JPH10241741A - Lithium ion battery and fluid injection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid injection structure overflow preventing of the electrolyte injected into a battery jar and smoothly inject the electrolyte. SOLUTION: A spacer 20 has a separator 25 at the center and has at each side of the separator 25 a first injection opening and a second injection opening 22. The separator 25 is formed, extending to reach on the surface of a sealing body 30. The sealing body 30 has a first injection hole 31 and a second injection hole 32 at the facing position of each side of the separator 25. Putting the sealing body 30 at the opening of the battery jar 10 to seal with welding around the opening of the battery jar, the electrolyte is injected through the firs injection hole 31. At this time, a pipe extended from an aspirator device is inserted into the second injection hole 32 and aspirating the gas inside the battery jar, the electrolyte is injected into the first injection hole 31. After injection of the electrode is finished each injection hole 31, 32 are sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium ion battery and, more particularly, to a pouring structure and a pouring method for pouring an electrolyte into the battery.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable reduction in the size and weight of electronic devices, and accordingly, there has been a great demand for smaller and lighter batteries that serve as power supplies. In the field of primary batteries, small and lightweight batteries such as lithium batteries have already been put to practical use, but since these are primary batteries, they cannot be used repeatedly, and their uses have been limited. On the other hand, in the field of secondary batteries, lead storage batteries, nickel-cadmium storage batteries, nickel-hydrogen storage batteries, and the like have been conventionally used, but these have major problems in terms of size and weight reduction.

Therefore, lithium-ion batteries have come into practical use as small, lightweight, high-capacity, chargeable / dischargeable batteries, and are used in portable electronic and communication devices such as small video cameras, mobile phones, and notebook personal computers. Is now available. This type of lithium ion battery uses a carbon-based material capable of inserting and extracting lithium ions as a negative electrode active material, and uses LiCoO ₂ , LiNiO ₂ , L as a positive electrode active material.
using IMN ₂ O _4, LiFeO lithium-containing transition metal oxides such as _2, the ion conductor obtained by dissolving a lithium salt as a solute using an organic solvent as an electrolytic solution, after assembling the battery, the positive electrode active material by the first charging This is a battery in which lithium ions discharged from the battery enter the carbon particles and can be charged and discharged.

In this lithium ion battery, a positive electrode plate and a negative electrode plate are formed by coating a positive electrode active material and a negative electrode active material on a metal core (foil), respectively, and a separator is interposed therebetween and wound to form an electrode. . After inserting this electrode body into a metal outer can, the outer can is sealed with a sealing body. After this,
The battery pack is assembled by filling the outer can with an electrolyte through a liquid injection hole provided in the sealing body and sealing the liquid injection hole.

[0005]

However, in such a lithium ion battery, there is usually one liquid injection hole provided in the sealing body. If there is only one injection hole, even if the electrolyte is pumped into the outer can through the injection hole provided in the sealing body, there is no escape for the gas in the outer can. It was difficult to enter and the problem of overflowing over the sealing body occurred. When the electrolyte overflows onto the sealing body, the overflowed electrolyte is deposited and powdered, which causes a problem that it becomes an obstacle in sealing the injection hole to be performed later.
Furthermore, if the injection hole is sealed while the overflowed, precipitated and powdered electrolyte is left as it is, there is a problem that a leak may occur.

Accordingly, the present invention has been made in view of the above problems, and has a liquid injection structure in which the electrolyte injected into the outer can does not overflow, and the electrolyte can be injected smoothly. Is to do so.

[0007]

Means for Solving the Problems and Actions / Effects of the Invention According to the present invention, a positive electrode plate and a negative electrode plate are wound around a separator to form an electrode body, and after this electrode body is housed in a metal outer can,
A spacer for holding the electrode body in the outer can is provided above the electrode body, and a sealing body for sealing the opening of the outer can is provided above the spacer for sealing. In order to solve the above-mentioned problem, in a lithium ion battery obtained by injecting a liquid, in the invention according to claim 1, a plurality of communication holes are provided in a spacer, and a space between these communication holes is provided. A partitioning wall is extended to the lower surface of the sealing body, and a liquid injection hole is provided at a position facing the plurality of communication holes of the sealing body.

As described above, when a plurality of liquid injection holes are provided in the sealing body, when the electrolyte is injected from one of the liquid injection holes, the gas in the outer can is discharged from the other liquid injection holes. , So that gas-liquid replacement can be performed smoothly.
Therefore, the gas existing in the outer can can be easily discharged, and the electrolytic solution in an amount corresponding to the discharged gas can be smoothly injected into the outer can. Therefore, it is possible to easily solve the problem that the electrolyte overflows onto the sealing body, and it is possible to immediately proceed to the step of sealing the injection hole after the injection. The productivity is improved and the yield is also improved.

Also, since the spacer is provided with a partition for partitioning between the communication holes extending to the lower surface of the sealing body, the injection of the electrolyte and the discharge of the gas in the outer can are performed through separate injection holes. As a result, gas / liquid replacement is performed efficiently.

The present invention also relates to a method for injecting a lithium ion battery having the above-described injection structure, wherein the electrode body is housed in an outer can. After placing a plurality of communication holes on the upper portion of the electrode body and a spacer extending from the lower surface of the sealing body with a plurality of communication holes and a partition partitioning between the communication holes, the opening of the outer can is provided with a plurality of liquid injection holes. And a lithium ion battery is assembled by sealing with a sealing body provided with at least one of a plurality of liquid injection holes provided in the sealing body.
While sucking the gas in the outer can from one injection hole, the electrolyte is injected into the other injection hole.

When a plurality of injection holes are provided in the sealing body, it becomes possible to inject the electrolyte into the other injection holes while exhausting air from at least one of the plurality of injection holes. . Therefore, the gas existing in the outer can can be easily discharged, and the electrolytic solution in an amount corresponding to the discharged gas can be smoothly injected into the outer can. Therefore, it is possible to easily solve the problem that the electrolyte overflows onto the sealing body, and it is possible to immediately proceed to the step of sealing the injection hole after the injection. The productivity is improved and the yield is also improved.

Further, since the spacer is provided with a partition for partitioning between the communication holes, the exhausted injection hole is provided before the electrolyte injected from the other injection hole is impregnated into the electrode body. Direct discharge from the inserted exhaust pipe can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the lithium ion battery of the present invention will be described below with reference to the drawings. FIG.
1A is a top view showing a state in which a sealing body is attached to an outer can, and FIG. 1B is a top view showing a state in which a sealing body is attached to the outer can. FIG. 1C is a top view showing a state before mounting. FIG.
1A is a cross-sectional view showing an AA cross section, and FIG. 1D is a cross-sectional view showing a BB cross section of FIG.
(E) is a sectional view showing a CC section of FIG. 1 (c).
FIG. 2 is a view showing a sealing body of the present embodiment.
(A) is a top view, and (b) of FIG.
It is sectional drawing which shows D cross section, and FIG.2 (c) is a bottom view. Further, FIG. 3 is a view showing the spacer of the present embodiment, FIG. 3 (a) is a top view, and FIG. 3 (b) is a side view thereof.

A. Preparation of electrode body A mixture of a negative electrode active material made of natural graphite and a binder made of polyvinylidene fluorite (PVDF) dissolved in an organic solvent made of N-methylpyrrolidone is mixed with a slurry or paste. I do. These slurries or pastes are prepared by using a die coater, a doctor blade or the like in the case of a slurry, or a metal core (for example, copper foil) by a roller coating method in the case of a paste.
To form a negative electrode plate coated with an active material layer.

Thereafter, the negative electrode plate coated with the active material layer is passed through a drier to remove an organic solvent necessary for preparing a slurry or a paste, followed by drying. The dried negative electrode plate is rolled by a roll press to form a negative electrode plate.

On the other hand, a positive electrode active material made of LiCoO ₂ , a carbon-based conductive agent such as acetylene black and graphite, a binder made of polyvinylidene fluorite (PVDF) and the like are mixed with an organic solvent made of N-methylpyrrolidone. Are mixed to form a slurry or paste. Note that additives such as polyethylene oxide, polyacrylonitrile, and cellulose may be added to the slurry or paste.

These slurries or pastes are uniformly applied to both surfaces of a metal core (for example, aluminum foil) by using a die coater, a doctor blade or the like in the case of a slurry, or by a roller coating method in the case of a paste. Then, a positive electrode plate coated with the active material layer is formed.

Thereafter, the positive electrode plate coated with the active material layer is passed through a drier to remove an organic solvent necessary for preparing a slurry or a paste, followed by drying. After drying, the dried positive electrode plate is rolled by a roll press to obtain a positive electrode plate.

A negative electrode plate and a positive electrode plate prepared as described above are sandwiched between a microporous film made of an inexpensive polyolefin-based resin having low reactivity with an organic solvent, preferably a polyethylene microporous film. And wound by a winder (not shown). Thereafter, the outermost periphery is taped to form a spiral electrode body, and then formed into a shape that can be inserted into a rectangular outer can with a press machine to obtain an electrode body.

B. Production of Lithium-ion Battery Then, a bottomed cylindrical prismatic outer can made of an aluminum alloy formed by pressing from one sheet (for example, the outer dimensions are 46 mm in height, 22 mm in width, 7.5 mm in thickness, and 0 mm in thickness) The electrode body manufactured as described above is inserted into the outer can 10 through the opening of (0.5 mm). The outer can 10 also functions as a positive electrode terminal.

After the electrode body is inserted into the outer can 10, a spacer 20 is placed on the upper part of the electrode body. Here, the spacer 20 is provided for holding the electrode body inserted into the outer can 10 so as not to move, and extends upward at the center portion thereof as shown in FIGS. 1 and 3. A partition wall 25 is disposed, a first liquid injection communication hole 21 and a positive electrode conductive tab through hole 23 are disposed on the left side of the partition wall 25, and a second liquid injection communication hole 22 and a negative electrode Through hole 2 for conductive tab
4 are arranged. In addition, the partition 25 is a sealing body 3 described later.
0 is formed to extend to the lower surface.

When the spacer 20 is mounted on the upper part of the electrode body, the positive electrode conductive tab 40 extending from the positive electrode of the electrode body is passed through the positive electrode conductive tab through hole 23 so that the positive electrode conductive tab 40 is The negative electrode conductive tab 50 protrudes above the spacer 20 while passing the negative electrode conductive tab 50 extending from the negative electrode of the electrode body through the negative electrode conductive tab through hole 24.

Thereafter, the positive electrode current collecting lead plate 41 welded to the outer can 10 and the positive electrode conductive tab 40 are welded and fixed to a negative electrode terminal 52 attached to a terminal hole 33 of the sealing body 30 described later. The negative electrode current collecting lead plate 51 and the negative electrode conductive tab 50 are welded. Next, after placing the sealing body 30 in the opening of the outer can 10, the periphery of the sealing body 30 and the outer can 10 are welded.

Here, the sealing body 30 is provided for sealing the opening of the outer can 10, and faces the partition wall 25 of the spacer 20 at the center as shown in FIGS. A first liquid injection hole 31 is provided on the left side of the position, and a second liquid injection hole 3 is provided on the right side of the position facing the partition 25 of the spacer 20.
2 and a through hole 33 for the negative electrode terminal. A peripheral wall 34 protruding from the upper surface of the sealing body 30 is provided around the upper part of the sealing body 30.

After the sealing body 30 is placed on the opening of the outer can 10 and the periphery thereof is welded to the outer can and sealed, 30 parts by weight of ethylene carbonate (EC) and diethyl An electrolyte obtained by adding 1M LiPF6 as an electrolyte salt to a mixed solvent composed of 70 parts by weight of carbonate (DEC) is injected. At this time, a pipe extending from a suction device (not shown) is inserted into the second liquid injection hole 32 to insert the outer can 10.
The electrolytic solution is injected into the first injection hole 31 while the gas inside is sucked. After the electrolyte is injected, the injection holes 31 and 32 are sealed, and then a predetermined charging process is performed to obtain a lithium ion battery of the present embodiment.

The electrolyte is an ionic conductor in which a lithium salt is dissolved as a solute in an organic solvent and has a high ionic conductivity and is chemically and electrochemically stable with respect to each of the positive and negative electrodes. Therefore, use an inexpensive one that has a wide usable temperature range, high safety, and low cost. For example, as the organic solvent, in addition to the above-mentioned mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC), propylene carbonate (PC), sulfolane (SL), tetrahydrofuran (THF), γ-butyrolactone (GBL),
Dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), 1,2 dimethoxyethane (DME)
Or a mixed solvent thereof is suitable. As the solute, a lithium salt having a strong electron-withdrawing property is used.
In addition to iPF6, for example, LiBF4, LiClO4, L
iAsF6, LiCF3SO3, Li (CF3SO2)
2N, LiC4F9SO3 and the like are preferred.

C. Experimental Results An injection experiment was performed using the lithium ion battery of the present embodiment manufactured as described above and the battery of the comparative example having only one injection hole manufactured by the conventional method, using 10,000 each. When the number of times of dispensing and the defective rate of the sealed can were obtained, the results shown in Table 1 below were obtained. The number of times of dispensing means that if a predetermined amount of electrolyte is to be injected into the outer can 10 with only one injection, the electrolyte overflows from the injection hole 31 or 32 and is divided into several times. Means the number of times

[0028]

[Table 1]

As is evident from Table 1, in the lithium ion battery of the present invention, the number of dispensing operations is reduced, and the defective rate of sealed cans is significantly reduced. The reason why the number of dispensing is reduced is that the pipe extending from the suction device is inserted into the second liquid injection hole 32 and the electrolyte is drawn into the first liquid injection hole 31 while the gas in the outer can 10 is sucked. Into the outer can 10 in an amount equivalent to the discharged gas.
This is because the amount of electrolytic solution that can be injected at one time has been increased.

Further, the reduction in the rate of defective cans can be prevented by increasing the amount of electrolyte that can be injected at one time, thereby preventing the electrolyte from overflowing onto the sealing body. This is because precipitation and powdering do not occur, and no trouble occurs when the injection hole is sealed.

As described above, in this embodiment,
A first liquid injection hole 31 and a second liquid injection hole 32 are provided in the sealing body 30, and the electrolyte is supplied into the first liquid injection hole 31 while the gas in the outer can 10 is sucked through the second liquid injection hole 32. Therefore, an amount of electrolyte solution corresponding to the discharged gas can be smoothly injected into the outer can 10. Therefore, it is possible to easily solve the problem that the electrolyte overflows onto the sealing body, and it is possible to immediately proceed to the step of sealing the injection hole after the injection. The productivity is improved and the yield is also improved.

Further, since the spacer 20 is provided with the partition wall 25 extending to the lower surface of the sealing body 20, the first liquid injection hole 3 is formed.
It is possible to prevent the electrolyte injected from 1 from being directly discharged from the exhaust pipe inserted into the second injection hole 32 before being impregnated into the electrode body.

In the above embodiment, an example in which natural graphite is used as the negative electrode active material has been described. In addition to natural graphite, a carbon-based material capable of inserting and extracting lithium ions, for example, graphite, carbon black, Coke, glassy carbon, carbon fiber, or a fired body of these are suitable. Further, an oxide such as tin oxide or titanium oxide capable of inserting and extracting lithium ions may be used.

In the above-described embodiment, an example in which LiCoO ₂ is used as the positive electrode active material has been described. In addition to LiCoO ₂ , a lithium-containing transition metal compound capable of accepting lithium ions as a guest, for example,
LiNiO ₂ , LiCoXNi (1-X) O ₂ , LiCr
O ₂ , LiVO ₂ , LiMnO ₂ , αLiFeO ₂ , LiT
iO ₂ , LiScO ₂ , LiYO ₂ , LiMn ₂ O _{4 and the} like are preferable, and particularly, LiNiO ₂ , LiCoXNi (1-
X) or whether to use the O ₂ alone is used as a mixture of two or more thereof are preferred. Further, a conductive polymer such as polyacetylene or polyaniline may be used.

[Brief description of the drawings]

FIG. 1 is a view showing a main part of a lithium ion battery according to one embodiment of the present invention, and FIG. 1 (a) is a top view showing a state where a sealing body is attached to an outer can, and FIG. 1 (b). FIG. 1C is a top view showing a state before the sealing body is attached to the outer can, FIG. 1C is a cross-sectional view taken along the line AA of FIG. 1A, and FIG. 1C is a cross-sectional view showing a BB cross section, and FIG. 1E is a cross-sectional view showing a CC cross section of FIG. 1C.

FIG. 2 is a view showing the sealing body of FIG. 1, FIG. 2 (a) is a top view, and FIG. 2 (b) is a cross-sectional view showing a DD section of FIG. 2 (a); 2 (c) is a bottom view.

FIG. 3 is a view showing the spacer of FIG. 1, and FIG.
Is a top view, and FIG. 3B is a side view thereof.

[Explanation of symbols]

Reference Signs List 10: outer can (positive electrode terminal), 20: spacer, 21: first communication hole for liquid injection, 22: second communication hole for liquid injection, 23 ...
Through hole for positive electrode conductive tab, 24 ... Through hole for negative electrode conductive tab,
25 ... partition wall, 30 ... sealing body, 31 ... first liquid injection hole, 32
... Second liquid injection hole, 33 ... Negative electrode terminal through hole, 40 ... Positive electrode conductive tab, 41 ... Positive electrode current collecting lead plate, 50 ... Negative electrode conductive tab, 51 ... Negative electrode current collecting lead plate, 52 ... Negative electrode terminal

Claims (2)

[Claims] A positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween to form an electrode body. After the electrode body is housed in a metal outer can, the electrode body is placed on the upper part of the electrode body in the same outer can. A lithium ion battery comprising a spacer to be held, a sealing body for sealing the opening of the outer can at the top of the spacer, and sealing, and then injecting an electrolytic solution. A plurality of communication holes are provided at the position, and a partition partitioning between the communication holes is provided so as to extend to the lower surface of the sealing body, and a position facing each of the plurality of communication holes of the sealing body is provided. A lithium ion battery characterized in that a liquid injection hole is provided in the battery. 2. A positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween to form an electrode body. After the electrode body is housed in a metal outer can, the electrode body is placed above the electrode body in the same outer can. A method for injecting a lithium ion battery, in which a spacer to be held is provided, and a sealing body for sealing the opening of the outer can is provided and sealed at an upper portion of the spacer, and then an electrolyte is injected. The electrode body was housed in the outer can, and a plurality of communication holes and a partition wall for partitioning between the communication holes were extended to the lower surface of the sealing body and placed on the upper part of the electrode body. Thereafter, the opening of the outer can is sealed with a sealing member provided with a plurality of liquid injection holes to assemble a lithium ion battery, and at least one of the plurality of liquid injection holes provided in the sealing member is filled. While sucking the gas in the outer can from the liquid hole, the electrolyte Pouring method of a lithium-ion battery, characterized in that as NOTE liquid.