JP2013251106A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which increases output voltages of individual power storage devices.SOLUTION: An electrode group 11 housed in a case 20 is composed of a first electrode body 31 and a second electrode body 41, and a first negative electrode collector part 33c of the first electrode body 31 is electrically connected with a second positive electrode collector part 42c of the second electrode body 41 in the case 20. A division wall 51, which is used for defining a first injection space 61 into which an electrolyte W1 reacting with the first electrode body 31 is injected and a second injection space 62 where an electrolyte W2 reacting with the second electrode body 41 is injected, is provided in the case 20.

Description

  The present invention relates to a power storage device including an electrode body.

  A secondary battery, which is a type of power storage device, is disclosed in Patent Document 1, for example. In such a secondary battery, a separator is interposed between the positive electrode and the negative electrode, the positive electrode and the negative electrode are insulated from each other by the separator, and a stacked electrode body in which these are alternately stacked is provided in the case. It is comprised by being accommodated with electrolyte solution.

  A positive electrode current collection group is formed on the positive electrode by integrating the positive electrode current collector. The positive current collector group is electrically connected to the positive current collector terminal, and the positive current collector terminal is electrically connected to a positive terminal provided on the case. A negative electrode current collecting group is formed on the negative electrode by integrating the negative electrode current collector. The negative electrode current collecting group is electrically connected to the negative electrode current collecting terminal, and the negative electrode current collecting terminal is electrically connected to the negative electrode terminal provided on the case. The assembled battery is configured by connecting a plurality of secondary batteries formed in this way in series.

JP-A-11-162443

By the way, in such a secondary battery, there is a demand to increase the output voltage of each secondary battery.
The present invention has been made to solve the above-described problems, and an object thereof is to provide a power storage device capable of increasing individual output voltages.

  In order to achieve the above object, according to the first aspect of the present invention, a first separator is interposed between a first positive electrode having a first positive electrode current collector and a first negative electrode having a first negative electrode current collector. In the state where the first positive electrode and the first negative electrode are insulated, a first electrode body formed by laminating these layers, a second positive electrode having a second positive electrode current collector, and a second negative electrode A second electrode body formed by laminating the second positive electrode and the second negative electrode in a state in which the second separator is interposed between the second negative electrode and the second negative electrode having the current collector, An electrode group including an insulator interposed between the first electrode body and the second electrode body is housed in a case together with an electrolyte, and the first positive electrode current collector is electrically connected to a positive electrode current collector terminal. And the second negative electrode current collector is electrically connected to a negative electrode current collector terminal, and the first negative electrode current collector and the And the 2 positive electrode current collector and summarized in that are electrically connected within the casing.

  According to this invention, since the first negative electrode current collector and the second positive electrode current collector are electrically connected within the case, the first electrode body and the second electrode body are connected in series, and the electrode group The output voltage can be increased. As a result, the output voltage of each power storage device can be increased.

  According to a second aspect of the present invention, in the first aspect of the present invention, the first negative electrode current collector is arranged such that the first negative electrode current collector and the second positive electrode current collector overlap each other. And the second positive electrode current collector are electrically connected.

  According to the present invention, for example, the first negative electrode current collector and the second positive electrode current collector are not overlapped, and the first negative electrode current collector and the second positive electrode current collector are in a shifted position, Compared to the case where the first negative electrode current collector and the second positive electrode current collector are electrically connected via the connecting member, the first negative electrode current collector and the second positive electrode current collector are easily electrically connected. can do.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the first positive electrode current collector and the second negative electrode current collector protrude from the same side of the electrode group. Is the gist.

  According to this invention, compared with the case where the first positive electrode current collector and the second negative electrode current collector protrude on different sides of the electrode group, the first positive electrode current collector and the second negative electrode current collector in the case. The arrangement space of the part can be reduced. Therefore, it is possible to reduce a useless space that does not contribute to the performance of the power storage device in the case.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the first positive electrode current collector, the first negative electrode current collector, and the second positive electrode current collector. The second negative electrode current collector is projected from the same side of the electrode group.

  According to this invention, compared with the case where the first negative electrode current collector and the second positive electrode current collector protrude from different sides of the first positive electrode current collector and the second negative electrode current collector and the electrode group, The arrangement space of the first negative electrode current collector and the second positive electrode current collector can be reduced. Therefore, it is possible to reduce a useless space that does not contribute to the performance of the power storage device in the case.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the electrolyte is an electrolytic solution, and the insulator is provided in the case in the first electrode. The gist of the present invention is a partition wall that partitions a first injection space into which the electrolytic solution that reacts with the body is injected and a second injection space into which the electrolytic solution that reacts with the second electrode body is injected.

  For example, if there is no partition wall and an electrolyte solution that reacts with the entire electrode group is injected into the case, the output voltage of the electrode group is increased. There is a risk of it. However, according to the present invention, the partition wall can separate the electrolytic solution that reacts with the first electrode body and the electrolytic solution that reacts with the second electrode body, so that the electrolytic solution is electrolyzed. Can be prevented.

The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the power storage device is a secondary battery.
According to this invention, the output voltage of each secondary battery can be increased.

  According to this invention, the output voltage of each power storage device can be increased.

(A) is sectional drawing of the secondary battery in embodiment, (b) is the 1-1 sectional view taken on the line in Fig.1 (a). The perspective view which shows a 1st electrode body and a 2nd electrode body. The perspective view which shows an electrode group.

  Hereinafter, an embodiment in which the present invention is embodied in a secondary battery mounted on a vehicle (for example, an industrial vehicle or a passenger vehicle) will be described with reference to FIGS. The secondary battery is used to drive a travel motor.

  As illustrated in FIGS. 1A and 1B, the secondary battery 10 includes an electrode group 11 and an aluminum case 20 that houses the electrode group 11. The case 20 includes a case main body 21 having a bottomed rectangular box shape in which an opening 21 a into which the electrode group 11 can be inserted is formed on one surface, and a rectangular plate-shaped lid 22 that closes the opening 21 a of the case main body 21. It is configured. A positive electrode terminal 23a and a negative electrode terminal 23b project outward from the terminal wall 23, which is one of the four side walls provided upright from the periphery of the lid 22.

  As shown in FIG. 2, the electrode group 11 includes a first electrode body 31 and a second electrode body 41. The first electrode body 31 includes a first positive electrode sheet 32 and a first positive electrode sheet 32 interposed between a first positive electrode sheet 32 as a first positive electrode and a first negative electrode sheet 33 as a first negative electrode. The first negative electrode sheet 33 is insulated and a plurality of these are laminated in a certain direction. That is, the first electrode body 31 of this embodiment is a stacked electrode body in which a plurality of first positive electrode sheets 32, first negative electrode sheets 33, and first separators 34 are stacked in a certain direction (stacking direction). is there.

  The 1st positive electrode sheet 32 has the 1st positive electrode active material layer 32a by which the active material was apply | coated, and the 1st positive electrode uncoated part 32b by which the active material is not apply | coated. The first positive electrode current collector 32c protrudes from one end of the first positive electrode sheet 32 in the longitudinal direction at the edge 321b of the first positive electrode uncoated part 32b. The 1st negative electrode sheet 33 has the 1st negative electrode active material layer 33a by which an active material is apply | coated, and the 1st negative electrode uncoated part 33b by which the active material is not apply | coated. The first negative electrode current collector 33c protrudes from the longitudinal center of the first negative electrode sheet 33 at the edge 331b of the first negative electrode uncoated portion 33b. The first positive electrode sheets 32 are stacked in a certain direction so that the first positive electrode current collectors 32c overlap, and the first negative electrode sheets 33 are overlapped with the first negative electrode current collectors 33c. Laminated in a certain direction. The metal foil that is the base material of the first positive electrode sheet 32 is an aluminum foil, and the metal foil that is the base material of the first negative electrode sheet 33 is a copper foil.

  The second electrode body 41 includes a second positive electrode sheet 42 as a second positive electrode and a second negative electrode sheet 43 as a second negative electrode with a sheet-like second separator 44 interposed therebetween. 2 The negative electrode sheet 43 is insulated and a plurality of these are laminated in a certain direction. That is, the second electrode body 41 of the present embodiment is a stacked electrode body in which a plurality of second positive electrode sheets 42, second negative electrode sheets 43, and second separators 44 are stacked in a certain direction (stacking direction). is there.

  The second positive electrode sheet 42 includes a second positive electrode active material layer 42a formed by applying an active material, and a second positive electrode uncoated portion 42b not applied with an active material. A second positive electrode current collector 42c protrudes from the longitudinal center of the second positive electrode sheet 42 at the edge 421b of the second positive electrode uncoated part 42b. The second negative electrode sheet 43 has a second negative electrode active material layer 43a formed by applying an active material, and a second negative electrode uncoated portion 43b not applied with an active material. A second negative electrode current collector 43c protrudes from the end 431b of the second negative electrode uncoated portion 43b near the other end in the longitudinal direction of the first negative electrode sheet 33. Each second positive electrode sheet 42 is laminated in a certain direction so that each second positive electrode current collector 42c overlaps, and each second negative electrode sheet 43 is arranged so that each second negative electrode current collector 43c overlaps. Laminated in a certain direction. The metal foil that is the base material of the second positive electrode sheet 42 is an aluminum foil, and the metal foil that is the base material of the second negative electrode sheet 43 is a copper foil.

  As shown in FIG. 1 (a), each first positive electrode current collector 32c is joined to a positive electrode current collector terminal 19a that is aggregated to form a rectangular plate by, for example, ultrasonic welding, thereby positive electrode current collector terminals. It is electrically connected to 19a. Each of the second negative electrode current collectors 43c is electrically connected to the negative electrode current collector terminal 19b by joining, for example, by ultrasonic welding to the negative electrode current collector terminal 19b having a rectangular plate shape.

  As shown in FIG. 1B, a partition wall 51 as an insulator having an insulating property is interposed between the first electrode body 31 and the second electrode body 41. The partition wall 51 has a plate shape and is formed of ceramics such as alumina. The partition wall 51 is formed to be larger in size than the first electrode body 31 and the second electrode body 41, and protrudes outward from all four sides of the first electrode body 31 and the second electrode body 41. It is interposed between the electrode body 31 and the second electrode body 41. Since the partition wall 51 is interposed between the first electrode body 31 and the second electrode body 41, a chemical reaction between the first electrode body 31 and the second electrode body 41 does not occur. It has become.

  As shown in FIG. 3, the first electrode body 31 and the second electrode body 41 are arranged such that the first negative electrode current collectors 33c and the second positive electrode current collectors 42c overlap each other. Each first negative electrode current collector 33c and each second positive electrode current collector 42c are arranged between the first positive electrode current collector 32c and the second negative electrode current collector 43c. The electrodes overlap at the same distance from the negative electrode current collector 43c. Then, as shown in FIG. 1B, the first negative electrode current collectors 33 c and the second positive electrode current collectors 42 c are aggregated toward the upper side of the partition wall 51, and above the partition wall 51. They are electrically connected to each other by, for example, ultrasonic welding. The first electrode body 31 and the second electrode body 41 are connected in series by electrical connection between the first negative electrode current collectors 33c and the second positive electrode current collectors 42c. Each first positive electrode current collector 32c, each first negative electrode current collector 33c, each second positive electrode current collector 42c, and each second negative electrode current collector 43c are on the same side of the electrode group 11 (facing the terminal wall 23). Projecting in the same direction (one direction) from the end face of the electrode group 11.

  The electrode group 11 configured as described above is accommodated in the case body 21 via the opening 21 a of the case body 21 so that the stacking direction of the electrode group 11 is orthogonal to the inner surface 221 of the lid 22. And each 1st positive electrode current collection part 32c of the 1st positive electrode sheet 32 and the positive electrode terminal 23a are electrically connected via the positive electrode current collection terminal 19a, and each 2nd negative electrode current collection of the 2nd negative electrode sheet 43 is carried out. The portion 43c and the negative electrode terminal 23b are electrically connected via the negative electrode current collecting terminal 19b.

  Furthermore, the inner surface 221 of the lid 22 and the end surface on the opening 21a side of the case body 21 are joined by laser welding, and the opening 21a of the case body 21 is closed by the lid 22 and sealed. Further, the partition wall 51 is erected on the wall 24 facing the terminal wall 23 in the case body 21, and the partition wall 51 allows the inside of the case 20 to be an electrolyte as an electrolyte that reacts with the first electrode body 31. The first injection space 61 into which W1 is injected and the second injection space 62 into which an electrolyte solution W2 as an electrolyte that reacts with the second electrode body 41 is injected. Then, the electrolytic solution W1 is injected into the first injection space 61 from one injection hole (not shown) provided in the case 20, and the second injection hole (not shown) provided in the case 20 is first. The secondary battery 10 is configured by injecting the electrolytic solution W2 into the 2-injection space 62.

Next, the operation of this embodiment will be described.
In the secondary battery 10 of the present embodiment, the first electrode body 31 and the second electrode body 41 are provided by electrical connection in the case 20 between the first negative electrode current collectors 33c and the second positive electrode current collectors 42c. Are connected in series, the output voltage of the electrode group 11 is increased. As a result, the output voltage of each secondary battery 10 is increased as compared with the conventional secondary battery.

In the above embodiment, the following effects can be obtained.
(1) The electrode group 11 accommodated in the case 20 is configured by the first electrode body 31 and the second electrode body 41, and the first negative electrode current collector 33 c of the first electrode body 31 and the second electrode body 41 The two positive electrode current collectors 42 c were electrically connected within the case 20. Therefore, since the first electrode body 31 and the second electrode body 41 are connected in series by the electrical connection between the first negative electrode current collector 33c and the second positive electrode current collector 42c, the output voltage of the electrode group 11 Can be increased. As a result, the output voltage of each secondary battery 10 can be increased.

  (2) The first negative electrode current collector 33c and the second positive electrode current collector 42c are disposed so as to overlap each other, thereby electrically connecting the first negative electrode current collector 33c and the second positive electrode current collector 42c. . Therefore, for example, the first negative electrode current collector 33c and the second positive electrode current collector 42c do not overlap, and the first negative electrode current collector 33c and the second positive electrode current collector 42c are in a shifted position, Compared to the case where the first negative electrode current collector 33c and the second positive electrode current collector 42c are electrically connected via a connecting member, the first negative electrode current collector 33c and the second positive electrode current collector 42c are more easily connected. Can be electrically connected.

  (3) The first positive electrode current collector 32 c and the second negative electrode current collector 43 c are projected from the same side of the electrode group 11. Therefore, compared with the case where the first positive electrode current collector 32c and the second negative electrode current collector 43c protrude from different sides of the electrode group 11, the first positive electrode current collector 32c and the second negative electrode current collector in the case 20 are provided. The arrangement space of the electric part 43c can be reduced. Therefore, it is possible to reduce a useless space that does not contribute to the performance of the secondary battery 10 in the case 20.

  (4) The first positive electrode current collector 32c, the first negative electrode current collector 33c, the second positive electrode current collector 42c, and the second negative electrode current collector 43c are projected from the same side of the electrode group 11. Therefore, compared with the case where the first negative electrode current collector 33c and the second positive electrode current collector 42c protrude from different sides of the first positive electrode current collector 32c and the second negative electrode current collector 43c and the electrode group 11, The arrangement space of the first negative electrode current collector 33c and the second positive electrode current collector 42c in the case 20 can be reduced. Therefore, it is possible to reduce a useless space that does not contribute to the performance of the secondary battery 10 in the case 20.

  (5) In the case 20, the first injection space 61 into which the electrolytic solution W1 that reacts with the first electrode body 31 is injected, and the second injection space 62 into which the electrolytic solution W2 that reacts with the second electrode body 41 is injected. Were partitioned by a partition wall 51. For example, if the partition wall 51 is not present and an electrolyte solution that reacts with the entire electrode group 11 is injected into the case 20, the output voltage of the electrode group 11 is increased. There is a risk of electrolysis. However, in the present embodiment, the partition wall 51 can separate the electrolytic solution W1 that reacts with the first electrode body 31 and the electrolytic solution W2 that reacts with the second electrode body 41. It is possible to prevent electrolysis.

  (6) The first positive electrode current collectors 32c are protruded from one end in the longitudinal direction of the first positive electrode sheet 32 at the edge 321b of the first positive electrode uncoated part 32b, and the second negative electrode current collectors 43c are The second negative electrode uncoated portion 43b is protruded from the end 431b of the second negative electrode uncoated portion 43b toward the other end in the longitudinal direction of the first negative electrode sheet 33. Thereby, since the electrode group 11 is being fixed to the case 20 via the positive electrode current collection terminal 19a and the negative electrode current collection terminal 19b in the both ends of a longitudinal direction, the electrode group 11 is hard to incline with respect to the case 20, The electrode group 11 can be stably fixed to the case 20.

  (7) The first negative electrode current collectors 33c and the second positive electrode current collectors 42c are arranged between the first positive electrode current collectors 32c and the second negative electrode current collectors 43c. And the second negative electrode current collector 43c overlap each other at the same distance. Therefore, between each 1st negative electrode current collection part 33c and each 2nd positive electrode current collection part 42c, and the 1st positive electrode current collection part 32c, and the 1st negative electrode current collection part 33c, the 2nd positive electrode current collection part 42c, and the 2nd The space between the negative electrode current collector 43c can be as much as possible. Accordingly, the connection between each first positive electrode current collector 32c and the positive electrode current collector terminal 19a, the connection between each second negative electrode current collector 43c and the negative electrode current collector terminal 19b, and each first negative electrode current collector 33c and each of the first current collectors 33c. The connection with the two positive electrode current collector 42c can be facilitated.

In addition, you may change the said embodiment as follows.
In the embodiment, the partition wall 51 may be deleted. In this case, it is necessary to arrange the first electrode body 31 and the second electrode body 41 so that, for example, the first negative electrode sheet 33 and the second negative electrode sheet 43 face each other with a separator interposed therebetween. In this case, the electrolyte injected into the case 20 is an electrolyte that can withstand the output voltage of the electrode group 11, or a solid electrolyte or a gel electrolyte is used as the electrolyte.

  In the embodiment, the first negative electrode current collector 33c and the second positive electrode current collector 42c may protrude from different sides of the first positive electrode current collector 32c and the second negative electrode current collector 43c and the electrode group 11. .

In the embodiment, the first positive electrode current collector 32 c and the second negative electrode current collector 43 c may protrude from different sides of the electrode group 11.
In the embodiment, each of the first negative electrode current collectors 33c and each of the second positive electrode current collectors 42c may be electrically connected, for example, by fastening with bolts, or each first negative electrode current collector 33c and each second positive electrode current collector 42c may be electrically connected by caulking with a caulking member.

  In the embodiment, the first negative electrode current collector 33c and the second positive electrode current collector 42c are not overlapped, and the first negative electrode current collector 33c and the second positive electrode current collector 42c are arranged at positions shifted from each other. May be. In this case, you may electrically connect the 1st negative electrode current collection part 33c and the 2nd positive electrode current collection part 42c via a connection member, for example.

In the embodiment, it is only necessary that at least one of the first negative electrode current collectors 33c and one of the second positive electrode current collectors 42c are electrically connected.
In the embodiment, for example, a wound-type first electrode configured by interposing a strip-shaped separator between a strip-shaped positive electrode sheet and a negative electrode sheet and winding them in a spiral around the winding axis. The electrode group may be constituted by the body and the second electrode body. Here, the wound-type electrode body is an electrode body formed by winding a series of positive electrode sheets, negative electrode sheets, and separators in layers. Further, for example, an electrode group may be constituted by a laminated first electrode body and a wound second electrode body.

  In the embodiment, as the first positive electrode, the first negative electrode, the second positive electrode, and the second negative electrode, the sheet-like first positive electrode sheet 32, the first negative electrode sheet 33, the second positive electrode sheet 42, and the second negative electrode sheet 43 are used. However, the present invention is not limited thereto, and for example, a plate-like positive electrode and negative electrode having a predetermined amount of thickness may be used.

In the embodiment, a solid electrolyte or a gel electrolyte may be used as the electrolyte.
The present invention has been embodied in the vehicle secondary battery 10, but is not limited thereto, and may be embodied in a secondary battery other than the vehicle.

  The present invention has been embodied in the secondary battery 10, but is not limited thereto, and may be embodied in a power storage device such as an electric double layer capacitor.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 11 ... Electrode group, 19a ... Positive electrode current collection terminal, 19b ... Negative electrode current collection terminal, 20 ... Case, 31 ... 1st electrode body, 32 ... 1st positive electrode as 1st positive electrode Sheet, 32c ... first positive electrode current collector, 33 ... first negative electrode sheet as first negative electrode, 33c ... first negative electrode current collector, 34 ... first separator, 41 ... second electrode body, 42 ... second positive electrode As a second positive electrode sheet, 42c as a second positive electrode current collector, 43 as a second negative electrode sheet as a second negative electrode, 43c as a second negative electrode current collector, 44 as a second separator, 51 as a partition as an insulator Wall, 61 ... 1st injection space, 62 ... 2nd injection space, W1, W2 ... Electrolyte as electrolyte.

Claims (6)

A first separator is interposed between the first positive electrode having the first positive electrode current collector and the first negative electrode having the first negative electrode current collector to insulate between the first positive electrode and the first negative electrode. A first electrode body formed by laminating these layers in a state;
A second separator is interposed between the second positive electrode having the second positive electrode current collector and the second negative electrode having the second negative electrode current collector to insulate between the second positive electrode and the second negative electrode. In a state, a second electrode body formed by laminating these layers,
An electrode group including an insulator interposed between the first electrode body and the second electrode body is housed in a case together with an electrolyte,
The first positive electrode current collector is electrically connected to a positive electrode current collector terminal, and the second negative electrode current collector is electrically connected to a negative electrode current collector terminal,
The power storage device, wherein the first negative electrode current collector and the second positive electrode current collector are electrically connected within the case.   The first negative electrode current collector and the second positive electrode current collector are disposed so that they overlap each other, so that the first negative electrode current collector and the second positive electrode current collector are electrically connected. The power storage device according to claim 1.   The power storage device according to claim 1, wherein the first positive electrode current collector and the second negative electrode current collector protrude from the same side of the electrode group.   The first positive electrode current collector, the first negative electrode current collector, the second positive electrode current collector, and the second negative electrode current collector protrude from the same side of the electrode group. The power storage device according to any one of claims 3 to 4. The electrolyte is an electrolytic solution,
The insulator includes a first injection space into which the electrolytic solution that reacts with the first electrode body is injected and a second injection space into which the electrolytic solution that reacts with the second electrode body is injected in the case. 5. The power storage device according to claim 1, wherein the power storage device is a partition wall that partitions the first and second partitions.   The power storage device according to any one of claims 1 to 5, wherein the power storage device is a secondary battery.