JP2003208879A - Secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery capable of maintaining the sealing ability in a connection part for fixation of an electrode terminal passing through a lid material even in the case where a pressure difference is generated between inside and outside of a can body of the secondary battery, especially in the case where the pressure is applied from the inside of the can body to the outside thereof. <P>SOLUTION: This secondary battery is formed by arranging a positive electrode, a negative electrode and a separator in a case, filling the electrolyte solution, and sealing with the lid material 22 having the electrode terminals 25 and 26 passing through it. The electrode terminals 25 and 26 are fixed by an insulator 24 provided between the lid material 22 and the electrode terminals 25 and 26 passing through the lid material 22, and a lock part 30 is provided in the connection part of the lid material 22 and the insulator 24. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery such as a lithium secondary battery, and more particularly to a large secondary battery used as a backup power source for factories and hospitals, a power source mounted on electric vehicles and the like. Regarding the next battery.

[0002]

2. Description of the Related Art Conventionally, a battery called a secondary battery has been widely used as a power source capable of storing DC power by repeating charging and discharging and supplying DC current to the outside as needed. . In particular, in the field of electronic devices such as mobile phones, digital cameras, and notebook personal computers, their production will increase with the promotion of miniaturization, thinning, and weight reduction, and the amount of secondary batteries used as power sources will increase. Is also increasing rapidly.

Under such circumstances, a secondary battery as a power source is also required to have higher performance, and a lithium secondary battery has been developed and widely spread as a high energy density battery replacing a lead storage battery or a nickel cadmium battery. There is. This lithium secondary battery is not only small and has a small capacity for the electronic devices described above, but is also large and large for use as an emergency power supply facility and power storage facility in factories and hospitals, or for powering electric vehicles. A capacity version is also being developed.

FIG. 7 shows a box-shaped lithium secondary battery as an example of the structure of a large secondary battery. In the figure, reference numeral 1 is a case, 2 is a positive electrode, 3 is a negative electrode, 4 is a separator, 5 is a positive electrode terminal, 6 is a negative electrode terminal, 7 is a safety valve, 8 is a lid material, and 10 is a lithium secondary battery. And case 1
An electrolytic solution (not shown) is filled inside. In this lithium secondary battery 10, as shown in the conceptual diagram of FIG.
A large number of positive electrodes 2, separators 4, negative electrodes 3, separators 4, positive electrodes 2, separators 4, negative electrodes 3, ... Are stacked in the case 1, and all positive electrodes 2 and negative electrodes 3 are connected in parallel. Further, the positive electrode 2 and the negative electrode 3 which are connected in parallel to each other are collected in the positive electrode terminal 5 and the negative electrode terminal 6, respectively. That is, the positive electrode 2 and the separator 4
A large number of unit batteries configured by the negative electrode 3 and the negative electrode 3 are all connected in parallel in the case 1. In addition,
Each of the positive electrode terminal 5 and the negative electrode terminal 6 is integrally provided by penetrating the lid member 8.

[0005]

By the way, in a secondary battery such as the lithium secondary battery 10 described above, weight reduction is a major problem. Therefore, various improvements have been made to the battery can made up of the case 1 and the lid member 8,
For example, one using a lightweight metal material such as aluminum has been proposed. In such a battery can, a positive electrode terminal 5 and a negative electrode terminal 6 (hereinafter, both terminals are collectively referred to as “electrode terminals”) are fixed by penetrating a lid member 8 made of a lightweight metal material. Therefore, it is necessary to prevent a short circuit between the electrode terminal using a metal material such as aluminum or copper and the metal lid member 8. For example, as shown in FIG. There has been proposed a lid member 8 having a structure in which a resin portion 9 of an insulator is provided so as to surround the, and the electrode portion is fixed by the resin portion 9.

However, in order to secure the safety against the above-mentioned short circuit between the lid member / electrode, it is preferable to set a large distance between the lid member 8 and the electrode terminal, so that the resin portion 9 serves as the lid portion 8. The proportion of the area will increase. Therefore, if the internal pressure rises due to an internal short circuit, etc.,
There is a problem that the resin portion 9 and the electrode terminal portion 5 or 6 are likely to come out of the battery.

In addition, in the resin portion 9 where sufficient strength is not obtained, when the pressure difference between the inside and the outside becomes large and deformation occurs, in the penetrating portion of the electrode terminal which is the connecting portion between the resin member and the metal member, It becomes difficult to maintain the hermeticity in the case hermetically sealed by the lid member 8. Such a problem of hermeticity is further disadvantageous because the larger the resin portion 9 is, the more the connecting (contacting) portion with the metallic lid member 8 is increased.

The above-mentioned internal short circuit is caused when the unit batteries connected in parallel inside the case 1 are partially short-circuited.
This is a phenomenon in which all the energy of the other unit cells is concentrated in the short-circuited portion and a large current instantaneously flows, and as a result, the chemical reaction proceeds abnormally to generate gas or generate heat. Therefore, when such an internal short circuit occurs, a sudden pressure increase or temperature increase will occur inside the case 1, and the safety valve 7 is provided as one of the measures against it.

From such a background, even if the pressure difference between the inside and the outside of the battery can formed by the case and the lid member becomes large, the sealing property of the connecting portion where the electrode terminal is fixed by penetrating the lid member can be maintained. Development of secondary batteries is desired. The present invention has been made in view of the above circumstances, and in the case where a pressure difference between the inside and outside of the can body in the secondary battery occurs, particularly when a pressure from the inside to the outside of the can body acts, the electrode terminal It is an object of the present invention to provide a secondary battery capable of maintaining the hermeticity of a connecting portion fixed by penetrating a lid member.

[0010]

The present invention adopts the following means in order to solve the above problems. The secondary battery according to claim 1, wherein the positive electrode, the negative electrode, and the separator are provided in a case, the electrolytic solution is filled in the case, and the electrode terminal is penetrated to seal the secondary battery. The electrode terminal is fixed by an insulator provided between the lid member and an electrode terminal penetrating the lid member, and a locking portion is provided at a connecting portion between the lid member and the insulator. To do.

According to such a secondary battery, the electrode terminal is fixed by the insulator provided between the lid member and the electrode terminal penetrating the lid member, and the electrode terminal is fixed to the connecting portion between the lid member and the insulator. Since the stopper is provided, even if the lid member is deformed due to the pressure difference between the inside and the outside, the locking portion functions as a stopper, so that the sealing property of the connecting portion can be maintained.

A secondary battery according to a second aspect is a secondary battery in which a positive electrode, a negative electrode, and a separator are provided in a case, an electrolytic solution is filled in the case, and the electrode terminal is penetrated to seal the secondary battery. The electrode terminal is fixed by an insulator provided between the lid member and an electrode terminal penetrating the lid member,
A locking portion is provided at a connecting portion between the electrode terminal and the insulator.

According to such a secondary battery, the electrode terminal is fixed by the insulator provided between the lid member and the electrode terminal penetrating the lid member, and the electrode terminal is fixed to the connecting portion of the insulator. Since the stopper is provided, even if the lid member is deformed due to the pressure difference between the inside and the outside, the locking portion functions as a stopper, so that the sealing property of the connecting portion can be maintained.

A secondary battery according to a third aspect is a secondary battery in which a positive electrode, a negative electrode, and a separator are provided in a case, an electrolytic solution is filled in the case, and the electrode terminal is penetrated to seal the secondary battery. The electrode terminal is fixed by an insulator provided between the lid member and an electrode terminal penetrating the lid member,
It is characterized in that a stopper for engaging with the inner surface of the insulator is provided inside the case of the electrode terminal.

According to such a secondary battery, the electrode terminal is fixed by the insulator provided between the lid member and the electrode terminal penetrating the lid member, and the inner surface of the insulator is provided inside the case of the electrode terminal. Since the retainer that engages is provided, even if the lid member is deformed due to the pressure difference between the inside and the outside, the electrode terminal does not come out, and therefore the sealing property of the connecting portion can be maintained.

A secondary battery according to a fourth aspect is a secondary battery in which a positive electrode, a negative electrode and a separator are provided in a case, an electrolytic solution is filled in the case, and the electrode terminal is penetrated to seal a secondary battery. The electrode terminal is fixed by an insulator provided between the lid member and an electrode terminal penetrating the lid member,
The conical electrode terminal is joined to the insulator.

According to such a secondary battery, the conical electrode terminal is fixed by the insulator provided between the lid member and the electrode terminal penetrating the lid member, and the conical electrode terminal is joined to the insulator. Even if the lid member is deformed due to the pressure difference between the inside and the outside, the electrode terminal does not come out, and therefore, the sealing property of the connecting portion can be maintained.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The secondary battery of the present invention will be described below with reference to the drawings of the lithium secondary battery. 1 is a perspective view of the secondary battery according to the present invention, and FIG.
FIG. 3 is a cross-sectional view of an essential part showing a lid structure of a secondary battery according to the present invention.

In FIG. 1, reference numeral 20 denotes a secondary battery, 2
1 is a case, 22 is a cover material, 23 is a liquid inlet lid, 24 is an insulator, 25 is a positive electrode terminal, 26 is a negative electrode terminal, 27a, 27b
Is a safety valve. The case 21 is a prismatic container having wall surfaces on four sides and a bottom surface and an open top surface, and is integrally formed by pressing an aluminum alloy plate or the like by deep drawing or ironing.

The lid member 22 is a constituent member of a battery can for accommodating and sealing the positive electrode and the negative electrode in the case 21 together with the electrolytic solution. The lid member 22 is a plate-shaped member formed of a plate material such as an aluminum alloy in order to close the upper opening of the case 21 and seal the inside of the case. A removable liquid injection port lid 23 is attached to the central portion of the lid member 22 in order to close the injection port of the electrolytic solution provided through the lid member 22. In addition, on both sides of the injection port lid 22 in the short side direction, safety valves 27a,
27b is provided.

Further, in the longitudinal direction of the lid member 22, a positive electrode terminal 25 and a negative electrode terminal 26 (both terminals are generically referred to as "electrode terminals") so as to sandwich the liquid injection port lid 23 therebetween.
Are arranged. As shown in FIG. 2, the electrode terminals 25 and 26 penetrate the lid member 22 and are fixed at the periphery with an insulator 24. The insulator 24 is preferably a hard resin material having an insulating property such as polyethylene, polypropylene, a fluororesin, or a phenolic resin, or a material containing at least one kind of the same material. In addition, the glass is used as an insulator 24
It is also possible to use as.

The electrode terminals 25 and 26 shown in FIG. 2 are of a double screw type in which female threads are respectively formed on the outside of the case above the paper surface (atmosphere side) and inside the case below the paper surface (wetted side). . In this case, a terminal member (not shown) that is screwed into each female screw is required. Inside the case 21, a large number of positive and negative electrodes (not shown) connected in parallel are aggregated, and the positive and negative terminals 25 and 25 are respectively provided. Negative electrode terminal 2
6 is connected. In addition, the electrode terminal and the terminal member,
One is made of aluminum and the other is made of copper.

Now, the above-mentioned insulator 24 is connected to the lid member 22 on the outer peripheral side thereof, and the electrode terminals 25,
It is connected to 26. The connecting portion between the lid member 22 and the insulator 24 is provided with a concavo-convex portion near the end of the lid member 22, and the engaging portion 30 is formed by integrally inserting the insulator 24 into the concavo-convex portion. . The locking portion 30 is preferably provided over the entire circumference of the connecting portion, but it may be provided partially.

Hereinafter, a specific example of the structure of the above-mentioned locking portion 30 will be described. In the first embodiment shown in FIG. 3, reference numeral 2 in the drawing is a lid material, 24 is an insulator, and 30A is a locking portion. In this embodiment, the engaging portion 3 having a configuration in which concave groove portions 31 are provided on both surfaces in the vicinity of an end portion that serves as a connecting portion of the lid member 22.
It is set as 0A. The illustrated groove portion 31 has a U-shaped cross-sectional shape, but a V-shaped or semi-circular shape may be adopted, and the cross-sectional shape is not limited.

By providing the recessed groove portion 31 as described above, in the vicinity of the end portion where the lid member 22 is connected to the insulator 24,
An uneven portion is formed by the concave groove portion 31 and the end portion 22a remaining outside thereof. Then, the concave-convex portion is made into the insulator 2
If they are connected so as to be surrounded by 4, the insulator 24 enters the groove 31 and is integrated, and the locking portion 30A configured in this way functions as a retaining member. As a result,
For example, when an internal short circuit occurs and the internal pressure rises, even if the lid member 22 receives the internal pressure and is deformed to bulge outward, the locking portion 30A acts as a retaining member, so that the sealing performance at the connecting portion is improved. Can be made. Therefore, it is possible to increase the size of the insulator 24 to further enhance the safety of short-circuit prevention between the electrode terminals 25 and 26 and the lid member 22.

Next, a second embodiment will be described with reference to FIG. In this case, the locking portion 30B is provided with a protrusion 32 having a substantially T-shaped cross section at the side end of the lid member 22. By providing this protrusion 32, the above-described first
In the same manner as in the above embodiment, the concavo-convex portion is formed, and if the concavo-convex portion is surrounded by the insulator 24 and connected, the protrusion 32 is formed.
Functions as a retainer. The cross-sectional shape of the protrusion 32 is not limited to the T-shape described above, and it is also possible to adopt an L-shape or the like.

With this structure, for example, even when the internal short circuit occurs and the internal pressure rises, and the lid member 22 receives the internal pressure and is deformed to bulge outward, the locking portion 30 is formed.
Since B acts as a retainer, it is possible to improve the sealing performance at the connecting portion. Therefore, it is possible to increase the size of the insulator 24 to further enhance the safety of short-circuit prevention between the electrode terminals 25 and 26 and the lid member 22.

By the way, in the above-mentioned first and second embodiments, the engaging portion is provided at the connecting portion between the lid member 22 and the insulator 24. However, as shown in FIG. , 2
The same locking portion 40 is also applied to the connecting portion between the insulator 6 and the insulator 24.
Is provided. Although the engaging portion 40 shown in FIG. 2 is provided with a protrusion having a substantially L-shaped cross-section protruding from the outer peripheral surfaces of the electrode terminals 25 and 26, the present invention is not limited to this protrusion cross-section. However, the protrusion may have a T-shaped cross-sectional shape, for example, like the lid member 22 shown in FIG. Then, the locking portion 30 on the side of the lid member 22 described above
The locking portions 40 on the side of the electrodes and the electrode terminals 25 and 26 can be used individually, but by using both together, further advantageous effects can be obtained.

Further, in the above-mentioned first and second embodiments, the electrode terminals 25 and 26 are described as the double screw type, but the electrode rod type electrode terminals 25A and 26A as shown in FIGS. It is also possible to do so. In the third embodiment shown in FIG. 5, the flange portion 50 is provided as a retaining member on the inner surface side (lower side of the drawing) of the electrode terminal 25A (26A).
Is provided. The flange portion 50 is integrally provided on the lower end portions of the electrode terminals 25A and 26A fixed to the insulator 24, and even if the insulator 24 is deformed due to internal pressure, the inner surface of the insulator 24 is not deformed. Is locked and the electrode terminal 25a,
26a does not come out.

Further, in the fourth embodiment shown in FIG. 6, since the electrode terminals 25A and 26A which are the connecting portions with the insulator 24 have a conical shape, the insulator 24 is deformed by the internal pressure. In the case of doing, the insulator 24 to the electrode terminal 25
It is possible to prevent A and 26A from coming off, and it is also possible to maintain high sealing performance by providing threads on the outer surface of the terminal and the inner surface of the insulator.

By using the above-mentioned flange 50 and the retaining member such as the conical shape together with the locking portion 30 on the lid member 22 side, it is possible to further contribute to the improvement of the sealing performance of the secondary battery. it can.

Although the secondary battery 20 is described as a lithium secondary battery in each of the embodiments described above, the present invention described above is not limited to the lithium secondary battery.
For example, lead acid batteries and nickel-cadmium batteries,
It goes without saying that it can be applied to other secondary batteries.

[0033]

According to the secondary battery of the present invention described in claim 1, the electrode terminal is fixed by the insulator provided between the lid member and the electrode terminal penetrating the lid member, Since the locking part is provided at the connection part with the insulator, the locking part functions as a stopper even if the lid material is deformed due to the pressure difference between the inside and the outside, so the sealing property of the connection part is maintained. You can Therefore, not only a great effect can be obtained in improving the reliability and durability of the secondary battery, but also the insulation can be increased to improve the insulation between the metallic lid member and the electrode terminal.

According to the secondary battery of the present invention described in claim 2, the electrode terminal is fixed by the insulator provided between the lid member and the electrode terminal penetrating the lid member, and the electrode terminal and the insulator are fixed. Since the engaging portion is provided at the connecting portion with the, even if the lid member is deformed due to the pressure difference between the inside and the outside, the engaging portion functions as a retaining member, so that the sealing property of the connecting portion can be maintained. . Therefore, it has a great effect on improving the reliability and durability of the secondary battery.

According to the secondary battery of the present invention as defined in claim 3, the electrode terminal is fixed by the insulator provided between the cover material and the electrode terminal penetrating the cover material, and the inside of the case of the electrode terminal is fixed. Since there is a retainer that engages with the inner surface of the insulator, the electrode terminal does not come out even if the lid material is deformed due to the pressure difference between the inside and outside, and therefore the sealing property of the connecting portion is improved. Can be kept. Therefore, it has a great effect on improving the reliability and durability of the secondary battery. By providing the locking member and / or the retaining member on both the lid member side and the electrode terminal side, the sealing performance of the secondary battery described above can be further improved.

According to the secondary battery of the present invention described in claim 4, the electrode terminal is fixed by the insulator provided between the lid member and the electrode terminal penetrating the lid member, and the conical electrode terminal is provided. Since it is joined to the insulator, the electrode terminal does not come out even if the lid member is deformed due to the pressure difference between the inside and the outside, and therefore the sealing property of the connecting portion can be maintained. Therefore, it has a great effect on improving the reliability and durability of the secondary battery.

[Brief description of drawings]

FIG. 1 is an external perspective view showing the overall configuration of a secondary battery according to the present invention.

FIG. 2 is a cross-sectional view of an essential part showing a lid member of the secondary battery shown in FIG.

FIG. 3 is an enlarged cross-sectional view of an essential part showing a first embodiment of a locking part shown in FIG.

FIG. 4 is an enlarged cross-sectional view of an essential part showing a second embodiment of the locking part shown in FIG.

FIG. 5 is an enlarged view of an essential part showing a third embodiment of the present invention.

FIG. 6 is an enlarged view of an essential part showing a fourth embodiment of the present invention.

FIG. 7 is a partial cross-sectional perspective view showing a configuration of a box-shaped lithium secondary battery as an example of the secondary battery.

8 is a conceptual diagram showing the arrangement of positive electrodes, negative electrodes and separators of the lithium secondary battery shown in FIG. 7 and the direction of electromotive force.

FIG. 9 is a view showing a conventional lid member, (a) is a plan view,
(B) is an AA sectional view of (a).

[Explanation of symbols]

20 secondary battery 21 cases 22 Lid 24 insulator 25,25A positive electrode terminal (electrode terminal) 26,26A Negative electrode terminal (electrode terminal) 30, 30A locking part 31 concave groove 32 protrusion 40 Locking part 50 Flange (retaining)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H011 AA01 AA17 BB03 CC06 EE04                       FF04                 5H022 AA09 CC03                 5H029 AJ11 AJ15 DJ02 DJ03 DJ05

Claims (4)

[Claims] 1. A secondary battery in which a positive electrode, a negative electrode, and a separator are provided in a case, the electrolytic solution is filled, and the electrode terminal is sealed with a lid material, wherein the electrode terminal is the lid. A secondary battery, wherein the secondary battery is fixed by an insulator provided between a cover material and an electrode terminal penetrating the cover material, and a locking portion is provided at a connecting portion between the cover material and the insulator. 2. A secondary battery in which a positive electrode, a negative electrode, and a separator are provided in a case, the electrolytic solution is filled, and the electrode terminal is sealed by a lid material, the electrode terminal being the lid. A secondary battery, wherein the secondary battery is fixed by an insulator provided between the electrode material and an electrode terminal penetrating the lid material, and a locking portion is provided at a connecting portion between the electrode terminal and the insulator. 3. A secondary battery in which a positive electrode, a negative electrode, and a separator are provided in a case, the electrolytic solution is filled in, and the electrode terminal is penetrated to seal the secondary battery. And an electrode terminal penetrating through the lid member, and is fixed by an insulator provided inside the case of the electrode terminal, and a retainer for engaging with an inner surface of the insulator is provided. battery. 4. A secondary battery in which a positive electrode, a negative electrode, and a separator are provided in a case, the electrolytic solution is filled, and the electrode terminal is sealed with a lid material, wherein the electrode terminal is the lid. A secondary battery, which is fixed by an insulator provided between a cover member and an electrode terminal penetrating the lid member, and the conical electrode terminal is joined to the insulator.