JP5838838B2 - Power storage device and vehicle - Google Patents

Description

  The present invention relates to a power storage device and a vehicle equipped with the power storage device.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. This type of secondary battery is disclosed in Patent Document 1, for example. As shown in FIG. 9, the secondary battery 50 of Patent Document 1 is configured by housing an electrode body 52 in an exterior body 51 and connecting a terminal member 53 to the electrode body 52. The electrode body 52 includes a negative electrode 54 obtained by applying a negative electrode active material layer 54b to a negative electrode current collector 54a made of a metal foil, and a positive electrode obtained by applying a positive electrode active material layer 55b to a positive electrode current collector 55a made of a metal foil. 55. The electrode body 52 is formed in layers with a separator 56 that insulates between the negative electrode 54 and the positive electrode 55 interposed therebetween. Further, a terminal member 53 is connected to each of the negative electrode current collector 54 a of the negative electrode 54 and the positive electrode current collector 55 a of the positive electrode 55 in a region where no active material is applied.

JP 2002-298825 A

  The outer body 51 of the secondary battery 50 has an electrode body 52 and a terminal member necessary for functioning the secondary battery 50 as a power generation element in a space set according to the size (size) of the outer body 51. 53 must be accommodated. On the other hand, it is difficult to increase the size of the secondary battery 50 indefinitely in consideration of the mounting space of the secondary battery in a vehicle or the like. For this reason, when designing and manufacturing the secondary battery 50, it is desired to have a structure that can effectively use a limited space.

  The present invention has been made paying attention to such problems existing in the prior art, and an object thereof is to provide a power storage device and a vehicle that can effectively use a space.

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a positive electrode and a negative electrode are insulated and laminated to form a layered electrode body, and a main body member that houses the electrode body A power storage device comprising: a lid member that closes the opening of the body member; a terminal that takes out electricity from each electrode; and a connection member that connects each electrode to each terminal. A current collector that is formed at the edge and is not coated with an active material, and a current collector that has the same polarity is collected within a range from one end to the other end in the stacking direction of the electrode body. And a connection portion electrically connected to the connection member on one outermost surface in the stacking direction of the current collection group, and at least one of the current collection groups includes the connection A bent part bent or bent to the side of the part and the product from the bent part Extending in a direction, and said extended portion having a connecting portion is formed, in the direction towards to the respective electrode side from the cover member side, the cover member, the extending portion, and are arranged in order of said connecting member In the connecting member, at least a portion disposed inside the bent portion of the current collecting group is formed in a rectangular flat plate shape, and the entire connecting member is located closest to the lid member in the current collecting group. The gist is that it is arranged on the side of each electrode from the end .

  According to this, since the bent portion is formed in the current collecting group and the connecting member is connected to the inside of the bent portion, the space necessary for connecting the current collecting group and the connecting member can be reduced. Specifically, the space can be reduced as compared with the case where the terminal member is connected to the outside of the bent portion as in the secondary battery disclosed in the background art. If the space is reduced in this way, the space can be effectively used. For example, the size of the power storage device can be reduced according to the reduced space. In addition, when the storage space for the electrode body and the like is made equal, the output can be increased by replacing the reduced space with a storage space for another member or increasing the amount of active material applied in accordance with the reduced space. obtain. Therefore, according to the configuration of the present invention, the space can be effectively used as described above.

The gist of the invention according to claim 2 is that, in the power storage device according to claim 1, the connecting member is formed with a chamfered portion at a side edge in contact with the bent portion.
According to this, when curving the current collector, stress is applied to the bent portion. For this reason, when the connection member which has not chamfered the bending part is touched, there exists a possibility of breaking a current collection part. However, according to the present invention, breakage of the current collector can be suppressed.

  According to a third aspect of the present invention, in the power storage device according to the first or second aspect, the current collecting group is formed by collecting the current collecting portions on one side of the electrode body positioned in the stacking direction. It is a summary.

  According to this, the cross-sectional area of the connection member connected to the current collection group can be increased. In the power storage device, the current collection resistance changes according to the cross-sectional area of the connection member. For this reason, current collection efficiency can be improved by enlarging the cross-sectional area of a connection member.

  According to a fourth aspect of the present invention, in the power storage device according to any one of the first to third aspects, the current collection group in which the bent portion and the extending portion are formed includes: The gist is that a bent portion bent or bent in the same direction is formed. According to this, the arrangement of the connection members can be made uniform. Therefore, it is easy to connect the terminal to the connection member.

  According to a fifth aspect of the present invention, in the power storage device according to any one of the first to fourth aspects, the current collector group formed on the electrode body includes the bent portion and the extension portion. The gist is that the protruding portion is formed. According to this, since all the current collection groups are curved or bent, the space required for the connection between the current collection group and the connecting member can be more significantly reduced.

  According to a sixth aspect of the present invention, in the power storage device according to any one of the first to fifth aspects, the connection member has a length along the extending direction of the extending portion. The gist is that it is set within a range from one end to the other end in the stacking direction of the body. According to this, a connection member is settled in the range from the one end of the lamination direction in an electrode body to the other end. That is, the connecting member does not protrude outside the electrode body. Therefore, insulation can be easily secured. Moreover, the occurrence of dead space can be suppressed.

  According to a seventh aspect of the present invention, in the power storage device according to any one of the first to sixth aspects, an insulation is provided on the other surface side of the current collecting group to which the connection member is not connected. The gist is that the members are arranged. According to this, it is possible to ensure insulation of the current collecting group.

The gist of an eighth aspect of the present invention is that, in the power storage device according to any one of the first to seventh aspects, the entire connection member is formed in a rectangular flat plate shape.
According to a ninth aspect of the present invention, in the power storage device according to any one of the first to eighth aspects, the extending portion extends from the bent portion to a tip portion of the current collecting group. The gist.
According to a tenth aspect of the present invention, in a vehicle that travels by supplying electric power stored in the power storage device to an electric motor, the power storage device according to any one of the first to ninth aspects is used as the power storage device. The gist is that it is installed.

  According to this, when the power storage device is downsized, the mounting space of the power storage device in the vehicle can be reduced, so that the space can be effectively used for other mounting spaces. For example, a storage battery can be further mounted. Further, when the output of the storage battery is increased, the running performance of the vehicle can be improved.

  According to the present invention, the space can be effectively used.

The exploded perspective view of a secondary battery. The perspective view which shows the external appearance of a secondary battery. The disassembled perspective view which shows the component of an electrode body. The perspective view of a current collecting plate. Sectional drawing which shows the electrode body inserted in the battery case can. Explanatory drawing explaining a mode that a current collection part is bundled. Explanatory drawing explaining the current collection group to which the current collecting plate was connected. Explanatory drawing explaining the bent current collection group. Sectional drawing explaining the connection aspect of the conventional current collection group and a current collecting plate.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, in the secondary battery 2 as the power storage device, an electrode body 5 is accommodated in a metal battery case 3. The battery case 3 includes a rectangular box-shaped main body member 4 and a rectangular flat plate-shaped lid member 6 that closes the opening 4 a of the main body member 4. Both the main body member 4 and the lid member 6 are made of metal (for example, stainless steel or aluminum). In addition, the secondary battery 2 of the present embodiment is a prismatic battery whose outer shell forms a square shape. Moreover, the secondary battery 2 of this embodiment is a lithium ion battery.

  A positive electrode terminal 7 and a negative electrode terminal 8 for taking out electricity from the electrode body 5 are electrically connected to the electrode body 5. The positive electrode terminal 7 and the negative electrode terminal 8 are exposed to the outside of the battery case 3 through a pair of opening holes 6 a arranged in parallel with the lid member 6 at a predetermined interval. Further, a ring-shaped insulating member 9 a for insulating from the battery case can 3 is attached to the positive electrode terminal 7 and the negative electrode terminal 8, respectively. Further, as shown in FIG. 5, the inner surface of the main body member 4 constituting the battery case 3 is insulated as an insulating member for insulating the metal main body member 4 and the electrode body 5 accommodated therein. A sheet 9b is attached. Further, as shown in FIG. 5, the inner surface of the lid member 6 constituting the battery case 3 is insulated as an insulating member for insulating the metal lid member 6 and the electrode body 5 accommodated therein. A sheet 9c is attached.

  As shown in FIG. 3, the electrode body 5 includes a positive electrode sheet 10 that serves as a positive electrode and a negative electrode sheet 11 that serves as a negative electrode. The positive electrode sheet 10 has a positive electrode metal foil (aluminum foil in this embodiment) 13 and a positive electrode active material layer 14 formed by applying a positive electrode active material on both surfaces thereof. The negative electrode sheet 11 has a negative electrode metal foil (copper foil in this embodiment) 17 and a negative electrode active material layer 18 formed by applying a negative electrode active material on both surfaces thereof. And the electrode body 5 is made into the laminated body which makes | forms the layer form by interposing the separator 12 which insulates between the positive electrode sheet 10 and the negative electrode sheet 11 between. For example, as illustrated in FIG. 6, the electrode body 5 is configured by laminating a plurality of positive electrode sheets 10 and a plurality of negative electrode sheets 11. That is, the electrode body 5 is provided with a plurality of sets each including the positive electrode sheet 10, the negative electrode sheet 11, and the separator 12.

  As shown in FIG. 3, a positive electrode tab-like portion 15 made of the positive electrode metal foil 13 is formed on a part of the edge of the positive electrode sheet 10. The positive electrode tab-like portion 15 has a positive electrode current collecting portion 16 that is a region where the positive electrode active material layer 14 is not applied. In the present embodiment, the positive electrode current collector 16 is the entire area of the positive electrode tab-like portion 15. In the present embodiment, the positive electrode current collector 16 is formed at the edge of the positive electrode sheet 10. Further, the positive electrode tab-like portion 15 and the positive electrode current collector portion 16 are formed in the same shape at the same position in each positive electrode sheet 10 constituting the electrode body 5.

  A negative electrode tab-like portion 19 made of the negative electrode metal foil 17 is formed on a part of the edge of the negative electrode sheet 11. The negative electrode tab-like portion 19 has a negative electrode current collector 20 that is a region where the negative electrode active material layer 18 is not applied. In the present embodiment, the negative electrode current collector 20 is the entire area of the negative electrode tab-like part 19. In the present embodiment, the negative electrode current collector 20 is formed at the edge of the negative electrode sheet 11. Further, the negative electrode tab-like portion 19 and the negative electrode current collector 20 are formed in the same position and in the same shape in each negative electrode sheet 11 constituting the electrode body 5. In the positive electrode sheet 10 and the negative electrode sheet 11, a region where the active material is applied becomes a coated portion, and a region where the active material is not applied becomes an uncoated portion.

  Each positive electrode sheet 10 constituting the electrode body 5 is laminated so that the respective positive electrode current collectors 16 are arranged in a line along the lamination direction. Similarly, each negative electrode sheet 11 constituting the electrode body 5 is laminated such that the respective negative electrode current collectors 20 are arranged in a row along the lamination direction so as not to overlap the positive electrode current collectors 16. . And each positive electrode current collection part 16 is collected in the range from the one end of the lamination direction in the electrode body 5 to the other end, and is made into the positive electrode current collection group 21, as shown in FIG. Similarly, each of the negative electrode current collectors 20 is also collected in a range from one end to the other end in the stacking direction of the electrode body 5 as shown in FIG.

  A positive electrode current collecting plate 23 as a connecting member for electrically connecting the electrode body 5 and the positive electrode terminal 7 is joined to the positive electrode current collecting group 21. Further, the negative electrode current collector group 22 is joined with a negative electrode current collector plate 24 as a connecting member for electrically connecting the electrode body 5 and the negative electrode terminal 8. The positive electrode terminal 7 and the positive electrode current collector plate 23 are electrically connected via an overcurrent protection circuit 25 as shown in FIG. Similarly, the negative electrode terminal 8 and the negative electrode current collector plate 24 are electrically connected via an overcurrent protection circuit 25 as shown in FIG.

  The positive electrode current collector plate 23 and the negative electrode current collector plate 24 have a rectangular flat plate shape as shown in FIG. A chamfered portion 26 is formed on one side edge along the longitudinal direction of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 so that the entire thickness direction forms an arc shape. In addition, the length along the short direction of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 is shorter than the length along the stacking direction of the electrode body 5. Further, the length along the longitudinal direction of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 is set to a length that does not interfere with other members when bonded to the positive electrode current collector group 21 and the negative electrode current collector group 22. . In the case of this embodiment, when the positive electrode current collector plate 23 and the negative electrode current collector plate 24 are joined to the positive electrode current collector group 21 and the negative electrode current collector group 22, as shown in FIGS. Projects in a direction perpendicular to the direction. Specifically, the battery case 3 protrudes toward the inner surface of the main body member 4. For this reason, the positive electrode current collector plate 23 and the negative electrode current collector plate 24 have a length that does not interfere with the inner surface of the main body member 4 when bonded to the positive electrode current collector group 21 and the negative electrode current collector group 22. The thickness of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 is set to a thickness (about 1.5 mm) that enables sufficient and sufficient current collection from the electrode body 5.

  Hereinafter, the joining structure of the positive electrode current collecting group 21 and the positive electrode current collecting plate 23, and the negative electrode current collecting group 22 and the negative electrode current collecting plate 24 will be described in detail with reference to FIGS. 6 to 8 illustrate the joining structure of the positive electrode current collector group 21 and the positive electrode current collector plate 23. FIG. The joining structure of the positive current collecting group 21 and the positive current collecting plate 23 is the same as the joining structure of the negative current collecting group 22 and the negative current collecting plate 24. Therefore, the joining structure of the positive electrode current collector group 21 and the positive electrode current collector plate 23 will be described below.

  As shown in FIG. 6, the positive electrode tab-like portion 15 having the positive electrode current collector portion 16 is directed from one end side (right side in FIG. 6) to the other end side (left side in FIG. 6). Collected. Specifically, the positive electrode current collector 16 (labeled “H1” in the drawing) located on the outermost side on one side (one end side) of the electrode body 5 is connected to the other side (the other end side). Each of the positive electrode current collectors 16 is collected so as to approach the positive electrode current collector 16 located at the outermost side (indicated by a symbol “H2” in the drawing). At this time, in this embodiment, the positive electrode current collector plate 23 is in contact with the outer side of the positive electrode current collector 16 (H1) located on the outermost side on one side, as indicated by the white arrow in the figure. Each positive electrode current collector 16 is collected by moving toward the other side. Note that the positive electrode current collector plate 23 causes the chamfered portion 26 to contact the positive electrode current collector portion 16. Moreover, when collecting each positive electrode current collection part 16, a support member is arrange | positioned on the outer side of the positive electrode current collection part 16 (H2) located in the outermost side in the other one side, and positive electrode current collection with low rigidity is carried out. It becomes easy to collect the part 16 (metal foil 13 for positive electrodes). The support member may be a welding electrode used when the positive current collector group 21 and the positive current collector plate 23 are joined.

  Thereby, each positive electrode current collection part 16 which was independent in the lamination | stacking step is integrated by the other end side, and becomes the positive electrode current collection group 21, as shown in FIG. And the positive electrode current collection group 21 and the positive electrode current collecting plate 23 are joined by resistance welding. Thereby, the positive electrode current collection group 21 and the positive electrode current collecting plate 23 are electrically connected. Resistance welding is a method in which the objects to be joined (positive current collecting group 21 and positive current collecting plate 23 in FIG. 6) are sandwiched between a pair of positive and negative welding electrodes and welded.

  In this embodiment, each positive electrode tab-shaped part 15 is formed in the same size. And when forming the positive electrode current collection group 21, each positive electrode current collection part 16 is gathered on the other one side with each positive electrode tab-shaped part 15. FIG. For this reason, as the positive electrode current collector 16 having a longer separation distance in the stacking direction from the positive electrode current collector 16 (H2) located on the outermost surface on the other side, the region overlapping with the other positive electrode current collector 16 becomes smaller. . Specifically, the positive electrode current collector 16 (H1) located on the outermost surface on one side has a small area overlapping with the other positive electrode current collector 16. Thus, in order to join all the positive electrode current collectors 16 constituting the positive electrode current collector group 21 and the positive electrode current collector plate 23, the welded portion W is set near the root of the positive electrode current collector group 21. In the present embodiment, the positive electrode current collection group 21 and the positive electrode current collector plate 23 are connected by the welded part W, and the connection part between the positive electrode current collector 16 (H1) and the positive electrode current collector plate 23 is a connection part. In addition, when collecting each positive electrode current collection part 16, the bending condition of the positive electrode current collection part 16 (H1) located in the outermost surface in one side becomes the tightest. For this reason, it is good to collect each positive electrode current collection part 16, adjusting a bending condition so that the bending part (it attaches code | symbol "K" to FIG. 7) of the positive electrode current collection part 16 may not fracture | rupture.

  After the joining of the positive electrode current collecting group 21 and the positive electrode current collecting plate 23, as shown in FIG. 8, the positive electrode current collecting group 21 is bent with the tip (chamfered portion 26) of the positive electrode current collecting plate 23 as a bending base point. The bending direction of the positive electrode current collecting group 21 at this time is a direction in which the positive electrode current collecting group 21 and the positive electrode current collecting plate 23 are tilted toward one side. That is, the positive electrode current collector group 21 is bent toward the side where the positive electrode current collector plate 23 is joined. Thereby, the positive electrode current collection group 21 is comprised by two elements of the bending part 27 curved to the side to which the positive electrode current collecting plate 23 is joined, and the extension part 28 extended from the bending part 27 in the lamination direction. The Further, the extending portion 28 of the positive electrode current collecting group 21 has a welded portion W as a connecting portion for connecting the positive electrode current collecting group 21 and the positive electrode current collecting plate 23.

  As shown in FIG. 8, when the positive electrode current collecting group 21 is bent, the positive electrode current collecting plate 23 is disposed inside the bent portion 27 of the positive electrode current collecting group 21. Further, in the present embodiment, the positive electrode current collector plate 23 is disposed inside the extension portion 28, that is, closer to the laminate of the positive electrode sheet 10, the negative electrode sheet 11, and the separator 12 than the extension portion 28. That is, in the present embodiment, the positive electrode current collector plate 23 is disposed in the space S formed inward by bending the positive electrode current collector group 21. This space S becomes a dead space when the positive electrode current collector plate 23 is disposed outside the extending portion 28 as indicated by a two-dot chain line in FIG. Therefore, in the present embodiment, by arranging the positive electrode current collector plate 23 inside the bent portion 27, the dead space can be reduced and the space can be effectively used.

  Further, the positive electrode current collector plate 23 after the positive electrode current collector group 21 is bent is disposed in a range from one end to the other end of the electrode body 5. In the present embodiment, the length of the positive electrode current collector plate 23 along the short direction is shorter than the length of the electrode body 5 along the stacking direction. For this reason, even if the positive electrode current collecting plate 21 is arranged along the stacking direction of the electrode body 5 by bending the positive electrode current collecting group 21, it is within the range from one end to the other end of the electrode body 5 in the stacking direction. Become. The length along the short direction of the positive electrode current collector plate 23 is the length along the extending portion 28.

  The chamfered portion 26 of the positive electrode current collector plate 23 is formed so as to form an arc shape as a whole. For this reason, the first arc surface R1 and the second arc surface R2 exist at a portion facing the positive electrode current collecting group 21. When the positive electrode current collecting group 21 is bent from the state shown in FIG. 7, the first arc surface R1 and the second arc surface R2 are formed in an arc shape so that the positive electrode current collecting group 21 (positive electrode current collecting portion 16) is formed. Can be folded without breaking. Further, after the bending shown in FIG. 8, even if the positive electrode current collector plate 23 comes into contact with the bent portion 27, the positive current collector group 21 is formed by the first arc surface R 1 and the second arc surface R 2 being arcuate. Breakage of the (positive electrode current collector 16) can be suppressed.

  In the above description, the bonding structure of the positive electrode current collecting group 21 and the positive electrode current collecting plate 23 has been described. However, the bonding structure of the negative electrode current collecting group 22 and the negative electrode current collecting plate 24 has the same structure. That is, the negative electrode current collector group 22 and the negative electrode current collector plate 24 are joined in the same manner in the procedure described with reference to FIGS. As a result, the negative electrode current collecting group 22 after bending is bent to the side where the negative electrode current collector plate 24 is joined, and the stacking direction from the bent portion 27 is the same as the positive electrode current collecting group 21 after bending. It is comprised by the two elements of the extension part 28 extended to. Further, the extending portion 28 of the negative electrode current collection group 22 has a welded portion W as a connection portion for connecting the negative electrode current collection group 22 and the negative electrode current collector plate 24. When the negative electrode current collecting group 22 is bent, the negative electrode current collecting plate 24 is disposed inside the bent portion 27 of the negative electrode current collecting group 22. That is, the negative electrode current collector plate 24 is also disposed in the space S formed inward by bending the negative electrode current collector group 22.

  Further, in the present embodiment, the positive electrode current collecting group 21 and the negative electrode current collecting group 22 are formed by collecting the positive electrode current collecting part 16 and the negative electrode current collecting part 20 in the same direction as shown in FIG. Yes. The positive electrode current collection group 21 and the negative electrode current collection group 22 are bent in the same direction. That is, both of the positive electrode current collecting group 21 and the negative electrode current collecting group 22 are bent toward one side of the electrode body 5. In addition, in the electrode body 5 of the present embodiment, two current collection groups including a single positive current collection group 21 and a single negative current collection group 22 are formed. The positive electrode current collection group 21 and the negative electrode current collection group 22 are bent in the same direction, so that all the current collection groups have a bent portion 27 curved in the same direction. In addition, the positive electrode current collecting plate 23 bonded to the positive electrode current collecting group 21 and the negative electrode current collecting plate 24 bonded to the negative electrode current collecting group 22 are formed as shown in FIGS. In 4), it protrudes toward each of the inner surfaces facing each other in the direction orthogonal to the stacking direction of the electrode body 5.

Hereinafter, the operation of the secondary battery 2 of the present embodiment will be described.
In the secondary battery 2 of the present embodiment, the positive electrode current collector plate 23 is disposed inward when the positive electrode current collector group 21 is bent. Similarly, in the secondary battery 2, the negative electrode current collector plate 24 is disposed inward when the negative electrode current collector group 22 is bent. Thereby, in the accommodation space of the electrode body 5 in the battery case 3, the space necessary for joining the positive current collector group 21 and the positive current collector plate 23 and the negative current collector group 22 and the negative current collector plate 24 is reduced. Has been. That is, as shown by a two-dot chain line in FIG. 8, when the positive electrode current collector plate 23 is joined to the upper surface of the positive electrode current collector group 21, a space corresponding to the thickness of the positive electrode current collector plate 23 is required. However, in this embodiment, the space is secured on the inner side of the positive electrode current collection group 21. As a result, the space for the thickness of the positive electrode current collector plate 23 required on the outer side of the positive electrode current collector group 21 becomes unnecessary, and the space necessary for joining the positive electrode current collector plate 23 is reduced. This also applies to the joining of the negative electrode current collector group 22 and the negative electrode current collector plate 24.

  Further, as shown in FIG. 8, the positive electrode current collector plate 23 is disposed inward of the positive electrode current collector group 21 by the thickness K of the positive electrode current collector group 21. Similarly, the negative electrode current collector plate 24 is also disposed inside the negative electrode current collector group 22 by the thickness K of the negative electrode current collector group 22. Therefore, using the space for the thickness K of the positive electrode current collection group 21 and the space for the thickness K of the negative electrode current collection group 22, as shown in FIG. The overcurrent protection circuit 25 can be disposed between the negative electrode terminal 8 and the negative electrode current collector plate 24. That is, the space for the thickness K is effectively used as a space for arranging other components. Therefore, the size of the secondary battery 2 can be reduced.

  Further, when the size of the secondary battery 2 is reduced, the space for mounting the secondary battery 2 can be reduced by mounting the secondary battery 2 on a vehicle. In the vehicle, the space is effectively used as a mounting space for other components. In other words, compared with a conventional secondary battery, electric power can be supplied more efficiently to an electric motor that becomes a prime mover of a vehicle even in the same space.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) A bent portion 27 is formed in the positive electrode current collecting group 21 and the negative electrode current collecting group 22, and the positive electrode current collecting plate 23 and the negative electrode current collecting plate 24 are connected to the inside of the bent portion 27. Thereby, the space required for each connection of the positive electrode current collection group 21 and the positive electrode current collection plate 23, and the negative electrode current collection group 22 and the negative electrode current collection plate 24 can be reduced. Specifically, the space can be reduced as compared with the case where the positive electrode current collector plate 23 and the negative electrode current collector plate 24 are connected to the outside of the bent portion 27. If the space is reduced in this way, the space can be effectively used. For example, the size of the secondary battery 2 can be reduced according to the reduced space. When the accommodation space for the electrode body 5 and the like is made equal, the reduced space is replaced with an accommodation space for another member (for example, the overcurrent protection circuit 25), or an active material layer is applied in accordance with the reduced space. The output can be increased by increasing the amount. Therefore, the space can be effectively used by the configuration of the present embodiment.

  (2) In addition, with the above configuration, the size of the electrode body 5 itself can be reduced. Moreover, when the electrode body 5 is made into the same physique, the volume of an active material layer can be increased. On the other hand, on the premise that the volume of the active material layer is not increased, the physique can be reduced in size, so that the space for accommodating the electrode body 5 in the battery case 3 can be reduced, and the physique of the secondary battery 2 can be reduced in size. Connected. Moreover, the space in the battery case 3 can also be used effectively by reducing the accommodation space of the electrode body 5 in the battery case 3.

  (3) A chamfered portion 26 was formed at the tips of the positive electrode current collector plate 23 and the negative electrode current collector plate 24. When the positive electrode current collecting group 21 and the negative electrode current collecting group 22 are bent, stress is applied to the bent portions. For this reason, when the positive electrode current collector plate 23 and the negative electrode current collector plate 24 that are not chamfered at the bent portion are contacted, the positive electrode current collector 16 (positive electrode current collector group 21) and the negative electrode current collector 20 ( The negative electrode current collecting group 22) may be broken. However, by forming the chamfered portion 26 on the positive electrode current collector plate 23 and the negative electrode current collector plate 24, it is possible to suppress breakage during bending.

  (4) Further, the chamfered portion 26 is formed so that the entire thickness of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 forms an arc shape. Therefore, it is possible to suppress breakage of the positive electrode current collector 16 (positive electrode current collector group 21) and the negative electrode current collector part 20 (negative electrode current collector group 22) as well as when bent.

  (5) The positive electrode current collector 16 and the negative electrode current collector 20 were formed on one side of the electrode body 5. Thereby, the cross-sectional areas of the positive electrode current collecting plate 23 and the negative electrode current collecting plate 24 joined to the positive electrode current collecting group 21 and the negative electrode current collecting group 22 can be increased. In the secondary battery 2, the current collection resistance changes according to the cross-sectional areas of the positive electrode current collector plate 23 and the negative electrode current collector plate 24. For this reason, current collection efficiency can be improved by enlarging the cross-sectional areas of the positive electrode current collector plate 23 and the negative electrode current collector plate 24.

  (6) The positive electrode current collection group 21 and the negative electrode current collection group 22 are bent in the same direction. Thereby, the arrangement of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 can be made uniform. Therefore, the positive electrode terminal 7 and the negative electrode terminal 8 can be easily connected to the positive electrode current collector plate 23 and the negative electrode current collector plate 24, respectively.

  (7) All of the positive electrode current collecting group 21 and the negative electrode current collecting group 22 formed on the electrode body 5 were bent. As a result, all of the positive electrode current collecting group 21 and the negative electrode current collecting group 22 are curved, so that each of the positive electrode current collecting group 21 and the positive electrode current collecting plate 23 and the negative electrode current collecting group 22 and the negative electrode current collecting plate 24 are joined. The space required for this can be reduced more significantly.

  (8) The lengths along the extending portions 28 of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 are set in the range of the length along the stacking direction of the electrode body 5. Thereby, the positive electrode current collecting plate 23 and the negative electrode current collecting plate 24 after the positive electrode current collecting group 21 and the negative electrode current collecting group 22 are bent are within the range from one end to the other end of the electrode body 5 in the stacking direction. That is, the positive electrode current collector plate 23 and the negative electrode current collector plate 24 do not protrude outside the electrode body 5. Therefore, it is possible to easily ensure insulation between the positive electrode current collector plate 23 and the negative electrode current collector plate 24 and other components (such as the battery case can 3). Moreover, the occurrence of dead space can be suppressed.

  (9) Insulating sheets 9 b and 9 c were attached to the inner surfaces of the main body member 4 and the lid member 6 of the battery case can 3. The inner surface of the lid member 6 is located on the positive electrode current collector 16 (H2) side to which the positive electrode current collector plate 23 is not connected. Similarly, the inner surface of the lid member 6 is located on the negative electrode current collector 20 side to which the negative electrode current collector plate 24 is not connected. Therefore, it is possible to ensure insulation between the positive electrode current collection group 21 and the negative electrode current collection group 22 and other components (such as the lid member 6 of the battery case can 3). The positive electrode current collector 16 (H2) side to which the positive electrode current collector plate 23 is not connected is the other surface side of the current collector group to which the connection member (positive electrode current collector plate 23) is not connected. Similarly, the negative electrode current collector part 20 side to which the negative electrode current collector plate 24 is not connected is the other surface side to which the connection member (negative electrode current collector plate 24) is not connected in the current collector group.

  (10) When the secondary battery 2 of this embodiment is mounted on a vehicle, when the secondary battery 2 is downsized, the space for mounting the secondary battery 2 in the vehicle can be reduced. Therefore, the space can be effectively used as a mounting space for other components. For example, the secondary battery 2 can be further mounted. Further, when the output of the secondary battery 2 is increased, the running performance (fuel consumption, acceleration, etc.) of the vehicle can be improved.

In addition, you may change this embodiment as follows.
The present invention is not limited to the laminated secondary battery 2 as in the embodiment, and may be applied to a wound secondary battery in which a belt-like positive electrode sheet and a belt-like negative electrode sheet are wound and laminated in layers. In the wound secondary battery, the positive electrode sheet and the negative electrode sheet are insulated with a separator interposed therebetween. When applied to a wound type secondary battery, the positive electrode tab-like portion 15 (positive electrode current collecting portion 16) and the negative electrode tab-like portion 19 (negative electrode current collecting portion 20) are formed as in the embodiment. It ’s fine.

  The entire region of the positive electrode tab-shaped portion 15 and the entire region of the negative electrode tab-shaped portion 19 may not be the positive electrode current collector 16 and the negative electrode current collector 20. That is, a coated portion and an uncoated portion may be formed on each of the positive electrode tab-shaped portion 15 and the negative electrode tab-shaped portion 19. In addition, the coating part used as the positive electrode current collection part 16 and the negative electrode current collection part 20 is formed in an outer side (edge part side) rather than an uncoated part.

  ○ Either one of the positive electrode current collection group 21 and the negative electrode current collection group 22 may be bent and the current collector plate may be joined inward. Even in this case, the space required for joining can be reduced on the side where the current collector plate is joined inward.

  O Three or more current collecting groups may be formed on the electrode body 5. In this case, a combination of a plurality of positive current collector groups 21 and a single negative current collector group 22, a combination of a single positive current collector group 21 and a plurality of negative current collector groups 22, or a plurality of positive current collector groups 21 and a plurality of positive current collector groups 21 Any combination of the negative electrode current collector group 22 may be used. Then, all of these current collecting groups may be bent and the current collecting plate may be joined inward, or one or a plurality of current collecting groups may be folded and the current collecting plate joined inward. You may do it.

  The positive electrode current collecting group 21 is formed by collecting the positive electrode current collecting part 16 toward the center of the electrode body 5, and the positive electrode current collecting group 21 is bent and the positive electrode current collecting plate 23 is joined inward. May be. Similarly, the negative electrode current collecting group 22 is formed by collecting the negative electrode current collecting part 20 toward the center of the electrode body 5, the negative electrode current collecting group 22 is bent, and the negative electrode current collecting plate 24 is formed inward. You may join.

  The positive electrode current collection group 21 is replaced with the positive electrode current collector 16 located on the outermost surface of the electrode body 5, and the positive electrode current collector 16 on the inner side of the positive electrode current collector 16 (near the center of the electrode body 5). You may collect it. Similarly, the negative electrode current collection group 22 is replaced with the negative electrode current collection part 20 located on the outermost surface in the electrode body 5, and the negative electrode current collection part inside the negative electrode current collection part 20 (near the center of the electrode body 5). You may collect towards 20.

  The length along the extending portion 28 of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 may be longer than the length from one end to the other end of the electrode body 5 in the stacking direction. In this case, the positive electrode current collector plate 23 and the negative electrode current collector plate 24 project outward from the electrode body 5, but it is only necessary to ensure insulation from the battery case can 3.

  ○ Although the positive electrode current collector plate 23 and the negative electrode current collector plate 24 are embodied as connection members, the connection member is not limited to a plate shape. For example, it may be embodied in a columnar (bar-shaped) connection member or a rectangular parallelepiped connection member.

  The chamfered portions 26 of the positive electrode current collector plate 23 and the negative electrode current collector plate 24 may be R chamfered or C chamfered. Further, rolling members (rollers) may be attached to the tips of the positive electrode current collector plate 23 and the negative electrode current collector plate 24. In this case, the rolling member becomes a chamfer.

The positive current collecting group 21 and the negative current collecting group 22 may be bent in different directions. In this case, the bending portion 27 is bent in different directions.
The bent portion 27 is formed by bending the positive electrode current collecting group 21 and the negative electrode current collecting group 22, but may be formed by bending the positive electrode current collecting group 21 and the negative electrode current collecting group 22. Further, any one of the bent portions 27 of the positive electrode current collecting group 21 and the negative electrode current collecting group 22 may be formed by bending, and the other may be formed by bending.

  ○ An insulating member such as an insulating sheet is directly attached to the positive current collector 16 side (the other surface side) to which the positive current collector 23 is not connected, and the positive current collector 16 and the battery case 3 (main body member) 4 and the lid member 6) may be secured. Similarly, an insulating member such as an insulating sheet is directly attached to the negative electrode current collector 20 side (the other surface side) to which the negative electrode current collector plate 24 is not connected, and the negative electrode current collector 20 and the battery case 3 ( You may ensure the insulation of the main body member 4 and the cover member 6). That is, if the insulation property of the positive electrode current collector 16 and the negative electrode current collector 20 and the battery case can 3 can be ensured, the insulating member is attached to the inner surface of the battery case can 3 as in the embodiment. Alternatively, they may be attached to the current collectors of the positive electrode current collector 16 and the negative electrode current collector 20. Further, the insulating member may be disposed between the inner surface of the battery case 3 and the current collector, even if it is not directly attached to the inner surface of the battery case 3 or the current collector.

  The positive electrode current collector plate 23 and the negative electrode current collector plate 24 may protrude toward the center of the electrode body 5. In this case, each length is set so that the positive electrode current collector plate 23 and the negative electrode current collector plate 24 do not interfere with each other. Further, an insulating member is disposed between the positive electrode current collector plate 23 and the negative electrode current collector plate 24.

The vehicle on which the secondary battery 2 of the embodiment is mounted may be an automobile or an industrial vehicle.
The present invention may be applied to other power storage devices such as electric double layer capacitors.

  The secondary battery 2 is a lithium ion secondary battery, but is not limited to this, and may be another secondary battery. In short, any ion may be used as long as ions move between the positive electrode active material layer and the negative electrode active material layer and transfer charge.

Next, a technical idea that can be grasped from the above embodiment and another example will be added below.
(A) In an electrode body in which a positive electrode and a negative electrode are insulated and laminated to form a layer, the same as the current collector formed on the edge of each electrode and not coated with an active material A current collecting group formed by collecting current collectors within a range from one end to the other end in the stacking direction of the electrode body, and on one outermost surface in the stacking direction of the current collecting group A connecting portion that is electrically connected to each electrode and a connecting member that connects each terminal that takes out electricity from each electrode, and at least one of the current collecting groups is curved toward the connecting portion side Alternatively, an electrode body comprising a bent portion bent and an extending portion extending from the bent portion in the stacking direction and having the connection portion.

  DESCRIPTION OF SYMBOLS 2 ... Secondary battery, 5 ... Electrode body, 7 ... Positive electrode terminal, 8 ... Negative electrode terminal, 9c ... Insulating sheet, 10 ... Positive electrode sheet, 11 ... Negative electrode sheet, 12 ... Separator, 13 ... Metal foil for positive electrodes, 14 ... Positive electrode Active material layer, 15 ... positive electrode tab-like portion, 16 ... positive electrode current collector portion, 17 ... negative electrode metal foil, 18 ... negative electrode active material layer, 19 ... negative electrode tab-like portion, 20 ... negative electrode current collector portion, 21 ... Positive electrode current collecting group, 22 ... Negative electrode current collecting group, 23 ... Positive electrode current collecting plate, 24 ... Negative electrode current collecting plate, 26 ... Chamfered portion, 27 ... Bending portion, 28 ... Extension portion.

Claims (10)

An electrode body that is formed by laminating and laminating the positive electrode and the negative electrode, a main body member that houses the electrode body, a lid member that closes the opening of the main body member, and each electrode In a power storage device comprising: a terminal for taking out each of the electricity; and a connecting member that connects each electrode and each terminal
A current collector formed at the edge of each electrode and not coated with an active material;
A current collection group formed by collecting current collecting parts of the same polarity within a range from one end to the other end in the stacking direction of the electrode body; and
One outermost surface in the stacking direction in the current collection group has a connection portion that is electrically connected to the connection member,
At least one of the current collection groups is formed with a bent portion that is bent or bent toward the connecting portion side, and an extending portion that extends from the bent portion in the stacking direction and has the connecting portion ,
In the direction from the lid member side to each electrode side, the lid member, the extending portion, and the connecting member are arranged in this order.
In the connecting member, at least a portion disposed inside the bent portion of the current collecting group is formed in a rectangular flat plate shape,
The power storage device according to claim 1, wherein the entire connection member is disposed closer to each electrode than an end portion closest to the lid member in the current collection group .   The power storage device according to claim 1, wherein the connecting member has a chamfered portion formed on a side edge in contact with the bent portion.   3. The power storage device according to claim 1, wherein the current collection group is formed by collecting the current collection unit on one side of the electrode body positioned in the stacking direction.   The bent portion that is bent or bent in the same direction is formed in all of the current collecting groups in which the bent portion and the extended portion are formed. The electrical storage apparatus as described in any one.   The electricity storage according to any one of claims 1 to 4, wherein the bent portion and the extending portion are formed in all current collecting groups formed in the electrode body. apparatus.   The length of the connecting member along the extending direction of the extending portion is set within a range from one end to the other end in the stacking direction of the electrode body. 5. The power storage device according to claim 1.   The power storage device according to any one of claims 1 to 6, wherein an insulating member is disposed on the other surface side of the current collection group to which the connection member is not connected. .   The power storage device according to claim 1, wherein the entire connection member is formed in a rectangular flat plate shape.   The power storage device according to any one of claims 1 to 8, wherein the extending portion extends from the bent portion to a distal end portion of the current collecting group. In a vehicle that travels by supplying electric power stored in a power storage device to an electric motor,
A vehicle comprising the power storage device according to any one of claims 1 to 9 as the power storage device.