JP5456952B2 - Battery with safety valve - Google Patents

Description

  The present invention relates to a battery provided with a safety valve in a battery container.

  As power sources for various portable electronic devices, primary batteries such as dry batteries and lithium batteries, secondary batteries such as lead-acid batteries, nickel-cadmium (Ni-Cd) batteries, and nickel-hydrogen (Ni-MH) batteries are used depending on the application. Many are used.

  Along with the reduction in size and weight of electronic devices, in recent years, batteries with high energy density have been demanded. As a high energy density battery, a non-aqueous electrolyte containing a composite metal oxide such as lithium cobaltate as a positive electrode active material, a carbon material such as graphite as a negative electrode active material, and an organic solvent and an electrolyte salt as an electrolyte is used. Water electrolyte secondary batteries are already on the market.

  Recently, with the increase in power consumption of electronic devices, a non-aqueous electrolyte secondary battery having a large capacity of 5 Ah to several hundreds Ah has been demanded. However, batteries with high energy density and large capacity tend to be in danger of rupture, etc. if misused. Becomes higher.

  Conventional non-aqueous electrolyte secondary batteries have been devised to prevent the battery from falling into a dangerous state by using various safety devices regardless of the capacity. A typical safety device is a safety valve. When the internal pressure of the battery rises for some reason, the safety valve releases the internal pressure when the pressure exceeds a certain level so that the battery does not rupture.

  Battery safety valves have been used in various batteries other than non-aqueous electrolyte secondary batteries. In particular, in the case of a large-capacity battery, a battery internal pressure release mechanism is required, and various safety valves have been devised.

  As a conventional safety valve, the one using a rubber reversible valve disclosed in Patent Document 1, the one using a bursting valve using a metal foil disclosed in Patent Document 2 and Patent Document 3, disclosed in Patent Document 4 Many proposals have been made to use a thin part of the battery case formed with a groove as a safety valve.

  When these safety valves are employed in high-capacity non-aqueous electrolyte secondary batteries with high energy density, it has been found that the greater the cross-sectional area of the safety valve, the lower the operating pressure and the safer the behavior during valve operation.

Further, in Patent Document 5, in a battery provided with a safety valve that closes an opening provided in the battery container, the battery container protects the safety valve from an unexpected external force and ensures that the safety valve operates when a battery abnormality occurs. The technology provided with the safety valve protection member which covers an opening part outside is disclosed.
Japanese Patent Laid-Open No. 07-037566 Japanese Patent Application Laid-Open No. 07-211305 Japanese Utility Model Publication No. 05-084025 JP 2000-149901 A JP 2003-346762 A

In the case of a large-capacity battery, the area of the safety valve needs to be about 50 mm ² (about 8 mmφ in diameter) or more in order to ensure safety. If the metal foil described in Patent Document 2 or Patent Document 3 is used in a battery with a large safety valve area, the metal foil is damaged by fingertips or protrusions, and the operating pressure of the safety valve fluctuates. was there. In addition, when a hole is formed in the metal foil, the function as a safety valve is lost, moisture enters from the outside and the battery performance deteriorates, and the electrolyte leaks to the outside and adversely affects peripheral devices.

  Note that the rubber reversible valve described in Patent Document 1 has a problem that moisture enters from the outside through the rubber valve body and a problem that it easily deteriorates by reacting with the electrolytic solution. It could not be used.

  As described above, in a large-capacity battery, when the area of the safety valve is increased, there is a drawback that the long-term reliability of the battery is lowered in exchange for an improvement in safety.

  In order to remedy such drawbacks, as described in Patent Document 4, a thin-walled portion is formed in a metal case by machining to form a rupture valve, and when the internal pressure rises, a rift occurs in the case to release the pressure. A battery was proposed. However, this battery has a problem that the machining cost is high, and metal bursting is used, so that the operating pressure of the burst valve is high and the operating pressure varies greatly.

  Furthermore, in the battery provided with the safety valve protection member described in Patent Document 5, a safety valve in which an aluminum or nickel foil having a thickness of about 75 μm is joined to the wall surface of a metal battery container by laser welding is used. There was a problem that welding conditions were required and the manufacturing process was complicated. In addition, the risk of damaging the metal foil from the outside of the battery with fingertips or protrusions could not be avoided.

  The purpose of the present invention is to prevent the safety valve from being damaged by the force from the outside of the battery, to prevent the ingress of moisture from the outside of the battery and the evaporation of the electrolyte to the outside. An object of the present invention is to provide a large-capacity battery that operates and can release the internal pressure of the battery, has a simple manufacturing method, and is excellent in safety.

The invention of claim 1 is a battery comprising a battery container and a safety valve provided in the battery container , wherein the safety valve releases the internal pressure of the battery when the internal pressure of the battery exceeds a certain level. The battery container is provided with an opening, and a sealing member that closes the opening is covered with a sheet, and the sheet includes the whole sealing member and a boundary between the opening and the sealing member. DOO is bonded to the battery container in a state of Tsu covering from the battery outward, said to at least one of the sealing member or the opening, a flange portion or guide portion is provided, said sealing member, It is fitted into the opening from the outside of the battery in a state of being locked by a flange portion or a guide portion .

  According to the first aspect of the present invention, the opening provided in the battery container is closed by the sealing member fitted into the opening from the outside of the battery, and includes a sheet that covers the entire sealing member from the outside of the battery. In addition, moisture intrusion from the outside of the battery and leakage or evaporation of the electrolyte solution inside the battery can be reliably prevented, and a highly reliable battery can be obtained.

  Further, since the sealing member is only fitted into the opening provided in the battery container from the outside of the battery, it is not necessary to laser-weld the sealing member to the battery container, and the manufacturing method is simplified.

  Furthermore, since the sealing member is fitted in the opening provided in the battery container, the mechanical strength from the outside is high, and when a force is applied to the sheet from the outside, the sheet is pressed against the sealing member, and the laminated sheet is damaged. It is possible to reliably prevent the occurrence of cracks and holes and ensure the safety of the battery at a high level.

  In an abnormal state (when the internal pressure of the battery increases), the joint between the battery container and the sheet along the periphery of the sealing member is peeled off, and a large-area opening is created in the battery to smoothly release the internal pressure of the battery. Battery safety can be ensured.

  The present invention relates to a battery safety valve for a battery including a battery container, a power generation element housed therein, and an electrolyte, the battery container having an opening, a sealing member for closing the opening, and at least the battery container. A sheet is provided that covers the boundary between the provided opening and the sealing member from the outside of the battery. The sealing member is fitted into the opening from the outside of the battery. The sheet is welded to the battery container.

FIG. 1 shows an example of the appearance of the battery according to the present invention. In FIG. 1, 1 is a battery container, 2 is a battery lid which is a part of the battery container, 3 is a sealing member, 4 is a sheet, P is a positive electrode terminal, and N is a negative electrode terminal. In the example of FIG. 1, an opening (not shown) is provided on the side surface of the rectangular battery container 1, and the sealing member 3 is fitted into the opening from the outside of the battery, and the sheet 4 is formed of the opening and the sealing member. 3 is covered from the outside of the battery. The sheet 4 is thermally welded to the battery container 1. The positive electrode terminal P and the negative electrode terminal N are insulated by a hermetic seal and attached to the battery lid.

  In addition, the shape of the battery of this invention can be made into a cylindrical shape or a long cylindrical shape other than the square shape shown in FIG.

  As the shape of the opening provided in the battery container, any shape such as a circle, a long cylindrical shape, an ellipse, a quadrangle, and a polygon can be used. However, when considering that it is easy to adjust the opening area to an arbitrary size, and that low-cost press workability is used for manufacturing a sealing member that fits into the opening, a round portion, an oval shape, or an R portion at a corner portion It is preferable to use a relatively simple shape such as a quadrangle having

  And the position which installs an opening part is suitable for the side of a battery, but you may install in a battery bottom or a battery cover. Further, it is preferable to install the opening in consideration of the shape of the power generation element and the direction of the power generation element housed in the battery container. For example, when the shape of the power generation element is a winding type, if the battery malfunctions and gas is generated from the power generation element, the gas is released in a direction parallel to the winding axis of the power generation element. It is preferable to provide an opening in the direction. A plurality of openings may be installed as necessary.

  When the safety valve is activated, the gas generated inside the battery is released to the outside of the battery through this opening, and the internal pressure of the battery is released.

  The shape of the sealing member is a shape that matches the shape of the opening, and is fitted into the opening from the outside of the battery. The function of the sealing member is to protect the sheet so that the sheet will not be pierced or torn when an external force is applied to the sheet, and does not essentially prevent leakage of the electrolyte. . That is, since it is not necessary to seal the opening with the sealing member, it is sufficient that the sealing member is fitted in the opening, and it is not necessary to weld the battery container. Therefore, in some cases, the sealing member may have a shape with a hole.

  As the material of the sealing member, for example, aluminum, iron, nickel, or stainless steel can be used. Considering the case corrosion and mechanical strength due to the potential difference of the metal, it is preferable to use the same material as the battery case. Further, not limited to metals, resins such as polyethylene (PE), polypropylene, and (PP) polyphenylene sulfide (PPS) may be used. As the sealing member, it is necessary to select a material that does not chemically react even when it comes into contact with the electrolytic solution.

  The cross-sectional shape of the sealing member may be selected so that it can be easily fitted into the opening provided in the battery container. A flange portion may be provided around the sealing member, or the flange portion may be partially provided or a flat plate. However, in the case of using a flat plate, it is necessary to prepare a guide for receiving the flat plate on the battery container side, so that a sealing member having a flange portion is superior in terms of cost.

  In addition, when providing a flange part in a sealing member, or when producing a guide in the battery container side, the mechanical strength which bears the force from the outside is required. For that purpose, it is preferable to have a flange or a guide around 10% or more of the area around the sealing member.

  The sheet that covers the sealing member from the outside of the battery functions as a safety valve and is joined to the battery container. And when the internal pressure of a battery rises and reaches a fixed value, this junction part peels and the internal pressure of a battery is open | released. Moreover, this sheet has a function of preventing water from entering the battery from the outside when the battery is in a normal state.

  As the material of the sheet, a metal thin film, a synthetic resin film, a combination of a metal thin film and a synthetic resin film, or the like can be used. However, since the inside of the sheet may come into contact with the electrolytic solution, it is necessary to use a material that does not react with the electrolytic solution.

  The pressure at which the bonded portion of the sheet peels can be adjusted by combining the bonding conditions, the area of the bonded portion, and the like.

  When a metal thin film is used as the material for the sheet, a method such as laser welding or ultrasonic welding can be used for joining the sheet and the battery container. When a synthetic resin film is used as the material for the sheet, For joining the sheet and the battery container, methods such as thermal welding and adhesion can be used. However, when a synthetic resin film is used alone, it is necessary to select a material that does not allow water to pass through and does not react with the electrolytic solution.

  Therefore, as the sheet, a laminated sheet comprising at least two layers of a heat-weldable resin film layer and a metal foil layer, or at least three layers of a heat-weldable resin film layer, a metal foil layer, and a rigid resin film layer. It is preferable to use a layer laminated sheet.

  For example, when a three-layer laminate of a heat-weldable resin film layer, a metal foil layer, and a rigid resin film layer is used, the order of lamination is as follows: heat-fusible resin film layer / metal foil layer / rigid resin film A layer is preferred.

  When these two-layer laminated sheets or three-layer laminated sheets are used, the battery container and the heat-weldable resin film layer can be joined by heat welding, and the pressure at which the joint portion of the sheet peels is the heat-weldable resin film. It can be adjusted by combining the material of the layer, the area of the heat welded portion, the heat welding conditions such as temperature and time, and the like. Further, the laminated sheet has an advantage that the cost is low as compared with the metal thin film.

  For the heat-fusible resin film layer of the sheet, for example, polyethylene, ionomer, ethylene vinyl acetate (EVA), or the like can be used. Moreover, as a metal foil layer, the material which does not let water pass, such as aluminum foil and nickel foil, can be used, for example.

  The rigid resin layer is a layer for preventing the metal foil layer from being scratched by an external force such as a scratch from the outside of the battery. Therefore, as the material of the resin layer having rigidity, for example, polyethylene terephthalate (PET), nylon, or the like can be used.

  As an example of a specific material of the three-layer laminated sheet used in the present invention, there is a three-layer laminated film made of PE / aluminum foil / PET.

  The shape of the sheet may be a simple sheet shape or may be formed into a convex shape in a butter cup shape. When a sealing member has a flange part and protrudes from the surface of a battery container, it is preferable to set it as a buttercup shape excellent in sealing performance.

  Moreover, when covering a sealing member with a sheet | seat, you may cover the whole sealing member, for example, when an opening part and a sealing member are circular, you may cover the boundary part of a battery container and a sealing member with a donut-shaped film. Good.

  Next, a cross section of an example of the relationship between the opening provided in the battery container, the sealing member, and the sheet according to the present invention will be described with reference to FIGS. In FIGS. 2 to 4, the upper part of the figure is the outside of the battery and the lower part is the inside of the battery. 2 to 4, symbols 1 to 4 are the same as those in FIG. 1, symbol 5 is an opening provided in the battery container, 6 is a guide provided in the opening of the battery container, and 7 is a battery container and a sheet. 8 is a hole in the center of the sheet, and 9 is a flange portion of the sealing member. 2 to 4, the opening, the sealing member, and the sheet are all circular, but the same fitting method can be used for shapes other than circular.

  The joint 7 is a welded part by laser welding or the like when the material of the sheet is a metal thin film, and a welded part or adhesive by thermal welding is used when the material of the battery container side of the sheet is a heat-fusible resin. It is the adhesion part used.

FIG. 2A shows a case where a flat sealing member 3 is fitted into a guide 6 provided in an opening 5, the sealing member 3 is covered with a sheet 4 from the outside of the battery, and joined around a periphery 7 of the sheet 4. 2 (b) shows an example of a case where the thickness of the flat plate-like sealing member 3 is equal to the thickness of the batteries container. In FIG. 2C, the opening 5 has no guide, but the sealing member 3 is provided with a guide and is fitted into the opening 5. The sealing member 3 protrudes outside the battery. In FIG. 2D, the flat sealing member 3 is fitted into a guide 6 provided in the opening 5, and the sealing member 3 projects outside the battery.

  FIG. 3A and FIG. 3B show an example in which a donut-shaped member having a hole 8 provided in the center portion of the sheet 4 is used. In the case of such a shape, depending on the combination of the material of the sheet 4 and the sealing member 3, the close contact between the inner peripheral portion of the donut-shaped sheet 4 and the sealing member 3 becomes insufficient. In that case, the inner peripheral portion of the doughnut-shaped sheet 4 and the sealing member 3 are joined by a method such as thermal welding or adhesion, thereby preventing leakage of the electrolyte solution or intrusion of moisture from the outside of the battery. it can.

In FIG. 4, a flange 9 is provided around the sealing member 3. FIG. 4 (a), in which fitting the flange portion 9 of the sealing member 3 to the guide 6 provided in the opening, an example of a case where the thickness of the sealing member 3 is equal to the thickness of the batteries container. FIG. 4 (b) shows an example in which a donut shape having a hole 8 in the center of the sheet 4 is used. In FIG. 4C, there is no guide in the opening 5, but the flange 9 around the sealing member 3 is fitted into the opening 5, and the flange 9 of the sealing member 3 protrudes outside the battery. .

  2C, FIG. 2D, and FIG. 4C, when the sealing member 3 has a shape protruding to the outside of the battery, the sheet has a circular shape when the opening is circular. As shown in FIG. 5 (a), and when the opening is rectangular, if the butter cup shape is used as shown in FIG. 5 (b), the battery container and the sheet can be easily joined. .

  The present invention can be used for a lithium primary battery using an organic electrolyte, a Ni-Cd or Ni-MH battery using an alkaline aqueous solution, but is applied to a non-aqueous electrolyte secondary battery such as a lithium ion battery. Is the best. The reason is that the lithium ion battery has a high energy density and it is necessary to ensure a large safety valve area.

In particular, it is suitable for batteries that require a capacity of 5 Ah or more and a sectional area of the safety valve of 50 mm ² (about 8 mmφ in diameter) or more. When the capacity exceeds 10 Ah and the cross-sectional area is 100 mm ² (about 10 mmφ in the case of the caliber), the possibility of damaging the safety valve with the fingertip is dramatically increased, which is optimal.

  Furthermore, in the case of a non-aqueous electrolyte secondary battery, high moisture-tightness is required because performance deteriorates when moisture enters the battery. By applying the present invention to a large-capacity non-aqueous electrolyte secondary battery, it is possible to guarantee a high level of safety during misuse, high mechanical strength from the outside, and moisture intrusion into the battery. It is possible to provide a highly reliable battery that does not leak or evaporate.

  Hereinafter, an embodiment using a nonaqueous electrolyte secondary battery as a battery will be described with reference to the drawings.

[Example 1 and Comparative Examples 1 to 3]
[Example 1]
The non-aqueous electrolyte secondary battery of the present invention was manufactured as follows. First, a rectangular battery case was manufactured as follows. Aluminum was molded to produce a rectangular battery container 1 and a battery lid 2 having a thickness of 1 mm. The obtained rectangular battery container had an outer diameter of 130 mm in width, 208 mm in height, and 50 mm in thickness.

  The external appearance of the nonaqueous electrolyte secondary battery of Example 1 is the same as that shown in FIG. As shown in FIG. 1, a circular opening having a diameter of 30 mm was provided on the side surface of the battery container 1, and an aluminum sealing member 3 having a flange portion in the opening was fitted from the outside of the battery. Separately, a circular three-layer laminated sheet 4 having a total thickness of 0.1 mm and a diameter of 40 mm made of PE / aluminum foil / PET is prepared, and this sheet 4 is adhered to the opening of the battery container and the sealing member 3. The periphery of the sheet 4 was heat-sealed to the battery container. Thereby, the clearance gap between the opening part of a battery container and a sealing member is sealed completely.

  In addition, since the sealing member 3 is inserted in the opening part provided in the side surface of the battery container 1, the opening part is not illustrated in FIG.

  In this rectangular nonaqueous electrolyte secondary battery, a positive electrode formed by applying a positive electrode mixture to an aluminum current collector and a negative electrode formed by applying a negative electrode mixture to a copper current collector were wound through a separator. An ellipse wound electrode group and a non-aqueous electrolyte are housed in a battery container.

The positive electrode plate is a positive electrode in which 86% by mass of lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, 8% by mass of polyvinylidene fluoride (binder), and 6% by mass of acetylene black (conductive agent) are mixed. N-methyl-2-pyrrolidone (NMP) was added to the compound material to prepare a paste, which was then applied to both sides of an aluminum foil current collector with a thickness of 20 μm and dried. The length is about 10 m.

  The negative electrode plate was prepared in a paste form by adding 90% by mass of non-graphitizable carbon, which is a negative electrode active material, and 10% by mass of polyvinylidene fluoride (binder) to N-methylpyrrolidone, and this was then formed into a 10 μm thick It is manufactured by applying and drying on both sides of a copper foil current collector, and has a width of 120 mm and a length of about 10 m.

A polyethylene microporous membrane was used for the separator. As the non-aqueous electrolyte, a solution in which 1 mol / L of LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate (EC): dimethyl carbonate (DMC): ethyl methyl carbonate (EMC) = 25: 35: 40 (volume ratio) was used. .

  Thus, the square nonaqueous electrolyte secondary battery (A) having a nominal capacity of 100 Ah of Example 1 was manufactured.

[Comparative Example 1]
Using the same battery container as in Example 1, cutting is performed on the side surface of the battery container from the outside of the battery, and a circular part with a diameter of 30 mm and a thin part with a thickness of 200 μm that is not penetrated is provided as in Example 1. The three-layer laminated sheet was not used. A rectangular nonaqueous electrolyte secondary battery (B) of Comparative Example 1 was produced in the same manner as in Example 1 except for the method of sealing the opening.

  The cross-sectional structure of the opening of Comparative Example 1 is shown in FIG. In FIG. 6, symbol 10 is a thin portion. 6 to 8, as in FIGS. 2 to 4, the upper part of the figure is the outside of the battery and the lower part is the inside of the battery.

[Comparative Example 2]
Using the same battery container as that of Example 1, a circular opening having a diameter of 30 mm is provided on the side surface of the battery container, and this opening is covered with a circular aluminum thin film having a diameter of 40 mm and a thickness of 100 μm from the inside of the battery. The periphery was laser welded to a battery container, and a three-layer laminated sheet was not used. A square nonaqueous electrolyte secondary battery (C) of Comparative Example 2 was produced in the same manner as in Example 1 except for the method of sealing the opening.

  A cross-sectional structure of the opening of Comparative Example 2 is shown in FIG. In FIG. 7, symbol 11 is an aluminum thin film, and 12 is a laser weld.

[Comparative Example 3]
The same battery container as in Example 1 was used, and a circular opening having a diameter of 30 mm was provided on the side surface of the battery container. This opening was covered from the outside of the battery with a three-layer laminated sheet having the same diameter of 40 mm as used in Example 1, and the periphery of the three-layer laminated sheet was heat-sealed to the battery container. A square nonaqueous electrolyte secondary battery (D) of Comparative Example 3 was produced in the same manner as in Example 1 except for the method of sealing the opening.

  A sectional structure of the opening of Comparative Example 3 is shown in FIG. In FIG. 8, symbol 4 is a three-layer laminated sheet, and 13 is a heat welded portion.

  Twenty batteries A to D of Example 1 and Comparative Examples 1 to 3 were manufactured, respectively, and overcharged to examine the internal pressure when the safety valve was activated. The test conditions were a temperature of 25 ° C. ± 10 ° C. and continuous charging (upper limit voltage of 10 V) until the safety valve was activated at a constant current of 50A. During the test, battery voltage, temperature, current, and internal pressure were measured. The internal pressure was measured by providing a 2 mm round hole in the battery case and connecting a pressure gauge. The overcharge test results are summarized in Table 1.

From Table 1, the operating pressures of the battery (A) of Example 1 of the present invention, the battery (C) of Comparative Example 2 and the battery (D) of Comparative Example 3 are within the range of 4.5 to 6.0 kg / cm ² . On the other hand, in the battery (B) of Comparative Example 1, the valve operating pressure was high at 10.0 to 20.0 kg / cm ² and the variation was large.

  Further, in the battery (B) of Comparative Example 1, there was a danger such as a loud sound when the valve was operated and the contents were scattered, but in the battery (A) of Example 1, the sound during the valve operation was small, It was found that there was no scattering of the contents and it was extremely safe.

In addition, although the battery (B) of Comparative Example 1 was made thinner to reduce the valve operating pressure to about 7 to 10 kg / cm ² , cracks occurred in the thin part and electrolyte leakage occurred. It was easy and stable processing was difficult.

  Next, the battery (A) of Example 1, the battery (C) of Comparative Example 2, and the battery (D) of Comparative Example 3 were each newly manufactured, and the number of damaged valves in various operations was compared. As a result, in the battery (C) of Comparative Example 2 and the battery (D) of Comparative Example 3 without a sealing member, 5% of the batteries were damaged and electrolyte leakage was observed. The damage rate of battery 1 (A) was 0%.

[Examples 2 to 4]
[Example 2]
A square nonaqueous electrolyte secondary battery (F) having a nominal capacity of 100 Ah was manufactured in the same manner as in Example 1 except that a sealing member made of polypropylene having the same shape and material was used instead of the sealing member made of aluminum. .

[Example 3]
Instead of the circular three-layer laminated sheet having a diameter of 40 mm, a rectangular non-layer having a nominal capacity of 100 Ah was used in the same manner as in Example 1 except that a doughnut-shaped three-layer laminated sheet having a diameter of 40 mm and an inner diameter of 20 mm was used. A water electrolyte secondary battery (E) was produced.

[Example 4]
Instead of the circular three-layer laminated sheet having a diameter of 40 mm, a circular aluminum thin film having a diameter of 40 mm and a thickness of 100 μm was used, and the periphery of the circular aluminum thin film was laser welded to the battery container in the same manner as in Example 1, A square nonaqueous electrolyte secondary battery (G) having a nominal capacity of 100 Ah was manufactured.

  Twenty batteries E to G of Examples 2 to 4 were produced, overcharged, and the internal pressure when the safety valve was activated was examined. The test conditions were the same as in Example 1. The overcharge test results are summarized in Table 2.

From Table 2, the working pressures of the batteries (E) to (G) of Examples 2 to 4 of the present invention were all stable in the range of 4.0 to 6.0 kg / cm ² .

  As is clear from the above description, according to the nonaqueous electrolyte secondary battery of the present invention, the opening of the battery container is closed by the sealing member, so that the mechanical strength from the outside is high, and it is damaged or damaged. Can be reliably prevented from opening. Furthermore, since the gap between the opening and the sealing member is sealed with a laminated sheet provided with a heat-welding resin film, it is possible to reliably prevent moisture from entering from the outside and evaporation of the electrolyte inside the battery. .

  When an abnormality occurs (when the internal pressure of the battery increases), the laminated film easily tears along the periphery of the cover plate, and a large-area opening is formed in the battery stably at a low pressure to smoothly release the internal pressure of the battery. Therefore, the safety of the battery can be ensured.

The figure which shows an example of the external appearance of the battery of this invention. Sectional drawing which shows the example of the relationship between an opening part, a sealing member, and a sheet | seat of the battery container of this invention. Sectional drawing which shows the example of the relationship between an opening part, a sealing member, and a sheet | seat at the time of using the doughnut-shaped sheet | seat of the battery container of this invention. Sectional drawing which shows the example of the relationship between an opening part, a sealing member, and a sheet | seat at the time of providing a flange part in the sealing member of the battery container of this invention. The figure which shows the external appearance of a buttercup-shaped sheet | seat. Sectional drawing which shows the relationship between the opening part and sealing member of a comparative example. The figure which shows the cross-section of the opening part of the comparative example 2. FIG. The figure which shows the cross-section of the opening part of the comparative example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery container 2 Battery cover 3 Sealing member 4 Sheet 5 Opening part 6 Guide 7 Joint part 8 Hole of the center part of a sheet | seat 9 Flange part 10 Thin part 11 Aluminum sheet 12 Laser welding part 13 Thermal welding part P Positive electrode terminal N Negative electrode terminal

Claims (2)

In a battery comprising a battery container and a safety valve provided in the battery container ,
The safety valve is to release the internal pressure of the battery when the internal pressure of the battery reaches a certain level,
The safety valve is formed by providing an opening in the battery container and covering a sealing member that closes the opening with a sheet,
The sheet is joined to the battery container in a state in which the entire sealing member and a boundary between the opening and the sealing member are covered from the outside of the battery ,
At least one of the sealing member and the opening is provided with a flange or a guide, and the opening is locked from the outside of the battery in a state of being locked by the flange or the guide. to have been fitted, the battery. In a battery manufacturing method comprising a safety valve in a battery container,
The safety valve is to release the internal pressure of the battery when the internal pressure of the battery reaches a certain level,
The safety valve is formed by providing an opening in the battery container and covering a sealing member that closes the opening with a sheet,
The sheet is joined to the battery container in a state in which the entire sealing member and a boundary between the opening and the sealing member are covered from the outside of the battery,
To at least one of the sealing member or the opening, the flange portion or guide portion is provided, the sealing member, the flange portion or the opening from the outside of the battery in locked state by the guide portion A method of manufacturing a battery that is fitted in .

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