JP2001135358A - Sealed secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed secondary battery, wherein a sealing structure of the battery possesses a safety valve function. SOLUTION: An electrode generation body 16 in which a positive electrode sheet and a negative electrode sheet are overlapped through a separator sheet is attached inside a cylindrical electric tank can 12 made of an aluminum material with a bottom. A negative electrode side collector terminal material 24 which is electrically connected with the negative sheet of the electrode generation body 16 is projected out of an inner bottom of the electric tank can 12. A lid 28 for sealing an opening of a positive electrode side collector terminal material 22 which is electrically connected with the positive electrode sheet of the electrode generation body 16 is welded in a sealed manner at a positive electrode side open edge of the electric tank can 12 by radiating laser light with such a strength that can be damaged by a previously set specified inner pressure that is to say about 15 to 20 kgf/cm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed secondary battery, and more particularly, to a battery structure such as a cylindrical lithium ion secondary battery, and more particularly, to a positive electrode side and a negative electrode side provided at both ends of the secondary battery. The present invention relates to an entire battery structure including the current collecting terminal member.

[0002]

2. Description of the Related Art Conventionally, as a battery structure of this type of sealed secondary battery, for example, those disclosed in JP-A-8-115744 and JP-A-9-92335 are known. For example, a cylindrical secondary battery disclosed in JP-A-8-115744 has an electrode in which a positive electrode sheet and a negative electrode sheet are spirally wound around a negative electrode can made of a nickel (Ni) -plated steel tube via a separator sheet. A power generator is mounted, a nickel (Ni) plated steel sealing lid (sealing lid) is welded on the negative electrode side, and an aluminum (Al) sealing lid (sealing lid) is insulated on the positive electrode side. It was attached by caulking through a gasket.

[0003] Japanese Unexamined Patent Publication No. 9-92335 has a structure in which the same SUS sealing lid is hermetically welded to both ends of a battery case made of stainless steel (SUS) steel by irradiating a laser beam. Bolts are screwed onto the protruding surfaces of the positive electrode terminal and the negative electrode terminal from the battery so as to sandwich and fix a conductive wire (or bus bar). Also in this case, the positive electrode terminal and the negative electrode terminal are insulated from the seal lid.

Although not disclosed in these publications, a positive electrode sheet and a negative electrode sheet are spirally wound through a separator sheet in a bottomed cylindrical battery case formed by deep drawing of a stainless steel plate. The negative electrode current collector lead led from the negative electrode sheet of the electrode power generator is fixed to the inner bottom surface of the battery case by resistance welding or the like, and the positive electrode current collector guided from the positive electrode sheet of the electrode power generator is attached. There is also known a configuration in which the lead is similarly fixed to the positive electrode terminal by resistance welding or the like, and a sealing lid is hermetically attached to the opening edge of the battery case can on the positive electrode side by caulking through an insulating gasket. In each of these examples, the battery case itself constitutes the negative electrode. The battery case is filled with an electrolytic solution, and a non-aqueous organic electrolytic solution is used particularly in a lithium ion secondary battery or the like.

[0005] In this type of secondary battery, if the battery is overcharged or short-circuited while the battery is in use, the electrolytic solution is decomposed to generate gas, and the internal pressure of the battery may increase. In order to avoid this, for example, Japanese Patent Publication No. Sho 62-25
No. 9342, Japanese Unexamined Patent Publication No. 1-220368, etc., provided with a safety valve mechanism in which a gas vent hole is provided in a battery case or a sealing lid, and a thin metal foil or a resin plate is stuck thereon. When the internal pressure of the battery rises abnormally due to abnormal heat generation or decomposition of the electrolyte, the metal foil or resin plate is broken, and the internal pressure of the battery is released to prevent the battery from exploding. Furthermore, in the case of a secondary battery that uses only a few amps, it is also practical to attach a polyswitch plate (PTC element) that serves as a heating fuse when an overcurrent flows, or to shut off electricity when the safety valve is destroyed. Has been

[0006]

However, when a stainless steel plate is used for the battery case, the material cost is high, and in particular, when the bottomed cylindrical deep drawing can is used, the processing cost is further increased. In the case of Ni-plated steel sheet, Ni plating disappears when sealed by welding, so it is desirable to seal the can by swaging. However, in the swaging, the electrolyte leaks due to insufficient airtightness of the sealed can part. There is a problem with the moisture permeability of the sealed can portion.

Further, the provision of a safety valve mechanism in the battery case or the sealing lid, or the provision of a PTC element or a power cutoff mechanism in the battery case also results in an increase in processing cost due to an increase in the number of processing steps and the like. In the case of providing the latter, there is a problem that a dead space which does not contribute to the battery output is generated in the battery case can, the battery output per unit volume of the unit cell is reduced, and the battery is prevented from being made compact.

Furthermore, in the case of a bottomed cylindrical battery case, even if the current collecting lead on the negative electrode side is welded to the inner bottom surface of the battery case by resistance welding, or as disclosed in -29329
Even in the case of using laser welding as disclosed in JP-A-9, there is a problem that it is difficult to weld the negative electrode current collecting lead to the inner bottom surface of the battery case.

It is an object of the present invention to provide a sealed secondary battery in which the sealing structure of the battery case has a safety valve function. This eliminates the need for a separate safety valve mechanism, and improves the battery output per unit volume as a unit cell or reduces the size of the battery by avoiding dead space in the battery by providing the safety valve mechanism. It is. Further, it is intended to reduce material costs and processing costs.

Further, the present invention achieves an overall improvement in battery mounting efficiency as a module by reducing the overall length of the sealed secondary batteries when they are connected in series, and by employing a space-saving connection structure. What you want to do.

[0011]

According to a first aspect of the present invention, there is provided a sealed secondary battery comprising a battery case having a positive electrode sheet and a negative electrode sheet in a battery case. At least one of the negative electrode current collector terminal member electrically connected to the negative electrode sheet of the electrode power generator and the positive electrode current collector terminal member electrically connected to the positive electrode sheet is mounted. The closed end face or the sealing lid of the battery case can project outward from the sealing cover, and the sealing cover is hermetically sealed at the opening edge of the battery case, and has a strength that can be broken at a predetermined internal pressure set in advance. The gist is that they are joined.

According to the sealed secondary battery having the above configuration,
If the internal pressure of the battery rises due to decomposition of the electrolytic solution during use of the battery, the joint between the battery case and the sealing lid joined to the opening edge of the battery is broken, and the decomposition gas in the battery is released and the battery explodes. Is prevented beforehand. That is, the function as a safety valve works. In this case, as a joining method, in addition to a welding method such as laser welding, a method using an adhesive or a method involving joining by caulking may be used.

The shape of the secondary battery includes all shapes. In addition, there are a bottomed can having a closed end surface and a pipe tube in a battery case (case). In the case of a bottomed can, one sealing lid is joined to an opening edge thereof, and In the case of a tube, the sealing lids are respectively joined to both opening edges (two sealing lids). Further, the battery case itself may be either one constituting the negative electrode or the positive electrode, or a neutral one having no polarity.

As a sealed secondary battery corresponding to claim 1, the one having the configuration shown in FIG. 1 is exemplified. FIGS. 1A and 1B show a cylindrical sealed secondary battery, and FIG.
(D) and (e) are examples of box-shaped sealed secondary batteries. In (a), (c) and (e), both the positive electrode current collecting terminal member and the negative electrode current collecting terminal member protrude, and in (b) and (d) only one current collecting terminal member protrudes. It was done. When the battery case has no polarity, the positive electrode current collecting terminal member and the negative electrode current collecting terminal member may be provided on opposite surfaces as shown in (c), or as shown in (e). May be provided on the same surface as described above.

In the present invention, the negative electrode current collecting terminal member or the positive electrode current collecting terminal member has a shape and function as a sealing lid, and these current collecting terminal members are battery case cans. It is preferable to be joined to the opening edge of the airtight member in a hermetically sealed manner with a strength that can be broken by a predetermined internal pressure set in advance. This facilitates attachment of the current collecting terminal member to the opening edge of the battery case, and simplifies the manufacturing process and reduces the manufacturing cost by reducing the number of parts.

FIG. 2 is a diagram corresponding to claim 2.
(A) to (d). In the figure, the white material is an iron-based material, and the black material is an aluminum (Al) -based material. 2 (a) and 2 (b) show that the battery case (case) itself constitutes a negative electrode of an iron-based material or the like, and (a) is a tube type battery case (case).
(B) shows an example of a bottomed can type battery case (case). In the case of (a), a positive electrode current collector terminal is protruded from a sealing lid attached to one opening end via an insulating gasket, and in the case of (b), a battery case (case) is provided. It is also protruded from the inner bottom surface via an insulating gasket. In both cases (a) and (b), the negative electrode current collecting terminal and the sealing lid are integrated to form a battery case (case). It is joined to the opening edge in a sealed state.

On the other hand, FIGS. 2 (c) and 2 (d) show that the battery case (case) itself constitutes a positive electrode made of an aluminum (Al) -based material, and FIG. 2 (c) shows a pipe tube type battery case (case). (D) shows an example of a bottomed can type battery case (case). In the case of (c), the negative electrode current collector terminal is protruded from the sealing lid attached to one opening end via an insulating gasket, and in the case of (d), the battery case (case) is closed. It is also protruded from the inner bottom surface via an insulating gasket, but in both cases (c) and (d), the positive electrode current collecting terminal and the sealing lid are integrated to form a battery case (case). It is joined to the opening edge in a sealed state.

According to the present invention, an engaging shaft is provided on one of the outer surfaces of the negative-side current collecting terminal member and the positive-side current collecting terminal member, and the other is provided with the engaging shaft. It is preferable that an engagement hole portion integrally connected to the shaft portion is provided. Thereby, when connecting the single battery cells in series, by connecting the engagement shaft portion of one battery cell to the engagement hole of the other battery cell, it is possible to shorten the overall battery length, The space-saving connection structure improves the total battery mounting efficiency as a module.

As a corresponding diagram of the third aspect, the configuration shown in FIG. 3 is given as an example. That is,
FIG. 3 shows a state in which the sealed secondary batteries shown in FIG. 2 (c) are connected in series, and an engagement hole is formed in the positive electrode current collector terminal of one of the secondary batteries. The secondary batteries are connected in series by connecting the engagement shaft of the negative electrode current collecting terminal of another secondary battery to this engagement hole by means such as fitting or screwing.

According to the present invention, as described in claim 4, the battery case can is formed of an aluminum material, and has a shape and function as a sealing lid or a sealing lid joined to an opening edge thereof. Is also preferably made of an aluminum material. This results in material costs,
In addition to reducing the processing cost, the output of laser welding can be selected, and the penetration depth and the joint burst pressure can be set within a relatively small range of variation. Function becomes stable. Then, the joint between the battery case and the sealing lid joined to the opening edge of the container can reliably function as a safety valve when the internal pressure of the battery increases due to a moderately stable constant breaking strength.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 4 shows a schematic configuration of a sealed secondary battery as one embodiment of the present invention. The sealed secondary battery 10 shown in FIG.
Shows an example of a lithium ion secondary battery. This secondary battery 10 is made of an aluminum (Al) material (A3003).
A positive electrode sheet and a negative electrode sheet were wound around a core 14 as separators in a cylindrical battery case 12 having a bottom shape formed by deep drawing of (H18 material) through a separator sheet. The electrode generator 16 is housed therein, and the battery case 12
The void inside is filled with a non-aqueous organic electrolyte.

In this case, the positive electrode sheet is made of lithium cobalt oxide (LiC) on both sides of a current collector sheet made of aluminum foil or the like.
oO ₂ ), a positive electrode active material such as lithium manganate (LiMn ₂ O ₄ ), or lithium nickelate (LiNiO ₂ ) is mixed with a conductive agent such as graphite and a binder such as polyvinylidene fluoride for coating. Have been.
Further, the negative electrode sheet is coated on both surfaces of a current collector sheet made of copper (Cu) foil or the like by mixing a negative electrode active material such as carbon or graphite with a binder such as polyvinylidene fluoride. Further, as the separator sheet, a polyolefin-based resin sheet (polypropylene, polyethylene or a hybrid of both) which is porous so as to have an insulating property and an ion mobility is used.

The winding core 14 is formed by coaxially screwing an aluminum shaft 20 of the same material as the positive electrode terminal member to one end of an insulating shaft 18 made of, for example, a plastic material. A positive current collecting terminal member 22 also made of aluminum material is provided by screwing, while a negative current collecting terminal member 24 made of copper (Cu) material is also provided by screwing on the other end of the insulating shaft 18. Have been.

The positive current collecting terminal member 22 has a positive current collecting portion 26 for collecting current from the positive electrode sheet of the electrode power generator 16.
And a sealing lid 28 attached to the opening on the positive electrode side of the secondary battery 10 are integrally formed, and the positive electrode sheet of the electrode power generator 16 and the positive electrode of the positive electrode current collecting terminal member 22 are formed. The power collector 26 is electrically connected to the power collector 26 via a positive current collector lead 30.

The negative electrode current collecting terminal member 24 is provided with a negative electrode current collecting section 32 for collecting current from the negative electrode sheet of the electrode power generator 16.
A negative electrode terminal bolt 34 also made of copper (Cu) protrudes from the other end surface of the negative electrode, and the negative electrode current collector 32 and the negative electrode sheet of the electrode power generator 16 are electrically connected via a negative electrode current collector lead 36. The negative electrode terminal bolt 34 projects outward from a through hole formed by press punching on the inner bottom surface of the battery case 12, and a washer 38 and a nut 40 are provided from the outer bottom surface side of the battery case 12.
It is fixed by tightening. At this time, the battery case 12
An insulating gasket 42 is interposed on the inner peripheral edge of the through hole, and the battery case 12 and the negative electrode current collecting terminal member 24 are electrically insulated.

In connection with the fact that the negative electrode terminal bolts 34 project from the negative electrode current collecting terminal member 24, the negative electrode terminal bolts 34 are screwed to the outer surface of the positive electrode current collecting terminal member 22. A female screw hole 44 is provided. The positive electrode current collecting terminal member 22 has a hermetically sealed structure by welding the outer peripheral edge of the sealing lid 28 along the positive side opening edge of the battery case 12 by irradiating a laser beam.

In this embodiment, ethylene carbonate (EC) and diethyl carbonate (DEC) are 3: 7 as the non-aqueous organic electrolyte to be charged in the battery case 12.
A solution obtained by dissolving lithium hexafluorophosphate (LiPF ₆ ) at a volume ratio of 1 mol / l in a mixed solution is used.

In manufacturing the secondary battery 10 shown in FIG. 4, an electrode generator 16 composed of a positive electrode sheet, a negative electrode sheet, and a separator sheet is wound around a shaft core 14 composed of an insulating shaft 18 and an aluminum shaft 20. A negative current collecting terminal member 24 is screwed to the insulating shaft 18 side, and the aluminum shaft 2
A positive current collecting terminal member 22 is screwed to the 0 side. Then, a positive current collecting lead 30 is connected between the positive electrode sheet of the electrode power generating body 16 and the positive current collecting portion 26 of the positive current collecting terminal member 22 by applying ultrasonic waves, and the negative electrode sheet and the negative current collecting terminal of the electrode power generating body 16 are connected. A negative electrode current collecting lead 36 is connected between the member 24 and the negative electrode current collecting section 32 by similarly applying ultrasonic waves.

Then, the electrode power generator 16 is inserted into the battery case 12 from the negative electrode current collecting terminal member 24 side, and the negative electrode terminal bolt 34 is made to protrude from a through hole formed in the inner bottom surface of the battery case 12. It is tightened and fixed by a nut 40 via a washer 38. Then, an electrolytic solution is loaded into the battery case 12 from the opening side, and thereafter, the sealing lid 28 of the positive electrode current collecting terminal member 22 is loaded.
Is adhered to the opening edge of the battery case 12 and a laser beam is irradiated along the peripheral edge to seal the battery case 12 in a hermetically sealed manner.

According to the sealed secondary battery constructed as described above, the pressure-resistant strength of the aluminum welding portion between the positive electrode current collecting terminal member 22 and the battery case can 12 is of such a degree that it is destroyed by the rise of the internal pressure of the battery. It is about 15 to 20 kgf / cm ² . Therefore, when the battery is overcharged or short-circuited during use, the electrolyte is decomposed, gas is generated, and the internal pressure of the battery rises. The aluminum welded part cannot withstand the rise in the internal pressure of the battery and is destroyed, and the gas in the battery escapes therefrom, thereby preventing the explosion of the battery itself.

According to the secondary battery 10, the sealing structure on the positive electrode side forms a joint structure in which the opening edge of the battery case 12 and the sealing lid 28 of the positive electrode current collecting terminal member 22 are welded. Since Ni-plated steel sheets are not caulked as in the case of battery case and sealing lid, they have good airtightness as a battery, and it is unlikely that electrolyte or gas inside leaks carelessly. Be avoided. Of course, joining with an adhesive,
Alternatively, it may be formed by caulking.

According to the secondary battery 10, the battery case 1
2 has a safety valve function of preventing explosion due to an increase in battery internal pressure, so that the PTC is conventionally provided in the battery case. It is no longer necessary to provide an element or an energization cutoff mechanism, which also avoids dead space that does not contribute to battery output in the battery case, and makes the unit cell itself compact, The battery output efficiency per battery volume is also improved.

Further, in the case where the battery case 12 is constituted by a deep drawn can made of aluminum material like the secondary battery 10, the material cost and the processing cost can be reduced, and a hole is formed in the inner bottom surface of the battery case 12. If the negative current collecting terminal member 24 is configured to be pierced to protrude, the operation of connecting the negative current collecting lead 36 to the negative electrode sheet of the electrode power generator 16 and the negative current collecting portion 32 of the negative current collecting terminal member 24 is performed by the battery. Since the connection can be performed outside, the connection work of the negative electrode current collecting lead 36 can be reliably performed, and the workability is good.

FIG. 5 shows a schematic configuration of a sealed secondary battery according to a second embodiment of the present invention. The secondary battery 50 shown in FIG. 5 does not use the core 14 used in the first embodiment shown in FIG. In the second embodiment, both the current collector terminal members 22a, 24a on the positive electrode side and the negative electrode side are used without using such a winding core 14.
A short-axis-shaped core portions 52 and 54 are integrally provided on the opposing surface side of a, and a positive electrode sheet and a negative electrode sheet are surrounded therearound while maintaining a predetermined interval between the two core portions 52 and 54. The electrode generator 16 is wound around a separator sheet.

Also in the case of the secondary battery 50, the electrode power generator 16 is connected to the battery case 1 from the negative current collecting terminal member 24a side.
2, the negative electrode terminal bolt 34 is made to protrude from the inner bottom surface of the battery case 12, and is tightened and fixed with the washer 38 and the nut 40. Then, the electrolytic solution is loaded into the battery case 12 from the opening side. Then, the sealing lid part 2 of the positive electrode current collecting terminal member 22a
8 is attached to the opening edge of the battery case 12, and the battery case 12 is hermetically sealed by irradiating a laser beam along the peripheral edge. Secondary battery 5 according to the second embodiment
0, the positive current collecting terminal member 2
The joint between the battery case 2a and the battery case 12 is destroyed, and the explosion of the battery itself is avoided.

In the case of the secondary battery 50 according to the second embodiment, similarly to the secondary battery 10 of the first embodiment,
Since the sealing structure on the positive electrode side has a joint structure in which the opening edge of the battery case 12 and the sealing lid 28 of the positive electrode current collecting terminal member 22a are welded, the airtightness of the battery is good, and the internal electrolyte Inadvertent leakage of gas and gas is avoided, and the joint structure also has a safety valve function of preventing explosion due to an increase in battery internal pressure. There is no occurrence, and the battery output efficiency per unit battery volume is good. Further, by forming the battery case 12 from a deep drawn can made of an aluminum material, material cost and processing cost can be reduced, and workability by connecting the negative electrode current collecting lead 36 outside the battery is improved.

Next, a description will be given of a case where the cells having the above configuration are connected in series and used. FIG. 6 shows a state where the sealed secondary batteries 10 according to the first embodiment shown in FIG. 4 are connected in series as single cells. As can be seen from the state shown in FIG. 6, the female screw hole 44 formed in the positive electrode current collecting terminal member 22 of one cell 10a is inserted into the negative electrode terminal bolt 34 of the negative electrode current collecting terminal member 24 of the other cell 10b.
Is screwed into the female screw hole 44 of the positive electrode current collecting terminal member 22 of the cell 10b, and the negative electrode current collecting terminal member 2 of another cell 10c is
Four negative electrode terminal bolts 34 are screwed. The length of the unit cell in this connected state is represented by “Lp” in the figure,
The actual length of the single cell was Lp = 190 mm.

On the other hand, FIG. 7 shows a schematic configuration of a sealed secondary battery 60 as a comparative example, and FIG. 8 shows a state in which the secondary batteries 60 of the embodiment shown in FIG. 7 are connected in series. Is shown. As described in the prior art, the secondary battery 60 shown in FIG. 7 uses a stainless steel (SUS) pipe cut into a fixed length in a battery case 62, and the both ends thereof are also made of stainless steel. The sealing lids 64a and 64b are applied by laser beam irradiation welding.

That is, in the sealed secondary battery 60 shown in FIG. 7, the same components and structures as those of the first embodiment of the present invention shown in FIG. Then, the shaft core 1 composed of the insulating shaft 18 and the aluminum shaft 20
4, an electrode generator 16 composed of a positive electrode sheet, a negative electrode sheet, and a separator sheet is formed by winding, and a negative electrode current collector terminal member having the same configuration as the negative electrode current collector terminal member 24 shown in FIG. And a positive current collecting terminal member 66 having a different configuration from the positive current collecting terminal member 22 shown in FIG. 4 is screwed to the aluminum shaft 20 side. In other words, the positive electrode current collector terminal member 66 has only the positive electrode current collector 26 and the sealing lid 28.
Does not have a configuration corresponding to. A terminal bolt (positive terminal bolt) 68 is provided on the end face of the positive electrode current collector 26, instead of the female screw hole 44, similarly to the negative electrode current collector terminal member 24.

Then, a positive electrode current collecting lead 30 is connected between the positive electrode sheet of the electrode power generator 16 and the positive electrode current collector 26 of the positive electrode current collecting terminal member 22 by applying ultrasonic waves, and the negative electrode sheet of the electrode power generator 16 and the negative electrode are connected. The negative electrode current collecting lead 32 is also connected between the negative electrode current collecting portion 32 of the current collecting terminal member 24 by applying ultrasonic waves, and then the electrode power generator 16 is connected to the negative electrode current collecting terminal member 2.
4, the negative electrode terminal bolt 34 is inserted through the gasket 42 into the sealing lid 64 on the negative electrode side,
The nut 40 is fastened and fixed via the washer 38, and the positive terminal bolt 68 of the positive current collecting terminal member 22 is also inserted through the gasket 42 into the sealing cover 64a on the positive electrode side. Tighten and fix. Then, the sealing lids 64a, 64b on the positive electrode side and the negative electrode side
Are respectively attached to both opening edges of the battery case can 62, and a laser beam is applied along the peripheral edge to seal the battery case 62 in a hermetically sealed manner.

In the secondary battery 60 of this comparative example, a gas vent hole 70 is provided in the sealing lid 64 on the positive electrode side, and an explosion-proof seal 72 made of nickel (Ni) foil is joined to the gas vent hole 70 by laser welding. When the internal pressure of the battery rises, the explosion-proof seal 72 is ruptured, and the internal gas is released to the outside air to prevent the battery from exploding.

In the series state of the secondary battery shown in FIG. 8, the positive terminal bolt 68 of the positive current collecting terminal member 66 of one cell 60a and the negative terminal of the negative current collecting terminal member 24 of the other cell 60b are connected. Connector 7 with terminal bolt 34
4, the positive electrode current collecting terminal member 6 of the unit cell 60b.
The positive terminal bolt 68 of Ob and the negative terminal bolt 34 of the negative current collecting terminal member 24 of another cell 60c are also connected by a connecting connector 74. The length of the unit cell in the connected state is represented by “Lc” in the figure, and the actual unit cell length was Lc = 205 mm.

Table 1 below shows a comparison between the battery configurations of the first and second embodiments of the present invention (Examples 1 and 2) and the comparative example. As can be seen from the numerical values shown in Table 1, the bottomed aluminum cans of Examples 1 and 2 have a thickness of 0.8 mm ^t, and the stainless steel pipe of the comparative example has a thickness of 0.3 mm ^t . In Examples 1 and 2, only one aluminum sealing lid was used on the positive electrode side (the plate thickness of the lid was 1 mm ^t ), whereas in the comparative example, the stainless steel sealing lids were the positive electrode side and the negative electrode side. 2
Used. Therefore, the welding of the sealed can was performed according to Example 1.
And 2, only one location is provided, whereas the comparative example is performed at two locations on the positive electrode side and the negative electrode side.

In the case of Examples 1 and 2, the safety valve is destroyed when a predetermined internal pressure of the battery is applied to the aluminum welded portion. In the case of the comparative example, the safety valve is provided with a sealing lid on the positive electrode side. Explosion-proof seal 7 attached to vent hole 70
2 is to be destroyed. Another difference in the configuration is that, in Examples 1 and 2, the battery case can has a positive polarity, whereas the comparative example has no polarity.
Regarding this point, the polarity of the battery case can be “negative electrode” in a conventionally well-known one, for example, a small-sized 18650 battery.

The number of parts to be assembled is also shown in Table 1. The number and necessity of gaskets, washers (washers), nuts, connecting connectors and the like in addition to the number of sealing lids are compared with those in Examples 1 and 2. Unlike the example, the comparative example has a larger number of parts. As can be seen from a comparison between FIG. 6 and FIG. 8 showing a state in which the cells are connected in series, the length per cell unit when the secondary cells are connected in series is shown in Examples 1 and 2. In the case of, Lp = 190 mm, whereas in the case of the comparative example, Lc = 205 mm.
In the case of (1), the overall length is shortened by providing a female screw hole 44 in the positive current collecting terminal member 22 and screwing the negative terminal bolt 34 of the negative current collecting terminal member 24 into the female screw hole 44. Has been made.

[0046]

[Table 1]

FIG. 9 shows the case where the sealing lid 28 of the positive electrode current collecting terminal member 22 is laser-welded to the opening edge of the battery case 12 in the secondary batteries of the first and second embodiments of the present invention. Shows the relationship between the pulse YAG laser output (W) and the weld penetration depth (mm). As shown in FIG. 9, the penetration depth (mm) of the welded portion gradually increases as the pulse YAG laser output (W) increases.

FIG. 10 shows the relationship between the pulse YAG laser output (W) and the welding part burst pressure (kgf / cm ² ). The breaking pressure at which the pressure release part of the battery case can be destroyed by the rise in battery internal pressure during battery use is 15 ~
It is said to be about 20 kgf / cm ² . Therefore, for that purpose, the pulse YAG laser output is set to 200-35.
With a range of 0 W, preferably 250-300 W, the weld will operate an ideal pressure relief function.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, an example of a lithium-ion secondary battery has been described. However, the present invention is not limited thereto, and may be applied to various alkaline secondary batteries, or nickel-based secondary batteries such as nickel-metal hydride batteries. .

In the first and second embodiments, the structure in which the positive current collecting terminal members 22 and 22a are joined to the battery case 12 is shown.
24a may be joined to the battery case 12. In this case, copper (Cu) material or iron-based material, N
The battery case 12 is made of a copper or iron-based material, a Ni-based material pipe or a deep drawn can in accordance with the i-type negative electrode current collecting terminal members 24, 24a.
Will be attached to the battery case 12 via an insulating gasket.

Further, in the first and second embodiments, as shown schematically in FIG. 11A, a current collecting terminal member is provided at the opening edge of the bottomed cylindrical battery case 12. The sealing lid 28 also serving as a laser is welded.
As shown in the schematic configuration of the embodiment compared to (b), the sealing lids 28, 28a may be joined to both open end edges of the hollow pipe-shaped battery case 12a by laser welding. In this case, of course, either one of the sealing lids has both the positive current collecting terminal member and the negative current collecting terminal member, and the other sealing lid has the opposite current collecting terminal member insulated by the insulating gasket. It will be inserted in the state.

As the external appearance of the sealed secondary battery of the present invention, as shown in FIG. 12, in addition to the cylindrical type, various types such as a rectangular (square), a track type, an elliptical type and the like can be mentioned. It is clear from the gist of the present invention that the present invention is not limited to the cylindrical type.

[0053]

According to the sealed secondary battery according to the first aspect of the present invention, the sealing lid that is hermetically joined to the opening edge of the battery case can rises to a predetermined battery internal pressure during use of the battery. When this occurs, the battery is broken at the joint and the internal gas is released, thereby avoiding a battery explosion trouble. Therefore, it is not necessary to provide a safety valve mechanism specially in order to avoid the explosion trouble of the battery unlike the conventional case, and the P
Since there is no need to provide a safety valve device such as a TC element,
A dead space that does not contribute to the battery output in the battery case can be avoided, and if the battery output per battery unit can be improved or the same battery output can be obtained, the size of the battery can be reduced.

If the positive electrode current collecting terminal member or the negative electrode current collecting terminal member has a shape and a function as a sealing lid, a gasket or a current collecting terminal member for an insulating seal can be formed. By reducing the number of components such as nuts for fastening and fixing to the inner bottom surface of the battery case and the sealing lid, simplification of the manufacturing process and reduction in manufacturing cost can be expected.

Further, the batteries can be connected in series by connecting an engagement shaft protruding from one side of the battery and an engagement hole formed on the other side of the battery. In addition to being able to increase the battery output, it is possible to shorten the overall length when batteries are connected in series, and to improve the battery volume mounting efficiency as a module with a space-saving connection structure. .

Further, by forming the battery case from an aluminum material, the material cost can be reduced as compared with the conventional case using stainless steel. By using an aluminum material for the sealing lid to be joined or the current-collecting terminal member having the shape and function as the sealing lid, in the case of joining by laser welding, etc., the variation in the penetration depth and the joint breaking pressure is reduced. As a result, the function as a safety valve when the internal pressure of the battery rises becomes stable, and the heat generated inside the battery while the battery is in use can be effectively dissipated to the outside. Burst is avoided as much as possible, and a battery with higher safety can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an external configuration of a sealed secondary battery according to claim 1 of the present invention.

FIG. 2 is a diagram showing an example of a sectional configuration of a sealed secondary battery according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a connection configuration example of a sealed secondary battery according to claim 3 of the present invention.

FIG. 4 is a schematic configuration diagram of a sealed secondary battery according to the first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a sealed secondary battery according to a second embodiment of the present invention.

6 is a diagram showing a state in which the sealed secondary batteries shown in FIG. 4 are connected in series.

FIG. 7 is a schematic configuration diagram of a sealed secondary battery as a comparative example.

8 is a diagram showing a state in which the sealed secondary batteries shown in FIG. 7 are connected in series.

FIG. 9 shows a pulse YA when the aluminum sealing lid is laser-welded to the opening edge of the aluminum battery case in the present invention.
It is a figure showing relation between G laser output (W) and penetration depth (mm) of a welding part.

10 is a diagram related to FIG. 9 and showing a relationship between a pulse YAG laser output (W) and a welding part burst pressure (kgf / cm ² ).

FIG. 11 is a cross-sectional view of a joint structure of a sealed secondary battery of the present invention,
(A) shows an example in which the upper lid is laser-welded to the bottomed can, and (b) shows an example in which the upper and lower lids are laser-welded to the hollow pipe.

FIG. 12 is a diagram illustrating various external appearances of the sealed secondary battery of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sealed secondary battery 10a, 10b, 10c Single cell 12 Battery case 16 Electrode generator 22, 22a Positive current collecting terminal member 24, 24a Negative current collecting terminal member 28 Sealing lid part 34 Negative terminal bolt 44 Female screw hole 50 Sealed two Secondary battery

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 10/04 H01M 10/04 W (72) Inventor Goro Watanabe 41, Nagakute-cho, Nagakute-cho, Aichi-gun, Aichi Prefecture 41 No. 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Akira Nakano 41, Nagakute-cho, Aichi-gun, Aichi-gun, Oku-cho, Yokomichi No. 1 Inside Toyota Central Research Laboratory Co., Ltd. (72) Inventor Miaki Ebine No. 41, 41, Yokomichi, Nagakute-machi, Yokomichi, Toyoda Central Research Laboratory Co., Ltd. (72) Inventor Toshihiko Inoue 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Tomoyasu Takeuchi Showa, Kariya City, Aichi Prefecture 1-cho, Town 1 F-term in DENSO Corporation (reference) 5H011 AA04 AA13 CC06 DD06 DD12 FF03 KK00 5H012 AA01 BB02 DD17 FF01 JJ02 5H022 AA09 AA18 AA19 CC03 CC08 CC12 CC19 EE04 KK01 5H028 AA01 AA05 BB01 BB04 BB05 BB07 CC05 CC07 CC12 EE01 HH00 5H029 AJ12 AJ14 AK03 AL06 AL07 AM03 AM05 AM07 BJ02 BJ06 BJ14 DJ03 DJ05 DJ05 DJ05 DJ05 DJ05 DJ05

Claims (4)

[Claims] 1. A negative electrode current collecting terminal in which an electrode power generator in which a positive electrode sheet and a negative electrode sheet are wound via a separator sheet is mounted in a battery case, and is electrically connected to the negative electrode sheet of the electrode power generator. The member, and at least one of the positive electrode current collecting terminal members electrically connected to the positive electrode sheet are protruded outwardly from the closed end face or the sealing lid of the battery case can, and the sealing cover is formed of the battery case can. A sealed secondary battery, wherein the sealed secondary battery is joined to an opening edge in a sealed manner and with a strength that is broken by a predetermined internal pressure set in advance. 2. The negative electrode current collecting terminal member or the positive electrode current collecting terminal member has a shape and a function as the sealing lid, and the current collecting terminal member is hermetically sealed at an opening edge of the battery case can.
The sealed secondary battery according to claim 1, wherein the sealed secondary battery is joined with a strength that is broken at a predetermined internal pressure set in advance. 3. An engaging shaft portion is provided on an outer surface of one of the negative electrode current collecting terminal member and the positive electrode current collecting terminal member, and the other is integrally connected to the engaging shaft portion. The sealed secondary battery according to claim 1, wherein an engagement hole is provided. 4. The battery case can is formed of an aluminum material, and the sealing lid or a current collecting terminal member having a shape and function as a sealing lid joined to an opening edge of the battery case can is also formed of an aluminum material. The sealed secondary battery according to claim 1, 2 or 3, wherein