JP2011108368A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery with a nonaqueous electrolyte injection function capable of simply replenishing nonaqueous electrolyte under a low-humidity environment. <P>SOLUTION: The nonaqueous electrolyte secondary battery is provided with: a housing body 101 equipped with a housing 102 for housing a power generating part 107 equipped with a positive electrode 103, a negative electrode 104, a separator 105, and the nonaqueous electrolyte 106, an opening 108 communicated with the housing 102, and a sub housing 109 communicated with the housing 102 through the opening 108 for housing nonaqueous electrolyte 111 for replenishment; and a plug 110 so structured to be free in attachment and detachment to and from the opening 108 from outside the housing body 101. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery that can be supplemented with a non-aqueous electrolyte.

  A non-aqueous electrolyte secondary battery such as a lithium ion secondary battery has a high voltage and a high energy density, and is excellent in reliability such as storability and leakage resistance. For this reason, non-aqueous electrolyte secondary batteries have already been put into practical use as small power sources for mobile phones and laptop computers, and are also being applied to medium and large applications such as automotive applications and power storage applications. Yes.

Examples of the positive electrode active material of the lithium ion secondary battery include general formulas LixMO ₂ such as titanium disulfide, vanadium pentoxide and molybdenum trioxide, lithium cobalt composite oxide, lithium nickel composite oxide and spinel type lithium manganese oxide. (Wherein M is one or more transition metals).

  Examples of the negative electrode active material of the lithium ion secondary battery include various materials such as metallic lithium and alloys containing lithium, and carbon materials capable of occluding and releasing lithium. In particular, when a carbon material is used, there is an advantage that a battery having a long cycle life can be obtained and safety is high.

For non-aqueous electrolytes of lithium ion secondary batteries, a mixed solvent of a high dielectric constant solvent such as ethylene carbonate or propylene carbonate and a low viscosity solvent such as diethyl carbonate is generally added to a supporting salt such as LiPF ₆ or LiBF _4. A dissolved electrolyte is used.

  Until now, lithium ion secondary batteries are hermetically sealed and have a long charge / discharge cycle life, so if they are used a predetermined number of times and their discharge capacity is significantly reduced, it is determined that the battery life has been exhausted. Disposal. The discarded lithium ion secondary battery is collected for recycling, and usable materials are extracted and reused.

  However, it is difficult to reuse 100% of the material constituting the battery, and there is a demand for the creation of an effective method of using the battery whose life has expired. In addition, in the case of the above-described medium / large-sized lithium ion secondary batteries, a life of 10 to 20 years and a charge / discharge cycle life of several thousand to several tens of thousands of cycles may be required. It is difficult to achieve a long service life with a conventional battery configuration.

  Corresponding to these, for example, in Patent Document 1, in order to recover the discharge capacity by replenishing a new non-aqueous electrolyte in a lithium ion secondary battery whose discharge capacity has decreased due to repeated charge and discharge cycles, A lithium ion secondary battery provided with an inlet plug has been proposed.

JP 2001-210309 A

  However, it is necessary to handle the nonaqueous electrolyte in a low humidity environment, and for example, it is necessary to re-inject the liquid in equipment such as a glove box whose humidity is controlled. For this reason, in general, when replenishing a lithium ion secondary battery with a nonaqueous electrolyte, it is necessary to move the lithium ion secondary battery into the facility, and there is a problem that the operation becomes complicated.

  Lithium ion secondary batteries for power storage and automobiles that aim for longer and longer life compared to small lithium ion secondary batteries used for conventional mobile phones and personal computers retain capacity due to liquid drainage. The decline in rate is a big problem and cannot be ignored.

  In addition, since lithium ion secondary batteries used for power storage and automotive applications are large, it may be difficult to work in equipment such as a glove box or may be difficult to carry into the glove box. . For this reason, there is a problem that it becomes difficult to inject the non-aqueous electrolyte into the middle / large-sized lithium ion secondary battery in a low humidity environment.

  Therefore, an object of the present invention is to provide a non-aqueous electrolyte secondary battery that can easily replenish the non-aqueous electrolyte in a low humidity environment.

  The present invention relates to a replenishment non-aqueous electrolyte that communicates with a storage chamber that houses a positive electrode, a negative electrode, a separator, and a power generation unit having a non-aqueous electrolyte, an opening that communicates with the storage chamber, and the opening. It is a nonaqueous electrolyte secondary battery provided with the storage body which has a sub-accommodating chamber for storing, and the plug body comprised so that attachment or detachment to the opening part can be freely performed from the outer side of a storage body.

  In the non-aqueous electrolyte secondary battery, a sub-opening for communicating the sub-accommodating chamber and the outside of the accommodating body is formed in a portion of the accommodating body that divides the sub-accommodating chamber, and a part of the plug is opened. It is preferable that the other part of the plug body is exposed to the outside of the container through the sub-opening.

  In the nonaqueous electrolyte secondary battery of the present invention, it is preferable that the opening and the sub-opening face each other.

  Further, in the nonaqueous electrolyte secondary battery of the present invention, it is preferable that the portion of the container that defines the opening and the plug are screwed, and further, the portion of the container that defines the sub-opening and the plug. It is preferable that the body is screwed.

  Further, in the nonaqueous electrolyte secondary battery of the present invention, a replenishment portion for injecting a nonaqueous electrolyte for replenishment into the sub-accommodating chamber from the outside of the accommodating body is formed in a portion of the accommodating body that divides the sub-accommodating chamber. It is preferable.

  Further, in the nonaqueous electrolyte secondary battery of the present invention, the replenishment portion is detachably fitted to the replenishment port portion, which communicates with the sub-accommodation chamber and communicates the sub-accommodation chamber and the outside of the container. It is preferable to have a plug for a replenishing port.

  Moreover, in the nonaqueous electrolyte secondary battery of the present invention, it is preferable that the portion of the container that defines the replenishing port and the replenishing plug are screwed together.

  According to the present invention, the nonaqueous electrolyte can be easily supplemented to the nonaqueous electrolyte secondary battery in a low humidity environment.

  Therefore, for example, when an electric vehicle using a non-aqueous electrolyte secondary battery (HEV, EV, etc.) is inspected, the non-aqueous electrolyte can be easily replenished in a low-humidity environment, so the battery can be recycled at the inspection factory. It becomes. In addition, for example, a nonaqueous electrolyte secondary battery used in a power storage system in solar power generation or wind power generation can be recycled locally without collecting the nonaqueous electrolyte secondary battery in a factory. Furthermore, when replenishing non-aqueous electrolyte, there is no need to use special equipment or equipment such as glove boxes or dry rooms, and jigs that are usually used by contractors in car inspection factories, solar power plants and wind power plants. Work with tools, etc.

It is sectional drawing of the nonaqueous electrolyte secondary battery which concerns on embodiment. It is a figure for demonstrating the shape of the sealing member with which a stopper is provided. It is a figure which shows the process of manufacturing the nonaqueous electrolyte secondary battery of FIG. It is a figure for demonstrating the injection | pouring operation | movement of the nonaqueous electrolyte for replenishment in the nonaqueous electrolyte secondary battery which concerns on embodiment. It is sectional drawing of a nonaqueous electrolyte secondary battery provided with a replenishment part.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. In this embodiment mode, a stacked rectangular lithium ion secondary battery is used.

<Configuration of non-aqueous electrolyte secondary battery>
FIG. 1 is a cross-sectional view of the nonaqueous electrolyte secondary battery according to the present embodiment.

  In FIG. 1, a lithium ion secondary battery 100 that is a nonaqueous electrolyte secondary battery includes a container 101 as a housing. In the container 101, a storage chamber 102, an opening 108 that communicates with the storage chamber 102, and a sub-accommodation chamber 109 that communicates with the storage chamber 102 through the opening 108 are partitioned. The opening 108 that allows the storage chamber 102 and the sub-accommodation chamber 109 to communicate with each other is closed by a plug 110, and a supplementary nonaqueous electrolyte 111 is accommodated in the sub-accommodation chamber 109 that is isolated from the storage chamber 102. Yes.

  A plurality of positive electrodes 103, separators 104, and negative electrodes 105 are stacked and stored in this order in the storage chamber 102, and are filled with a nonaqueous electrolyte 106. The positive electrode 103, the separator 104, the negative electrode 105, and the nonaqueous electrolyte 106 form a power generation unit 107.

  Each positive electrode 103 and each negative electrode 105 are respectively connected to a positive current collector lead and a negative current collector lead (not shown) in the storage chamber 102. A part of each of the positive electrode current collecting lead and the negative electrode current collecting lead is formed so as to protrude to the outside of the housing body 101, and the protruding portions serve as a positive electrode terminal and a negative electrode terminal of the lithium ion secondary battery, respectively.

The positive electrode 103 has a configuration in which a positive electrode active material is formed on the current collector surface. As the positive electrode active material, a composite oxide of lithium and a transition metal, which is generally used in a lithium ion secondary battery, can be used. Examples of the complex oxide type of lithium and transition metal include spinel type, NASICON type, and olivine type. Among these, a lithium transition metal oxide represented by Li _x MPO ₄ having an olivine structure (where X is a positive number and M is one or more transition metals) is a lithium ion secondary battery. High thermal stability during charging. Therefore, in this embodiment, when a large-capacity lithium ion secondary battery that needs to have particularly high safety is used, it is preferable to use a compound having an olivine structure as the material of the positive electrode 103. More specifically, it is preferable to use lithium iron phosphate that is less decomposed and has high stability.

  The separator 104 separates the positive electrode 103 and the negative electrode 105 to prevent an internal short circuit, and retains a non-electrolyte that is an electrolytic solution to maintain ionic conductivity between the positive and negative electrodes. As a material for the separator 104, a polyolefin microporous film such as polyethylene or polypropylene can be used.

  The negative electrode 105 has a configuration in which a negative electrode active material is formed on the current collector surface. As the negative electrode active material, a material generally used in lithium ion secondary batteries can be used. In particular, it is preferable to use a carbon-based material such as graphite having excellent reversibility.

The nonaqueous electrolytes 106 and 111 are electrolytic solutions made of a lithium ion conductor and a nonaqueous organic solvent and a lithium salt. For example, a solution obtained by dissolving LiPF ₆ in ethylene carbonate, diethyl carbonate, or the like can be used. . The electrolytic solution may have a viscosity.

  The plug 110 that closes the opening 108 may be configured so that it can be attached to and detached from the opening 108 from the outside of the container 101. For example, as shown in FIG. 1, the shaft portion 110 a that is a part of the plug body 110 closes the opening 108, and the head portion 110 b that is another part of the plug body 110 is exposed to the outside of the container body 101. It can be constituted as follows. In this case, the plug 110 can be easily removed from the opening 108 by moving the head 110b of the plug 110 upward in the drawing, and the opening 110 can be removed by moving the removed plug 110 downward in the drawing. 108 can be easily inserted.

  In addition, when the head 110b is exposed to the outside of the container 101 as shown in FIG. 1, it is necessary to form the sub-opening 112 in a portion that defines the sub-accommodating chamber 109 of the container 101. 112 and the opening 108 are preferably opposed to each other. For example, when the sub-opening 112 is on the side surface of the container 101 that defines the sub-accommodating chamber 109 and the sub-opening 112 and the opening 108 do not face each other, the shape of the plug 110 becomes complicated, which is not preferable.

  The shape of the portion of the container 101 that partitions the opening 108 (hereinafter referred to as “opening wall portion”) and the shape of the plug 110 that is connected to the opening wall are not particularly limited, and the storage chamber 102 is sub-accommodated. Any shape may be used as long as it can be isolated from the chamber 109. For example, as shown in FIG. 1, it is preferable that a spiral groove is formed at a position where the opening wall portion and the plug 110 are in contact with each other. Since the opening wall portion and the plug body 110 each have a spiral groove, they can be screwed together, and the storage chamber 102 can be easily isolated from the sub storage chamber 109. Moreover, the opening wall part and the plug body 110 may have an oblique groove instead of the spiral groove, and may have any shape as long as they can be detachably fitted to each other.

  Further, even when a part of the plug 110 penetrates the sub opening 112 and is exposed to the outside of the container 101, the portion of the container 101 that divides the sub opening 112 (hereinafter referred to as “sub opening wall”). The shape of the plug body 110 connected to the auxiliary opening wall portion is not particularly limited as long as the auxiliary housing chamber 109 can be isolated from the outside. For example, as shown in FIG. 1, spiral grooves are formed at positions where the auxiliary opening wall portion and the plug 110 are in contact with each other, so that they can be screwed together, It can be easily isolated from the outside. Moreover, the sub opening wall part may have a slanting groove | channel instead of a spiral groove | channel, and should just be a shape which mutually fits so that attachment or detachment is possible.

  In this case, the lithium ion secondary battery 100 is preferably provided with a seal member for filling the gap between the plug 110 and the sub opening 112 in order to improve the airtightness of the sub housing chamber 109. For example, as shown in FIGS. 2A and 2B, an O-ring-shaped or rectangular seal member 200 can be provided at a portion where the head portion 110b and the shaft portion 110a of the plug body 110 are connected. . Further, a sealing member may be provided on the outer surface side of the container 101 and in the vicinity of the sub opening 112. Note that the lithium ion secondary battery 100 may include a seal member 200 for filling a gap between the plug 110 and the opening 108.

  As the sealing member 200, a material that can withstand an organic electrolyte, such as polypropylene (PP), polyethylene (PE), a copolymer of PP and PE, styrene butadiene rubber, ethylene propylene diene monomer, butyl rubber, silicon rubber, rubber containing fluororesin Teflon (registered trademark) seal tape made of polytetrafluoroethylene is preferable.

Here, it is preferable that the container 101 has an area of each surface on which the opening 108 and / or the sub-opening 112 are formed be 8 cm ² or more. When the area of each surface where the opening 108 and / or the sub-opening 112 of the container 101 is formed is less than 8 cm ² , the opening 108, the sub-opening 112 and the plug 110 must be very small. This is not preferable from the viewpoint of cost and workability of the injection operation. Further, when the area of the surface on which the opening 108 and / or the sub-opening 112 is formed is less than 8 cm ^2, it is conceivable that the container 101 cannot maintain sufficient strength. More preferably, the area of the surface on which the opening 108 and / or the sub-opening 112 is formed is 10 cm ² or more.

  More specifically, as in the present embodiment, when the container 101 is square, each side of the surface on which the opening 108 and / or the sub-opening 112 of the container 101 is formed is at least 1 cm. The above is preferable. Moreover, when the container 101 is cylindrical, it is preferable that each diameter of the surface in which the opening part 108 and / or the subopening 112 of the container 101 are formed is at least 1 cm or more. The material of the container 101 is not particularly limited, and for example, iron, iron-plated nickel, stainless steel, or aluminum can be used.

  When the opening 108 and / or the sub-opening 112 and the plug 110 are attached to each other, the thickness of the member of the container 101 that forms the opening 108 and / or the sub-opening 112, that is, the opening wall And / or the thickness of the sub-opening wall is preferably 1.5 mm or more. When the thickness of the opening wall and / or the sub-opening wall is less than 1.5 mm, the screw-shaped plug body 110 cannot be reliably screwed to the opening 108 and / or the sub-opening 112. There is a possibility that the airtight state of the storage chamber 102 and the airtight state of the sub storage chamber 109 cannot be maintained.

  Here, in general, a lithium ion secondary battery is provided with a safety valve for releasing the battery internal pressure in order to avoid dangers such as battery explosion when the battery internal pressure rises during overcharge or in a high temperature state. ing. For this reason, when the lithium ion secondary battery 100 includes a safety valve, it is necessary to prevent the plug 110 from being detached from the opening 108 before the safety valve is activated. Therefore, when the safety valve is provided, the stopper 110 that closes the opening 108 is configured such that the pressure resistance of the stopper 110 is equal to or higher than the operating pressure of the safety valve. The pressure resistance here refers to a pressure at which the plug 110 does not come off from the opening 108.

<Preparation of nonaqueous electrolyte secondary battery>
Next, an example of a method for manufacturing the above-described lithium ion secondary battery 100 will be described.

  3A to 3C are diagrams illustrating an example of a process for manufacturing the nonaqueous electrolyte secondary battery in FIG.

  First, as shown in FIG. 3A, a container 101 that contains a power generation unit 107 in a storage chamber 102 is prepared. In addition to the opening 108 and the sub-opening 112, the container 101 at this time is formed with an injection part 300 for injecting the supplementary nonaqueous electrolyte into the sub-accommodating chamber 109.

  The method for accommodating the power generation unit 107 in the accommodation chamber 102 can follow a general method for manufacturing a laminated lithium ion secondary battery. Specifically, first, a laminated body in which the positive electrode 103, the separator 104, and the negative electrode 105 are laminated in this order is accommodated in the accommodating chamber 102 having an open bottom surface. Here, the bottom surface is a portion of the housing body 101 that partitions the housing chamber 102 and refers to the lowermost surface of the lithium ion secondary battery 100 in FIG. Each positive electrode 103 and each negative electrode 105 accommodated in the accommodating chamber 102 are connected to a positive electrode terminal and a negative electrode terminal via a positive current collector lead and a negative current collector lead (not shown), respectively. The positive electrode terminal and the negative electrode terminal are provided in a member constituting the bottom surface of the storage chamber 102 so as to penetrate the member, and the member 101 and the container 101 whose bottom surface is opened are laser-welded. A storage chamber 102 is formed.

  By this housing method, the housing body 101 that partitions the housing chamber 102 having the positive electrode terminal and the negative electrode terminal on the bottom surface is formed. Thereafter, the non-aqueous electrolyte 106 is injected into the accommodation chamber 102 through the sub-opening 112 and the opening 108, whereby the accommodation chamber 102 containing the power generation unit 107 as shown in FIG. And an empty sub-accommodating chamber 109 are produced.

  Next, as shown in FIG. 3B, by moving the plug body 110 while rotating from the upper side to the lower side in the figure, the plug body 110 is fitted to the sub-opening wall part and fitted to the opening wall part. Let As a result, the opening 108 is closed and the storage chamber 102 is isolated from the sub-storage chamber 109. Then, the nonaqueous electrolyte 111 for replenishment is injected from the injection unit 300 into the sub-accommodating chamber 109.

  Next, as shown in FIG. 3C, the injection part 300 is laser-sealed. Thereby, the sub-accommodating chamber 109 is isolated from the outside, and the lithium ion secondary battery 100 of FIG. 1 is manufactured.

<Injection operation of nonaqueous electrolyte for replenishment of nonaqueous electrolyte secondary battery>
Next, the replenishment nonaqueous electrolyte injection operation using the lithium ion secondary battery 100 will be described.

  First, in the lithium ion secondary battery 100 shown in FIG. 1, the plug 110 is moved while rotating upward in the drawing, and the opening 108 is opened as shown in FIG. By opening the opening 108, the non-aqueous electrolyte 111 stored in the sub storage chamber 109 can move to the storage chamber 102. At this time, as shown in FIG. 1, when the opening wall and the plug 110 are screwed together, the opening 108 can be gradually opened. Move smoothly. FIG. 4 does not show the nonaqueous electrolyte.

  When the replenishment of the non-aqueous electrolyte 111 to the power generation unit 107 is completed, the plug 110 is moved while rotating downward in the figure to close the opening 108. With the above operation, the power generation unit 107 can be replenished without exposing the nonaqueous electrolyte 111 to the external environment.

  As described above, according to the present embodiment, the nonaqueous electrolyte 111 previously stored in the sub-accommodating chamber 109 isolated from the outside is not exposed to the external environment, that is, in a low humidity environment. It is possible to inject into the accommodation chamber 102 through the opening 108. Note that the configuration for isolating the storage chamber 102 from the sub-accommodation chamber 109 and the configuration for isolating the sub-storage chamber 109 from the outside are simple, and there are no problems such as an increase in cost and an increase in footprint.

  The amount of the nonaqueous electrolyte 111 stored in the sub-accommodating chamber 109 may be a single replenishment amount or a few replenishment amount. When a replenishment amount of several times is accommodated, the time required for injecting one nonaqueous electrolyte is measured in advance, and the opening time of the opening 108 at the time of replenishment is measured, etc. There is a need.

  Further, there may be a plurality of sub-accommodating chambers 109. For example, in the lithium ion secondary battery 100 of FIG. 1, the container 101 may have another sub-accommodating chamber that communicates with the sub-accommodating chamber 109 via the sub-opening 112. In this case, the plug 110 is configured to pass through the opening 108 and the sub-opening 112 and further pass through a portion of the container that defines another sub-accommodating chamber and be exposed to the outside of the container 101. be able to. With this configuration, even after the nonaqueous electrolyte in the sub-accommodating chamber 109 has been injected into the accommodating chamber 102 by opening the opening 108, another sub-acoustic is opened by opening the sub-opening 112. The non-aqueous electrolyte stored in the storage chamber can be injected into the storage chamber 102 through the sub opening 112, the sub storage chamber 109, and the opening 108 in this order.

  In addition, the lithium ion secondary battery 100 according to the present embodiment may include a replenishment unit for injecting a nonaqueous electrolyte for replenishment into the sub-accommodating chamber 109. Below, an example is shown using FIG.

FIG. 5 is a cross-sectional view of a nonaqueous electrolyte secondary battery including a replenishing unit.
As shown in FIG. 5, the replenishing unit 400 includes a replenishing port 401 formed in a portion of the container 101 that divides the sub-accommodating chamber 109 so that the sub-accommodating chamber 109 communicates with the outside of the container 101. The replenishing port plug body 402 can be detachably closed. With this configuration, a supplementary nonaqueous electrolyte can be injected into the sub-accommodating chamber 109, so that the life of the lithium ion secondary battery 100 can be extended. However, the replenishing unit 400 is not limited to the configuration shown in FIG.

  In general non-aqueous electrolyte secondary batteries that do not have a sub-accommodating chamber, there is no concept of newly replenishing the non-aqueous electrolyte from the outside, and the discharge capacity is reduced due to so-called liquid withering that the non-aqueous electrolyte decreases. Sometimes, the nonaqueous electrolyte could not be replenished from the outside. In addition, the battery must be manufactured in an environment with a dew point temperature of −40 ° C. or lower and a moisture content of 0.013% or lower. A low humidity environment is also required when replenishing a nonaqueous electrolyte. Not only the non-aqueous electrolyte secondary battery but also the configuration of the lithium ion secondary battery disclosed in Patent Document 1 could not satisfy this.

  On the other hand, in the case of a lithium ion secondary battery as shown in FIG. 5, the non-aqueous electrolyte can be stored in advance in the sub-accommodating chamber 109. When the water electrolyte is injected, the injection operation can be performed while maintaining the internal environment of the battery without being affected by the external environment. Therefore, for example, not only the operation of injecting the non-aqueous electrolyte stored in the secondary storage chamber 109 into the storage chamber 102 when the lithium ion secondary battery 100 is manufactured, but also the second or subsequent non-water electrolyte into the secondary storage chamber 109. Even in the electrolyte injection operation, replenishment in a low humidity environment is possible.

  In the above embodiment, the prismatic lithium ion secondary battery has been described. However, the nonaqueous electrolyte secondary battery used in the present invention is not limited to the prismatic shape described above. For example, in the present embodiment, the case has been described in which the opening 108 for injecting the nonaqueous electrolyte for replenishment is opposed to the edge direction of the laminate composed of the positive electrode 103, the negative electrode 105, and the separator 104. The edge direction of the laminated body may face the lateral direction in FIG. The positive electrode 103, the negative electrode 105, and the separator 104 may be wound, or a cylindrical nonaqueous electrolyte secondary battery may be used.

  However, as shown in FIG. 1, it is easier for the replenishing nonaqueous electrolyte to be injected from the opening 108 to permeate when the opening 108 faces the edge portion of the laminated body and the wound body. Is preferable. In addition, a rectangular nonaqueous electrolyte secondary battery is preferable to a cylindrical nonaqueous electrolyte secondary battery in that it has many flat portions suitable for forming the opening 108.

<Preparation of nonaqueous electrolyte secondary battery>
1. Preparation of positive electrode 90 parts by weight of LiFePO _{4 as an} active material, 5 parts by weight of acetylene black as a conductive material and 5 parts by weight of polyvinylidene fluoride as a binder are mixed, and N-methyl-2-pyrrolidone as a solvent is appropriately added. In addition, each material was dispersed to prepare a slurry. This slurry was uniformly applied on both sides of an aluminum current collector having a thickness of 20 μm and dried. Then, the dried aluminum current collector was compressed with a roll press and cut into a length of 140 mm and a width of 250 mm to produce 32 plate-like positive electrodes 103. The thickness of the positive electrode 103 was 230 μm. Then, an aluminum current collector lead was welded to each positive electrode 103.

2. Preparation of Negative Electrode 90 parts by weight of natural graphite as an active material and 10 parts by weight of polyvinylidene fluoride as a binder are mixed, and N-methyl-2-pyrrolidone as a solvent is added as appropriate to disperse each material to prepare a slurry. Prepared. This slurry was uniformly applied to both sides of a 16 μm thick copper current collector and dried. Then, the dried copper current collector was compressed with a roll press and cut into a length of 142 mm and a width of 255 mm to produce 33 plate-like negative electrodes 105. The thickness of the negative electrode 105 was 146 μm. A nickel current collector lead was welded to each negative electrode 105.

3. Production of Separator A microporous polyethylene film having a thickness of 25 microns was cut into a length of 145 mm and a width of 255 mm to produce 64 separators 104.

4). Preparation of ethylene carbonate and diethyl carbonate in the nonaqueous electrolyte, and mixed in a volumetric ratio of 30:70, the non-aqueous concentration of LiPF ₆ to the mixture obtained by dissolving LiPF ₆ as a 1 mol / L electrolyte 106 250 ml was prepared.

5. Production of Lithium Ion Secondary Battery 100 A stacked body in which all of the produced positive electrode 103, separator 104, and negative electrode 105 are laminated in this order and the outermost layer becomes the negative electrode 105 is formed in a storage chamber 102 having a bottom open. Housed. Then, according to the above-described conventional accommodation method, the container 101 that partitions the accommodation chamber 102 having the positive electrode terminal and the negative electrode terminal on the bottom surface is formed by laser welding the member constituting the bottom surface of the accommodation chamber 102 and the accommodation body 101. Formed. Thereafter, 200 ml of the non-aqueous electrolyte 106 is injected into the accommodation chamber 102 through the sub-opening 112 and the opening 108, and the accommodation chamber 102 containing the power generation unit 107 as shown in FIG. And an empty sub-accommodating chamber 109 were produced.

  Next, as shown in FIG. 3 (b), the stopper 110 is fitted into the sub opening 112 and the opening 108 to isolate the storage chamber 102 from the sub storage chamber 109, and then the sub storage through the injection portion 300. 30 ml of the nonaqueous electrolyte 106 produced as described above was injected into the chamber 109 as the nonaqueous electrolyte 111. Thereafter, the sub-accommodating chamber 109 was isolated from the outside of the accommodating body 101 by laser-sealing the injection part 300.

  In the lithium ion secondary battery 100 manufactured as described above, the outer dimensions of the box-shaped container 101 were 20 mm long × 150 mm wide × 320 mm high. The size of the upper surface of the container 101, that is, the surface on which the sub-opening 112 is formed is 20 mm long × 150 mm wide, and the diameter of the shaft portion of the plug 109 is 3 mm. Further, the thickness of the upper surface of the container 101 was 0.5 mm, and a reinforcing plate was laminated on the upper surface, and the thickness of the upper surface portion was adjusted to 1.0 mm. Further, the dimensions of the portion separating the storage chamber 102 and the sub-storage chamber 109, that is, the surface on which the opening 108 was formed were 20 mm long × 150 mm wide and 1.5 mm thick.

6). Initial Battery Performance When the initial battery performance of the manufactured lithium ion secondary battery 100 was measured, the nominal voltage was 3.2 V and the internal resistance was 3 mΩ. In addition, the discharge capacity was 50 Ah when charged at a constant current / constant voltage of 10 A / 3.8 V for 6 hours under a condition of an ambient temperature of 25 ° C. and discharged to 2.25 V at 10 A.

<Charge / discharge cycle test>
Using the manufactured lithium ion secondary battery 100, a cycle test was performed under the same conditions as the charge / discharge conditions in the above-described discharge capacity measurement under the condition of an ambient temperature of 25 ° C. When the number of cycles was 1500, the discharge capacity was less than 70% of the initial discharge capacity.

<Replenishment of non-aqueous electrolyte>
1. Replenishment operation In the lithium ion secondary battery 100 whose discharge capacity is less than 70% of the initial discharge capacity, the opening 108 is opened by moving the plug 110, and 30 ml of non-water stored in the sub-accommodating chamber 109 is opened. The electrolyte 111 was injected into the accommodation chamber 102 through the opening 108. As a result, the power generation unit 107 was supplemented with 30 ml of the nonaqueous electrolyte 111. After completion of refilling, the stopper 110 was returned to the original position to close the opening 108.

2. Battery performance after replenishment After the lithium ion secondary battery 100 supplemented with the nonaqueous electrolyte as described above is allowed to stand at room temperature for 24 hours, it is the same as the charge / discharge conditions at the time of measuring the discharge capacity at an ambient temperature of 25 ° C. The cycle test under the above conditions was performed twice. And when the discharge capacity of the lithium ion secondary battery 20 was measured by the above method, it was found that the discharge capacity after replenishment was 47 Ah, and it was recovered to 94% in the first cycle.

  Further, when the amount of the replenishing non-aqueous electrolyte to be replenished was 10 ml and the same examination as described above was performed, the discharge capacity after replenishment was 44.9 Ah with respect to the initial discharge capacity 50 Ah, and 89.8 in the first cycle. It turned out that it has recovered to%.

  Further, when the amount of the replenishing nonaqueous electrolyte to be replenished was 50 ml and the same examination as described above was performed, the discharge capacity after replenishment was 48.1 Ah with respect to the initial discharge capacity 50 Ah, and 96.2 in the first cycle. It turned out that it has recovered to%.

  In addition, the same effect was obtained with a cylindrical battery in which a long positive and negative electrode and a separator were wound together.

  Based on the above results, a lithium ion secondary battery whose discharge capacity is reduced to 70% or less of the initial discharge capacity is supplemented with a nonaqueous electrolyte in an amount of 5 to 25% of the initial nonaqueous electrolytic mass (200 ml). As a result, the discharge capacity was recovered to 89.8% or more, and as a result, the life of the lithium ion secondary battery could be extended.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for replenishing a non-aqueous electrolyte for a medium / large non-aqueous electrolyte secondary battery that is difficult to move into a glove box.

  100 Lithium ion secondary battery, 101 container, 102 container, 103 positive electrode, 104 separator, 105 negative electrode, 106 nonaqueous electrolyte, 107 power generation unit, 108 opening, 109 sub-accommodation chamber, 110 plug, 110a shaft, 110b head, 111 non-aqueous electrolyte for replenishment, 202 seal member, 300 injection part, 400 replenishment part, 401 replenishment port part, 402 plug for replenishment port.

Claims (8)

A positive chamber, a negative electrode, a separator, and a storage chamber for storing a power generation unit having a non-aqueous electrolyte, an opening communicating with the storage chamber, and a communication with the storage chamber via the opening, and a replenishing non-aqueous electrolyte A container having a sub-accommodating chamber for accommodating;
A non-aqueous electrolyte secondary battery comprising: a plug configured to be freely attached to and detached from the opening from the outside of the container. A sub-opening that communicates the sub-accommodating chamber and the outside of the accommodating body is formed in the portion of the accommodating body that defines the sub-accommodating chamber,
2. The plug according to claim 1, wherein a part of the plug is detachably fitted to the opening, and the other part of the plug penetrates the sub-opening and is exposed to the outside of the container. The nonaqueous electrolyte secondary battery as described.   The nonaqueous electrolyte secondary battery according to claim 1, wherein the opening and the sub-opening are opposed to each other.   The nonaqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein a portion of the container that defines the opening and the stopper are screwed together.   The nonaqueous electrolyte secondary battery according to any one of claims 2 to 4, wherein a portion of the container that defines the sub-opening and the plug are screwed together.   The replenishment part for inject | pouring the nonaqueous electrolyte for replenishment into the said sub accommodating chamber from the outer side of the said accommodating body is formed in the part of the said container which divides the said sub accommodating chamber. The nonaqueous electrolyte secondary battery according to any one of the above.   The replenishing portion includes a replenishing port portion that communicates with the sub-accommodating chamber to communicate the sub-accommodating chamber and the outside of the container, and a replenishing port plug body that is detachably fitted to the replenishing port portion. The nonaqueous electrolyte secondary battery according to claim 6.   The nonaqueous electrolyte secondary battery according to claim 7, wherein a portion of the container that defines the replenishing port and the replenishing plug are screwed together.

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