JP6972175B2 - Battery pack - Google Patents

Description

Embodiments of the present invention relate to a power storage module and a battery pack.

Batteries such as primary batteries and secondary batteries generally include an electrode group including a positive electrode and a negative electrode, an exterior member for accommodating the electrode group, and a positive electrode terminal and a negative electrode terminal provided on the exterior member.

Currently, metal cans and containers made of laminated film have been put into practical use as exterior members. The metal can is obtained by deep drawing from a metal plate such as aluminum. In order to make a can by deep drawing, the metal plate needs to have a certain thickness, which hinders the thinning of the exterior member and leads to volume capacity loss. For example, when an outer can having a plate thickness of 0.5 mm is applied to a battery having a thickness of 13 mm, the ratio of the total plate thickness of the outer can to the battery thickness is about 7.7%. Further, since the outer can has high rigidity and is inferior in flexibility, a gap is likely to be generated between the inner wall of the outer can and the electrode group. Therefore, a gap may be formed between the positive electrode and the negative electrode of the electrode group, and the charge / discharge cycle performance may be deteriorated. Further, the highly rigid outer can is liable to cause problems such as cracking when an excessive force is applied to the vicinity of the welded portion.

In order to solve the above-mentioned problems, it is considered to reduce the thickness of the metal can.

However, if the thickness of the metal can is reduced, when a component such as a bus bar is welded to the positive electrode terminal or the negative electrode terminal, the metal can is easily deformed by the force applied to the metal can during welding. As a result, the position of the component with respect to the positive electrode terminal or the negative electrode terminal is displaced, and it becomes difficult to weld the component to a predetermined position of the positive electrode terminal and the negative electrode terminal.

Japanese Unexamined Patent Publication No. 2011-233492 Japanese Unexamined Patent Publication No. 2012-252811

An object to be solved by the present invention is to provide a power storage module and a battery pack having excellent reliability.

According to the embodiment, a battery pack including a plurality of batteries and a plurality of bus bars for electrically connecting the plurality of batteries is provided. The battery includes a flat electrode group, an exterior member, and a positive electrode external terminal and a negative electrode external terminal. The electrode group includes a band-shaped positive electrode current collector and a positive electrode material layer formed on the positive electrode current collector except for one end parallel to the long side of the positive electrode collector, and the positive electrode material layer is not formed. On the negative electrode collector except for the positive electrode whose one end parallel to the long side of the positive electrode current collector forms a positive electrode current collection tab, the strip-shaped negative electrode current collector, and the one end parallel to the long side of the negative electrode current collector. One end parallel to the long side of the negative electrode current collector, which includes the negative electrode material layer formed in the negative electrode material layer, is arranged between the negative electrode and the negative electrode forming the negative electrode current collecting tab. The separator is wound into a flat shape. The positive electrode current collecting tab wound in a flat shape is located on the first end surface, and the negative electrode current collecting tab wound in a flat shape is located on the second end surface. The exterior member includes a first exterior portion made of stainless steel having a bottomed square tube shape and a flange portion at an opening, and a second exterior portion made of stainless steel. The electrode group is housed in the space formed by welding the flange portion of the first exterior portion and the second exterior portion. The first end surface and the second end surface of the electrode group face the inner surface of the side wall of the first exterior portion, and the first exterior portion has a through hole opened in the side wall. In the positive electrode external terminal and the negative electrode external terminal, the positive electrode external terminal is connected to the positive electrode current collecting tab on the first end surface, and the negative electrode external terminal is connected to the negative electrode current collecting tab on the second end surface, and extends from the head and the head, respectively. The shaft portion includes the protruding shaft portion, the shaft portion is caulked and fixed to the through hole opened in the side wall of the first exterior portion, and the head portion protrudes to the outside of the first exterior portion. The plurality of batteries are stacked in a state where the main surfaces of the exterior members face each other, and the positive electrode external terminal and the negative electrode external terminal are located next to each other among the batteries located next to each other. The plurality of bus bars are arranged in parallel with the extending direction of the flange portion of the first exterior portion, and rise from the flat plate-shaped first connection portion having a through hole and the first connection portion, and the first exterior portion is formed. It has a second connecting portion that is bent along the side surface of the portion. For the batteries located next to each other, the second connection portion of one bus bar is fixed to the head of the positive electrode external terminal of one battery, and the second connection portion of the other bus bar is fixed to the head of the negative electrode external terminal of another battery. The connection is fixed and the first connection of one bus bar and the first connection of the other bus bar are connected through the through holes of each other.

The schematic perspective view of the battery of the power storage module of 1st Embodiment. An enlarged perspective view of the vicinity of the positive electrode terminal portion of the battery shown in FIG. 1. The plan view of the second exterior part. The plan view of the first exterior part. The perspective view of the electrode group of the battery shown in FIG. The perspective view which shows the state which expanded the electrode group partially. FIG. 3 is a perspective view showing the vicinity of the external terminal of the power storage module in which a bus bar is attached to the external terminal of the battery shown in FIG. 1. FIG. 6 is a cross-sectional view of the power storage module shown in FIG. 7 cut along a line shown by VIII-VIII. The perspective view which shows the process of attaching a bus bar to the external terminal of the battery shown in FIG. FIG. 6 is a cross-sectional view showing the vicinity of a positive electrode terminal portion in a power storage module shown in FIG. 7 cut in the long side direction. The perspective view which shows the other example of the external terminal of the battery of the power storage module of embodiment. FIG. 11 is a perspective view showing the vicinity of the external terminal in an example of a power storage module in which a bus bar is fixed to the external terminal of the battery shown in FIG. FIG. 12 is a cross-sectional view in which the vicinity of the external terminal of the power storage module shown in FIG. 12 is cut along the line XIII-XIII. FIG. 11 is a perspective view showing the vicinity of the external terminal in another example of the power storage module in which the bus bar is fixed to the external terminal of the battery shown in FIG. 11. FIG. 14 is a perspective view showing a state in which the vicinity of the positive electrode external terminal of the power storage module of FIG. 14 is cut in the long side direction of the battery. FIG. 11 is a perspective view showing the vicinity of the external terminal in another example of the power storage module in which the bus bar is fixed to the external terminal of the battery shown in FIG. 11. The perspective view which shows the example of the assembled battery of the battery pack of 2nd Embodiment. FIG. 6 is a perspective view showing the vicinity of one of the short side side surfaces of the assembled battery shown in FIG. A perspective view of the assembled battery shown in FIG. 17 as viewed from the side surface on the other short side. FIG. 19 is an enlarged perspective view of the vicinity of the side surface on the other short side of the assembled battery shown in FIG. The perspective view which shows the other example of the assembled battery of the battery pack of 2nd Embodiment. FIG. 2 is a perspective view showing the vicinity of one of the short side side surfaces of the assembled battery shown in FIG. 21. FIG. 21 is a perspective view seen from the other short side side surface of the assembled battery shown in FIG. 21. FIG. 23 is an enlarged perspective view of the vicinity of the side surface on the other short side of the assembled battery shown in FIG. 23. FIG. 3 is a perspective view showing the vicinity of an external terminal in an example of the power storage module of the third embodiment. FIG. 5 is a cross-sectional view of the power storage module shown in FIG. 25 cut along the long side direction. A perspective view of the assembled battery of the power storage module of the third embodiment as viewed from the side surface on one short side. FIG. 27 is an enlarged perspective view of the vicinity of one short side side surface of the assembled battery shown in FIG. 27. A perspective view of the assembled battery shown in FIG. 27 as viewed from the side surface on the other short side. FIG. 29 is an enlarged perspective view of the vicinity of the side surface on the other short side of the assembled battery shown in FIG. 29. A perspective view of another example of the assembled battery of the power storage module according to the third embodiment as viewed from the side surface on one short side. FIG. 31 is an enlarged perspective view of the vicinity of one of the short side side surfaces of the assembled battery shown in FIG. 31. A perspective view of the assembled battery shown in FIG. 31 as viewed from the side surface on the other short side. FIG. 31 is an enlarged perspective view of the vicinity of the side surface on the other short side of the assembled battery shown in FIG. 31.

Hereinafter, embodiments will be described with reference to the drawings. It should be noted that the same reference numerals are given to the common configurations throughout the embodiments, and duplicate description will be omitted. In addition, each figure is a schematic diagram for explaining the embodiment and promoting its understanding, and the shape, dimensions, ratio, etc. are different from those of the actual device, but these are described below and known techniques. The design can be changed as appropriate by taking into consideration.

[First Embodiment]
According to the first embodiment, a battery including a flat electrode group, an exterior member, and a terminal portion is provided. The flat electrode group includes a positive electrode, a positive electrode current collecting tab electrically connected to the positive electrode, a negative electrode, and a negative electrode current collecting tab electrically connected to the negative electrode. The positive electrode current collecting tab wound in a flat shape is located on the first end surface, and the negative electrode current collecting tab wound in a flat shape is located on the second end surface. The exterior member includes a first exterior portion made of stainless steel having a bottomed square tube shape and a flange portion at an opening, and a second exterior portion made of stainless steel. The electrode group is housed in the space formed by welding the flange portion of the first exterior portion and the second exterior portion. The first end surface and the second end surface of the electrode group face the inner surface of the side wall of the first exterior portion. The terminal portion includes a through hole opened in the side wall of the first exterior portion and an external terminal electrically connected to the positive electrode or the negative electrode. The external terminal includes the head and a shaft portion extending from the head. The head protrudes to the outside of the first exterior portion. The shaft portion is caulked and fixed to the through hole of the first exterior portion. A pair of tapered portions is provided on the head of the external terminal. The bus bar is fixed to the taper part.

The power storage module of the first embodiment will be described with reference to FIGS. 1 to 10.

The power storage module 100 includes a battery and a bus bar. The battery shown in FIG. 1 is a non-aqueous electrolyte battery. The battery includes an exterior member 1, an electrode group 2, a positive electrode terminal portion 3, a negative electrode terminal portion 4, and a non-aqueous electrolyte (not shown).

As shown in FIGS. 1 to 3, the exterior member 1 includes a first exterior portion 5 and a second exterior portion 6. The first exterior portion 5 is a stainless steel bottomed square tube container, and has a flange portion 5b in the opening portion 5a. As shown in FIGS. 1, 2 and 4, a recess is provided near the center of the corner connecting the short side wall and the bottom of the first exterior portion 5, and the bottom of the recess is inclined. The surface is 5c. The first exterior portion 5 has a depth equal to or less than the size of the opening 5a (the maximum length of the portion that becomes the opening area). A more preferable first exterior portion 5 has a depth equal to or less than the short side of the portion to be the opening area (for example, the one shown in FIG. 1). The first exterior portion 5 is manufactured from, for example, a stainless steel plate by shallow drawing. On the other hand, the second exterior portion 6 is a rectangular plate made of stainless steel. The electrode group 2 is housed in a space formed by welding the flange portion 5b of the first exterior portion 5 to the four sides of the second exterior portion 6. For welding, for example, resistance seam welding is used. Resistance seam welding can achieve high airtightness and heat resistance at a lower cost than laser welding.

As shown in FIG. 5, the electrode group 2 has a flat shape. Further, as shown in FIG. 6, the electrode group 2 includes a positive electrode 7, a negative electrode 8, and a separator 9 arranged between the positive electrode 7 and the negative electrode 8. The positive electrode 7 has, for example, a strip-shaped positive electrode collector made of foil, a positive electrode current collecting tab 7a having one end parallel to the long side of the positive electrode collector, and a positive electrode collecting except at least a portion of the positive electrode collecting tab 7a. The positive electrode material layer (positive electrode active material-containing layer) 7b formed on the electric body is included. On the other hand, the negative electrode 8 is excluding, for example, a band-shaped negative electrode current collector made of foil, a negative electrode current collector tab 8a having one end parallel to the long side of the negative electrode current collector, and at least a portion of the negative electrode current collector tab 8a. The negative electrode material layer (negative electrode active material-containing layer) 8b formed on the negative electrode current collector is included. In the electrode group 2, the positive electrode material layer 7b of the positive electrode 7 and the negative electrode material layer 8b of the negative electrode 8 face each other via the separator 9, and the positive electrode current collecting tab 7a on one side of the winding shaft is larger than the negative electrode 8 and the separator 9. The positive electrode 7, the separator 9, and the negative electrode 8 are wound in a flat shape so as to protrude and the negative electrode current collecting tab 8a protrudes from the positive electrode 7 and the separator 9 on the other side. Therefore, in the electrode group 2, the positive electrode current collecting tab 7a wound in a flat spiral shape is located on the first end surface perpendicular to the winding axis. Further, the negative electrode current collecting tab 8a wound in a flat spiral shape is located on the second end surface perpendicular to the winding axis. The insulating sheet (not shown) covers the outermost periphery of the electrode group 2 except for the positive electrode current collecting tab 7a and the negative electrode current collecting tab 8a. The electrode group 2 holds a non-aqueous electrolyte (not shown).

The backup positive electrode lead 11 (first positive electrode lead) is made by bending a conductive plate into a U shape, and sandwiches a portion (near the center) of the positive electrode current collecting tab 7a excluding curved portions at both ends. The layers of the electric tab 7a are brought into close contact with each other. The positive electrode current collecting tab 7a and the backup positive electrode lead 11 are integrated by welding, whereby the positive electrode 7 is electrically connected to the backup positive electrode lead 11 via the positive electrode current collecting tab 7a. Welding is performed, for example, by ultrasonic welding.

The backup negative electrode lead 12 (first negative electrode lead) is made by bending a conductive plate into a U shape, and sandwiches a portion (near the center) of the negative electrode current collecting tab 8a excluding curved portions at both ends. The layers of the electric tab 8a are brought into close contact with each other. The negative electrode current collecting tab 8a and the backup negative electrode lead 12 are integrated by welding, whereby the negative electrode 8 is electrically connected to the backup negative electrode lead 12 via the negative electrode current collecting tab 8a. Welding is performed, for example, by ultrasonic welding.

The positive electrode terminal portion 3 and the negative electrode terminal portion 4 will be described. Since the positive electrode terminal portion 3 and the negative electrode terminal portion 4 have the same structure, the positive electrode terminal portion 3 will be described as an example. FIG. 7 is a perspective view showing a portion where a bus bar is attached to the head of the positive electrode terminal portion 3 of the battery shown in FIG. 1. Further, FIG. 8 shows a cross-sectional view of the battery shown in FIG. 1 cut along the axial direction of the positive electrode external terminal 14 (direction indicated by the line VIII-VIII in FIG. 7).

As shown in FIG. 8, the positive electrode terminal portion 3 includes a through hole 13 opened in the inclined surface 5c of the first exterior portion 5, a positive electrode external terminal 14, a positive electrode insulating gasket 15, and a positive electrode insulating plate (first). (Positive electrode insulating member) 16 and the like.

The first through hole 13 is provided on the inclined surface 5c of the first exterior portion 5 by burring processing, and the rising portion serving as a side wall protrudes inward of the first exterior portion 5.

As shown in FIG. 8, the positive electrode external terminal 14 has a substantially pyramidal trapezoidal shape, and includes a head portion 17 having a long side in the short side direction of the first exterior portion 5, and a cylindrical shaft portion 18. As shown in FIG. 7, the head 17 has a rectangular top surface 17a, first and second inclined surfaces 17b and 17c connected to opposite long sides of the top surface 17a, and four sides of the lower surface with respect to the top surface 17a. It has a tapered portion 17d provided in the above. The columnar shaft portion 18 extends from the lower surface of the head portion 17. The positive electrode external terminal 14 is formed of a conductive material such as aluminum or an aluminum alloy.

Since the tapered portion 17d is provided on each side of the lower surface of the head 17, the tapered portion provided on the facing short side and the tapered portion provided on the facing long side form a pair. Each of the two pairs of tapered portions 17d is inclined so that the area of the cross section of the head portion 17 becomes smaller toward the bottom. Therefore, the two pairs of tapered portions 17d form a quadrangular pyramid-shaped tapered portion.

The positive electrode external terminal 14 has a quadrilateral top surface 17a and first and second inclined surfaces 17b and 17c connected to two opposite sides of the top surface, so that any one of the three surfaces can be formed. The welding direction can be changed by selecting the welding surface.

As shown in FIG. 8, the positive electrode insulating gasket 15 is a cylindrical body (cylinder portion) having a flange portion 15a at one open end. As shown in FIG. 8, the positive electrode insulating gasket 15 has a cylindrical body portion inserted into the through hole 13, and a flange portion 15a is arranged on the outer periphery of the through hole 13 on the outer surface of the first exterior portion 5. .. The positive electrode insulating gasket 15 includes, for example, fluororesin, fluororubber, polyphenylene sulfide resin (PPS resin), polyether ether ketone resin (PEEK resin), polypropylene resin (PP resin), polybutylene terephthalate resin (PBT resin), and the like. It is made of resin.

As shown in FIG. 8, the positive electrode insulating plate (first positive electrode insulating member) 16 is a rectangular insulating plate having through holes. The positive electrode insulating plate 16 is arranged on the outer surface 5c of the first exterior portion 5. As shown in FIG. 8, the flange portion 15a of the positive electrode insulating gasket 15 is inserted into the through hole of the positive electrode insulating plate 16.

As shown in FIG. 9, the bus bar 200 rises substantially perpendicularly from one side of the flat plate-shaped first connecting portion 201 having the through hole 201a and the first connecting portion 201, and the short side of the first exterior portion 5. It has a second connecting portion 202 bent along the side surface and a rectangular notch 203 provided near the center of the long side of the second connecting portion 202. As shown in FIG. 8, the end surface 204 of the notch 203 has a tapered shape that is inclined so that the opening area becomes smaller toward the lower side (positive electrode insulating plate 16 side). The tapered shape of the end face 204 of the cutout portion 203 corresponds to the shape of the tapered portion 17d. The cutout portion 203 of the bus bar 200 is inserted into the tapered portion 17d of the head portion 17 of the positive electrode external terminal 14, and the end surface 204 of the cutout portion 203 is fitted to the tapered portion 17d as shown in FIG. The portion where the tapered portion 17d and the end surface 204 of the notch portion 203 are in contact with each other is joined by welding, for example, whereby the positive electrode external terminal 14 and the bus bar 200 are electrically connected. The first connection portion 201 can be used for electrically connecting to another battery or the like. Examples of the welding method include laser welding, resistance welding, ultrasonic welding and the like.

The positive electrode terminal portion 3 may further include a positive electrode terminal lead 19. The positive electrode terminal lead 19 is a conductive plate having a through hole 19a.

When the positive electrode terminal portion 3 includes the positive electrode terminal lead 19 (second positive electrode lead), the positive electrode terminal portion 3 can further include the positive electrode insulating reinforcing member 20. As shown in FIG. 10, the positive electrode insulating reinforcing member 20 reinforces the side wall on the short side including the inclined surface 5c of the first exterior portion 5, and has a substantially U-shaped cross section. That is, the positive electrode insulating reinforcing member 20 is formed from the rectangular bottom plate 20a, the side plate 20b rising vertically from the long side of the bottom plate 20a, the inclined plate 20c connected to the long side of the side plate 20b, and the long side of the inclined plate 20c. The upper plate 20d extending horizontally is integrated. The inclined plate 20c has a recess 20e. The recess 20e is provided with a through hole 20f. In the positive electrode insulating reinforcing member 20, the bottom plate 20a and the side plate 20b cover a corner portion composed of a second exterior portion 6 and a first exterior portion 5. The shaft portion 18 of the positive electrode external terminal 14 is inserted into the through hole 20f of the inclined plate 20c. The lower end surface of the positive electrode insulating gasket 15 and the end surface of the side wall of the through hole 13 of the first exterior portion 5 are in contact with the surface of the recess 20e of the inclined plate 20c. Further, the back surface of the recess 20e of the inclined plate 20c is in contact with the positive electrode terminal lead 19. Further, the upper plate 20d is in contact with the bottom surface of the first exterior portion 5.

With the above-mentioned arrangement, the positive electrode insulating reinforcing member 20 insulates the first exterior portion 5 and the positive electrode terminal lead 19, and also includes the short side of the exterior member, particularly the inclined surface 5c of the first exterior portion 5. The vicinity of the side wall can be reinforced.

The shaft portion 18 of the positive electrode external terminal 14 is inserted into the positive electrode insulating gasket 15, the through hole 20f of the positive electrode insulating reinforcing member 20, and the through hole 19a of the positive electrode terminal lead 19, and then plastically deformed by caulking. As a result, these members are integrated, and the positive electrode external terminal 14 is electrically connected to the positive electrode terminal lead 19. Therefore, the positive electrode external terminal 14 also plays the role of a rivet. The boundary between the end surface of the shaft portion 18 of the positive electrode external terminal 14 and the through hole 19a of the positive electrode terminal lead 19 may be welded by a laser or the like to provide a stronger connection and improve electrical conductivity.

The positive electrode intermediate lead 21 (third positive electrode lead) is a rectangular or strip-shaped conductive plate bent in a substantially U shape. The positive electrode intermediate lead 21 is arranged between the backup positive electrode lead 11 and the positive electrode terminal lead 19. One outer surface of the positive electrode intermediate lead 21 is fixed to the backup positive electrode lead 11 by, for example, welding, and the other outer surface is fixed to the positive electrode terminal lead 19 by, for example, welding. With such a configuration, the backup positive electrode lead 11, the positive electrode intermediate lead 21, and the positive electrode terminal lead 19 are electrically connected. Examples of the welding method include laser welding, resistance welding, ultrasonic welding and the like.

The negative electrode terminal portion 4 has the same structure as the positive electrode terminal portion 3. That is, the negative electrode terminal portion 4 includes a through hole opened in the inclined surface 5c of the first exterior portion 5, a negative electrode external terminal, a negative electrode insulating gasket, and a negative electrode insulating plate (first negative electrode insulating member). .. Further, the negative electrode terminal portion 4 can further include a negative electrode terminal lead (second negative electrode lead). The negative electrode terminal lead is a conductive plate having a through hole. When the negative electrode terminal portion 4 includes the negative electrode terminal lead, the negative electrode terminal portion 4 can further include a negative electrode insulating reinforcing member. Further, a negative electrode intermediate lead (third negative electrode lead) is arranged between the backup negative electrode lead and the negative electrode terminal lead. These members have the same structure as described in the positive electrode terminal portion 3. For example, the bus bar having the structure shown in FIG. 9 is fitted to the head of the negative electrode external terminal. That is, the notch portion of the bus bar is inserted into the tapered portion of the head of the negative electrode external terminal, and the notch portion is fitted into the tapered portion. The portion where the tapered portion and the end face of the notched portion are in contact with each other is joined by welding, for example, whereby the negative electrode external terminal and the bus bar are electrically connected.

The electrode group 2 is housed in the first exterior portion 5 so that the first end surface 7a faces the positive electrode terminal portion 3 and the second end surface 8a faces the negative electrode terminal portion 4. Therefore, the plane intersecting the first end surface 7a and the second end surface 8a of the electrode group 2 faces the bottom surface in the first exterior portion 5, and the curved surface intersecting the first end surface 7a and the second end surface 8a is the first exterior. It faces the long side side surface in the portion 5.

In the corner portion connecting the short side wall surface and the bottom portion of the first exterior portion 5, there are gaps between the first end surface 7a and the second end surface 8a of the electrode group 2. By providing an inwardly projecting recess in the corner portion connecting the short side wall surface and the bottom of the first exterior portion 5 and making the bottom of the recess a inclined surface 5c, the dead space in the first exterior portion 5 is reduced. Therefore, it is possible to increase the volumetric energy density of the battery. Further, by arranging the positive electrode terminal portion 3 and the negative electrode terminal portion 4 on each of the inclined surfaces 5c, the terminal portion is installed as compared with the case where the positive electrode terminal portion 3 and the negative electrode terminal portion 4 are provided on the short side side surface having no inclined surface. The area can be increased. Therefore, it is possible to increase the diameters of the shaft portion 18 of the positive electrode external terminal 14 and the shaft portion of the negative electrode external terminal, so that a large current (high rate current) can be passed with low resistance.

The second exterior portion 6 functions as a lid for the first exterior portion 5. The electrode group 2 is sealed in the exterior member 1 by welding the flange portion 5b of the first exterior portion 5 and the four sides of the second exterior portion 6.

The power storage module shown in FIGS. 1 to 10 described above is in a space formed by welding a first stainless steel exterior portion having a flange portion at an opening and a second stainless steel exterior portion. Includes an exterior member in which the electrode group is housed. Since the first and second exterior parts are made of stainless steel, high strength can be maintained even when the plate thickness of the first and second exterior parts is reduced. As a result, since the flexibility of the exterior member can be increased, it becomes easy to restrain the electrode group by decompression sealing or applying a load from the outside of the exterior member. As a result, the distance between the electrodes of the electrode group can be stabilized and the resistance can be lowered, and it becomes easy to realize a battery pack having vibration resistance and impact resistance. Further, if the flexibility of the first and second exterior parts is high, the distance from the inner surface of the first and second exterior parts to the electrode group can be easily shortened, so that the heat dissipation of the battery can be improved. ..

The first and second exterior parts made of stainless steel are easy to weld and can be sealed by inexpensive resistance seam welding. Therefore, it is possible to realize an exterior member having a higher gas sealing property than a container made of a laminated film at a low cost. In addition, the heat resistance of the exterior member can be improved. For example, SUS304 has a melting point of 1400 ° C, whereas Al has a melting point of 650 ° C.

Further, by providing the tapered portion on the head of the external terminal, it becomes easy to fix a component such as a bus bar to the head. Therefore, when a component such as a bus bar is welded to the head of the external terminal, the external terminal can be easily positioned and welded to a desired position with high strength. Therefore, the reliability of the battery can be further improved.

For example, as illustrated in FIG. 8, since the tapered end surface 204 of the notch 203 of the bus bar 200 is fitted to the quadrangular pyramid-shaped tapered portion 17d on the lower surface of the head 17, the positioning of the bus bar 200 becomes easy. The bus bar 200 is welded with high strength to a predetermined position on the top surface 17a of the head 17. As a result, the reliability of the battery can be improved.

Further, since a new insulating member can be fixed between the tapered portion of the head of the external terminal and the first exterior portion, a short circuit or the like due to contact between the first exterior portion and another battery or the like can occur. It can be avoided.

The pair of tapered portions may be provided only on the short side or only on the long side instead of being provided on all sides of the lower surface of the head of the external terminal. The pair of tapered portions need not be provided over the entire side, and may be in a point-symmetrical relationship with each other. The pair of tapered portions is not limited to one set, and may have a plurality of sets.

Instead of providing the tapered portion on the lower surface of the head, the side surface of the head may be used as the tapered portion. An example thereof is shown in FIGS. 11 to 16.

11 and 12 are examples in which the shape of the head is a quadrangular pyramid shape (pyramid shape). As shown in FIG. 11, the head 117 of the positive electrode terminal portion and / or the negative electrode terminal portion has a quadrangular pyramid shape (pyramid shape). That is, the top surface 117a of the head 117 is a rectangular plane. The four side surfaces 117b, 117c, 117d, and 117e are pyramidal surfaces, and are inclined so that the cross-sectional area of the head increases toward the bottom. The four side surfaces 117b, 117c, 117d, 117e function as tapered portions.

As shown in FIG. 12, the bus bar 300 rises substantially vertically from one side of the flat plate-shaped first connecting portion 301 and the first connecting portion 301, and runs along the side surface of the short side of the first exterior portion 5. It has a bent second connecting portion 302 and a rectangular through hole 303 provided in the second connecting portion 302. As shown in FIG. 13, the inner side surface of the through hole 303 has a tapered shape that is inclined so that the opening area increases toward the lower side (insulating plate 116 side). The tapered shape of the inner surface of the through hole 303 corresponds to the shape of the tapered portions 117b, 117c, 117d, 117e of the head 117. The through hole 303 of the bus bar 300 is inserted into the tapered portions 117b to 117e of the head portion 117, and the through hole 303 is fitted into the tapered portions 117b to 117e as shown in FIG. The portions where the tapered portions 117b to 117e are in contact with the inner side surface of the through hole 303 are joined by welding, for example, whereby the positive electrode external terminal and / or the negative electrode external terminal and the bus bar are electrically connected. The first connection portion 301 can be used for electrically connecting to another battery or the like. Examples of the welding method include laser welding, resistance welding, ultrasonic welding and the like. The first insulating member 116 is arranged between the inclined surface 5C of the first exterior portion 5 and the lower surface of the head 117 and the second connecting portion 302 of the bus bar 300 to insulate them.

As shown in FIGS. 14 and 15, the bus bar 400 rises substantially vertically from one side of the flat plate-shaped first connecting portion 401 and the first connecting portion 401, and is attached to the short side side surface of the first exterior portion 5. It has a second connecting portion 402 bent along the line and a rectangular notch 403 provided near the center of the long side of the second connecting portion 402. The three end faces of the notch 403 have a tapered shape that is inclined so that the opening area increases toward the lower side (insulating plate 116 side). The tapered shapes of the three end faces of the cutout portion 403 correspond to the shapes of the tapered portions 117b, 117c, 117d, 117e of the head 117. The cutout portion 403 of the bus bar 400 is inserted into the tapered portions 117b, 117c, 117d of the head 117, and the cutout portion 403 is fitted into the tapered portions 117b, 117c, 117d as shown in FIGS. 14 and 15. The portions where the tapered portions 117b, 117c, 117d and the end faces of the notched portions 403 are in contact with each other are joined by welding, for example, whereby the positive electrode external terminal and / or the negative electrode external terminal and the bus bar are electrically connected. The first connection portion 401 can be used for electrically connecting to another battery or the like. Examples of the welding method include laser welding, resistance welding, ultrasonic welding and the like. The first insulating member 116 is arranged between the inclined surface 5C of the first exterior portion 5 and the lower surface of the head 117 and the second connecting portion 402 of the bus bar 400 to insulate them.

FIG. 16 is an example in which the shape of the head is a truncated cone shape. As shown in FIG. 16, the head 217 of the positive electrode terminal portion and / or the negative electrode terminal portion has a truncated cone shape. That is, the top surface 217a of the head 217 is a circular plane. The side peripheral surface 217b is a pyramidal surface, and is inclined so that the cross-sectional area of the head increases toward the bottom. The side peripheral surface 217b functions as a tapered portion.

As shown in FIG. 16, the bus bar 500 rises substantially vertically from one side of the flat plate-shaped first connecting portion 501 and the first connecting portion 501, and runs along the side surface of the short side of the first exterior portion 5. It has a bent second connection portion 502 and a circular through hole 503 provided in the second connection portion 502. The inner peripheral surface of the through hole 503 has a tapered shape that is inclined so that the opening area increases toward the lower side (insulating plate 116 side). The tapered shape of the inner peripheral surface of the through hole 503 corresponds to the shape of the tapered portion 217b of the head head 217. The through hole 503 of the bus bar 500 is inserted into the tapered portion 217b of the head portion 217, and the through hole 503 is fitted into the tapered portion 217b as shown in FIG. The portion where the tapered portion 217b and the inner peripheral surface of the through hole 503 are in contact with each other is joined by welding, for example, whereby the positive electrode external terminal and / or the negative electrode external terminal and the bus bar are electrically connected. The first connection 501 can be used to electrically connect to another battery or the like. Examples of the welding method include laser welding, resistance welding, ultrasonic welding and the like. The first insulating member 116 is arranged between the inclined surface 5C of the first exterior portion 5 and the lower surface of the head portion 217 and the second connecting portion 502 of the bus bar 500 to insulate them.

The material constituting the bus bar is not particularly limited, and includes, for example, aluminum, an aluminum alloy, and the like.

The tapered portion may be provided only on one of the positive electrode external terminal or the negative electrode external terminal, or may be provided on both the positive electrode external terminal and the negative electrode external terminal. By providing tapered portions on both the positive electrode external terminal and the negative electrode external terminal, the reliability of the battery can be further improved.

It is desirable that the plate thickness of the first exterior portion and the second exterior portion is in the range of 0.02 mm or more and 0.3 mm or less. Within this range, the contradictory properties of mechanical strength and flexibility can be achieved at the same time. A more preferable range of the plate thickness is 0.05 mm or more and 0.15 mm or less.

The inclined portion is not limited to the one provided near the center of the short side of the exterior member, and may extend over the entire short side of the exterior member.

As the second exterior portion, a flat plate as illustrated in FIG. 3 can be used, but instead of the flat plate, one having a flange portion at the opening may be used. Examples of such a structure include those similar to the first exterior portion.

The exterior member may further be provided with a safety valve or the like that can release the pressure inside the battery when the internal pressure of the battery rises above a specified value.

The backup positive electrode lead and the backup negative electrode lead are not limited to the U-shaped conductive plate, and a conductive flat plate may be used. It is also possible to configure the configuration so that the backup positive electrode lead, the backup negative electrode lead, or both are not used.

As described above, according to the power storage module of the first embodiment, since the tapered portion is provided on the head of the external terminal and the bus bar is fixed to the tapered portion, the plates of the first and second exterior portions are provided. High strength and reliability can be obtained even when the thickness is reduced. Therefore, it is possible to provide a power storage module having excellent flexibility and heat dissipation, and having high strength and reliability.

The battery of the power storage module according to the embodiment may be a primary battery or a secondary battery. An example of the battery according to the embodiment is a lithium ion secondary battery.

The first positive electrode lead and the first negative electrode lead can be formed from, for example, aluminum, an aluminum alloy material, copper, nickel-plated copper, or the like. In order to reduce the contact resistance, the material of the lead is preferably the same as the material of the positive electrode current collector or the negative electrode current collector which can be electrically connected to the lead.

The first positive electrode insulating member and the first negative electrode insulating member, and the positive and negative insulating reinforcing members are, for example, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polypropylene (PP), polyethylene (PE), and the like. It is formed from a thermoplastic resin such as nylon, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), and polyetheretherketone (PEEK).

The positive electrode, the negative electrode, the separator, and the non-aqueous electrolyte contained in the battery of the power storage module of the embodiment will be described below.

1) Positive electrode The positive electrode may include, for example, a positive electrode current collector, a positive electrode material layer held by the positive electrode current collector, and a positive electrode current collector tab. The positive electrode material layer can contain, for example, a positive electrode active material, a conductive agent, and a binder.

As the positive electrode active material, for example, an oxide or a sulfide can be used. Examples of oxides and sulfides include manganese dioxide (MnO ₂ ) that stores lithium, iron oxide, copper oxide, nickel oxide, lithium manganese composite oxides (eg Li _x Mn ₂ O ₄ or Li _x MnO ₂ ), lithium nickel composite oxides (e.g., Li _x NiO _2), lithium cobalt composite oxide (e.g., Li _x CoO _2), lithium nickel cobalt composite oxide (e.g., _{LiNi 1-y Co y O 2} ), lithium manganese cobalt composite oxide (For example, Li _x Mn _y Co _1-y O ₂ ), lithium manganese nickel composite oxide having a spinel structure (for example, Li _x Mn _2-y Ni _y O ₄ ), lithium phosphorus oxide having an olivine structure (for example, Li _x). FePO ₄ , Li _x Fe _1-y Mn _y PO ₄ , Li _x CoPO ₄ ), iron sulfate (Fe ₂ (SO ₄ ) ₃ ), vanadium oxide (eg V ₂ O ₅ ), and lithium nickel cobalt manganese composite oxidation Things can be mentioned. In the above equation, 0 <x ≦ 1 and 0 <y ≦ 1. As the active material, these compounds may be used alone, or a plurality of compounds may be used in combination.

The binder is compounded to bind the active material to the current collector. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorinated rubber.

The conductive agent is added as necessary in order to improve the current collecting performance and suppress the contact resistance between the active material and the current collector. Examples of conductive agents include carbonaceous materials such as acetylene black, carbon black and graphite.

In the positive electrode material layer, the positive electrode active material and the binder are preferably blended in a proportion of 80% by mass or more and 98% by mass or less and 2% by mass or more and 20% by mass or less, respectively.

Sufficient electrode strength can be obtained by setting the amount of the binder to 2% by mass or more. Further, by setting the content to 20% by mass or less, the blending amount of the insulating material of the electrode can be reduced and the internal resistance can be reduced.

When a conductive agent is added, the positive electrode active material, the binder and the conductive agent are 77% by mass or more and 95% by mass or less, 2% by mass or more and 20% by mass or less, and 3% by mass or more and 15% by mass or less, respectively. It is preferable to mix in a ratio. The above-mentioned effect can be exhibited by setting the amount of the conductive agent to 3% by mass or more. Further, by setting the content to 15% by mass or less, the decomposition of the non-aqueous electrolyte on the surface of the positive electrode conductive agent under high temperature storage can be reduced.

The positive electrode current collector is preferably an aluminum foil or an aluminum alloy foil containing at least one element selected from Mg, Ti, Zn, Ni, Cr, Mn, Fe, Cu and Si.

The positive electrode current collector is preferably integrated with the positive electrode current collector tab. Alternatively, the positive electrode current collector may be separate from the positive electrode current collector tab.

2) Negative electrode The negative electrode can include, for example, a negative electrode current collector, a negative electrode material layer held by the negative electrode current collector, and a negative electrode current collector tab. The negative electrode material layer can contain, for example, a negative electrode active material, a conductive agent, and a binder.

As the negative electrode active material, for example, a metal oxide, a metal nitride, an alloy, carbon or the like that can occlude and release lithium ions can be used. It is preferable to use a substance capable of occluding and releasing lithium ions at a noble potential of 0.4 V or more (against Li / Li ^{+) as the negative electrode active material.}

The conductive agent is blended in order to improve the current collecting performance and suppress the contact resistance between the negative electrode active material and the current collector. Examples of conductive agents include carbonaceous materials such as acetylene black, carbon black and graphite.

The binder is added to fill the gaps between the dispersed negative electrode active materials and to bind the negative electrode active material and the current collector. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorinated rubber, and styrene butagen rubber.

The active material, the conductive agent and the binder in the negative electrode material layer are blended in a ratio of 68% by mass or more and 96% by mass or less, 2% by mass or more and 30% by mass or less, and 2% by mass or more and 30% by mass or less, respectively. Is preferable. By setting the amount of the conductive agent to 2% by mass or more, the current collecting performance of the negative electrode layer can be improved. Further, by setting the amount of the binder to 2% by mass or more, the binding property between the negative electrode material layer and the current collector can be sufficiently exhibited, and excellent cycle characteristics can be expected. On the other hand, it is preferable that the conductive agent and the binder are 28% by mass or less, respectively, in order to increase the capacity.

As the current collector, a material that is electrochemically stable at the occlusion potential and the emission potential of lithium, which is the negative electrode active material, is used. The current collector is preferably made of copper, nickel, stainless steel or aluminum, or an aluminum alloy containing at least one element selected from Mg, Ti, Zn, Mn, Fe, Cu, and Si. The thickness of the current collector is preferably in the range of 5 to 20 μm. A current collector having such a thickness can balance the strength of the negative electrode and the weight reduction.

The negative electrode current collector is preferably integrated with the negative electrode current collector tab. Alternatively, the negative electrode current collector may be separate from the negative electrode current collector tab.

For the negative electrode, for example, a negative electrode active material, a binder and a conductive agent are suspended in a general-purpose solvent to prepare a slurry, and this slurry is applied to a current collector and dried to form a negative electrode material layer. , Made by pressing. The negative electrode may also be manufactured by forming a negative electrode active material, a binder and a conductive agent in the form of pellets to form a negative electrode material layer, which is arranged on a current collector.

3) Separator The separator may be formed of, for example, a porous film containing polyethylene, polypropylene, cellulose, or polyvinylidene fluoride (PVdF), or a non-woven fabric made of synthetic resin. Above all, the porous film made of polyethylene or polypropylene can be melted at a constant temperature to cut off the electric current, so that the safety can be improved.

4) Electrolyte As the electrolyte, for example, a non-aqueous electrolyte can be used.

The non-aqueous electrolyte may be, for example, a liquid non-aqueous electrolyte prepared by dissolving the electrolyte in an organic solvent, or a gel-like non-aqueous electrolyte in which a liquid electrolyte and a polymer material are combined.

The liquid non-aqueous electrolyte is preferably one in which the electrolyte is dissolved in an organic solvent at a concentration of 0.5 mol / L or more and 2.5 mol / L or less.

Examples of electrolytes to be dissolved in organic solvents include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), and lithium hexafluoroarsenide (LiAsF _6). ), Lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), and lithium salts such as bistrifluoromethylsulfonylimide lithium [LiN (CF ₃ SO ₂ ) ₂ ], and mixtures thereof. The electrolyte is preferably one that is difficult to oxidize even at a high potential, and LiPF ₆ is most preferable.

Examples of organic solvents include cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), and vinylene carbonate; such as diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate (MEC). Chain carbonates; cyclic ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), and dioxolane (DOX); chain ethers such as dimethoxyethane (DME) and diethoxyethane (DEE); γ-butyrolactone. (GBL), acetonitrile (AN), and sulfolane (SL) are included. These organic solvents can be used alone or as a mixed solvent.

Examples of polymeric materials include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), and polyethylene oxide (PEO).

Alternatively, as the non-aqueous electrolyte, a room temperature molten salt (ionic melt) containing lithium ions, a polymer solid electrolyte, an inorganic solid electrolyte, or the like may be used.

The room temperature molten salt (ionic melt) refers to a compound that can exist as a liquid at room temperature (15 to 25 ° C.) among organic salts composed of a combination of an organic cation and an anion. The room temperature molten salt includes a room temperature molten salt that exists as a liquid by itself, a room temperature molten salt that becomes a liquid when mixed with an electrolyte, and a room temperature molten salt that becomes a liquid when dissolved in an organic solvent. Generally, the melting point of a room temperature molten salt used in a non-aqueous electrolyte battery is 25 ° C. or lower. In addition, the organic cation generally has a quaternary ammonium skeleton.

According to the power storage module of the embodiment described above, the bus bar is fixed to the tapered portion provided on the head of the external terminal, so that the reliability can be improved.

The terminal portion may be applied to both the positive electrode terminal portion and the negative electrode terminal portion, but it can also be applied to either the positive electrode terminal portion or the negative electrode terminal portion.
(Second embodiment)
The battery pack of the second embodiment includes at least one of the power storage modules of the embodiment. The battery pack of the embodiment may include an assembled battery having the power storage module of the embodiment as a unit cell.

Examples of the assembled battery of the battery of the second embodiment are shown in FIGS. 17 to 24.

As shown in FIGS. 17 to 20, the battery pack 601 includes an assembled battery 101 using the power storage module 100 of the first embodiment shown in FIG. 1 as a unit cell. A plurality of (for example, four) unit cells 100 _{1 to} 100 ₄ are laminated so that the main surfaces of the exterior members 1 face each other. A plurality of unit cells 100 _{1 to} 100 ₄ are connected in series. As shown in FIGS. 17 and 18, the bus bar 200 is used on one short side side surface of the assembled battery 101. On the other side of the short side, as shown in FIGS. 19 and 20, a triangular columnar bus bar 602 is used. In other short side face, as shown in FIG. 20, the outermost positive electrode external terminal 14 (in the figure the uppermost layer) unit cell 100 _1, the unit cell 100 ₂ is located next to the unit cell 100 ₁ The negative electrode external terminal 314 is electrically connected to the triangular columnar bus bar 602. The triangular columnar bus bar 602 is arranged between the top surface 17a of the head of the positive electrode external terminal 14 and the top surface 317a of the head of the negative electrode external terminal 314.

Also, the positive electrode external terminal 14 of the unit cell 100 ₃ is located next to the unit cell 100 _2, electrical and negative external terminal 314 of the unit cell 100 ₄ located next to the unit cell 100 ₃ is the triangular busbar 602 It is connected to the. The triangular columnar bus bar 602 is arranged between the top surface 17a of the head of the positive electrode external terminal 14 and the top surface 317a of the head of the negative electrode external terminal 314. The negative electrode insulating plate (first negative electrode insulating member) 216 is arranged between the inclined surface 5C and the head of the negative electrode external terminal 314 to insulate them.

The two top surfaces of the external terminals and the bus bar are electrically connected by welding. For welding, for example, laser welding, arc welding, and resistance welding are used.

On the other hand, as shown in FIG. 18, the bus bar 200 is attached to the head of each of the positive and negative electrode external terminals connected by the triangular columnar bus bar. The method of fixing the bus bar 200 is as described with reference to FIG. The first connection portion 201 of the bus bar 200 fixed to the positive electrode external terminal 14 of the unit cell 100 ₂ and the first connection portion 201 of the bus bar 200 fixed to the negative electrode external terminal (not shown) of _{the unit cell 100 3.} And are superimposed. The bolt 603 is inserted into the through hole of the first connecting portion 201, and the bolt 603 is fixed by the nut 604, whereby the negative electrode external terminal and the positive electrode external terminal are electrically connected by the bus bar.

As shown in FIG. 18, the bus bar 200 fitted to the tapered portion of the head of the negative electrode external terminal of _one of the outermost (top layer in the figure) unit cell 1001 serves as the negative electrode external terminal of the assembled battery 101. Can work. Furthermore, (in the drawing the lowermost layer) other bus bar 200 is fitted into the tapered portion of the head of the positive electrode external terminal 14 of the unit cell 100 ₄ can function as a positive electrode external terminal of the battery pack 101.

As a result of the connection described above, the unit cells 100 _{1 to} 100 ₄ are connected in series to obtain a 4-series assembled battery 101. In the battery pack including the assembled battery 101, a triangular columnar bus bar is arranged between the top surface of the head of the negative electrode external terminal and the top surface of the head of the positive electrode external terminal, and these are electrically joined by being joined. It is connected to the. Further, the positive and negative electrode external terminals having a counter electrode relationship with these positive and negative electrode external terminals are electrically connected by using a bus bar fitted to the tapered portion of the head. As a result, the gap between unit cells can be reduced. Therefore, the volumetric energy density of the assembled battery 101 can be increased.

The battery pack 601 shown in FIGS. 21 to 24 includes an assembled battery in which two assembled battery units in which two unit cells are connected in parallel are connected in series. As the unit cell, the power storage module 100 of the first embodiment shown in FIG. 1 is used. A plurality of (for example, four) unit cells 100 _{1 to} 100 ₄ are laminated so that the main surfaces of the exterior members 1 face each other.

One of the short side face of the battery pack in the (first short side face), as shown in FIG. 22, the outermost negative electrode external terminal 314 of the unit cell 100 ₁ (uppermost in the figure), the unit cell It is electrically connected to the negative electrode external terminal 314 of the unit cell 100 ₂ located next to 100 _{1 by a triangular columnar bus bar 602.} The triangular columnar bus bar 602 is arranged between the top surfaces 317a of the head of the negative electrode external terminal 314. Reference numeral 216 shows a negative electrode insulating plate (first negative electrode insulating member).

Also, the positive electrode external terminal 14 of the unit cell 100 ₃ is located next to the unit cell 100 ₂ is electrically by the positive external terminal 14 and the triangular prism-shaped bus bar 602 of the unit cell 100 ₄ located next to the unit cell 100 ₃ It is connected. The triangular columnar bus bar 602 is arranged between the top surfaces 17a of the head of the positive electrode external terminal 14.

The two top surfaces of the external terminals and the bus bar are electrically connected by welding. For welding, for example, laser welding, arc welding, and resistance welding are used.

In the unit cell 100 ₁ and the unit cell 100 ₂ , as shown in FIG. 22, the negative electrode external terminal 314 is provided on the first short side side surface, but the other short side side surface (second short side). As shown in FIG. 24, a positive electrode external terminal 14 is provided on the side surface). Positive electrode external terminal of the unit cell 100 ₁ 14 are electrically connected by the positive electrode external terminal 14 and the triangular prism-shaped bus bar 602 of the unit cell 100 _2. The triangular columnar bus bar 602 is arranged between the top surfaces 17a of the head of the positive electrode external terminal 14.

By the above method, the unit cell 100 ₁ and the unit cell 100 ₂ are connected in parallel to obtain the first assembled battery unit 102.

On the other hand, in the unit cell 100 ₃ and the unit cell 100 ₄ , as shown in FIG. 22, the positive electrode external terminal 14 is provided on the first short side side surface, but the second short side side surface is provided. As shown in FIG. 24, the negative electrode external terminal 314 is provided. Negative external terminal 314 of the unit cell 100 ₃ is electrically connected by a negative electrode external terminal 314 and the triangular prism-shaped bus bar 602 of the unit cell 100 _4. The triangular columnar bus bar 602 is arranged between the top surfaces 317a of the head of the negative electrode external terminal 314.

By the above method, the unit cell 100 ₃ and the unit cell 100 ₄ are connected in parallel to obtain the second assembled battery unit 103.

In the second short side face of the assembled battery 101, the positive electrode external terminal 14 of the unit cell 100 _2, the negative electrode external terminal 314 of the unit cells 100 _3, as shown in FIG. 24, the bus bar 200 is attached There is. The method of fixing the bus bar 200 is as described with reference to FIG. The first connection portion 201 of the bus bar 200 fixed to the positive electrode external terminal 14 of the unit cell 100 ₂ and the first connection portion 201 of the bus bar 200 fixed to the negative electrode external terminal 314 of the _{unit cell 100 3 are overlapped with each other.} Has been done. The bolt 603 is inserted into the through hole of the first connecting portion 201, and the bolt 603 is fixed by the nut 604, whereby the negative electrode external terminal 314 and the positive electrode external terminal 14 are electrically connected by the bus bar 200. As a result, the first assembled battery unit 102 and the second assembled battery unit 103 are connected in series.

As shown in FIG. 22, the first short side side surface of the assembled battery 101 fits into the tapered portion of the head of the negative electrode external terminal 314 of the _one (top layer in the figure) unit cell 1001 located on the outermost side, as shown in FIG. The resulting bus bar 200 can function as a negative electrode external terminal of the assembled battery 101. Furthermore, (in the drawing the lowermost layer) other bus bar 200 is fitted into the tapered portion of the head of the positive electrode external terminal 14 of the unit cell 100 ₄ can function as a positive electrode external terminal of the battery pack 101.

As a result of the connection described above, the first set battery unit 102 in which _{the unit cell 100 1} and the unit cell 100 _{2 are connected in parallel and the second set in which the unit cell 100 3} and the unit cell 100 ₄ are connected in parallel are connected. An assembled battery 101 in which the battery units 103 are connected in series can be obtained. In the battery pack including the assembled battery 101, a triangular columnar bus bar is arranged between the top surfaces of the heads of the positive electrode external terminal and the negative electrode external terminal, and these are electrically connected by being joined. .. Further, the first assembled battery unit 102 and the second assembled battery unit 103 are electrically connected by using a bus bar fitted to the tapered portion of the head of the external terminal. Therefore, the gap between the unit cells can be reduced. As a result, the volumetric energy density of the assembled battery 101 can be increased.

Insulation space may be provided between adjacent unit cells, and a gap of 0.03 mm or more may be provided, or an insulating member (for example, polypropylene or polyphenylene sulfide or epoxy as a resin, alumina or zirconia as fine ceramics, etc.) may be provided. Etc. can be sandwiched between them.

The bus bar can be formed of, for example, aluminum, an aluminum alloy material, or the like.

Since the battery pack of the second embodiment contains at least one power storage module of the embodiment, the battery pack can be made thinner and more flexible, has excellent reliability, and can reduce the manufacturing cost. be able to.

The battery pack is used, for example, as a power source for electronic devices and vehicles (railroad vehicles, automobiles, motorized bicycles, light vehicles, trolley buses, etc.).

The assembled battery may include a plurality of power storage modules connected in series, in parallel, or in series and in parallel in combination and electrically connected. Further, the battery pack can be provided with a circuit such as a battery control unit (Battery Control Unit) in addition to the assembled battery, but the circuit possessed by the one on which the assembled battery is mounted (for example, a vehicle) is used as the battery control unit. can do. The battery control unit has a function of monitoring the voltage and / or both of a single battery and an assembled battery to prevent overcharging and overdischarging.

The power storage module according to at least one embodiment described above provides a power storage module having high energy density and reliability because a tapered portion is provided on the head of the external terminal and the bus bar is fixed to the tapered portion. be able to.

In the power storage module of the first embodiment, a tapered portion is provided on the head of the external terminal and the bus bar is fixed to the tapered portion. However, the bus bar is fixed to the head without providing the tapered portion on the head of the external terminal. Is also good. This embodiment will be described below as a third embodiment.

(Third embodiment)
The power storage module of the third embodiment will be described with reference to FIGS. 25 and 26. The power storage module 1000 shown in FIGS. 25 and 26 has the same structure as the power storage module shown in FIGS. 1 to 10 except that the heads of the external terminals and the bus bar are different in structure.

As shown in FIG. 26, the positive electrode external terminal 14 includes a head portion 417 and a columnar shaft portion 418. The head 417 has a substantially rectangular parallelepiped shape and has a rectangular top surface 417a. The columnar shaft portion 418 extends axially from the head portion 417 and is inserted into the hollow portion of the positive electrode insulating gasket 15 and the through hole 19a of the positive electrode terminal lead 19. The tip of the shaft portion 418 protrudes from the through hole 19a of the positive electrode terminal lead 19. The protruding portion is enlarged in diameter by caulking to cover the peripheral edge of the through hole 19a. The flange portion 15a of the positive electrode insulating gasket 15 and the positive electrode insulating plate 16 are sandwiched between the stepped portion connecting the head portion 417 and the shaft portion 418 and the first exterior portion 5.

As shown in FIGS. 25 and 26, the bus bar 700 extends from the long side of the first flat plate-shaped connecting portion 701 having the rectangular through hole 701a and the first and first connecting portions 701. It has a plate-shaped second connecting portion 702 that is horizontal in the plane direction of the exterior portions 5 and 6 of 2.

The back surface of the first connecting portion 701 of the bus bar 700 is in contact with the top surface 417a of the head 417. The peripheral edge of the through hole 701a on the back surface is fixed to the top surface 417a by welding. The second connecting portion 702 of the bus bar 700 is arranged parallel to the extending direction of the flange portion 5b of the first exterior portion 5. In other words, the second connecting portion 702 is arranged in the plane direction of the first and second exterior portions 5 and 6, that is, parallel to the upper and lower surfaces of the power storage module.

According to the third power storage module described above, since the bus bar is fixed to the head of the external terminal, it is possible to provide a power storage module having high energy density and reliability. Further, the bus bar is provided with a plate-shaped connecting portion arranged in parallel with the extending direction of the flange portion of the first exterior portion, so that the storage modules are electrically connected to each other with a small gap between them. Will be possible.

(Fourth Embodiment)
The battery pack of the fourth embodiment includes the power storage module of the third embodiment. The battery pack of the embodiment may include an assembled battery having the power storage module of the embodiment as a unit cell.

Examples of the assembled battery including the power storage module of the third embodiment are shown in FIGS. 27 to 34.

As shown in FIGS. 27 to 30, the battery pack 601 includes an assembled battery using the power storage module 1000 of the third embodiment shown in FIGS. 25 and 26 as a unit cell. A plurality of (for example, four) unit cells 1000 _{1 to 1000 4} are laminated in the first direction X with the main surfaces of the exterior members 1 facing each other. A plurality of unit cells 1000 _{1 to 1000 4} are connected in series. Each unit cell 1000 _{1 to 1000 4} includes a bus bar 800 having the structure described below instead of the bus bar 700. The bus bar 800 has a flat plate-shaped first connecting portion 801 having a rectangular through hole 801a, an intermediate portion 802 extending from the long side of the first connecting portion 801 and extending from the long side of the intermediate portion 802. It has a plate-shaped second connection portion 803. The plane direction of the intermediate portion 802 is parallel to the side surface of the first exterior portion 5. The surface direction of the second connecting portion 803 is horizontal to the surface direction of the first and second exterior portions 5 and 6. The second connection portion 803 has a circular through hole 803a.

As shown in FIGS. 27 and 28, the bus bar 800 is used on one short side side surface of the assembled battery. On the other side of the short side, as shown in FIGS. 29 and 30, a triangular columnar bus bar 602 is used. On the other short side side surface, as shown in FIG. 30, the positive electrode external terminal 14 of the _{unit cell 1000 1} located on the outermost side (top layer in the figure) is a unit cell facing the unit cell _{1000 1 in the first direction X.} The negative electrode external terminal 314 of 1000 ₂ is electrically connected by a triangular columnar bus bar 602. The triangular columnar bus bar 602 is sandwiched between the top surface of the head of the positive electrode external terminal 14 and the top surface of the head of the negative electrode external terminal 314, and is fixed to these by welding or the like.

Also, the positive electrode external terminal 14 of the unit cell 1000 ₃ facing the unit cell 1000 ₂ in the first direction X is the unit cell 1000 ₃ and the negative electrode external terminal 314 and the triangular prism-shaped unit cell 1000 ₄ facing in the first direction X It is electrically connected by the bus bar 602 of. The triangular columnar bus bar 602 is sandwiched between the top surface of the head of the positive electrode external terminal 14 and the top surface of the head of the negative electrode external terminal 314, and is fixed to these by welding or the like.

The two top surfaces of the external terminals and the bus bar are electrically connected by welding. For welding, for example, laser welding, arc welding, and resistance welding are used.

On the other hand, as shown in FIGS. 27 and 28, the bus bar 800 is attached to the head of each of the positive and negative electrode external terminals connected by the triangular columnar bus bar. The back surface of the first connection portion 801 of the bus bar 800 is in contact with the top surface 417a of the head of the positive electrode external terminal or the top surface 314a of the head of the negative electrode external terminal. The peripheral edge of the through hole 701a on the back surface is fixed to the top surfaces 417a and 314a by welding. The second connecting portion 803 of the bus bar 800 is arranged in the plane direction of the first and second exterior portions 5 and 6, that is, parallel to the upper and lower surfaces of the power storage module.

The second connection portion 803 of the bus bar 800 fixed to the positive electrode external terminal 14 of the unit cell 1000 ₂ and the second connection portion 803 of the bus bar 800 fixed to the negative electrode external terminal 314 of the _{unit cell 1000 3 are overlapped with each other.} Has been done. The bolt 603 is inserted into the through hole 803a of the second connecting portion 803, and the bolt 603 is fixed by the nut 604, whereby the negative electrode external terminal and the positive electrode external terminal are electrically connected by the bus bar.

As shown in FIG. 28, the bus bar 800 fitted to the tapered portion of the head of the negative electrode external terminal of one of the outermost (top layer in the figure) unit cell 1000 _{1 is used as the negative electrode external terminal of the battery pack 601.} Can work. Further, the bus bar 800 fitted to the tapered portion of the head of the positive electrode external terminal 14 of the other (bottom layer in the figure) unit cell 1000 _{4 can function as the positive electrode external terminal of the battery pack 601.}

As a result of the connection described above, the unit cells 1000 _{1 to 1000 4} are connected in series to obtain a 4-series assembled battery. In the battery pack 601 including this assembled battery, a triangular columnar bus bar is arranged between the top surface of the head of the negative electrode external terminal and the top surface of the head of the positive electrode external terminal, and these are electrically joined by joining them. It is connected to the. Further, the positive and negative electrode external terminals having a counter electrode relationship with these positive and negative electrode external terminals are electrically connected by using a bus bar fixed to the top surface of the head. By electrically connecting the unit cells in this way, the gap between the unit cells can be reduced. Therefore, the volumetric energy density of the assembled battery can be increased.

The battery pack 601 shown in FIGS. 31 to 34 includes two assembled battery units in which two unit cells are connected in parallel, and includes those in which these assembled battery units are connected in series as an assembled battery. A power storage module 1000 is used as the unit cell. A plurality of (for example, four) unit cells 1000 _{1 to 1000 4} are laminated in the first direction X with the main surfaces of the exterior members 1 facing each other.

On one short side side surface (first short side side side surface) of the assembled battery, as shown in FIG. 32, the negative electrode external terminal 314 of the _{unit cell 1000 1 located on the outermost side (top layer in the figure) is the first.} It is electrically connected to the negative electrode external terminal 314 of the unit cell 1000 _{2 facing the unit cell 1000 1} in the direction X by a triangular columnar bus bar 602. The triangular columnar bus bar 602 is arranged between the top surfaces of the heads of the negative electrode external terminals 314. Reference numeral 216 shows a negative electrode insulating plate (first negative electrode insulating member).

Also, the positive electrode external terminal 14 of the unit cell 1000 ₃ facing the unit cell 1000 ₂ in the first direction X is positive electrode external terminal 14 of the unit cell 1000 ₄ facing the unit cell 1000 ₃ in the first direction X and triangular prism It is electrically connected by a bus bar 602. The triangular columnar bus bar 602 is arranged between the top surfaces of the heads of the positive electrode external terminals 14.

The two top surfaces of the external terminals and the bus bar are electrically connected by welding. For welding, for example, laser welding, arc welding, and resistance welding are used.

In the unit cell 1000 ₁ and the unit cell 1000 ₂ , as shown in FIG. 32, the negative electrode external terminal 314 is provided on the first short side side surface, but the other short side side surface (second short side). On the side surface), as shown in FIG. 34, a positive electrode external terminal 14 is provided. The positive electrode external terminal 14 of the unit cell 1000 ₁ is electrically connected to the positive electrode external terminal 14 of the unit cell 1000 _{2 by} a triangular columnar bus bar 602. The triangular columnar bus bar 602 is arranged between the top surfaces of the heads of the positive electrode external terminals 14.

By the above method, the unit cell 1000 ₁ and the unit cell 1000 ₂ are connected in parallel to obtain the first assembled battery unit 1002.

On the other hand, in the unit cells 1000 ₃ and the unit cell 1000 ₄ , as shown in FIG. 32, the positive electrode external terminal 14 is provided on the first short side side surface, but the second short side side surface is provided. As shown in FIG. 34, the negative electrode external terminal 314 is provided. Negative external terminal 314 of the unit cell 1000 ₃ are electrically connected by a negative electrode external terminal 314 and the triangular prism-shaped bus bar 602 of the unit cell 1000 _4. The triangular columnar bus bar 602 is arranged between the top surfaces of the heads of the negative electrode external terminals 314.

By the above method, the unit cells 1000 ₃ and the unit cells 1000 ₄ are connected in parallel to obtain the second assembled battery unit 1003.

In the second short side face of the assembled battery, a positive electrode external terminal 14 of the unit cell 1000 _2, the negative electrode external terminal 314 of the unit cell 1000 _3, as shown in FIG. 34, the bus bar 800 is attached .. The method of fixing the bus bar 800 is as described with reference to FIG. 28. The second connection portion 803 of the bus bar 800 fixed to the positive electrode external terminal 14 of the unit cell 1000 ₂ and the second connection portion 803 of the bus bar 800 fixed to the negative electrode external terminal 314 of the _{unit cell 1000 3 are overlapped with each other.} Has been done. The bolt 603 is inserted into the through hole of the second connecting portion 803, and the bolt 603 is fixed by the nut 604, whereby the negative electrode external terminal 314 and the positive electrode external terminal 14 are electrically connected by the bus bar 800. As a result, the first assembled battery unit 1002 and the second assembled battery unit 1003 are connected in series.

On the side surface on the first short side of the assembled battery, as shown in FIG. 32, the bus bar 800 fixed to the head of the negative electrode external terminal 314 of the _{unit cell 1000 1 located on the outermost side (top layer in the figure) is} , Can function as the negative electrode external terminal of the assembled battery. Further, the bus bar 800 fixed to the head of the positive electrode external terminal 14 of the other (bottom layer in the figure) unit cell 1000 _{4 can function as the positive electrode external terminal of the assembled battery.}

As a result of the connection described above _{, the first set battery unit 1002 in which the unit cells 1000 1} and the unit cell 1000 ₂ are connected in parallel, and the second set in which the unit cells 1000 ₃ and the unit cell 1000 ₄ are connected in parallel. An assembled battery in which the battery units 1003 are connected in series can be obtained. In the battery pack 601 including this assembled battery, a triangular columnar bus bar is arranged between the top surfaces of the heads of the positive electrode external terminal and the negative electrode external terminal, and these are electrically connected by being joined. .. Further, the first assembled battery unit 1002 and the second assembled battery unit 1003 are electrically connected by using a bus bar fixed to the head of the external terminal. By electrically connecting the unit cells in this way, the gap between the unit cells can be reduced. As a result, the volumetric energy density of the assembled battery can be increased.

Since the battery pack of the fourth embodiment contains at least one power storage module of the embodiment, the battery pack can be made thinner and more flexible, has excellent reliability, and can reduce the manufacturing cost. be able to.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.
Hereinafter, the inventions described in the scope of claims at the time of filing the application of the present application will be added.
[1] A power storage module including a battery and a bus bar.
The battery is
The first is a positive electrode current collecting tab that includes a positive electrode, a positive electrode current collecting tab electrically connected to the positive electrode, a negative electrode, and a negative electrode current collecting tab electrically connected to the negative electrode, and is wound in a flat shape. A group of flat electrodes with a negative electrode current collecting tab located on the end face and wound in a flat shape on the second end face.
A stainless steel first exterior portion having a bottomed square tube shape and an opening having a flange portion, and a stainless steel second exterior portion, and the flange portion of the first exterior portion. An exterior member in which the electrode group is housed in a space formed by welding the second exterior portion, and the first end surface and the second end surface face the inner surface of the side wall of the first exterior portion.
A through hole opened in the side wall of the first exterior portion, a head portion and a shaft portion extending from the head portion, the head portion projecting to the outside of the first exterior portion, and the shaft portion. The portion includes a terminal portion that is caulked and fixed to the through hole of the first exterior portion and includes an external terminal that is electrically connected to the positive electrode or the negative electrode.
A power storage module in which the bus bar is fixed to the head of the external terminal.
[2] A tapered portion is provided on the head of the external terminal.
The power storage module according to [1], wherein the bus bar is fixed to the tapered portion.
[3] A quadrangular pyramid-shaped tapered portion is provided on the side surface or the lower surface of the head as the tapered portion.
The bus bar has a rectangular through hole with a tapered inner surface.
The power storage module according to [2], wherein the through hole of the bus bar is fitted in the tapered portion of the head.
[4] A quadrangular pyramid-shaped tapered portion is provided on the side surface or the lower surface of the head as the tapered portion.
The busbar has a rectangular notch with a tapered end face and
The power storage module according to [2], wherein the through hole of the bus bar is fitted in the tapered portion of the head.
[5] A conical tapered portion is provided on the side surface of the head as the tapered portion.
The bus bar has a circular through hole with a tapered inner peripheral surface.
The power storage module according to [2], wherein the through hole of the bus bar is fitted in the tapered portion of the head.
[6] A conical tapered portion is provided on the side surface of the head as the tapered portion.
The bus bar has an elliptical through hole with a tapered inner peripheral surface and
The power storage module according to [2], wherein the through hole of the bus bar is fitted in the tapered portion of the head.
[7] The power storage module according to [2], wherein the bus bar includes a connection portion in which the bus bar is arranged in parallel with the extending direction of the flange portion of the first exterior portion.
[8] The storage storage according to any one of [1] to [7], further comprising an insulating member arranged between the head of the external terminal and the first exterior portion of the exterior member. module.
[9] A battery pack containing the power storage module according to any one of [1] to [8].
[10] The battery pack according to [9], wherein the battery pack includes a plurality of the power storage modules, and the plurality of power storage modules are electrically connected by the bus bar.

Claims (7)

A battery pack including a plurality of batteries and a plurality of bus bars for electrically connecting the plurality of batteries.
The battery is
The band-shaped positive electrode current collector and the positive electrode material layer formed on the positive electrode current collector except for one end parallel to the long side of the positive electrode current collector, and the positive electrode material layer is not formed. The negative electrode current collector is excluded from the positive electrode whose one end parallel to the long side of the positive electrode current collector forms a positive electrode current collection tab, the strip-shaped negative electrode current collector, and the one end parallel to the long side of the negative electrode current collector. A negative electrode including a negative electrode material layer formed on the body, one end parallel to a long side of the negative electrode current collector on which the negative electrode material layer is not formed forms a negative electrode current collector tab, and the positive electrode and the negative electrode. a separator disposed between the wound in a flat shape, located in the positive electrode current collection tabs that are wound in a flat shape a first end surface, and is wound the negative electrode current collector tab was a flat shape A group of flat electrodes located on the second end face,
A stainless steel first exterior portion having a bottomed square tube shape and an opening having a flange portion, and a stainless steel second exterior portion, and the flange portion of the first exterior portion. the electrode group is housed inside surface facing said first end surface and the side of the second end surface of the first outer portion to said second space exterior portion is formed by welding, the first With an exterior member , the exterior portion of the steel having a through hole opened in the side wall thereof.
The first end surface is connected to the positive electrode current collecting tab, the second end surface is connected to the negative electrode current collecting tab, and the head portion and a shaft portion extending from the head portion are included, respectively, and the shaft portion is said. A positive electrode external terminal and a negative electrode external terminal, which are crimped and fixed to the through hole opened in the side wall of the first exterior portion and whose head protrudes to the outside of the first exterior portion, are included.
The plurality of batteries are stacked in a state where the main surfaces of the exterior members face each other, and the positive electrode external terminal and the negative electrode external terminal are located next to each other among the batteries located next to each other.
The plurality of bus bars rise from a flat plate-shaped first connecting portion having a through hole, which is arranged in parallel with the extending direction of the flange portion of the first exterior portion, and the first connecting portion. It has a second connecting portion bent along the side surface of the first exterior portion and has a second connecting portion.
The batteries located next to each other have the second connection portion of one bus bar fixed to the head of the positive electrode external terminal of one battery, and another to the head of the negative electrode external terminal of another battery. A battery pack in which the second connection portion of the bus bar is fixed, and the first connection portion of the one bus bar and the first connection portion of the other bus bar are connected through a through hole to each other. Tapered portions are provided on the head of the positive electrode external terminal and the head of the negative electrode external terminal, respectively.
The battery pack according to claim 1, wherein the second connection portion of the one bus bar and the second connection portion of the other bus bar are fixed to the tapered portion, respectively. A quadrangular pyramid-shaped tapered portion is provided on the side surface or the lower surface of the head as the tapered portion.
The second connection of the bus bar has a rectangular through hole with a tapered inner surface.
The battery pack according to claim 2, wherein the through hole of the bus bar is fitted in the tapered portion of the head. A quadrangular pyramid-shaped tapered portion is provided on the side surface or the lower surface of the head as the tapered portion.
The second connection of the bus bar has a rectangular notch with a tapered end face.
The notch of the bus bar to said tapered portion of said head has been fitted, the battery pack according to claim 2. A conical tapered portion is provided on the side surface of the head as the tapered portion.
The second connection of the bus bar has a circular through hole with a tapered inner peripheral surface.
The battery pack according to claim 2, wherein the through hole of the bus bar is fitted in the tapered portion of the head. A conical tapered portion is provided on the side surface of the head as the tapered portion.
The second connection of the bus bar has an elliptical through hole with a tapered inner peripheral surface.
The battery pack according to claim 2, wherein the through hole of the bus bar is fitted in the tapered portion of the head. Arranged between the head of the positive electrode external terminal and the first exterior portion of the exterior member, and between the head of the negative electrode external terminal and the first exterior portion of the exterior member, respectively. The battery pack according to any one of claims 1 to 6 , further comprising the provided insulating member.

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