outer can with a sealing plate. The sealing plate is formed in a shape corresponding to the opening of the outer can, and the outer periphery of the sealing plate is joined to the inner wall of the opening of the outer can by laser welding, for example.

In such a nonaqueous electrolyte battery, when lithium ions move from the negative electrode to the positive electrode during discharge, the positive electrode swells due to the entry of the lithium ions into the positive electrode. When the positive electrode swells, the electrolyte is excessively absorbed by the swollen positive electrode, and the electrolyte may be insufficient at the end of discharge to reduce the discharge capacity.

As a method of suppressing the expansion of the positive electrode, for example, it is conceivable to provide a material mixture pressure ring on the upper surface of the positive electrode, and to press the material mixture pressure ring by an inner protrusion formed on the inner peripheral surface of the outer can when the positive electrode expands and the material mixture pressure ring rises.

Patent document 1: japanese patent laid-open No. 2001-273911

Patent document 2: japanese patent laid-open publication No. 2005-216740

Patent document 3: japanese patent laid-open No. 2008-91260

However, in order to suppress the expansion of the positive electrode by pressing the electrode mixture holding ring, it is necessary to form the inner protrusion on the inner peripheral surface of the outer can as described above, which causes a problem that the production process of the nonaqueous electrolyte battery becomes complicated. That is, for example, in the case where the sealing plate is joined to the outer can by caulking, the inner protrusion may be formed in the outer can in association with the caulking, but in the case where the sealing plate is joined to the outer can by laser welding, a step of independently forming the inner protrusion is required. In this case, after the positive electrode, the negative electrode, the mixture pressing ring, and the like are accommodated in the outer can, an inner protrusion for pressing the mixture pressing ring is formed on the inner circumferential surface of the outer can, and thus the work efficiency is lowered.

Disclosure of Invention

The present disclosure has been made in view of the above problems, and an object thereof is to provide a nonaqueous electrolyte battery and a method for manufacturing the nonaqueous electrolyte battery, in which expansion of a positive electrode can be suppressed without forming a protrusion on an outer can.

In one embodiment, a nonaqueous electrolyte battery disclosed in the present application includes: a container-shaped outer can having an opening formed in one surface thereof; a cylindrical positive electrode arranged along an inner peripheral surface of the outer can and containing a positive electrode active material; an insulating cylindrical separator disposed inside the positive electrode; a negative electrode disposed inside the separator and containing a negative electrode active material; a sealing plate for sealing the opening of the outer can; and an insertion member that is inserted between the positive electrode and the sealing plate, one end surface of which abuts against an end surface of the positive electrode and the other end surface of which abuts against the sealing plate, wherein the other end surface of the insertion member abuts against the sealing plate at a position closer to the center than the outer periphery of the sealing plate joined to the outer can.

According to one embodiment of the nonaqueous electrolyte battery and the method for manufacturing the nonaqueous electrolyte battery disclosed in the present application, the positive electrode can be prevented from swelling without forming a protrusion on the outer can.

Drawings

Fig. 1 is a schematic diagram showing a cross-sectional structure of a nonaqueous electrolyte battery according to an embodiment.

Fig. 2 is an enlarged view of a main part of a nonaqueous electrolyte battery according to an embodiment.

Fig. 3 is a perspective view showing the shape of the positive electrode ring.

Fig. 4 is a diagram showing a specific example of the relationship between voltage and discharge time.

Fig. 5 is a flowchart illustrating a method of manufacturing a nonaqueous electrolyte battery.

Fig. 6 is a diagram showing a modification of the nonaqueous electrolyte battery.

Description of reference numerals:

externally canning; a sealing plate; a terminal; a gasket; a washer; a positive electrode; a separator plate; a negative electrode; a current collector; a positive ring; a lower surface; an upper surface; a joint portion; a slit; inclined surface of 110e

Detailed Description

Hereinafter, one embodiment of the nonaqueous electrolyte battery and the method for manufacturing the nonaqueous electrolyte battery disclosed in the present application will be described in detail with reference to the drawings. The present invention is not limited to the embodiment.

Fig. 1 is a schematic diagram showing a cross-sectional structure of a nonaqueous electrolyte battery 100 according to an embodiment. The nonaqueous electrolyte battery 100 shown in fig. 1 includes an outer can 101, a sealing plate 102, a terminal 103, a gasket 104, a gasket 105, a positive electrode 106, a separator 107, a negative electrode 108, a current collector 109, and a positive electrode ring 110.

The outer can 101 is a cylindrical metal container, and an opening is formed in one bottom surface (upper surface in fig. 1) of the two bottom surfaces. The outer can 101 accommodates a positive electrode 106, a separator 107, a negative electrode 108, a current collector 109, and the like.

The lid plate 102 is a lid body having a shape corresponding to the opening of the outer can 101, and is joined to the opening of the outer can 101 to seal the outer can 101. As shown in fig. 1, the outer periphery of the lid plate 102 stands along the inner peripheral surface of the outer can 101, and the entire lid plate 102 has a concave shape. The height of the portion of the sealing plate 102 standing on the outer periphery is, for example, about 1.2 mm. A through hole through which the terminal 103 is inserted is formed in the center of the concave shape of the sealing plate 102, and the through hole is sealed by a gasket 104.

The terminal 103 is inserted through a through hole formed in the center of the sealing plate 102, one end of which protrudes outside the outer can 101, and the other end of which is in contact with the current collector 109 inside the outer can 101. The terminal 103 is electrically connected to the negative electrode 108 via a current collector 109. That is, the terminal 103 functions as a negative electrode terminal.

The gasket 104 seals a through hole through which the terminal 103 of the sealing plate 102 is inserted. That is, the gasket 104 is attached around the through hole of the sealing plate 102 so as to sandwich the sealing plate 102 from both sides and fill the gap between the sealing plate 102 and the terminal 103.

The gasket 105 holds an end portion of the terminal 103 inside the outer can 101 to fix the terminal 103. As shown in fig. 1, the sealing plate 102 and the gasket 104 are sandwiched between the terminal 103 and the gasket 105, and the terminal 103, the gasket 104, and the gasket 105 are integrated with the sealing plate 102.

The positive electrode 106 contains a positive electrode active material such as manganese dioxide, and is formed in a cylindrical shape along the inner peripheral surface of the outer can 101. Since the positive electrode 106 is disposed in contact with the inner peripheral surface of the outer can 101, the outer can 101 functions as a current collector of the positive electrode. The exterior can 101 is filled with a volatile nonaqueous electrolytic solution, not shown, and the nonaqueous electrolytic solution is impregnated into the positive electrode 106.

The separator 107 is formed by molding a liquid-permeable and insulating material such as polypropylene into a cylindrical shape, and is disposed inside the cylindrical shape of the positive electrode 106. Since the separator 107 has insulation, the cylindrical inner side of the separator 107 is insulated from the positive electrode 106.

The negative electrode 108 contains a negative electrode active material such as lithium or zinc, and is formed into a cylindrical shape along the inner peripheral surface of the separator 107. As described above, the cylindrical inner side of the separator 107 is insulated from the positive electrode 106, and therefore the negative electrode 108 is insulated from the positive electrode 106. However, since the separator 107 has liquid permeability for allowing the nonaqueous electrolytic solution to pass therethrough, for example, lithium ion plasma moves from the negative electrode 108 to the positive electrode 106 through the separator 107.

The current collector 109 electrically connects the negative electrode 108 to the terminal 103. That is, one end of the current collector 109 is in contact with the inside of the cylindrical shape of the negative electrode 108, and the other end is in contact with the terminal 103 below the sealing plate 102.

The positive electrode ring 110 is an annular insertion member formed of a resin such as polyethylene or polypropylene, for example, and having a through hole in the center thereof through which the separator 107 is inserted, and is inserted between the upper surface of the positive electrode 106 and the lower surface of the sealing plate 102. That is, the lower end surface of the positive electrode ring 110 abuts on the upper surface of the positive electrode 106, and the upper end surface of the positive electrode ring 110 abuts on the lower surface of the sealing plate 102. The portion of the upper end surface of the positive electrode ring 110 that contacts the sealing plate 102 is located closer to the center of the sealing plate 102 than the outer periphery of the sealing plate 102 that is joined to the inner peripheral surface of the outer can 101. In other words, the positive electrode ring 110 abuts on the lower surface of the sealing plate 102 at a position closer to the terminal 103 than the outer periphery of the sealing plate 102.

Fig. 2 is an enlarged view showing the periphery of the positive electrode ring 110. As shown in fig. 2, the lower surface 110a of the positive electrode ring 110 abuts on the upper surface of the positive electrode 106. In the vicinity of the inner peripheral surface of the outer can 101, a gap 111 is formed by the upper surface of the positive electrode 106, the positive electrode ring 110, and the inner peripheral surface of the outer can 101. The upper surface 110b of the positive electrode ring 110 abuts against the lower surface of the sealing plate 102.

The positive electrode ring 110 is inserted between the upper surface of the positive electrode 106 and the lower surface of the sealing plate 102, and the lower surface 110a and the upper surface 110b of the positive electrode ring 110 are in contact with the positive electrode 106 and the sealing plate 102, respectively, thereby suppressing the positive electrode 106 from expanding in the direction of the sealing plate 102. That is, when lithium ions enter positive electrode 106 due to discharge, positive electrode 106 tends to expand in the direction of sealing plate 102. However, since the upper surface of the positive electrode 106 is in contact with the lower surface 110a of the positive electrode ring 110 and the upper surface 110b of the positive electrode ring 110 is in contact with the sealing plate 102, the positive electrode ring 110 presses the upper surface of the positive electrode 106 without moving in the direction of the sealing plate 102, thereby suppressing the expansion of the positive electrode 106. As a result, the nonaqueous electrolytic solution, not shown, can be prevented from being excessively absorbed by the expanded positive electrode 106.

Further, a gap 111 is formed on the outer periphery of the lower surface 110a of the positive electrode ring 110, and the nonaqueous electrolytic solution can be held in the gap 111. Therefore, even if positive electrode ring 110 is placed on the upper surface of positive electrode 106, the contact area between the nonaqueous electrolytic solution and positive electrode 106 is secured, and the movement of lithium ions is not inhibited. As a result, defects of discharge can be suppressed.

The contact portion between the upper surface 110b of the positive electrode ring 110 and the sealing plate 102 is closer to the terminal 103 than the joint portion 102a where the sealing plate 102 is joined to the inner peripheral surface of the outer can 101 by laser welding. That is, the upper surface 110b of the positive electrode ring 110 is not directly below the joint portion 102a of the sealing plate 102 with the outer can 101, but is in contact with the sealing plate 102 at a position distant from the joint portion 102 a. Further, since the outer periphery of the sealing plate 102 rises along the inner peripheral surface of the outer can 101 and the sealing plate 102 has a concave shape, the distance between the joint portion 102a and the upper surface 110b of the positive electrode ring 110 increases according to the rising height of the outer periphery of the sealing plate 102. Therefore, when the joining portion 102a of the sealing plate 102 is joined to the outer can 101 by laser welding, the heat of the laser welding does not reach the positive electrode ring 110, and the positive electrode ring 110 can be prevented from being deformed or melted.

Fig. 3 is a perspective view showing the shape of the positive electrode ring 110. Fig. 3 (a) is a view showing the upper surface 110b side of the positive electrode ring 110, and fig. 3 (b) is a view showing the lower surface 110a side of the positive electrode ring 110.

As shown in fig. 3, the positive electrode ring 110 has a shape in which two rings, a lower ring on the lower surface 110a side and an upper ring on the upper surface 110b side, are connected by a plurality of connecting portions 110c. Since the upper ring has a larger diameter than the lower ring, the coupling portion 110c protrudes laterally from the lower ring and then extends in the direction of the upper ring. Slits 110d are formed between the plurality of coupling portions 110c.

The inner diameter of the lower ring is almost equal to the outer diameter of the separator 107, and the positive electrode ring 110 is positioned in a direction parallel to the sealing plate 102 by inserting the separator 107 into the lower ring. On the other hand, the outer diameter of the upper ring is smaller than the diameter of the outer periphery of the sealing plate 102, and is, for example, 97% or less of the outer diameter of the outer can 101. Therefore, for example, when the outer diameter of the outer can 101 is 14.00mm, the outer diameter of the upper ring of the positive electrode ring 110 is 13.58mm or less. By reducing the outer diameter of the upper ring, the upper surface 110b of the positive electrode ring 110 can be brought into contact with the sealing plate 102 at a position away from the joint portion 102a between the sealing plate 102 and the outer can 101. As a result, the positive electrode ring 110 can be prevented from being deformed or melted by the heat of the laser welding.

By forming the slits 110d between the plurality of connecting portions 110c, the nonaqueous electrolytic solution is not cut by the positive electrode ring 110, and movement of lithium ions between the positive electrode 106 and the negative electrode 108 is not inhibited. In addition, an inclined surface 110e inclined with respect to the lower surface 110a is formed at a portion of the coupling portion 110c protruding toward the lateral side of the downward ring. Further, a gap 111 is formed by the inclined surface 110e, the upper surface of the positive electrode 106, and the inner peripheral surface of the outer can 101. The nonaqueous electrolytic solution outside the positive electrode ring 110 is held in the gap 111, and the held nonaqueous electrolytic solution is always in contact with the positive electrode 106. Therefore, a contact region between the nonaqueous electrolytic solution and the positive electrode 106 is secured, and defects of discharge can be suppressed without inhibiting the movement of lithium ions.

By bringing the lower ring of the positive electrode ring 110 into contact with the positive electrode 106 and bringing the upper ring into contact with the sealing plate 102, expansion of the positive electrode 106 during discharge can be suppressed, and the nonaqueous electrolytic solution can be prevented from being absorbed by the expanded positive electrode 106. As a result, the nonaqueous electrolytic solution is not insufficient at the end of discharge, and the discharge capacity can be improved.

Specifically, fig. 4 shows an example of the discharge time of the nonaqueous electrolyte battery without the positive electrode ring 110 and the nonaqueous electrolyte battery 100 with the positive electrode ring 110. In fig. 4, a graph of the voltage change of the nonaqueous electrolyte battery without the positive electrode ring 110 is shown by a broken line, and a graph of the voltage change of the nonaqueous electrolyte battery 100 is shown by a solid line. As is clear from the figure, the time required for the voltage to decrease to 1.5V in the nonaqueous electrolyte battery without the positive electrode ring 110 is about 1600 to 1700 hours, for example, whereas the time required for the voltage to decrease to 1.5V in the nonaqueous electrolyte battery 100 is about 1900 to 2000 hours, for example. In particular, in the nonaqueous electrolyte battery 100, it was found that the voltage drop after the lapse of about 1300 hours of the discharge time was gradual, and the discharge capacity was improved.

Next, a method for manufacturing the nonaqueous electrolyte battery 100 having the above-described structure will be described with reference to a flowchart shown in fig. 5.

First, the positive electrode 106 formed in a cylindrical shape is disposed on the cylindrical outer can 101 (step S101). The outer peripheral surface of the positive electrode 106 is in contact with the inner peripheral surface of the outer can 101. Since the positive electrode 106 has a cylindrical shape, a cylindrical space is also formed in the center of the positive electrode 106.

On the other hand, the negative electrode 108 is disposed on the separator 107 (step S102). Since the separator 107 and the negative electrode 108 are also cylindrical, the negative electrode 108 is disposed inside the separator 107 so that the outer peripheral surface of the negative electrode 108 is in contact with the inner peripheral surface of the separator 107. Then, a current collector 109 is attached to the inner peripheral surface of the negative electrode 108. The separator 107 having the negative electrode 108 and the current collector 109 disposed therein is inserted into the central space of the positive electrode 106 (step S103). Thus, the cylindrical separator 107 protrudes from the center of the cylindrical positive electrode 106 inside the outer can 101.

Then, the separator 107 protruding from the center of the positive electrode 106 is inserted into the positive electrode ring 110, and the positive electrode ring 110 is disposed so that the lower surface 110a of the positive electrode ring 110 is in contact with the upper surface of the positive electrode 106 (step S104). In this state, the upper surface 110b of the positive electrode ring 110 is positioned at a height near the opening of the outer can 101. Then, a nonaqueous electrolytic solution is injected into the exterior can 101 (step S105). The nonaqueous electrolytic solution injected into the separator 107 is impregnated into the negative electrode 108 and impregnated into the positive electrode 106 through the separator 107. The nonaqueous electrolytic solution injected outside the separator 107 mainly passes through the slits 110d of the positive electrode ring 110, and infiltrates into the positive electrode 106 and the negative electrode 108 through the separator 107. Since the slits 110d are formed in the positive electrode ring 110 in this manner, the movement of the nonaqueous electrolytic solution is not hindered by the positive electrode ring 110, and the nonaqueous electrolytic solution can be sufficiently impregnated into the positive electrode 106 and the negative electrode 108. The nonaqueous electrolytic solution is injected to a level between the lower surface 110a and the upper surface 110b of the positive electrode ring 110, for example.

Meanwhile, the sealing plate 102 is attached with a gasket 104 so as to cover the through hole and the periphery thereof, and the terminal 103 and the gasket 105 are attached so as to sandwich the gasket 104. That is, the terminal 103 is inserted into the through hole from the upper surface of the sealing plate 102, and the gasket 105 is fixed to the tip of the inserted terminal 103.

The sealing plate 102 with the terminal 103 attached thereto is laser-welded to the opening of the outer can 101 (step S106). Specifically, the outer periphery of the lid plate 102 and the inner peripheral surface of the outer can 101 are laser welded to seal the opening of the outer can 101. At the time of laser welding, the joint portion 102a of the lid plate 102 and the outer can 101 is heated. However, in the present embodiment, since the outer periphery of the sealing plate 102 is raised and the portion of the sealing plate 102 in contact with the positive electrode ring 110 is located near the center of the terminal 103, the positive electrode ring 110 is separated from the joint portion 102a, and the positive electrode ring 110 is not deformed or melted by heat.

The opening of the outer can 101 is sealed with a sealing plate 102, thereby completing the nonaqueous electrolyte battery 100. This nonaqueous electrolyte battery 100 discharges lithium ions by moving from the negative electrode 108 to the positive electrode 106. As the discharge time becomes longer, lithium ions are occluded in the positive electrode 106, but in the present embodiment, the positive electrode ring 110 is inserted between the upper surface of the positive electrode 106 and the lower surface of the sealing plate 102, and the upper surface of the positive electrode 106 is pressed by the positive electrode ring 110. Therefore, even if lithium ions are occluded in the positive electrode 106, swelling of the positive electrode 106 is suppressed, and the nonaqueous electrolytic solution can be less absorbed by the positive electrode 106. As a result, the nonaqueous electrolytic solution is not insufficient, and the discharge capacity can be improved.

As described above, according to the present embodiment, the positive electrode ring abutting on the upper surface of the positive electrode and the lower surface of the sealing plate is interposed between the positive electrode and the sealing plate. Therefore, even if lithium ions are occluded in the positive electrode by the discharge, the expansion of the positive electrode can be suppressed. In other words, the expansion of the positive electrode can be suppressed without forming a protrusion on the outer can, and the discharge capacity can be prevented from being reduced due to the shortage of the nonaqueous electrolytic solution.

In the above-described embodiment, the upper ring has a larger diameter than the lower ring of the positive electrode ring 110, but the shape of the positive electrode ring is not limited to this. For example, as in the positive electrode ring 120 shown in fig. 6, the diameter of the upper ring may be the same as or smaller than the diameter of the lower ring. In fig. 6, the positive electrode ring 120 has a truncated cone shape in which the upper ring has a smaller diameter than the lower ring. By making the upper ring smaller in diameter, the contact portion between the positive electrode ring 120 and the sealing plate 102 can be further separated from the joint portion 102a between the outer can 101 and the sealing plate 102, and the influence of heat generated when the sealing plate 102 is laser-welded can be reduced.

In the above-described embodiment, the bottom surface side of the two bottom surfaces of the outer can 101 on which the opening is formed is defined in the vertical direction of the "upper surface" and the "lower surface" as the upper side of the nonaqueous electrolyte battery 100, but it goes without saying that the nonaqueous electrolyte battery 100 can be used and manufactured in any posture. That is, for example, the nonaqueous electrolyte battery 100 may be used in a posture in which the longitudinal direction thereof is horizontal, or in a posture in which the opening of the outer can 101 is located downward.