JP2013175280A - Secondary battery - Google Patents

Abstract

An object of the present invention is to provide a secondary battery capable of easily discharging gas generated in an electrode group to the outside of the battery.
A battery case having a closed end and an open other end, an electrode group housed in the battery case and having a central hole, a convex plate disposed on one end side of the electrode group, and a battery case The convex plate has a convex portion connected to one end of the battery case at a position corresponding to the central hole, a side hole on the side surface of the convex portion, and an outer peripheral portion. By forming the outer peripheral hole, the gas discharged from the closed one end side of the battery case first passes through the outer peripheral hole of the convex plate, and then passes through the gap on the one end side of the battery case, It passes through the side hole on the side of the convex part of the convex plate, then passes through the hollow part of the core, and then passes through the cleaving part of the safety valve and can be discharged to the other end side of the battery case. .
[Selection] Figure 1

Description

  The present invention relates to a secondary battery, and more particularly to a secondary battery having a gas flow path in order to improve the explosion-proof exhaust capability when gas is generated in the battery.

  In recent years, demand for secondary batteries such as nickel metal hydride, nickel cadmium, and lithium ion that can be repeatedly used is increasing from the viewpoint of resource saving and energy saving. Among these, lithium ion secondary batteries are characterized by high electromotive force and high energy density while being lightweight. For this reason, there is an increasing demand for power sources for driving various types of portable electronic devices such as mobile phones, digital cameras, video cameras, laptop computers, and mobile communication devices. Further, in order to reduce the amount of fossil fuel used and the amount of CO2 emission, studies are underway to use a secondary battery as a power source for driving a motor of an automobile or the like.

  A secondary battery as a power source is required to have a high energy density. On the other hand, when a failure occurs in the secondary battery having a high energy density, the energy stored therein is released without control. In order to prevent such a situation, various safety structures have been studied in parallel.

  FIG. 9 is a cross-sectional view schematically showing a configuration of a conventional secondary battery 300. Here, as an example, a cylindrical lithium ion secondary battery will be described. The secondary battery 300 includes a safety mechanism that releases gas to the outside of the battery when the pressure in the battery increases due to an internal short circuit or the like. Hereinafter, a specific configuration of the secondary battery 300 will be described with reference to FIG.

  As shown in FIG. 9, an electrode group 4 in which a positive electrode 1 and a negative electrode 2 are wound through a separator 3 is housed in a battery case 7 together with a non-aqueous electrolyte. Insulating plates 9, 10 are arranged above and below the electrode group 4, the positive electrode 1 is joined to the filter 12 via the positive electrode lead 5, and the negative electrode 2 is connected to the negative electrode terminal 6 via the negative electrode lead 6. Is joined to the bottom.

  The filter 12 is connected to the inner cap 13, and the protruding portion of the inner cap 13 is joined to the metal valve body 14. Further, the valve body 14 is connected to a terminal plate 8 that also serves as a positive electrode terminal. The terminal plate 8, the valve body 14, the inner cap 13, and the filter 12 are integrated, and the opening of the battery case 7 is sealed through the gasket 11.

  When an internal short circuit or the like occurs in the secondary battery 300 and the pressure in the secondary battery 300 increases, the valve body 14 swells toward the terminal plate 8 and the inner cap 13 and the valve body 14 are disconnected. The current path is interrupted. When the pressure in the secondary battery 300 further increases, the valve body 14 is broken. As a result, the gas generated in the secondary battery 300 is transferred to the outside through the through hole 12 a of the filter 12, the through hole 13 a of the inner cap 13, the tear of the valve body 14, and the opening 8 a of the terminal plate 8. Discharged.

  However, since the insulating plate 10 has no holes other than the center, the gas discharged to the bottom side of the battery case 7 is prevented from moving in the direction of the valve body 14 on the upper side of the battery case 7. Further, under the situation where gas is generated in the electrode group 4, since the inside of the battery is at a high temperature, the separator 3 and the insulating plate 10 below the electrode group 4 are softened and attached to the bottom of the battery case 7. It is deformed to attach. Therefore, the movement of the generated gas in the direction of the valve body 14 is further prevented. As a result, it becomes difficult to discharge the generated gas to the outside of the battery. Moreover, it may be in an unsafe state because gas is not discharged | emitted outside the battery in this way.

  For example, Patent Document 1 describes a secondary battery that takes measures against gas discharged to the bottom side of the battery case.

  In Patent Literature 1, as shown in FIG. 10, the secondary battery 400 includes a substantially cylindrical core 25 housed in the space of the electrode group 4 and an insulating plate disposed on the bottom side of the electrode group 4. 10 and a perforated plate 20, and a perforated plate 20 is formed with a central hole 20a and an outer peripheral hole 20b. And the technique of the secondary battery in which the convex part 20c is formed in the direction of the bottom side of the battery case 7 in the perforated plate 20 is disclosed.

  According to the secondary battery 400, the substantially cylindrical core 25 accommodated in the space portion of the electrode group 4 and the perforated plate 20 including the outer peripheral hole 20 b disposed on the bottom side of the electrode group 4 are provided. Therefore, out of the gas generated in the electrode group 4, the gas discharged from the bottom side of the battery case 7 first passes through the outer peripheral hole 20 b of the perforated plate 20, and then the gap on the bottom side of the battery case 7. Passes through the center hole 20a of the perforated plate 20 and the hollow portion of the core 15 and then passes through the slit of the valve body 14 through the open portion 8a of the terminal plate 8 of the battery case 7. And discharged to the outside. For this reason, even if gas is generated near the bottom of the battery, smooth gas exhaust to the outside of the battery is possible.

JP 2001-229905 A

  However, since the technique disclosed in Patent Document 1 forms a gap on the bottom side of the battery case 7 by the convex portion 20c of the perforated plate 20, the effect when the perforated plate 20 does not deform is assumed. Therefore, when the perforated plate 20 is deformed so as to stick to the bottom side of the battery case 7 and there is no gap on the bottom side of the battery case 7, the generated gas core 16 is opened to the opening. Movement is blocked. As a result, it becomes difficult to discharge the generated gas to the outside of the battery. Further, in the conventional secondary battery, the negative electrode 2 needs to be joined to the bottom of the battery case 7 that also serves as the negative electrode terminal via the negative electrode lead 6, so that it is difficult to connect the negative electrode lead 6 and the bottom of the battery case 7. It was necessary to perform welding. Further, the connection between the negative electrode lead 6 and the battery case is a factor that hinders the high output of the secondary battery in addition to the ease of welding.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a secondary battery that can easily discharge the gas generated in the electrode group 4 to the outside of the battery.

  In order to solve the conventional problems, a secondary battery of the present invention includes a battery case having a closed end and an open other end, an electrode group housed in the battery case and having a central hole, and an electrode group A convex plate disposed on one end of the battery case and a safety valve provided on the other end of the battery case. The convex plate has a convex portion connected to one end of the battery case at a position corresponding to the center hole. And the side hole is formed in the side surface of the convex part, and the outer peripheral hole is formed in the outer peripheral part.

  With this configuration, of the gas generated in the electrode group, the gas discharged from the closed one end side of the battery case first passes through the outer peripheral hole of the convex plate, and then the gap on the one end side of the battery case Through the side, through the side hole on the side of the convex part of the convex plate, then through the hollow part of the core, and then through the cleaving part of the safety valve and discharged to the other end of the battery case It becomes possible.

  The secondary battery module of the present invention includes an outer peripheral hole of the convex plate, a gap between the convex plate and the battery case, a side hole of the convex portion of the convex plate, a hollow portion of the core, and a safety valve. By providing a discharge path for the gas discharged from the closed one end side of the battery case, the gas discharged from the closed one end side of the battery case can be discharged to the outside of the battery.

It is sectional drawing which showed typically the structure of the secondary battery in Example 1 of this invention. It is the schematic which showed typically the convex plate of the secondary battery in Example 1 of this invention. It is sectional drawing which showed typically the assembly of the secondary battery in Example 1 of this invention. It is sectional drawing which showed typically the structure of the other secondary battery in Example 1 of this invention. It is the schematic which showed typically the convex plate of the other secondary battery in Example 1 of this invention. It is sectional drawing which showed typically the structure of the secondary battery in Example 2 of this invention. It is the schematic which showed typically the convex-type board (current collection board) of the secondary battery in Example 2 of this invention. It is sectional drawing which showed typically the assembly of the secondary battery in Example 2 of this invention. It is sectional drawing which showed the structure of the conventional secondary battery typically. It is sectional drawing which showed the structure of the other conventional secondary battery typically.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing the configuration of a secondary battery 100 in Example 1 of the present invention.

  As the secondary battery 100 in the present invention, for example, a cylindrical lithium ion secondary battery as shown in FIG. 1 can be adopted. This lithium ion secondary battery may be a general-purpose battery used as a power source for portable electronic devices such as notebook computers. In this case, since a high-performance general-purpose battery can be used as the secondary battery of the battery module, it is possible to easily improve the performance and cost of the battery module. In addition, the secondary battery 100 includes a safety mechanism that releases gas to the outside of the battery when the pressure in the battery increases due to an internal short circuit or the like. Hereinafter, a specific configuration of the secondary battery 100 will be described with reference to FIG.

  As shown in FIG. 1, an electrode group 4 in which a positive electrode 1 and a negative electrode 2 are wound through a separator 3 is housed in a battery case 7 together with a non-aqueous electrolyte. At this time, the substantially cylindrical core 15 is accommodated in the central space of the electrode group 4. An insulating plate 9, an insulating plate 10, and a metal convex plate 16 are arranged above and below the electrode group 4, the positive electrode 1 is joined to the filter 12 via the positive electrode lead 5, and the negative electrode 2 is connected to the negative electrode lead 6. It is joined to the bottom of the battery case 7 via

  The filter 12 is connected to the inner cap 13, and the protruding portion of the inner cap 13 is joined to the metal valve body 14. Further, the valve body 14 is connected to a terminal plate 8 that also serves as a positive electrode terminal. The terminal plate 8, the valve body 14, the inner cap 13, and the filter 12 are integrated, and the opening of the battery case 7 is sealed through the gasket 11.

  When an internal short circuit or the like occurs in the secondary battery 100 and the pressure in the secondary battery 100 increases, the valve body 14 swells toward the terminal plate 8 and the inner cap 13 and the valve body 14 are disconnected. The current path is interrupted. When the pressure in the secondary battery 100 further increases, the valve body 14 is broken. As a result, the gas generated in the secondary battery 100 is transferred to the outside through the through hole 12 a of the filter 12, the through hole 13 a of the inner cap 13, the tear of the valve body 14, and the opening 8 a of the terminal plate 8. Discharged.

  The insulating plate 9, the insulating plate 10, and the convex plate 16 disposed above and below the electrode group 4 will be further described. The insulating plate 9 is flat and has a large central hole 9a. The insulating plate 10 is formed with a central hole 10 a at a position corresponding to the core 15, that is, at the center of the electrode portion 4, and an outer peripheral hole 10 c at the outer peripheral portion of the insulating plate 10. The convex plate 16 has a shape having a convex portion 16a connected to the closed end of the battery case 7 at a position corresponding to the center core 15, that is, the center of the electrode portion 4, and the side surface of the convex portion 16a. An outer peripheral hole 16 c is formed in the outer peripheral portion of the side hole 16 b and the convex plate 16. In other words, the convex plate 16 has a shape in which a hole is opened in the vertical portion of the edge and the head portion of the straw hat.

  Further, the side holes 16b and the outer peripheral holes 16c of the convex plate 16 will be described. 2A and 2B are schematic views schematically showing the convex plate 16 of the secondary battery in Example 1 of the present invention. FIG. 2A is a top view and FIG. 2B is a side view. As shown in FIG. 2A, the convex plate 16 has outer peripheral holes 16c at equal angular intervals in a flat portion on the outer periphery. Further, no hole is formed in the bottom surface of the central convex portion 16a. However, as shown in FIG. 2B, the side holes 16b are provided on the side surfaces of the convex portions 16a of the convex plate 16 at equal angular intervals of the same angle as the outer peripheral holes 16c.

  Furthermore, the discharge path of the gas generated in the electrode group 4 of the secondary battery 100 will be described in detail. Since the gas generated in the electrode group 4 is along the positive electrode 1, the negative electrode 2, and the separator 3, the direction of one end of the battery case 7 (the direction of the insulating plate 10) and the direction of the other open end (the insulating plate 9). In two directions).

  The gas discharged in the direction of the opened other end passes through a large hole in the center of the insulating plate 9, passes through the through hole 12a of the filter 12, the through hole 13a of the inner cap 13, the tear of the valve body 14, and the terminal plate. 8 is discharged to the outside through the open portion 8a.

  In addition, the gas discharged in the direction of one end first passes through the outer peripheral hole 10 c of the insulating plate 10, then passes through the outer peripheral hole 16 c of the convex plate 16, and then the void on the bottom side of the battery case 7. And then passes through the side hole 16b of the convex plate 16 and the hollow portion of the center core 15, the through hole 12a of the filter 12, the through hole 13a of the inner cap 13, the tear of the valve body 14, and the terminal plate 8 is discharged to the outside through the open portion 8a.

  Further, as shown in FIG. 1, by arranging the open portion 8 a of the terminal plate (positive electrode terminal) 8 at the center of the terminal plate (positive electrode terminal) 8, the insulating plate 10, the center of the convex portion 16 a of the convex plate 16, The hole center of the core 15, the hole center of the filter 12, the hole center of the inner cap 13, and the hole center of the positive terminal plate 8 are connected in a straight line. Thereby, the gas generated toward the closed one end side of the battery case 7 can be discharged in a straight line through each hole.

  In addition, the inner surface R of the corner portion of the battery case 7 which is closed is formed with a radius larger than that of the outer surface R by deep drawing. As a result, the gas generated toward the closed one end side of the battery case 7, particularly the gas generated near the outer periphery of the battery case 7, is bent smoothly along the inner surface R, so that the convex shape is smooth. It can go in the direction of the side hole 16b of the plate 16.

  Next, assembly of the secondary battery 100 will be described. FIG. 3 is a cross-sectional view schematically showing the assembly of the secondary battery in Example 1 of the present invention. First, the positive electrode side of the wound electrode group 4 is disposed on the lower surface and the negative electrode side is disposed on the upper surface, the insulating plate 10 is placed on the positive electrode side of the electrode group 4, and the convex plate 16 is further placed on the insulating plate 10. And the negative electrode lead 6 protruding from the negative electrode side of the electrode group 4 is bent so as to come on the convex portion 16a of the convex plate 16. Then, the battery case 7 is put on the electrode group 4 from the convex plate 16 side. That is, the electrode group 4 is inserted into the battery case 7 from the convex plate 16 side. The negative electrode lead 6, the convex plate 16, and the battery case 7 are resistance-welded by the welding electrode inserted from the center hole of the electrode group 4 and the welding electrode disposed on the bottom surface side of the battery case 7.

  After resistance welding, the core 15 is inserted into the center hole of the electrode group 4, and finally the battery case 7 is opened with the insulating plate 9, the terminal plate 8, the valve body 14, the inner cap 13, the filter 12, etc. The opening that is the end is sealed.

  According to such a configuration, the electrode is formed by the convex plate having the convex portion, the outer peripheral hole, and the side hole disposed on the closed one end side of the battery case, and the substantially cylindrical central core housed in the center of the electrode group. Among the gases generated in the group, the gas discharged from the closed one end side of the battery case first passes through the outer peripheral hole of the convex plate, and then passes through the gap on the one end side of the battery case, It passes through the side hole on the side of the convex part of the convex plate, then passes through the hollow part of the core, and then passes through the cleaving part of the safety valve and can be discharged to the other end side of the battery case. .

  In the present embodiment, the side hole 16b is formed in the convex plate 16, but the side hole 16b may be a slanted hole directed from below to above. This prevents the gas that has entered from the side of the side hole 16b of the convex plate 16 from exiting from the side hole 16b on the opposite side of 180 ° and the gas that has entered from the side hole 16b in the direction of the center core 15. Can lead to.

  In this embodiment, the negative electrode 2 is bonded to the bottom of the battery case 7 via the negative electrode lead 6. However, the negative electrode 2 is welded to the peripheral portion of the convex plate 16 via the negative electrode lead 6. The convex portion 16 a of the convex plate 16 may be joined to the bottom portion of the battery case 7. For example, as shown in FIG. 4, the insulating plate 10 and the convex plate 16 are connected to the electrode group 4, and the plurality of negative electrode leads 6 connected to the negative electrode 2 are connected to the peripheral portion of the convex plate 16. In FIG. 4, two negative leads are shown, but the number of negative leads 6 can be increased to three or more. And what integrated the electrode group 4, the insulating board 10, and the convex board 16 is inserted in the battery case 7, and the convex part 16a of the convex board 16 and the bottom part of the battery case 7 are welded. Thereby, welding of the electrode group 4 and the battery case 7 is easy, and the negative electrode 2 can be connected to the convex plate 16 by the plurality of negative electrode leads 6 to cope with high output of the secondary battery. it can.

  In this embodiment, the peripheral hole of the convex plate 16 is formed in such a shape that several round holes are formed as shown in FIG. 2, but a fan shape or a rectangle extending from the center of the convex plate 16 toward the periphery as shown in FIG. It is good also as a hole. When the gas discharge location of the electrode group 4 is a metal part that is not a hole, the gas tends to be emitted in the direction in which the positive electrode 1, the negative electrode 2, and the separator 3 are wound, that is, in the circumferential direction. It is desirable that there is a hole in the vicinity of the winding direction.

  In the present embodiment, the core 15 is inserted into the center hole of the electrode group 4. However, if the possibility of breakage of the electrode group 4 due to pressing is low, the core may be unnecessary.

  Although the secondary battery 100 is a cylindrical battery, a square battery may be used. Moreover, the kind in particular of secondary battery is not restrict | limited, For example, a lithium ion battery, a nickel-water secondary battery, etc. can be used.

  For Example 1, the negative electrode lead connected to the negative electrode of the electrode group was welded to the bottom surface of the battery case. In Example 2, the end face current collection was performed by directly welding the negative electrode of the electrode group to the convex plate (current collector plate), thereby improving the weldability of the negative electrode of the electrode group to the battery case and improving the secondary battery Improvements have been made to support output.

  FIG. 6 is a cross-sectional view schematically showing the configuration of the secondary battery 200 in Example 2 of the present invention.

  As the secondary battery 200 in the present invention, for example, a cylindrical lithium ion secondary battery as shown in FIG. 6 can be adopted. This lithium ion secondary battery may be a general-purpose battery used as a power source for portable electronic devices such as notebook computers. In this case, since a high-performance general-purpose battery can be used as the secondary battery of the battery module, it is possible to easily improve the performance and cost of the battery module. In addition, the secondary battery 200 includes a safety mechanism that releases gas to the outside of the battery when the pressure in the battery increases due to an internal short circuit or the like. Hereinafter, a specific configuration of the secondary battery 200 will be described with reference to FIG.

  As shown in FIG. 6, an electrode group 4 in which a positive electrode 1 and a negative electrode 2 are wound through a separator 3 is housed in a battery case 7 together with a non-aqueous electrolyte. At this time, the substantially cylindrical core 15 is accommodated in the central space of the electrode group 4. An insulating plate 9 and a convex plate (current collector plate) 17 are arranged above and below the electrode group 4, the positive electrode 1 is joined to the filter 12 via the positive electrode lead 5, and the negative electrode 2 is a convex plate made of a core material. It is welded to the (current collector plate) 17 so that end face current collection is possible. Further, a convex plate (current collector plate) 17 is joined to the bottom of the battery case 7.

  The filter 12 is connected to the inner cap 13, and the protruding portion of the inner cap 13 is joined to the metal valve body 14. Further, the valve body 14 is connected to a terminal plate 8 that also serves as a positive electrode terminal. The terminal plate 8, the valve body 14, the inner cap 13, and the filter 12 are integrated, and the opening of the battery case 7 is sealed through the gasket 11.

  When an internal short circuit occurs in the secondary battery 200 and the pressure in the secondary battery 200 increases, the valve body 14 swells toward the terminal plate 8 and the inner cap 13 and the valve body 14 are disconnected. The current path is interrupted. When the pressure in the secondary battery 200 further increases, the valve body 14 is broken. As a result, the gas generated in the secondary battery 200 is transferred to the outside through the through hole 12 a of the filter 12, the through hole 13 a of the inner cap 13, the tear of the valve body 14, and the opening 8 a of the terminal plate 8. Discharged.

  The insulating plate 9 and the convex plate (current collector plate) 17 disposed above and below the electrode group 4 will be further described. The insulating plate 9 is flat and has a large central hole 9a. The convex plate (current collector plate) 17 has a shape having a convex portion 17a connected to the closed end of the battery case 7 at a position corresponding to the center core 15, that is, in the center of the electrode portion 4. A side hole 17b is formed on the side surface of the convex portion 17a, and an outer peripheral hole 17c is formed on the outer peripheral portion of the current collector plate. In other words, the convex plate (current collector plate) 17 has a shape in which holes are formed in the vertical portion of the edge and head portion of the straw hat.

  Further, the side hole 17b and the outer peripheral hole 17c of the convex plate (current collector plate) 17 will be described. 7 is a schematic diagram schematically showing a convex plate (current collector plate) 17 of a secondary battery in Example 2 of the present invention, FIG. 7 (a) is a top view, and FIG. 7 (b) is a top view. It is a side view. As shown in FIG. 7A, the convex plate (current collector plate) 17 has outer peripheral holes 17c at equal angular intervals in the outer peripheral flat portion. Further, no hole is formed in the bottom surface of the central convex portion 17a. However, as shown in FIG. 7 (b), side holes 17b are provided at equal angular intervals at the same angle as the outer peripheral holes 17c on the side surfaces of the convex portions 17a of the convex plate (current collector plate) 17.

  Furthermore, the discharge path of the gas generated in the electrode group 4 of the secondary battery 200 will be described in detail. Since the gas generated in the electrode group 4 is along the positive electrode 1, the negative electrode 2, and the separator 3, the battery case 7 is closed at one end (direction of the convex plate (current collector plate 17)) and the other open end. Are discharged in two directions (direction of the insulating plate 9).

  The gas discharged in the direction of the opened other end passes through a large hole in the center of the insulating plate 9, passes through the through hole 12a of the filter 12, the through hole 13a of the inner cap 13, the tear of the valve body 14, and the terminal plate. 8 is discharged to the outside through the open portion 8a.

  Further, the gas discharged in the direction of one end first passes through the outer peripheral hole 17c of the convex plate (current collector plate) 17, then passes through the gap on the bottom side of the battery case 7, and then convex. Passing through the side hole 17b of the plate (current collector plate) 17 and the hollow portion of the core 15, the through hole 12a of the filter 12, the through hole 13a of the inner cap 13, the tear of the valve body 14, and the opening of the terminal plate 8 It is discharged to the outside through the part 8a.

  Further, as shown in FIG. 6, by arranging the open portion 8 a of the terminal plate (positive electrode terminal) 8 at the center of the terminal plate (positive electrode terminal) 8, the center of the convex portion 17 a of the convex plate (current collector plate) 17. The hole center of the core 15, the hole center of the filter 12, the hole center of the inner cap 13, and the hole center of the positive terminal plate 8 are connected in a straight line. Thereby, the gas generated toward the closed one end side of the battery case 7 can be discharged in a straight line through each hole.

  In addition, the inner surface R of the corner portion of the battery case 7 which is closed is formed with a radius larger than that of the outer surface R by deep drawing. As a result, the gas generated toward the closed one end side of the battery case 7, particularly the gas generated near the outer periphery of the battery case 7, is bent smoothly along the inner surface R, so that the convex shape is smooth. The plate (current collector plate) 17 can go in the direction of the side hole 17b.

  Next, assembly of the secondary battery 200 will be described. FIG. 8 is a cross-sectional view schematically showing the assembly of the secondary battery in Example 2 of the present invention. First, the positive electrode side of the wound electrode group 4 is disposed on the lower surface and the negative electrode side is disposed on the upper surface. It is welded to a template (current collector plate) 17. Then, the battery case 7 is covered with the electrode group 4 from the convex plate (current collector plate) 17 side. That is, the electrode group 4 is inserted into the battery case 7 from the convex plate (current collector plate) 17 side. The convex plate (current collector plate) 17 and the battery case 7 are resistance-welded by the welding electrode inserted from the center hole of the electrode group 4 and the welding electrode disposed on the bottom surface side of the battery case 7.

  After resistance welding, the core 15 is inserted into the center hole of the electrode group 4, and finally the battery case 7 is opened with the insulating plate 9, the terminal plate 8, the valve body 14, the inner cap 13, the filter 12, etc. The opening that is the end is sealed.

  According to such a configuration, the electrode is provided by the current collector plate having the convex portion, the outer peripheral hole, and the side hole disposed on the closed one end side of the battery case, and the substantially cylindrical central core housed in the center of the electrode group. Among the gases generated in the group, the gas discharged from the closed one end side of the battery case first passes through the outer peripheral hole of the current collector plate, then passes through the gap on the one end side of the battery case, It passes through the side hole on the side surface of the convex part of the current collector plate, then passes through the hollow part of the core, and then passes through the cleavage part of the safety valve and can be discharged to the other end side of the battery case. . Furthermore, it becomes possible to improve so as to cope with improvement in weldability of the negative electrode of the electrode group to the battery case and higher output of the secondary battery.

  In the present embodiment, the side surface hole 17b is formed in the convex plate (current collector plate) 17, but the side surface hole 17b may be a slanted hole directed from below to above. This prevents the gas that has entered from the side of the side hole 17b of the convex plate (current collector plate) 17 from exiting from the side hole 17b on the opposite side of 180 °, and the gas that has entered through the side hole 17b. It can be led in the direction of the core 15.

  The secondary battery 200 is a cylindrical battery, but may be a square battery. Moreover, the kind in particular of secondary battery is not restrict | limited, For example, a lithium ion battery, a nickel-water secondary battery, etc. can be used.

  INDUSTRIAL APPLICABILITY The present invention is useful as a driving power source for automobiles, electric motorcycles, personal computers, portable devices, electric playground equipment and the like.

DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Separator 4 Electrode group 5 Positive electrode lead 6 Negative electrode lead 7 Battery case 8 Terminal board (positive electrode terminal)
8a Opening portion 9 Insulating plate 9a Central hole 10 Insulating plate 10a Central hole 10c Outer peripheral hole 11 Gasket 12 Filter 12a Through hole 13 Inner cap 13a Through hole 14 Valve body 15 Middle core 16 Convex plate 16a Protruding part 16b Side hole 16c Outer peripheral hole 17 Convex plate (current collector plate)
17a Convex part 17b Side hole 17c Outer peripheral hole 100, 100b, 200 Secondary battery

Claims (5)

A battery case having one closed end and the other open end;
An electrode group housed in the battery case and having a central hole;
A convex plate disposed on the one end side of the electrode group;
A safety valve provided on the other end side of the battery case,
The convex plate has a convex portion connected to the one end of the battery case at a position corresponding to the central hole, and a side hole is formed on a side surface of the convex portion, and an outer peripheral hole is formed on an outer peripheral portion. A secondary battery characterized by. The secondary battery according to claim 1, wherein the convex plate is connected to the negative electrode of the electrode group by a negative electrode lead, and is further connected to the battery case by the convex part. The secondary battery according to claim 1, wherein the convex plate is a current collector plate welded to a negative electrode core of the electrode group. The center of the convex part of the convex plate, the hole center of the center hole center of the electrode group, the hole center of the filter, and the center of the open part of the positive terminal plate are connected in a straight line. Secondary battery. The secondary battery according to claim 1, wherein an inner surface R of a corner portion of the closed end of the battery case has a radius larger than that of the outer surface R.

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