JP2001023586A - Electrolyte-incorporating battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a battery by decreasing the plate thickness of a battery case and to increase the allowable extent of flaws caused by the surface roughness of components or by the cleaning of components, by providing a sealing means capable of reducing the fastening torque of a bolt fitted into an electrolyte injection port of an electrolyte-incorporating battery. SOLUTION: Sealing an electrolyte injection port is performed by disposing a washer 72 having a ring-shaped partition part and a seal 73 made of an elastic material on the injection port and fitting a plug bolt 71 into the injection port. Further, it is performed by packing the elastic material in a pressed state into a space, demarcated by the partition part of the washer 72, a head part of the plug bolt 71, and a surface portion of a battery case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery with a built-in electrolyte. More specifically, the present invention relates to a battery with a built-in electrolytic solution having a means for preventing leakage of the built-in electrolytic solution.

[0002]

2. Description of the Related Art When manufacturing a battery containing an electrolyte, it is necessary to seal the electrolyte injection port after the electrolyte is injected so that the electrolyte does not leak. This is because if the electrolyte leaks, it does not function as a battery.

As means for preventing leakage of the electrolyte, Japanese Patent Application Laid-Open No. 9-092224 discloses that a female screw is cut on the inner side surface of the electrolyte injection port for a relatively large capacity nonaqueous electrolyte secondary battery. By placing a metal seal between the stopper bolt for sealing the electrolyte inlet and the electrolyte inlet, and tightening the stopper bolt to the electrolyte inlet through the metal seal, the electrolyte inlet is closed. A sealing technique is disclosed.

[0004]

However, a metal seal is arranged between the electrolyte injection port and the plug bolt, and the plug bolt is tightened to the electrolyte injection port via the metal seal to secure airtightness. , For example, M
When the hexagonal bolt No. 4 is used as a stopper bolt, a tightening torque of about 50 kgf · cm is required. This is because when the metal seal is tightened via a metal seal, the metal seal has no elasticity, so it is necessary to tighten the metal seal with a correspondingly large tightening torque. As a result, in order to secure the thread of the female screw, for example, in the case of a battery case made of stainless steel, the thickness of the lid of the case needs to be about 3 mm. However, this results in an increase in battery weight, which degrades battery characteristics such as weight energy density and weight output density.

[0005] In addition, if the metal surface in contact with the metal seal is not polished and smoothed to obtain a hermetic seal, the cost of parts such as a battery case lid and a plug bolt increases. Further, there has been a problem that a flaw formed in a part washing step or the like impairs the hermeticity.

[0006] The present invention has been made in view of the above problems. That is, an object of the present invention is to provide a battery with a built-in electrolytic solution having a sealing means capable of reducing the tightening torque of a bolt screwed into the electrolytic solution inlet to seal the electrolytic solution inlet. I do.

It is another object of the present invention to reduce the thickness of the battery case by reducing the tightening torque and to reduce the weight of the battery. That is, an object of the present invention is to reduce the weight of a large battery that requires a large amount of an electrolytic solution.

Further, by changing the member for sealing the electrolyte injection port, the allowable range of the surface roughness of the parts and the scratches caused by cleaning the parts can be expanded, and as a result, the cost of the parts decreases and the productivity improves. The purpose is to plan.

[0009]

According to the present invention, there is provided a battery with a built-in electrolyte, comprising: a positive electrode and a negative electrode; an electrolyte for mediating an electrochemical reaction between the positive electrode and the negative electrode; and an inlet for injecting the electrolyte. And a sealing means for sealing the inlet, and a battery with a built-in electrolytic solution having the positive electrode, the negative electrode, and a battery case for holding and holding the electrolytic solution. A bolt having a male screw portion inserted into the inlet, a head formed integrally with the male screw portion and covering the inlet and the periphery thereof, and surrounding the male screw portion of the bolt at a distance. A ring-shaped partition wall portion sandwiched between the head portion of the bolt and a surface portion of the battery case defining the inlet, an outer peripheral surface of the male screw portion, the partition wall portion, and the head portion of the bolt. Elastic material sealed in a pressurized state in a space defined by a portion and the surface portion of the battery case Characterized by comprising the more becomes sealed.

That is, the sealing of the electrolyte injection port is performed by disposing a washer provided with a circular hole and an elastic material inscribing the inner wall surface (ring-shaped partition wall) of the circular hole at the electrolyte injection port. Then, the bolt is inserted into the electrolyte inlet through a washer having a partition wall and a seal made of an elastic material. The elastic material is sealed in a pressurized state in a space defined by the partition of the washer, the head of the bolt, and the surface of the battery case by inserting the bolt, so that the airtightness is ensured. Here, the ring-shaped partition portion refers to the inner wall surface of a circular hole provided in the washer, surrounds the outer periphery of the male screw at an interval, and presses the seal made of an elastic material on the outer peripheral surface of the seal.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a battery with a built-in electrolyte according to the present invention will be described with reference to the drawings, taking a lithium ion secondary battery having a relatively large capacity as an example. The reason why a battery having a relatively large capacity is adopted as the embodiment is that one of the objects of the present invention is to cope with an increase in the size of the battery. However, the battery is not limited to a large battery, and may be a small battery. The battery with a built-in electrolyte of the present invention is not limited to a lithium ion secondary battery. That is, a battery having a positive electrode, a negative electrode, an electrolytic solution, an inlet for injecting the electrolytic solution, and sealing means for sealing the inlet, and containing and holding the positive electrode, the negative electrode, and the electrolytic solution Any battery with a built-in electrolytic solution having a case may be used. This is because a means for sealing the electrolyte injection port is required. For example, other types of batteries such as a nickel hydride battery and a nickel cadmium battery may be used.
Further, the sealing means of the battery with a built-in electrolytic solution of the present invention can be applied to an electric double layer capacitor having an electrode in which an electrode mixture containing activated carbon as an active material is formed in a layer on the surface of a current collector. Therefore, it is meant that the battery with a built-in electrolyte of the present invention also includes a “capacitor”.

The lithium ion secondary battery of the present embodiment has a positive electrode, a negative electrode, an electrolyte, an inlet for injecting the electrolyte, and sealing means for sealing the inlet. A battery case for housing and holding the positive electrode, the negative electrode, and the electrolytic solution; FIG. 1 shows a schematic diagram of a cross section of the present lithium ion secondary battery.

FIG. 2 is a schematic view of an electrode body wound around a winding core, and FIG. 3 is an expanded view of a positive electrode, a negative electrode, a separator and the like. In the present lithium ion secondary battery, a sheet-like positive electrode 10a and a sheet-like negative electrode 10b
It is wound around a winding core 40 via a separator 30. Winding core 40, positive electrode sheet 10a, negative electrode sheet 10b,
An electrode body is composed of the separator 30, the positive electrode lead 20a connecting the positive electrode sheet 10a and the positive electrode current collecting terminal 41a, and the negative electrode lead 20b connecting the negative electrode sheet 10a and the negative electrode current collecting terminal 41b. Such an electrode body is inserted into a cylindrical battery case, and the battery case contains an electrolytic solution. The winding core 40 includes a positive current collecting terminal portion 41a, a negative current collecting terminal portion 41b, and an insulating portion 44.

In this lithium ion secondary battery, the wound end faces of the electrode body (the positive electrode sheet 10a and the negative electrode sheet 10b
The current collecting terminal portions 41a and 41b, which are the tips of the winding core 40, protrude from an end surface of a portion where the layer is wound to form a layered structure). In addition, the ends of the current collecting terminals 41a and 41b at both ends of the winding core 40 are inserted through the cover 75 of the battery case to the outside, so that the current collecting terminals 41a and 41b are formed.
In this embodiment, the leading end of b serves as the external terminals 42a and 42b. Further, in the present lithium ion secondary battery, nuts 45a and 45b are fastened to the external terminal portions 42a and 42b to hold the electrode body in the battery case.

The positive electrode sheet 10a is composed of a positive electrode current collector 11a made of a strip-shaped metal foil and a positive electrode mixture containing a positive electrode active material coated on both surfaces thereof. It has a coated portion 12a and a positive electrode mixture uncoated portion 13a at one end in the width direction of the positive electrode current collector 11a. The negative electrode sheet 10b is composed of a negative electrode current collector 11b made of a strip-shaped metal foil and a negative electrode mixture containing a negative electrode active material applied to both surfaces thereof,
Negative electrode mixture coated portion 12b coated with negative electrode mixture and negative electrode mixture uncoated portion 13 at one end in the width direction of negative electrode current collector 11b
b. The uncoated portion 13a of the positive electrode mixture and the uncoated portion 13b of the negative electrode mixture are provided at one end in the width direction of the positive electrode sheet 10a and the negative electrode sheet 10b with a predetermined width over the entire length, respectively.

As the positive electrode current collector 11a, a metal foil such as aluminum may be used. The width and length can be arbitrary depending on the capacity of the battery. The positive electrode mixture is obtained by mixing a conductive material such as graphite, a binder such as polyvinylidene fluoride, and a suitable amount of a solvent such as n-methylpyrrolidone with a positive electrode active material such as a lithium composite oxide powder and the like. Before the work, a paste-like material may be used. The negative electrode current collector 11b may use metal foil such as copper. The width and the length can be arbitrarily set according to the capacity of the battery, as in the case of the positive electrode current collector 11a. The negative electrode mixture is obtained by mixing a binder such as polyvinylidene fluoride with a negative electrode active material made of a carbon material powder such as graphite, and adding an appropriate amount of a solvent such as n-methylpyrrolidone. May be used.

The step of forming the electrode mixture application portions 12a and 12b on the positive electrode sheet 10a and the negative electrode sheet 10b, that is, the step of applying the electrode mixture on the surfaces of the current collectors 11a and 11b is performed by various methods. However, it is preferable to use a coating machine called a coater which can perform continuous coating and drying. In this case, uncoated portions 13a and 13b may be provided at one end of the current collectors 11a and 11b in the width direction.

The positive electrode lead 20a and the negative electrode lead 20b for current collection are usually preferably made of the same kind of metal as the current collectors 11a and 11b. Therefore, aluminum or the like may be used for the positive electrode, and copper or the like may be used for the negative electrode. . The form may be a strip shape. The leads 20a and 20b are
a, uncoated portions 13a, 13 of the electrode mixture of the negative electrode sheet 10b
b. The joining method is ultrasonic joining, resistance welding,
Any method such as caulking is possible. However, uncoated part 13
a, 13b may be made wider and cut out using a means such as pressing or laser cutting to be formed integrally with the current collector. The length of the leads 14a and 14b may be set to an appropriate length according to the current collection processing method up to the external terminal portions 41a and 41b. In this lithium ion secondary battery, the leads 14a and 14b are connected to the current collecting terminal 41a,
The outer peripheral surface of the flange portion 41b is connected to 43a and 43b.

As described above, the winding core 40 is provided between the positive current collecting terminal portion 41a, the negative current collecting terminal portion 41b, and the positive current collecting terminal portion 41a and the negative current collecting terminal portion 41b. And an insulating portion 44 for electrically insulating the electrical terminal portion. In the case of the present lithium ion secondary battery, the winding core 40 has a cylindrical rod shape.

In the case of the present lithium-ion secondary battery, the tip of the positive current collecting terminal portion 41a and the negative current collecting terminal portion 41b, which are opposed to each other via the insulating portion, protrude beyond the battery case housing the electrode body. The tips projecting from the battery case play the role of the positive and negative external terminals 42a and 42b.

The positive current collecting terminal portion 41a and the negative current collecting terminal portion 41b are connected to the insulating portion 44 by forming a female screw at the connection end of the insulating portion 44, and the positive current collecting terminal portion 41a and the negative current collecting terminal portion are formed. This is performed by forming a male screw at the connection end of 41b and screwing the male screw and the female screw.

The positive current collecting terminal portion 41a and the negative current collecting terminal portion 41b are connected to the positive electrode lead 20a and the negative electrode lead 20b.
Considering good bonding and electrochemical stability at each electrode, it is preferable to use aluminum or the like for the positive electrode current collecting terminal 41a, and use copper, nickel-plated stainless steel or the like for the negative electrode current collecting terminal 41b. Good.

The material of the insulating section 44 is not particularly limited. Any material can be used as long as it can secure electrical insulation and is chemically stable and does not corrode or dissolve in the electrolytic solution. In consideration of weight reduction of the battery, for example, it is desirable to form the battery from a resin such as polypropylene or Teflon.

The positive electrode sheet 10a thus formed,
The negative electrode sheet 10b is connected to the positive electrode lead 20a and the negative electrode lead 2
0b face each other, and two separators 3
Then, they are piled up through a loop, and they are integrally wound around the core 40 in a spiral shape. The separator 30 has a role of physically isolating the positive electrode sheet 10a and the negative electrode sheet 10b and holding an electrolytic solution, and is preferably a microporous film of polyethylene or the like having a thickness of about 20 to 40 μm.

In the present lithium ion secondary battery, the positive electrode lead 2 is attached to the flange 42a of the positive electrode current collecting terminal portion 41a.
The negative electrode lead 20b is joined to the flange 42b of the negative electrode current collecting terminal 41b. Bonding can be performed by ultrasonic bonding or the like. The electrode body that has completed the current collection process is inserted into a battery case for assembly, and the battery case stores and holds the electrode body and the electrolyte.

In the present lithium ion secondary battery, the battery case comprises a hollow cylindrical case pipe portion 76 and two lids 75 closing both ends of the pipe portion 76. At the center of the lid 75, a terminal hole is provided, into which the external terminals 42a and 42b are inserted. The connection between the lid 75 of the battery case and the pipe portion 76 may be performed by welding or the like. A sealing material (gasket 5) for securing the battery and ensuring insulation between the electrodes is provided between the terminal hole of the battery case cover 75 and the winding core 40.
0) is interposed, and the external terminal portion 4 in which a male screw is formed
Nuts 45a and 45b are fastened to 2a and 42b.

After the electrode body is inserted into the battery case, the electrolyte is injected from the electrolyte injection port 70, and the positive electrode sheet 10
a, the negative electrode sheet 10b and the separator 30 are impregnated.

In the case of the present lithium ion secondary battery, the electrolytic solution includes ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (γ-BL),
Lithium tetrafluoroborate (LiBF ₄ ) using one or a mixture of two or more of dimethyl sulfoxide (DMSO), diethyl carbonate (DEC), dimethyl carbonate (DMC), and dimethoxyethane (DMC) as a solvent , Lithium hexafluorophosphate (LiP
F ₆ ), lithium perchlorate (LiClO ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), or the like can be used as a supporting electrolyte.

In general, in a battery with a built-in electrolyte, in consideration of an abnormal increase in internal pressure due to gas generation in the case of overcharging or the like, a part of the battery case (generally, a lid having a flat surface) is provided with a gas vent. Safety valve is provided. Also in the present lithium ion secondary battery, a safety valve 60 is provided in the battery case by welding a nickel foil to a gas vent hole. The present lithium ion secondary battery has an electrolyte injection port sealing means for sealing the electrolyte injection port 70 after injecting the electrolyte from the electrolyte injection port 70. In the present lithium ion secondary battery, an inlet 70 for injecting the electrolyte is bored in a lid 75 of a battery case.
FIG. 4 shows a metal washer 72 having a ring-shaped partition wall and a seal made of an elastic material (hereinafter referred to as an “elastic seal”).
73 and the washer 72 and the elastic seal 73.
Shows a state in which the plug bolt 71 is held between the head of the stopper bolt 71 and the surface of the lid 75.

In the present lithium ion secondary battery, the plug bolt 71 is inserted into the electrolyte injection port 70 through the metal washer 72 having the annular partition wall and the elastic seal 73. A metal washer 72 having a partition wall and an elastic seal 73 inscribed in the partition wall 73 are provided between the head of the plug bolt 71 and the surface of the battery case which defines the electrolyte injection port 70. The head of the plug bolt 72 and the surface of the cover 75 of the battery case are
And the elastic seal 73, and as a result, a space defined by the partition wall of the metal washer 72, the head of the plug bolt 71, the outer peripheral surface of the male screw portion of the plug bolt 71, and the surface portion of the battery case, When the elastic seal 73 is pressurized and sealed, the hermeticity is ensured.

From the viewpoint of easy handling, it is preferable that the washer 72 and the elastic seal 73 are integrally connected. The bonding method may be, for example, a method using baking or a method using an adhesive or the like. Further, in terms of hermeticity, it is preferable that the thickness of the elastic seal 73 in the non-pressurized state is larger than the thickness of the washer 72 having the partition.

The sealing means for the electrolyte injection port is as follows.
Other embodiments such as those described below are also possible.

FIG. 5 is a diagram showing an outline of the resistance welding of the nut, FIG. 6 is a diagram showing an outline before tightening the plug bolt 71 and the nut 74, and FIG. 7 is a diagram showing the plug bolt 71 and the nut 74.
The figure which shows the outline of the tightening by the plug bolt 7 is shown.
In view of the insertion strength of 1, the nut 74 is welded in advance to the back of the lid 75 where the electrolyte injection port 70 is located, and the nut 74 and the head of the plug bolt 71 are used to secure the lid 75 of the battery case. It is preferable that the metal washer 72 and the elastic seal 73 are sandwiched. What is necessary is just to weld the lid 75 and the nut 74 to the nut 75 on the back surface of the lid 76 of the battery case by applying a pressurizing current by a resistance welding machine. For example, resistance welding may be performed using a chromium copper electrode. After injecting the electrolyte, the plug bolt 71 and the nut 74 are tightened via a metal washer 72 and an elastic seal 73 to seal. By using the nut 74 by welding it to the back side of the lid 75, it is not necessary to form a screw on the lid, and a thinner lid 75 can be used, contributing to a reduction in battery weight. Will be. Further, since the plug bolt 71 and the nut 74 are used, the tightening is assured.

When the nut 74 is resistance-welded, the cover 75 of the battery case may be slightly distorted or deformed, but the deformation of the elastic seal 73 can absorb the distortion. Therefore, it is possible to sufficiently secure the airtightness. In addition, the liquid injection port is made of an inexpensive through-hole method, and the female screw is sealed with an inexpensive commercially available nut by resistance welding, which can be processed at high speed. Is also possible.

Another embodiment is also possible. FIG. 8 shows a diagram in which the electrolyte injection port 70 is subjected to burring processing. From the viewpoint of the insertion strength of the stopper bolt 71, the electrolyte injection port 70 is subjected to burring processing and bent inward of the lid 75. It is also preferable to form an internal thread in the portion provided and insert the stopper bolt 71 through the thin metal plate 72 and the elastic seal 73 to seal the electrolyte injection port 70. Since the female screw is formed at the portion of the lid 75 bent inward by performing burring, the tightening of the stopper bolt 71 is ensured. Also, since a burring process is performed to form a female screw in a portion bent inside the cover, the cover 75
Can be made thinner, and the absence of the nut can further reduce the weight of the battery.

Still other embodiments are possible. From the viewpoint of ease of handling, it is preferable that the thin metal plate 72 be bonded in advance to the surface of the head of the plug bolt 71 where the male screw protrudes. This is because the male screw portion of the plug bolt 71 may be inserted into the hole of the elastic seal 73 and the plug bolt 71 may be screwed to the electrolyte inlet 70.

FIG. 9 shows that the partition wall 72 and the head of the plug bolt 71 are integrally formed so that the electrolyte injection port 70 is formed.
A metal washer 72 having a ring-shaped partition portion is shown from the viewpoint of ease of handling and airtightness.
Is preferably formed integrally with the head of the stopper bolt 71. Since the metal washer 72 and the head of the plug bolt 71 are integrally formed in advance, the surface of the metal washer 72 and the plug bolt 7 are pressed when the elastic seal is pressed.
Part of the elastic seal is not caught between the heads, and the sealing performance is assured by that much. Further, as described above, the male screw portion of the stopper bolt 71 may be inserted into the hole of the elastic seal 73 and the stopper bolt 71 may be screwed to the electrolyte injection port 70, so that the handling is facilitated.

Although the embodiment has been described with reference to a lithium ion secondary battery as an example, as described above, any other battery that incorporates an electrolyte and requires electrolyte sealing means may be used. Types of batteries. For example, a nickel hydrogen battery, a nickel cadmium battery, or the like may be used. In the case of a nickel metal hydride battery, an aqueous solution mainly containing potassium hydroxide is used as an electrolyte, and in the case of a nickel cadmium battery, potassium hydroxide, sodium hydroxide, lithium hydroxide, or the like is used. . The materials of the positive electrode sheet, the negative electrode sheet, the separator and the like also differ depending on the type of the battery.

In a lithium ion secondary battery,
The shape of the battery need not necessarily be cylindrical. Other shapes may be used. For example, a cylindrical battery having an elliptical or polygonal cross section may be used.

Further, in the present lithium ion secondary battery, an electrode body in which a positive electrode sheet and a negative electrode sheet are wound around a core with a separator interposed therebetween is used. Other forms, for example, those in which a plurality of positive electrode sheets and negative electrode sheets are arranged in parallel may be used.

The structure, form, and the like of the current collection processing method, the electrode body, the winding core, the external terminal portion, and the like are not limited to those shown here.

Furthermore, although the form in which the electrolyte injection port is provided in the lid is shown here, it is not necessarily required to be provided in the lid, and it may be a pipe portion of the battery case.

In short, there are a positive electrode and a negative electrode, an electrolytic solution that mediates an electrochemical reaction between the positive electrode and the negative electrode, an inlet for injecting the electrolytic solution, and sealing means for sealing the inlet. However, the structure, form, and material of the battery are not limited to those shown here, as long as the battery has a battery case that contains and holds the positive electrode, the negative electrode, and the electrolyte solution.

The washer 72 having a partition wall is preferably made of metal from the viewpoint of strength, and more preferably made of stainless steel from the viewpoint of corrosion resistance. Aluminum is preferable from the viewpoint of reducing the weight of the battery case. The shape of the washer itself does not have to be particularly ring-shaped, as long as the partition wall portion is ring-shaped. The material of the elastic seal 73 may be any material having elasticity, but a rubber seal such as ethylene propylene is preferable in consideration of the electrolyte of the lithium ion secondary battery.
Further, by using a rubber seal, it is possible to increase the allowable range of the surface roughness of the parts and the scratches caused by the cleaning of the parts, and as a result, it is possible to reduce the cost of parts and improve the productivity. .

[0045]

EXAMPLES In order to confirm the tightness of the sealing means at the electrolyte inlet of a lithium ion secondary battery, a cylindrical lithium ion secondary battery was manufactured and tested.

(Production of cylindrical lithium ion secondary battery)
A cylindrical lithium secondary battery was manufactured. The manufacturing method is as described in the embodiment. That is, the positive electrode sheet 10a,
The negative electrode sheet 10b and the separator 30 are manufactured, and the positive electrode sheet 10a, the negative electrode sheet 10b, and the
The electrode body is formed by being wound to zero. Positive electrode sheet, positive electrode lead 20a and negative electrode lead 20 joined to negative electrode sheet
b is a flange 43 of the current collecting terminal portions 41a and 41b, respectively.
a, 43b. After the configured electrode body is inserted into the battery case, a non-aqueous electrolyte is injected from the electrolyte injection port 70. After the non-aqueous electrolyte is injected from the electrolyte injection port 70, a metal thin plate 72 and a rubber seal 73 are provided, and the stopper bolt 71 is inserted through the metal thin plate 72 and the rubber seal 73. 70. The tightening torque of the plug bolt 71 was 30 kgf · cm.

The battery case is made of stainless steel (SUS304)
(JISG4311)). Case lid 75
Thickness is 1.5 mm, and wall thickness of the pipe portion 76 is 0.3 m
m. The surface roughness of the lid 75 is the ten-point average roughness (JI
SB0601) was 25 μmRz. An M4 female screw is 0.7 m in the electrolyte injection port 70 attached to the lid 75.
It was formed at an m pitch. The shape of the electronic case is 30m in diameter
m, cylindrical type with a length of 180 mm.

The shapes of the metal washer 72 having the partition and the rubber seal 73 are shown in FIG. The metal washer was made of SUS304. The rubber seal 73 was made of ethylene propylene rubber. The outer diameter of the metal washer 72 was 7.4 mm, the inner diameter was 5.3 mm, and the thickness was 1.0 mm. The inner diameter of the rubber seal 73 is 4.3
mm. The stopper bolt 72 is an M4 hexagon bolt and S
Made in US304. The outer diameter of the sealing surface of the plug bolt 71 was 6.7 mm.

(Test 1: Seal pressure test) A seal pressure test was performed on the cylindrical lithium ion secondary batteries manufactured in the examples to check the sealing performance. The outline of the test method is shown in FIG. The test conditions are shown in Table 1. However, in this test, the electrolyte was not injected into the battery case. The battery case of this test was provided with an air injection port for pressurizing the air in the battery case.

[0050]

[Table 1]

Air was injected through an air port attached to the battery case, and air leakage from the electrolyte inlet was examined. It was pressurized for 1 minute at a pressure of 2.4 MPa, which is larger than the designed opening pressure of the safety valve, 2 MPa. The test was performed with 10 pieces. About ten pieces, the presence or absence of air bubbles was visually observed.
There were no leaks for all 10 samples.

(Test 2: Seal pressure resistance test after immersion in electrolyte solution) A seal pressure resistance test after immersion in the electrolyte solution was performed on the cylindrical lithium ion secondary batteries manufactured in Examples. It was tested whether the hermeticity was maintained even after being immersed in the electrolytic solution. The outline of the test method is shown in FIG. The test conditions are shown in Table 2. However, in this test, as in Test 1, the electrolyte was not injected into the battery case, and an air injection port was provided in the battery case.

[0053]

[Table 2]

The sample was left immersed in the electrolytic solution. Thereafter, Test 1 and a seal pressure test were performed again. There were no leaks for all 10 samples. Therefore, there was no deterioration of each component used for the sealing, and it was confirmed that the electrolyte solution resistance of the structure of the present invention was good.

(Test 3: Battery Vibration Test) A battery vibration test was performed on the cylindrical lithium secondary battery manufactured in the example. This is to check whether the hermeticity is lost due to the vibration. The outline of the test method is shown in FIG. The test conditions are shown in Table 3. However, in this test, the electrolyte was not injected into the battery case.

[0056]

[Table 3]

First, as a preliminary experiment, the return torque of the stopper bolt tightened at 30 kgf · cm was examined. As a result of examining the return torque of the ten batteries, it was found that all the values were within the range of 21 to 23 kgf · cm, although there was some variation.

One vibration test was performed in each of the Z direction and the Y direction. After the vibration test, the return torque was examined. As a result, it was 22.0 kgf · cm in the Z direction. 2 in Y direction
It was 1.5 kgf · cm. All were within the range of the return torque in the initial state. Therefore, the sealing portion did not loosen due to the vibration, and it was confirmed that the vibration resistance of the structure of the present invention was good.

[0059]

In other words, the battery with a built-in electrolyte according to the present invention has an effect that the tightening torque of a bolt screwed into the electrolyte inlet for sealing the electrolyte inlet can be reduced.

Further, the reduction of the tightening torque can reduce the thickness of the battery case, which has the effect of reducing the weight of the battery.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a cross section of a lithium ion secondary battery that is an embodiment of a battery with a built-in electrolyte according to the present invention.

FIG. 2 is a schematic diagram of an electrode body in which a positive electrode sheet, a negative electrode sheet, and a separator of the lithium ion secondary battery of the present embodiment are wound around a core.

FIG. 3 is a developed view of a positive electrode sheet, a negative electrode sheet, and a separator of the lithium ion secondary battery of the embodiment.

FIG. 4 is a diagram showing a metal washer having a partition wall portion and an elastic seal, and a diagram showing a state where the metal washer is held by a stopper bolt.

FIG. 5 is a diagram showing an outline of resistance welding of a nut.

FIG. 6 is a diagram showing an outline before a metal washer and an elastic seal are fastened by a stopper bolt and a nut.

FIG. 7 is a view showing a state in which a metal washer and an elastic seal are tightened and sealed with a stopper bolt and a nut.

FIG. 8 is a diagram showing a state in which burring is performed, and a metal washer and an elastic seal are tightened with a stopper bolt and sealed.

FIG. 9 is a view showing a state in which a metal washer and a stopper bolt are integrally formed and an elastic seal is tightened.

FIG. 10 is a diagram showing an outline of a seal pressure test.

FIG. 11 is a diagram showing an outline of a seal pressure test after immersion in an electrolytic solution.

FIG. 12 is a diagram showing an outline of a battery vibration test.

[Explanation of symbols]

10a: Positive electrode sheet (positive electrode) 10b: Negative electrode sheet (negative electrode) 11a: Positive electrode current collector 11b: Negative electrode current collector 12a: Positive electrode mixture coating section 12b: Negative electrode mixture coating section 13a: Positive electrode mixture non-coating Part 13b: Negative electrode mixture uncoated part 20a: Positive electrode lead 20b: Negative electrode lead 30: Separator 40: Core 41a: Positive current collecting terminal part 41b: Negative current collecting terminal part 42a: Positive external terminal part 42b: Negative external terminal Part 43a: Positive electrode flange part 43b: Negative electrode flange part 44: Insulating part 45a: Nut 45b: Nut 50: Gasket 60: Safety valve 70: Electrolyte injection port 71: Plug bolt 72: Metal washer 73: Elastic seal 74: Nut 75: Lid 76: Pipe

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideyuki Masaki 41, Chukumi Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central Research Laboratory, Inc. (72) Inventor Masayuki Matsui Nagakute-cho, Nagakute-cho, Aichi County, Aichi Prefecture No. 41, Yokomichi, Toyota Central Research Laboratory, Inc. (72) Inventor Toshihiko Inoue 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 5H011 AA09 AA17 FF02 GG02 HH03 JJ02 KK01 5H023 AA03 AS01 BB05 CC11 CC15 CC19 CC28 5H029 AJ14 AJ15 AK03 AL06 AL07 AM02 AM03 AM04 AM05 AM07 BJ02 BJ14 CJ03 CJ13 DJ03 DJ14 EJ11 HJ04

Claims (3)

[Claims] A positive electrode and a negative electrode, an electrolytic solution that mediates an electrochemical reaction between the positive electrode and the negative electrode, an inlet for injecting the electrolytic solution, and sealing means for sealing the inlet. Having a positive electrode, the negative electrode and a battery case for storing and holding the electrolytic solution, wherein the sealing means comprises: a male screw portion inserted into the inlet;
A bolt integrally formed with the male screw portion and having a head covering the inlet and the periphery thereof, surrounding the male screw portion of the bolt at a distance,
A ring-shaped partition wall portion sandwiched between the head portion of the bolt and a surface portion of the battery case defining the inlet; an outer peripheral surface of the male screw portion, the partition wall portion, and the head portion of the bolt; And a seal made of an elastic material sealed under pressure in a space defined by the battery case and the surface portion of the battery case. 2. The electrolysis according to claim 1, wherein the seal is integrally connected to the partition wall, and a thickness of the seal in a pressure direction in a non-pressurized state is larger than a thickness of the partition wall. Battery with built-in liquid. 3. The battery with a built-in electrolyte according to claim 1, wherein the partition wall is formed integrally with the head of the bolt.