JP2019212413A - Secondary cell and manufacturing method of secondary cell - Google Patents

Abstract

To provide a secondary cell in which the factor of utilization of the space in a battery case can be improved, and to provide a manufacturing method of the secondary cell.SOLUTION: A secondary cell 10 comprises an electrode plate group 20 where a positive electrode plate 21 and a negative electrode plate 22 are superimposed alternately via a separator 23, and a battery case 11 in which the electrode plate group 20 is received, and a CID15 for electrically connecting an external terminal 13P, located on the outside of the battery case 11, and a collector plate 14P for connection with the electrode plate group 20 is placed to project from a lid 12 toward the bottom of the battery case 11. The electrode plate group 20 includes a notch 50 into which the CID15 enters.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a secondary battery and a method for manufacturing the secondary battery.

  A lithium ion secondary battery, which is one of secondary batteries, is used as a driving power source for electric vehicles and hybrid vehicles that require high energy density and large battery capacity. The electrode plate group included in the lithium ion secondary battery includes a positive electrode plate and a negative electrode plate that overlap each other via a separator, and a large current can be taken out using a large facing area between the positive electrode plate and the negative electrode plate. . The overcharge prevention mechanism provided in the lithium ion secondary battery blocks the current flowing through the electrode plate group when the internal pressure of the battery case exceeds the operating pressure, thereby preventing the occurrence of problems due to overcharge (for example, Patent Documents) 1).

Japanese Patent Laid-Open No. 2006-95928

  The overcharge prevention mechanism described above is a mechanism that connects the electrode plate group located in the battery case and an external terminal, and is a structure that protrudes from the lid member of the battery case into the battery case. In the space inside the battery case, the vicinity of the overcharge prevention mechanism is a space that does not contribute to charging / discharging of the lithium ion secondary battery. For example, in the space immediately below the lid member of the battery case, the overcharge prevention mechanism is located in a part of the space, while the space other than the overcharge prevention mechanism does not contribute to charging / discharging of the lithium ion secondary battery. It exists as space.

  Therefore, in the lithium ion secondary battery provided with the overcharge prevention mechanism, there is still room for improvement in increasing the energy density. In addition, the subject which raises the utilization factor of the space in a battery case is common in not only the secondary battery provided with the overcharge prevention mechanism mentioned above but the battery provided with the structure which protrudes in a battery case from a battery case. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a secondary battery and a method for manufacturing the secondary battery that can improve the space utilization rate in the battery case. is there.

  A secondary battery that solves the above problems is a secondary battery electrode plate group in which a positive electrode plate and a negative electrode plate are alternately stacked via a separator, and the secondary battery electrode plate group is accommodated and sealed with a lid. A structure that electrically connects an external terminal located outside the battery case and a current collector connected to the electrode group for the secondary battery from the lid body. The battery case disposed so as to protrude toward the bottom of the battery case, and the electrode group for the secondary battery includes a notch portion into which the structure body enters.

  A manufacturing method of a secondary battery that solves the above problem is a secondary battery electrode plate group in which a positive electrode plate and a negative electrode plate are alternately stacked with a separator interposed therebetween, and a secondary battery including a notch portion into which a structure enters. Forming the battery electrode group, the external terminal located outside the battery case, and the structure for electrically connecting the current collector connected to the electrode group for the secondary battery, The secondary battery electrode plate group is accommodated in the battery case so as to protrude from the lid that seals the battery case toward the bottom of the battery case and so that the structure enters the notch. Including.

  According to each structure or method described above, the structure protruding from the lid member of the battery case enters the notch of the electrode plate group accommodated in the battery case. The vicinity of the structure in the space inside the battery case is filled with the electrode plate group. As a result, the space that does not contribute to charging / discharging of the battery can be reduced by the electrode plate group, and the utilization factor of the space in the battery case can be improved.

  In the secondary battery, the structure is located at an upper corner of the battery case having a rectangular parallelepiped shape, and the electrode group for the secondary battery is formed by the inner surface of the battery case and the notch. You may provide the said notch part so that an upper corner | angular part may be divided | segmented.

According to the above configuration, since the electrode plate group is positioned so as to surround the structure located at the upper corner of the battery case, a space that does not contribute to charging / discharging of the battery can be removed from the periphery of the structure.
The secondary battery further includes a first connection portion to which a first current collector is connected and a second connection portion to which a second current collector is connected, and the first connection portion is notched. The distance between the first connection part and the bottom part of the secondary battery electrode plate group is greater than the distance between the second connection part and the bottom part of the secondary battery electrode plate group. May be small.

  If it is the said structure, in the bottom part side of the battery case with respect to a notch part, the site | part which an electric current will flow will leave | separate from the cover body of a battery case rather than a 2nd connection part. As a result, it is possible to suppress the increase in current density in a region where the current path is complex, and to increase the usage efficiency of the electrode plate group.

In the electrode plate group for a secondary battery, the structure may be an overcharge prevention mechanism.
According to the above configuration, since the electrode plate group is positioned so as to surround the overcharge prevention mechanism, it is possible to remove a space that does not contribute to charging / discharging of the battery from the periphery of the overcharge prevention mechanism.

In the secondary battery electrode plate group, the secondary battery electrode plate group may be a lithium ion secondary battery electrode plate group.
According to the above configuration, in the lithium ion secondary battery, the space that does not contribute to charging / discharging of the battery is reduced by the electrode plate group, and the utilization factor of the space in the battery case can be improved.

  According to the present invention, the utilization factor of the space in the battery case can be improved.

The block diagram which shows the structure of the secondary battery in one Embodiment of a secondary battery. Sectional drawing which shows the overcharge prevention device of the embodiment. The disassembled perspective view which shows the layer structure of the electrode group of the same embodiment. The flowchart which shows the method of manufacturing the secondary battery of the embodiment. The action figure shown about the current distribution of the embodiment. The block diagram which shows the structure of the secondary battery in other embodiment of a secondary battery.

  An embodiment of a secondary battery and a method for manufacturing the secondary battery will be described with reference to FIGS. In the present embodiment, the secondary battery is a lithium ion secondary battery. The secondary battery of this embodiment comprises an assembled battery by connecting two or more with a bus bar. The assembled battery is mounted on an electric vehicle or a hybrid vehicle, and supplies power to an electric motor or the like. The secondary battery is a sealed battery whose outer shape is a rectangular parallelepiped shape.

  As shown in FIG. 1, the secondary battery 10 includes a battery case 11, a lid body 12, an electrode plate group 20, and an electrolyte solution 27. The battery case 11 has a rectangular parallelepiped shape having an opening on the upper side. The lid 12 seals the space in the battery case 11 by covering the opening. The battery case 11 and the lid 12 are made of a metal such as an aluminum alloy. The secondary battery 10 constitutes a sealed battery case by attaching a lid 12 to the battery case 11. The electrode plate group 20 and the electrolytic solution 27 are accommodated inside the battery case 11. The secondary battery 10 includes two external terminals 13 </ b> M and 13 </ b> P used for charging and discharging power on the lid 12. In FIG. 1, the right side is a positive external terminal 13P, and the left side is a negative external terminal 13M.

The electrolytic solution 27 is a composition (nonaqueous electrolyte) in which a supporting salt is contained in a nonaqueous solvent. As the non-aqueous solvent, one or two or more materials selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, and ethyl methyl carbonate are used. The supporting salt is composed of LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiI. One or more lithium compounds (lithium salts) selected from the group are used.

  The electrode plate group 20 has a rectangular parallelepiped shape in which the positive electrode plate 21 and the negative electrode plate 22 are alternately stacked in the stacking direction (direction perpendicular to the paper surface in FIG. 1) with the separator 23 interposed therebetween. The electrode plate group 20 constitutes a stacked electrode plate group by laminating the positive electrode plate 21, the negative electrode plate 22, and the separator 23 while being maintained in a flat shape. Thereby, the positive electrode plate 21, the negative electrode plate 22, and the separator 23 are laminated in multiple layers.

  The separator 23 is a nonwoven fabric made of polypropylene or the like for holding the electrolytic solution 27 between the positive electrode plate 21 and the negative electrode plate 22. As the separator 23, a porous polymer film such as a porous polyethylene film, a porous polyolefin film, and a porous polyvinyl chloride film, or a lithium ion or ion conductive polymer electrolyte film may be used alone or in combination. it can.

  The electrode plate group 20 includes a positive electrode lead portion 21A in which only the positive electrode plate 21 protrudes from one end side (right side in FIG. 1) of a rectangular parallelepiped shape, and a negative electrode to the other end side (left side in FIG. 1) in the same longitudinal direction. Only the plate 22 has a negative lead portion 22A protruding. The lead portion 21A of the positive electrode is a portion where the positive electrode base material 211 (see FIG. 3) of the positive electrode plate 21 is disposed, and the stacked positive electrode base material 211 is compressed in the stacking direction and welded. . The positive lead portion 21A is electrically connected to a current collector plate 14P as a current collector connected to the external terminal 13P. The negative electrode lead portion 22A is a portion where the negative electrode base material 221 (see FIG. 3) of the negative electrode plate 22 is disposed. The laminated negative electrode base material 221 is compressed in the stacking direction and welded. Yes. A current collector plate 14M as a current collector connected to the external terminal 13M is electrically connected to the negative lead portion 22A.

  On the positive electrode side of the battery case 11, a pressure type current interrupt device (CID: Current Interrupt Device) 15 is provided between the external terminal 13P and the current collector plate 14P. The CID 15 is mechanically fixed to the lid 12 while maintaining electrical insulation. On the other hand, the CID 15 is electrically connected to the external terminal 13P and the current collector plate 14P, and ensures electrical connection between the external terminal 13P and the current collector plate 14P. The CID 15 has a function as an overcharge prevention mechanism that cuts off the electrical connection between the external terminal 13P and the current collector plate 14P when the pressure in the battery case 11 becomes higher than a predetermined value. Yes. Note that CID 15 corresponds to a structure.

  The CID 15 will be described with reference to FIG. The CID 15 operates when the internal pressure Pa of the battery case 11 exceeds a predetermined operating pressure Pc, enters a state where the charging / discharging current does not flow (off state), and blocks the charging / discharging current flowing through itself. In addition, FIG. 2 has shown the state (ON state) in which charging / discharging electric current flows through self before an operation | movement (before interruption | blocking).

  The lid 12 is provided with gaskets 16 and 17, a conductive plate 18, a current collecting terminal 25, a reversing plate 30 and a rivet 40. The gasket 16 and the conductive plate 18 are disposed on the outside of the lid body 12 (outside of the battery case 11). The gasket 17 is disposed inside the lid body 12 (inside the battery case 11). The current collecting terminal 25 is a portion electrically connected to the current collecting plate 14M, and the upper end of the current collecting plate 14M is connected to the CID 15.

  The lid 12 has a through hole 12H. The gasket 16 has a cylindrical portion 16H disposed in the through hole 12H. Caulking is performed in a state where a part of the rivet 40 is inserted into the through hole 12H (cylindrical portion 16H), whereby the rivet 40 fixes the conductive plate 18 and the gaskets 16 and 17 to the lid body 12 and also the through hole 12H. Is sealed. The current collecting terminal 25 is electrically connected to the positive external terminal 13 </ b> P through the inversion plate 30, the rivet 40 and the conductive plate 18.

  The rivet 40 includes a caulking portion 41, a small diameter portion 42, a connecting portion 43, and a large diameter portion 44. The small diameter portion 42 has a cylindrical shape. The caulking portion 41 is formed by caulking the end side of the small diameter portion 42 after inserting the small diameter portion 42 into the through hole 12H. The space formed inside the connecting portion 43 and the large diameter portion 44 allows a reversing operation of the reversing plate 30 described later.

  The reversing plate 30 includes a top surface portion 31, an inclined portion 32, and a peripheral edge portion 33, and is made of an aluminum alloy or the like. The top surface portion 31 has a circular shape. The inclined portion 32 has an annular shape surrounding the top surface portion 31. The peripheral portion 33 has an annular shape surrounding the inclined portion 32. The reversing plate 30 is held by the rivet 40 by welding the entire circumference of the peripheral edge portion 33 of the reversing plate 30 and the large diameter portion 44 of the rivet 40.

  The small diameter portion 42 of the rivet 40 has a cylindrical shape, and a communication hole 41 </ b> H is provided inside the small diameter portion 42. The communication hole 41 </ b> H is provided so as to pass through the small diameter portion 42 of the rivet 40 and penetrate the lid body 12. Therefore, the inside and the outside of the battery case 11 communicate with each other through the communication hole 41H.

  The current collecting terminal 25 includes a thick portion 22E, a thin portion 23F, a through hole 23H, and an annular groove 23G, and is formed of an aluminum alloy or the like. The thin portion 23F has a thickness that is thinner than the thick portion 22E. The through hole 23H and the annular groove 23G are both provided in the thin portion 23F. The top surface portion 31 of the reversing plate 30 is welded to the thin portion 23F.

  In the ON state of CID15, the reversing plate 30 has a convex shape in which the top surface portion 31 protrudes toward the current collecting terminal 25 (thin wall portion 23F) (on state), and the current collecting terminal 25 is The reversal plate 30, the rivet 40 and the conductive plate 18 are electrically connected to the external terminal 13 </ b> P. The current flows in the order of the current collecting terminal 25, the reverse plate 30, and the rivet 40. Thereby, electric power is supplied from the secondary battery 10 to the outside during discharging, and current flows in the opposite direction during charging.

  On the other hand, when the internal pressure Pa of the battery case 11 rises, the top surface portion 31 of the reversing plate 30 is pressed by the gas in the battery case 11. When the internal pressure Pa of the battery case 11 becomes higher than the operating pressure Pc, the thin wall portion 23F is broken starting from the annular groove 23G, and the top surface portion 31 of the reversing plate 30 together with a part of the thin wall portion 23F from the current collecting terminal 25. It is deformed in the direction of moving away and becomes an inverted shape 30B. By the reversing operation of the reversing plate 30, the current collecting terminal 25 and the reversing plate 30 are separated from each other and turned off. Since the conduction between the reversing plate 30 and the current collecting terminal 25 is cut off, the conduction between the electrode plate group 20 and the external terminal 13P is also cut off.

  As shown in FIG. 3, the positive electrode plate 21 includes a positive electrode base material 211 that is a flat electrode core, and a positive electrode mixture layer 212 having a positive electrode mixture on both sides of the surface of the positive electrode base material 211. For the positive electrode base material 211, a metal foil suitable for the positive electrode is used, for example, an aluminum foil. Further, the positive electrode base material 211 has an uncoated portion 211M where the positive electrode mixture layer 212 is not provided along one side at the end in the longitudinal direction of the electrode plate group 20, and the uncoated portion 211M It has a positive lead portion 21A. The positive electrode mixture layer 212 is formed by applying a positive electrode mixture containing a positive electrode active material to the positive electrode base material 211.

The positive electrode mixture layer 212 includes positive electrode active material particles, a conductive material, and a binder. As the positive electrode active material particles, a material that can be used as a positive electrode active material of a lithium ion secondary battery can be used. In addition to the transition metal element (that is, at least one of Ni, Co, and Mn), the positive electrode active material particles may additionally contain one or more elements. Preferably, the positive electrode active material is “LiNiCoMnO ₂ -based positive electrode active material”. “LiNiCoMnO ₂ positive electrode active material” means a composite oxide containing Li, Ni, Co, and Mn, and may further contain a metal element different from Li, Ni, Co, and Mn.

  Further, the positive electrode mixture layer 212 may include a conductive material. As the conductive material, for example, carbon black such as acetylene black (AB) and ketjen black, and graphite (graphite) can be used.

  The positive electrode plate 21 is formed, for example, by kneading a positive electrode active material, a conductive material, a solvent, and a binder (binder). It is produced by applying and drying. As the solvent, for example, an NMP (N-methyl-2-pyrrolidone) solution can be used. As the binder, for example, polyvinylidene fluoride (PVdF), styrene butadiene rubber (SBR), polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), or the like can be used.

  Next, the negative electrode plate 22 includes a negative electrode base material 221 that is a flat electrode core, and a negative electrode mixture layer 222 having a negative electrode mixture on both sides of the surface of the negative electrode base material 221. The negative electrode plate 22 can use the same components as those of a conventional secondary battery. For example, a metal having good conductivity is used as the material of the negative electrode base material 221, for example, a thin film (foil) made of copper, nickel, or an alloy thereof. Further, the negative electrode base material 221 is provided with a negative electrode mixture layer 222 along the other side which is an end portion in the longitudinal direction of the electrode plate group 20 and is not provided with the uncoated portion 211M of the positive electrode. An uncoated portion 221M is provided, and the uncoated portion 221M has a negative lead portion 22A. The negative electrode mixture layer 222 is formed by applying a negative electrode mixture containing a negative electrode active material to the negative electrode base material 221.

  The negative electrode mixture layer 222 contains a thickener and a binder that can be used in the same manner as the negative electrode active material particles and the positive electrode mixture. The negative electrode active material particles are a material capable of inserting and extracting lithium, and for example, a powdery carbon material made of graphite or the like can be used. The negative electrode plate 22 is prepared by kneading a negative electrode active material, a solvent that can be used in the same manner as the positive electrode mixture, and a binder, and coating the negative electrode substrate 221 with a slurry for an electrode that includes the negative electrode mixture layer 222 after kneading. And dried.

(Notch 50)
As shown in FIG. 1, the electrode plate group 20 has a notch 50 that is partitioned so as to avoid the CID 15 protruding from the lid 12 toward the bottom surface of the battery case 11. For example, the electrode plate group 20 has a shape in which a right upper corner is cut out to form a notch 50 in a rectangular shape viewed from the stacking direction.

  The cutout portion 50 is provided over the entire range of the electrode plate group 20 in the stacking direction, and has a predetermined length 50L from the lead portion 21A of the positive electrode in the longitudinal direction of the electrode plate group 20, The plate group 20 has a predetermined height 50H from the upper side facing the lid 12 in the short direction.

  As shown in FIG. 3, the notch 50 includes a notch 51 formed in the positive electrode plate 21, a notch 52 formed in the negative electrode 22, and a notch 53 formed in the separator 23. ing. In other words, the cutout portion 51 of the positive electrode plate 21, the cutout portion 52 of the negative electrode plate 22, and the cutout portion 53 of the separator 23 are stacked so as to be aligned in the stacking direction. 50 is provided.

The notch 51 of the positive electrode plate 21 is provided on the uncoated part 211M side, has a height of 50H in the short direction, and has a length of 50L from the uncoated part 211M of the positive electrode in the longitudinal direction. .
The negative electrode plate 22 is laminated so as not to overlap the positive electrode lead portion 21A. Therefore, the cutout portion 52 of the negative electrode plate 22 is provided on the side that is not the uncoated portion 221M, has a height of 50H in the short direction, and does not overlap the positive electrode plate 21 in the longitudinal direction when stacked. Only shorter than 50L.

  The separator 23 is the same size as or larger than the range where the positive electrode plate 21 and the negative electrode plate 22 face each other. Therefore, the notch portion 53 of the separator 23 is aligned with the notch portion 51 of the positive electrode plate 21 and the notch portion 52 of the negative electrode plate 22, or has a short length and a long length that protrude slightly. doing. That is, the notch 50 may have a configuration in which the separator 23 protrudes somewhat.

(Method for manufacturing secondary battery)
With reference to FIG. 4, the manufacturing method of the secondary battery 10 is demonstrated.
When the production of the secondary battery 10 is started, a notch forming process for forming the notches 51, 52, 53 in the positive electrode plate 21, the negative electrode plate 22, and the separator 23 is performed (step S10). For example, in the positive electrode plate 21, the positive electrode mixture layer 212 is formed on the rectangular positive electrode base material 211, and then the notch 51 is formed on the side where the uncoated part 211 </ b> M is provided. In the negative electrode plate 22, after the negative electrode mixture layer 222 is formed on the rectangular negative electrode base material 221, a cutout portion 52 is formed on the side where the uncoated part 221M is not provided. In the separator 23, a notch 53 is formed in a portion of the rectangular shape corresponding to the notch 50 of the electrode plate group 20.

  Next, an electrode plate group creating step is performed in which the electrode plate group 20 is formed by laminating the positive electrode plate 21, the negative electrode plate 22, and the separator 23 (step S11). In the positive electrode plate 21 and the negative electrode plate 22, the uncoated portions 211 </ b> M and 221 </ b> M are arranged so as to be opposite to each other in the longitudinal direction of the electrode plate group 20, and the notch portion 51 and the notch portion 52 are provided. The layers are laminated so that the sides in the longitudinal direction and the sides in the short direction are aligned with each other. Further, the separator 23 is stacked between the positive electrode plate 21 and the negative electrode plate 22 so that the notch portion 51 of the positive electrode plate 21 or the notch portion 52 of the negative electrode plate 22 is aligned with the notch portion 53 of the separator 23. . Thereby, the electrode group 20 which has the notch part 50 is created.

  Subsequently, an external terminal connection step is performed (step S12). The CID 15 protrudes from the lid 12, and the notched portion 50 of the electrode plate group 20 is provided in the protruding portion of the CID 15. When the lid 12 is attached to the electrode plate group 20, the CID 15 enters the notch 50 of the electrode plate group 20. Therefore, the vicinity of the CID 15 in the space in the battery case 11 is filled with the electrode plate group 20. As a result, the space that does not contribute to charging / discharging of the battery is reduced by the electrode plate group 20, and the utilization factor of the space in the battery case 11 can be improved.

  In the external terminal connection step, the electrode plate group 20 is attached to the lid 12. More specifically, the positive current collecting plate 14P and the positive lead portion 21A are electrically connected to the negative current collecting plate 14M and the negative lead portion 22A, respectively. Specifically, the welding point 14C of the positive current collector plate 14P is welded to the first connection portion 21C of the positive lead portion 21A, and the negative current collector plate 14M is connected to the second connection portion 22C of the negative lead portion 22A. The welding point 14C is welded. The distance from the lid 12 to the second connection portion 22C of the negative current collector 14M is longer than the distance from the lid 12 to the first connection portion 21C of the positive current collector 14P. In other words, the distance between the first connection portion 21C of the positive electrode lead portion 21A and the bottom portion 20B of the electrode plate group 20 is the distance between the second connection portion 22C of the negative electrode lead portion 22A and the bottom portion 20B of the electrode plate group 20. Less than the distance between.

  Further, as shown in FIG. 5, the first connection portion 21 </ b> C is located near the center of the positive lead portion 21 </ b> A with respect to the length in the vertical direction from the lid body 12 toward the bottom portion. The second connection portion 22C is near the center of the negative lead portion 22A in the vertical direction. By providing the first connection portion 21C and the second connection portion 22C near the center, the current path distribution of the electrode plate group 20 can be made uniform. In the vicinity of the notch 50, the current path distribution may be complicated.

  Furthermore, with respect to the vertical direction, the position of the first connecting portion 21C is closer to the bottom portion 20B of the electrode plate group 20 than the position of the second connecting portion 22C. That is, the distance between the first connection portion 21 </ b> C and the bottom portion 20 </ b> B of the electrode plate group 20 is smaller than the distance between the second connection portion 22 </ b> C and the bottom portion 20 </ b> B of the electrode plate group 20. This is because the first lead portion 21 </ b> A approaches the bottom portion 20 </ b> B of the electrode plate group 20 in accordance with the provision of the cutout portion 50 on the lid 12 side. That is, the distance from the first connection portion 21 </ b> C to the cutout portion 50 is ensured by the first connection portion 21 </ b> C approaching the bottom portion 20 </ b> B of the electrode plate group 20.

  Therefore, by reducing the density of the current path (lowering the current distribution) in the notch portion 50 where the current path distribution (current distribution in FIG. 5) becomes complicated, the deterioration of the battery performance due to the notch portion 50 is suppressed. be able to. Further, the use efficiency of the electrode plate can be increased by increasing the density of the current paths in other portions instead of the notches 50. More specifically, the current has a higher current path density at a portion where the distance between the first connection portion 21C and the second connection portion 22C is short, and the current path tends to be lower as the distance becomes longer. By separating the notch portion 50 from the first connection portion 21C, the density of the current path in the vicinity of the notch portion 50 can be reduced, and the current distribution can be reduced. On the other hand, since the density of the current path in the portion that is not the notch 50 is increased, there is little risk of lowering the battery performance, and the use efficiency of the electrode plate is improved.

  That is, in order to improve the use efficiency of the electrode plate, as described above, the first connection portion 21C is provided at a position shifted to the bottom 20B side (lower side) by a predetermined distance from the second connection portion 22C. It is preferred that Here, the predetermined distance is preferably a value from 50% to 150% of the height 50H of the notch 50, and from 70% to 130% of the height 50H of the notch 50. The value of is more preferable. Note that the connection position of the second connection portion 22C is determined in the same manner as a normal battery. That is, it is determined based on the material constituting each member, the cost of the material, the structure of the electrode plate group, the structure of the battery, and the like.

  Then, an in-case arrangement process is performed (step S13). In the in-case arrangement process, the electrode plate group 20 in which the space that does not contribute to charging / discharging of the battery is reduced is arranged in the battery case 11 and the lid 12 is welded to the opening of the battery case 11. As a result, the electrode plate group 20 in which the space that does not contribute to charging / discharging of the battery is reduced is disposed in the battery case 11, and a secondary battery with improved space utilization in the battery case is manufactured.

As described above, according to the present embodiment, the effects listed below can be obtained.
(1) The CID 15 protruding from the lid 12 of the battery case 11 enters the notch 50 of the electrode plate group 20 accommodated in the battery case 11. In the space in the battery case 11, the vicinity of the CID 15 is filled with the electrode plate group 20. As a result, the space that does not contribute to charging / discharging of the battery is reduced by the electrode plate group 20, and the utilization factor of the space in the battery case 11 can be improved.

  (2) Since the electrode plate group 20 is positioned so as to surround the CID 15 positioned at the upper corner of the battery case 11, it is possible to remove a space that does not contribute to charging / discharging of the battery from the periphery of the CID 15.

  (3) When the first connection portion 21C approaches the bottom portion 20B of the electrode plate group 20, the portion where the current flows more easily on the bottom side of the battery case 11 with respect to the notch portion 50 than the second connection portion 22C. The case 11 is separated from the lid 12 of the case 11. As a result, it is possible to increase the use efficiency of the electrode plate group 20 by suppressing an increase in current density in a region where the current path is complicated.

(4) In the lithium ion secondary battery, the space that does not contribute to charging / discharging of the battery is reduced by the electrode plate group, and the utilization factor of the space in the battery case can be improved.
In addition, the said embodiment can be changed as follows.

  In the above embodiment, the case where the notch 50 of the electrode plate group 20 is provided on the positive electrode side is illustrated. However, the present invention is not limited to this, and when the CID is provided on the negative electrode side, The notch portion may be provided on the negative electrode side.

  -In above-mentioned embodiment, it illustrated about the case where the notch part 50 of the electrode group 20 is one place. However, the present invention is not limited to this, and a plurality of notches may be provided in the electrode plate group. Thereby, if the space can be reduced by the electrode plate group, the utilization factor of the space of the battery case is increased.

  As shown in FIG. 6, when the CID 15M is also provided on the negative electrode side of the lid body 12, a notch 50B may be provided in the negative electrode lead portion 22A of the electrode plate group 20. As a result, the space is reduced by the electrode plate group.

  Moreover, as shown in FIG. 6, you may provide the notch part 50C in the position corresponding to the injection port 12A of the electrolyte solution 27. As shown in FIG. Although the space may be reduced by the electrode plate group 20, the spread of the injected electrolyte solution 27 may be restricted. However, by providing the notch 50C corresponding to the injection port, The spread can be quickly expanded so that the electrolyte solution 27 can penetrate suitably.

  In the above embodiment, the case where the external terminals 13P and 13M are attached to the lid body 12 is illustrated, but the present invention is not limited thereto, and the external terminals may be provided on the side surface of the battery case, for example. At this time, the CID may be provided on the side surface of the battery case, and a notch may be provided at a corresponding position of the electrode plate group. Thereby, the utilization factor of the space in a battery case is improved, ensuring a suitable space | interval between the electrode group arrange | positioned in a battery case, and CID.

  In the above embodiment, the case where the first connection portion 21C is closer to the bottom portion 20B of the electrode plate group 20 than the second connection portion 22C is illustrated. However, the present invention is not limited to this, and the position of the first connecting portion and the number of the first connection portions are set so that the distribution of the current path is not complicated in the electrode plate and the distribution is more uniform according to the position where the structure protrudes. You may adjust the position of 2 connection parts.

  -In above-mentioned embodiment, it illustrated about the case where CID15 as a structure protrudes in the battery case 11. As shown in FIG. However, the present invention is not limited to this, and the structure projecting into the battery case may be a structure other than the CID such as a current collector plate structure or an electrode structure. Also by this, by positioning the electrode plate group so as to surround the structure located at the upper corner of the battery case, it is possible to remove the space that does not contribute to charging / discharging of the battery from the periphery of the structure.

-When forming the notch part 51 in the positive electrode plate 21, you may make it form the positive mix layer 212 in the positive electrode base material 211 in which the notch part 51 is formed.
-When forming the notch 52 in the negative electrode plate 22, you may make it form the negative mix layer 222 in the negative electrode base material 221 in which the notch 52 is formed.

-When forming the notch part 53 in the separator 23, you may form the notch part 53 by cutting | disconnection by the punching die etc. which form the notch part 53 simultaneously.
The secondary battery 10 may not be mounted on an electric vehicle or a hybrid vehicle. For example, the secondary battery 10 may be mounted on a vehicle such as a gasoline vehicle or a diesel vehicle. Further, the secondary battery 10 may be used as a power source for a moving body such as a railway, a ship, and an aircraft, a robot, and an electrical product such as an information processing apparatus.

DESCRIPTION OF SYMBOLS 10 ... Secondary battery, 11 ... Battery case, 12 ... Cover body, 12H ... Through-hole, 13M ... External terminal, 13P ... External terminal, 14C ... Welding point, 14M, 14P ... Current collecting plate, 15, 15M ... Pressure type Current interruption mechanism (CID), 16, 17 ... gasket, 18 ... conductive plate, 20 ... electrode plate group, 20B ... bottom, 21 ... positive electrode plate, 21A ... lead part, 21C ... first connection part, 22 ... negative electrode plate, 22A ... lead part, 22C ... second connection part, 22E ... thick part, 23 ... separator, 23F ... thin part, 23G ... annular groove, 23H ... through hole, 25 ... current collecting terminal, 27 ... electrolyte, 30 ... Inversion plate, 30B ... inverted shape, 31 ... top surface portion, 32 ... inclined portion, 33 ... peripheral edge portion, 40 ... rivet, 41 ... caulking portion, 41H ... communication hole, 42 ... small diameter portion, 43 ... communication portion, 44 ... large Diameter, 50, 50B, 50C, 51, 52, 53 Notch part, 50H ... height, 50L ... length, 211 ... positive electrode base material, 211M ... uncoated part, 212 ... positive electrode mixture layer, 221 ... negative electrode base material, 221M ... uncoated part, 222 ... negative electrode Mixture layer.

Claims (6)

A group of electrode plates for a secondary battery in which a positive electrode plate and a negative electrode plate are alternately stacked via a separator;
A battery case in which the electrode group for secondary batteries is accommodated and sealed with a lid, and an external terminal located outside the battery case and a collector connected to the electrode group for secondary batteries A structure that electrically connects the electric body, the battery case disposed so as to protrude from the lid toward the bottom of the battery case, and
The electrode group for a secondary battery includes a notch into which the structure is inserted. The structure is located at an upper corner of the battery case having a rectangular parallelepiped shape,
The secondary battery according to claim 1, wherein the secondary battery electrode plate group includes the cutout portion so as to divide the upper corner portion by an inner surface of the battery case and the cutout portion. A first connection part to which the first current collector is connected;
A second connecting portion to which the second current collector is connected,
The first connection portion is located on the bottom side with respect to the notch,
The distance between the first connection part and the bottom part of the electrode group for the secondary battery is smaller than the distance between the second connection part and the bottom part of the electrode plate group for the secondary battery. Secondary battery. The secondary battery according to claim 1, wherein the structure is an overcharge prevention mechanism. The secondary battery according to claim 1, wherein the electrode group for the secondary battery is an electrode group for a lithium ion secondary battery. Forming a secondary battery electrode plate group having a notch portion into which the structure enters, wherein the positive electrode plate and the negative electrode plate alternately overlap with each other via a separator;
The structure for electrically connecting an external terminal located outside the battery case and a current collector connected to the electrode group for the secondary battery, from the lid for sealing the battery case to the battery A method of manufacturing a secondary battery, comprising: arranging the electrode plate group for a secondary battery in the battery case so as to protrude toward a bottom of the case, and so that the structure enters the notch. .

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