JP5825155B2 - Case for power storage device, power storage device, secondary battery, and moving body - Google Patents

Description

  The present invention relates to a power storage device case, a power storage device, a secondary battery, and a moving body.

  Power storage devices such as secondary batteries and capacitors are widely used as power sources because they can be recharged and can be used repeatedly. In general, a power storage device having a large capacity includes a case for accommodating an electrode body, and the electrode body is accommodated in the case. And extraction of the electric power from an electrode body is performed through the electrode terminal connected to the positive electrode and the negative electrode.

  2. Description of the Related Art Conventionally, a case of a secondary battery is configured as a separate part from a case main body and a lid, and after housing the electrode body, the lid is fixed by welding so as to cover the opening of the case main body. In addition, in order to prevent the reaction of the electrode body (power generation element) in the case excessively due to overcharging etc., gas is generated and accumulated inside the case, and the internal pressure rises abnormally, A safety valve is provided to vent the internal gas when the internal pressure exceeds the set pressure.

  Conventionally, an explosion-proof structure capable of forming a safety valve simultaneously with injection molding of a rectangular case has been proposed (see Patent Document 1). In Patent Document 1, at least one of the four outer corners of the square case made of synthetic resin is made thinner than the other outer corners to function as an explosion-proof safety valve, and the four inner corners of the square case It is disclosed that the radius of curvature of at least one inner corner of the corner is smaller than the radius of curvature of the other inner corner to function as an explosion-proof safety valve. The thin portion is formed by providing a notch at the corner. Moreover, combining each structure and forming the central part of at least one side surface of the wide side surface of the case in a slender shape along the longitudinal direction and thinner than the other portions are also disclosed.

JP 10-144279 A

  However, in Patent Document 1, a case made of a synthetic resin is assumed, and no consideration is given to a case having a structure in which a metal lid is fixed to a metal case body by welding. When the opening of the metal case body is sealed with a metal lid as a separate part, it is necessary to weld the entire periphery of the opening, which takes time and effort. In addition, when a metal lid is connected to the metal case body so that it can be opened and closed, a hinge or a part for smoothly folding the lid so that the lid accurately covers the opening of the case body Is required. However, the lid is not intended to open and close, but is intended to seal the opening of the case body, so long as the lid can be folded so that it can be accurately placed at the sealing position. Excess quality.

  The present invention has been made in view of the above-mentioned problems, and a first object is to reduce the trouble in sealing the opening of the case main body with a lid and to have a function of a safety valve. An object of the present invention is to provide a case for a power storage device that can be folded so that a lid can be accurately placed at a sealing position. A second object is to provide a power storage device and a secondary battery using the case for the power storage device, and a third object is to provide a mobile body equipped with the power storage device.

In order to achieve the first object, the invention according to claim 1 includes a case main body having at least one opening, and a lid covering the opening, and the case main body and the lid are made of metal. The lid has a part of the outer peripheral portion of the lid that is continuously formed at the opening end portion of the case body continuously at the continuous portion, and is integrally formed with the case body, and the continuous portion is folded in the folded state. The thin portion extending along the continuous portion is formed at least in the continuous portion, and the thin portion formed in the continuous portion is formed in a part of the continuous portion. .

  In this invention, a lid that covers the opening of the case main body having at least one opening is formed integrally with the case main body in a continuous portion at the opening end of the case main body in a part of the outer peripheral portion of the lid, and It is formed so that the opening can be covered in a state where the continuous portion is bent. Therefore, compared with the case where the lid is configured as a separate part, the number of welded portions when the opening is sealed with the lid is reduced, so that the labor of welding can be reduced and the airtightness and pressure resistance are improved. Moreover, since the thin part is formed in a part of continuous part, it can bend | folded so that a cover can be arrange | positioned in the position which bends a continuous part and covers an opening part. In addition, when the internal pressure of the power storage device case is abnormally increased in a state where the power storage device case is used for the power storage device, the thin-walled portion is torn and functions as a safety valve. Therefore, it is possible to reduce time and labor when the opening of the case main body is sealed with the lid, and it is possible to bend the lid having the function of the safety valve so as to be accurately arranged at the sealing position.

The invention according to claim 2 is the invention according to claim 1, wherein the continuous portion is formed with a bending portion along the continuous portion, and the bending portion has an average thickness other than that. It is a structure formed thinner, the thin portion is formed at least in a part of the bending processing portion, and the average thickness is formed thinner than the bending processing portion , the bending processing portion is , Ru groove der formed entirely of the continuous portion.

In this invention, since the bending process part is formed along a continuous part and the average thickness is formed thinner than the average thickness of the other part, the bending process part becomes easy to bend. In addition, since the thin wall portion is formed to have an average thickness thinner than that of the bending processing portion, when the internal pressure of the power storage device case becomes abnormally high with the power storage device case being used in the power storage device, the safety valve It becomes easy to function as. In addition, the bending portion can be easily formed by press working, and the bending portion can be easily bent accurately.

According to a third aspect of the present invention, in the second aspect of the present invention, the thin portion is formed at the center of the bending portion in the direction in which the continuous portion extends. In a state where the power storage device case is used in the power storage device, when the internal pressure of the power storage device acts on the thin wall portion, the thin wall portion is easily torn from the boundary portion between the thin wall portion and the bending processing portion. In the present invention, since the thin portion is formed at the center of the bending processing portion in the extending direction of the continuous portion, the thin portion is easily torn from both sides, and the thin portion is more likely to function as a safety valve.

In order to achieve the second object, according to a fourth aspect of the present invention, an electrode body is accommodated in the power storage device case according to any one of the first to third aspects and covers the opening. The power storage device in which the lid is joined to the case body by welding. In this invention, since the lid of the case for the power storage device constituting the power storage device is continuous with the case main body at the continuous portion, when assembling the power storage device, the lid covering the opening of the case main body is welded to the case main body Compared to the case where the lid is a separate part from the case body, the amount of time required for the continuous portion can be reduced. Moreover, it has the effect as a safety valve of a thin part when the case for electrical storage apparatuses of the invention as described in any one of Claims 1-3 is used.

The invention according to claim 5 is a secondary battery having the structure of the power storage device according to claim 4 . Therefore, the secondary battery of the present invention has the effects of the invention described in claim 4 .
In order to achieve the third object, an invention according to claim 6 is a mobile body on which the power storage device according to claim 4 is mounted. Here, the “moving body” includes not only vehicles but also ships and robots. In the mobile body of the present invention, the installed power storage device has the effect of the power storage device.

According to the first to third aspects of the present invention, it is possible to reduce the trouble in sealing the opening of the case body with the lid and bend the lid so that it can be accurately placed at the sealing position. It is possible to provide a case for a power storage device that can be used. According to invention of Claim 4 , the electrical storage apparatus which uses the case for electrical storage apparatuses can be provided. According to the invention described in claim 5 , it is possible to provide a secondary battery capable of obtaining the same effect as that of the invention described in claim 4 . According to the invention described in claim 6 , it is possible to provide a mobile body on which the power storage device described in claim 4 is mounted.

1 shows an embodiment, (a) is a schematic perspective view of the case, (b) is a partially enlarged view, (c) is a schematic cross-sectional view taken along line AA of (b), and (d) is an electrode body in the case. The side view of the state accommodated. The front view of a secondary battery. (A) is a schematic perspective view of the case of another embodiment, (b) is the elements on larger scale corresponding to FIG.1 (b). The schematic perspective view of the case of another embodiment. The schematic perspective view of the case of another embodiment. (A) is a schematic perspective view of the case of another embodiment, (b) is a side view which shows the process part for bending of another embodiment.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1A, a case 10 for a secondary battery as a case for a power storage device has a case main body 11 having a bottomed tubular shape (in this embodiment, a rectangular tubular shape), that is, one opening 12. A case body 11 and a lid 13 that covers the opening 12 of the case body 11 are provided. The lid 13 is formed in such a manner that a part of the outer peripheral portion of the lid 13 is formed integrally with the case main body 11 continuously at the opening end of the case main body 11 and is bent at the continuous portion 14. It is formed so that it can be covered. A pair of holes 15 through which the electrode terminals of the electrode body of the secondary battery pass is formed at the bottom of the case body 11.

  The continuous portion 14 is formed with a bending processing portion 16, and the bending processing portion 16 is formed thinner than other portions. The continuous portion 14 is formed over the entire length of one side of the rectangular opening 12, and the bending processing portion 16 is formed over the entire length of the continuous portion 14. A thin portion 17 extending along the continuous portion 14 is formed in the continuous portion 14, and the thin portion 17 is formed in a part of the continuous portion 14. The thin portion 17 has a structure in which the thickness is thinner than that of the bending processing portion 16. More specifically, as shown in FIGS. 1B and 1C, the bending portion 16 is entirely formed as a groove portion (in this embodiment, a V groove), and the thin portion 17 is formed in the bending portion 16. It is formed by forming the groove part 18 which comprises a part of the process part 16 for bending. In the direction in which the continuous portion 14 extends, the thin portion 17 is formed at the central portion in the longitudinal direction of the bending processing portion 16.

  The secondary battery case 10 is formed in a shape in which a lid 13 is continuous with a rectangular bottomed cylindrical case body 11 by drawing a metal plate, for example, an aluminum alloy plate. The bending portion 16 is formed by stamping the V-groove by pressing. When the V-groove is engraved, the groove portion 18 for forming the thin portion 17 is also engraved at the same time to form the thin portion 17.

Next, a method for assembling a secondary battery and a cell as a power storage device using the secondary battery case 10 configured as described above will be described.
When assembling a unit cell, as shown in FIG. 1 (d), an electrode body in which a positive electrode plate and a negative electrode plate are alternately stacked on a secondary battery case 10 configured as described above with a separator interposed therebetween. After the (electrode group) 20 is accommodated in the case main body 11, the lid 13 is bent by the bending processing portion 16. Then, the periphery of the lid 13 is welded to the case body 11 with the lid 13 covering the opening 12 of the case body 11. The separator which comprises the electrode body 20 is formed with the polymer electrolyte, and the unit cell using this electrode body 20 does not use electrolyte solution.

  The electrode body 20 is formed so that a positive electrode terminal 21 p and a negative electrode terminal 21 n as electrode terminals protrude from the hole 15 of the case main body 11 in a state of being accommodated in the case main body 11. Therefore, as shown in FIG. 1D, the electrode body 20 is inserted into the case body 11 from the side of the positive electrode terminal 21p and the negative electrode terminal 21n with the case body 11 facing the lid 13, and the positive electrode terminal 21p and the negative electrode After the terminal 21 n is accommodated in a state protruding from the hole 15, the lid 13 is bent at the bending processing portion 16. In this state, when a portion other than the bending processing portion 16 is welded around the lid 13 and the opening 12 is sealed with the lid 13, as shown in FIG. Is completed. The unit cell 21 is used with the side from which the positive electrode terminal 21p and the negative electrode terminal 21n protrude as the top, and the lid 13 is the bottom of the unit cell 21.

  Next, the operation of the unit cell 21 configured as described above will be described. The unit cell 21 is used alone, but is normally used in a state in which a plurality of unit cells 21 are connected in series or in parallel via a terminal connection member and an assembled battery as a power storage device. . The assembled battery is used for various purposes. For example, the assembled battery is mounted on a vehicle as a moving body and used as a power source for a traveling motor.

  When an assembled battery is used, the reaction of the electrode body 20 in the secondary battery case 10 proceeds excessively due to overcharging or the like, and gas is generated and accumulated in the secondary battery case 10 to cause internal pressure. May rise abnormally. When the internal pressure of the unit cell 21 constituting the assembled battery becomes equal to or higher than a preset pressure, the thin portion 17 is torn and the internal gas is vented. That is, the thin portion 17 functions as a safety valve.

According to this embodiment, the following effects can be obtained.
(1) A power storage device case (secondary battery case 10) has a lid 13 that covers an opening 12 of a bottomed cylindrical case body 11 continuously at an opening end of the case body 11 at a continuous portion 14. It is formed integrally with the case body 11 and can cover the opening 12 in a state where the continuous portion 14 is bent. Therefore, compared with the case where the lid 13 is configured as a separate part, the number of welded portions when the opening 12 is sealed with the lid 13 is reduced, so that the labor of welding can be reduced and the airtightness and pressure resistance are improved. Moreover, since the welding length is shortened, the probability of occurrence of defective welds is reduced, and the yield (productivity) is improved.

  (2) The case main body 11 is formed in a square bottomed cylindrical shape, and the lid 13 is continuous to the case main body 11 at a continuous portion 14 having a width extending over the entire length of one long side of the substantially rectangular opening 12. Therefore, the welding length is shorter than when the continuous portion 14 is continuous with the short side of the opening 12.

  (3) Since the thin portion 17 is formed in the continuous portion 14 that continuously and integrally forms the lid 13 on the opening end portion of the case body 11, the lid 13 covers the opening portion 12 by bending the continuous portion 14. It can be bent so that it can be placed accurately at the position. Further, in the state where the power storage device case (secondary battery case 10) is used in the power storage device, when the internal pressure of the power storage device case rises abnormally, the thin portion 17 is torn and functions as a safety valve.

  (4) Since the bent portion 16 is formed along the continuous portion 14 in the continuous portion 14, and the bent portion 16 is thinner than the thickness of other portions, the bent portion 16 becomes easy to bend. Further, since the thin portion 17 is formed in a part of the bending processing portion 16, that is, in a part of the continuous portion 14, and the wall thickness is formed thinner than that of the bending processing portion 16, the power storage device case stores power. When the internal pressure of the power storage device case becomes abnormally high in a state where it is used in the device, it easily functions as a safety valve.

  (5) The bending processing portion 16 is constituted by a groove formed in the entire continuous portion 14. Therefore, the folding processing portion 16 can be easily formed by press working, and the folding processing portion 16 can be easily folded accurately.

  (6) In the direction in which the continuous portion 14 extends, the thin portion 17 is formed at the center of the bending processing portion 16. In a state where the power storage device case is used in the power storage device, when the internal pressure of the power storage device acts on the thin portion 17, the thin portion 17 is easily torn from the boundary portion between the thin portion 17 and the bending processing portion 16. When the thin portion 17 is formed at the center of the bending processing portion 16, the thin portion 17 is easily torn from both sides, and the thin portion 17 can easily function as a safety valve.

  (7) The power storage device (unit cell 21) uses the power storage device case (secondary battery case 10) having the above-described configuration. Therefore, since the lid 13 is continuous with the case main body 11 at the continuous portion 14, when assembling the power storage device, the effort for welding the lid 13 covering the opening 12 of the case main body 11 to the case main body 11 is reduced. 13 can be reduced by the amount of the continuous portion 14 as compared with the configuration of the case main body 11 and a separate part. Moreover, it has the effect as a safety valve of the thin part 17 when the case for electrical storage devices mentioned above is used.

  (8) As for the electrode body 20 which comprises a secondary battery and an electrical storage apparatus (unit cell 21), the separator is formed with the polymer electrolyte, and the unit cell 21 does not have electrolyte solution. Therefore, by forming the thin wall portion 17 on the lid 13 which is the bottom when the unit cell 21 is in use, the electrolyte solution is discharged out of the secondary battery case 10 when the thin wall portion 17 functions as a safety valve. There is nothing.

(9) The power storage device (unit cell 21) is mounted on a vehicle as a moving body and used as a power source. Therefore, the moving body has the effect of the power storage device included in the power storage device mounted.
The embodiment is not limited to the above, and may be embodied as follows, for example.

  The thin portion 17 may be formed not only on the continuous portion 14 but also on portions other than the continuous portion 14. For example, as shown in FIGS. 3A and 3B, a first groove portion 19 a formed so as to constitute a part of the bending processing portion 16, and the lid 13 branched from the first groove portion 19 a. The thin portion 17 may be configured by providing the second groove portion 19b formed above. In this case, when the power storage device case (secondary battery case 10) is used in the power storage device and the internal pressure of the power storage device case becomes equal to or higher than the preset internal pressure, the thin-walled portion 17 is accurately It becomes easy to be in a state to escape.

  As shown in FIG. 4, the secondary battery case 10 may be formed with holes 15 into which the electrode terminals (the positive terminal 21 p and the negative terminal 21 n) are inserted into the lid 13. In this case, the lid 13 is positioned at the top in the usage state of the unit cell 21. Therefore, even if a configuration in which an electrolytic solution is used as the unit cell 21 without using a polymer electrolyte as a separator that constitutes the electrode body 20, when the thin portion 17 functions as a safety valve, the electrolytic solution is not recovered. It is not discharged out of the secondary battery case 10. However, in a state where the electrode body 20 is accommodated in the case main body 11 and the positive electrode terminal 21 p and the negative electrode terminal 21 n protrude from the hole 15, the lid 13 is disposed at a position where the continuous portion 14 is bent to cover the opening 12. Is difficult. Therefore, as the positive electrode terminal 21p and the negative electrode terminal 21n, the protruding portion from the lid 13 is separable, and the lid 13 is disposed and sealed at a position covering the opening 12, and then the protruding portion is connected to the positive electrode terminal 21p and the negative electrode terminal 21n. It is preferable that the negative electrode terminal 21n be fixed to the main body. For example, the protruding portion is configured to be screwed to the main body portions of the positive electrode terminal 21p and the negative electrode terminal 21n.

  The secondary battery case 10 is not limited to the structure in which the hole 15 from which the electrode terminal of the electrode body 20 protrudes is formed on the surface opposite to the bottomed square cylindrical opening 12 or the lid 13. As shown in FIG. 5, a hole 15 may be formed in the side wall adjacent to the side wall provided with the lid 13 of the case body 11. In this case, the thin portion 17 is formed not on the center of the bending processing portion 16 but on the side close to the wall on which the hole 15 is provided. Therefore, even when the unit cell 21 is configured to use an electrolytic solution, when the unit cell 21 is in use, the thin portion 17 is present above the unit cell 21 and the thin portion 17 functions as a safety valve. The electrolytic solution is not discharged out of the secondary battery case 10.

  The secondary battery case 10 may be applied to a power storage device (secondary battery) in which the positive electrode terminal 21p and the negative electrode terminal 21n protrude from the wall facing the lid 13 of the secondary battery case 10 and uses an electrolytic solution. . In that case, when used in a state where the positive electrode terminal 21p and the negative electrode terminal 21n are on the upper side, the electrolyte solution is discharged out of the secondary battery case 10 when the thin portion 17 functions as a safety valve. Therefore, the usage state of the power storage device and the secondary battery is a state in which the positive electrode terminal 21p and the negative electrode terminal 21n are on the lower side, or a state in which the positive electrode terminal 21p and the negative electrode terminal 21n protrude in the horizontal direction and the position of the thin portion 17 is on the upper side. It is necessary to limit to. If it is this use state, when the thin part 17 functions as a safety valve, it will prevent that electrolyte solution is discharged | emitted out of the case 10 for secondary batteries.

○ The shape of the case main body 11 is not limited to the bottomed rectangular tube shape. For example, as shown in FIG. 6A, a bottomed long cylindrical shape may be used.
The case main body 11 is not limited to a bottomed cylindrical shape, and may have a configuration in which lids 13 are formed at both ends of the cylindrical shape. That is, the power storage device case (secondary battery case 10) includes a case main body 11 having at least one opening 12 and a lid 13 covering the opening 12, and the lid 13 is one of the outer peripheral portions of the lid 13. It is sufficient that the portion is formed integrally with the case main body 11 continuously at the opening end of the case main body 11 with the continuous portion 14 and can cover the opening 12 in a state where the continuous portion 14 is bent. .

  (Circle) the groove part which comprises the process part 16 for bending is not restricted to a continuous groove | channel, You may form by the intermittent groove | channel. In this case, the bending processing portion 16 is in a state where a portion where the thickness is thinner than the other portion and a portion having the same thickness as the other portion are mixed, but the average thickness of the bending processing portion 16 Is formed thinner than other portions.

The groove part which comprises the process part 16 for bending may not be formed over the full length of the process part 16 for bending, and if it can be folded easily, you may form it partially instead of the full length.
The thin-walled portion 17 may be formed so that the average thickness is thinner than the average thickness of the bending-processed portion 16, and the groove portion 18, the first groove portion 19a, and the second groove portion 19b are formed by intermittent grooves. Also good.

  ○ The thin portion 17 functions as a safety valve by forming portions with different depths and adjusting the depth without forming the groove portion 18, the first groove portion 19a, and the second groove portion 19b at a constant depth. The operating pressure at the time may be adjusted.

○ The thin portion 17 is not limited to one location, and may be provided at a plurality of locations.
O The processing part 16 for bending is not restricted to the structure by which thickness was made thinner than another part. For example, as shown in FIG. 6 (b), the wall thickness may be constituted by a curved portion 22 or a bent portion having the same thickness as other portions.

  O Only the thin part 17 may be provided in a part of the continuous part 14 without particularly forming the bending processing part 16. In this case, the continuous portion 14 can be easily bent by providing the thin portion 17. Moreover, it becomes possible to exhibit the function as a safety valve by securing the required length and area of the thin portion 17.

The thin-walled portion 17 is not limited to the center of the bending processing portion 16, and may be formed at a position approaching any one end side or a position continuous with the end portion.
The engraving of the V-groove constituting the bending processing portion 16 may be performed from the front surface side or from both sides, not from the back surface side of the lid 13.

  ○ The formation (engraving) of the groove 18 and the first groove 19a and the second groove 19b for forming the thin portion 17 is not performed from the back side of the lid 13 but from the front side. You may go.

  The second groove portion 19b is not limited to the configuration that branches vertically from the first groove portion 19a, and may be branched obliquely. Further, the second groove portion 19b may be formed so as to branch to the case body 11 side without being formed in the lid 13, or may be formed so as to branch into both the lid 13 and the case body 11.

  The moving body is not limited to a general vehicle or a forklift provided with a traveling motor, and may be another industrial vehicle such as an excavator loader or a towing tractor. Further, the vehicle is not limited to a vehicle that requires a driver, and may be an automatic guided vehicle.

○ The moving body is not limited to a vehicle but may be a ship or a robot.
The power storage device is not limited to an assembled battery in which a plurality of single cells 21 are electrically connected in series or in parallel by a terminal connection member. For example, a capacitor such as an electric double layer capacitor or a lithium ion capacitor, or a capacitor It may be electrically connected in series or in parallel by a terminal connecting member.

  ○ The electrode body is not limited to the laminated type, and may be a wound type.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery case as a power storage device case, 11 ... Case main body, 12 ... Opening part, 13 ... Cover, 14 ... Continuous part, 16 ... Bending part, 17 ... Thin part, 18 ... Groove part, 19a ... 1st groove part, 19b ... 2nd groove part, 20 ... Electrode body, 21 ... Single cell as an electrical storage apparatus.

Claims (6)

A case main body having at least one opening; and a lid covering the opening. The case main body and the lid are made of metal, and a part of an outer peripheral portion of the lid is an opening of the case main body. It is formed integrally with the case body continuously at the end portion at the continuous portion, and is formed so as to be able to cover the opening in a state where the continuous portion is bent, and at least the continuous portion is along the continuous portion. A case for a power storage device, characterized in that a thin-walled portion extending is formed, and the thin-walled portion formed in the continuous portion is formed in a part of the continuous portion. The continuous portion is formed with a bending portion along the continuous portion, the bending portion has a structure in which an average thickness is formed thinner than other portions, and the thin portion is the bending portion. at least formed on a part of the section, and is formed average thickness is thinner than the processing unit for folding the said folded for processing unit, the Ru groove der formed entirely of a continuous section to claim 1 The power storage device case described. The power storage device case according to claim 2 , wherein the thin portion is formed at a center of the bending processing portion in a direction in which the continuous portion extends. An electrical storage device in which an electrode body is accommodated in the electrical storage device case according to any one of claims 1 to 3 , and the lid that covers the opening is joined to the case body by welding. The secondary battery provided with the structure of the electrical storage apparatus of Claim 4 . A moving body on which the power storage device according to claim 4 is mounted.