JP6098922B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device including a power storage element having an external terminal and a bus bar connected to the external terminal, and a method for manufacturing the power storage device. The present invention also relates to a bus bar connected to the external terminal of a power storage element having the external terminal.

  In recent years, batteries (lithium ion batteries, nickel metal hydride batteries, etc.) and capacitors (electric double layer capacitors, etc.) are used as power sources for vehicles (automobiles, motorcycles, etc.) and various devices (mobile terminals, notebook computers, etc.). Possible power storage elements are employed.

  When a large amount of power is required, a power storage device including a plurality of power storage elements and a bus bar (see Patent Document 1) that electrically connects the power storage elements is adopted as a power source. Is done.

  Each power storage element includes a power generation element, a case that houses the power generation element, and an external terminal that is disposed outside the case. The external terminal is electrically connected to the power generation element via a shaft-like connection body that is formed integrally with or separate from the external terminal. In connection with this, an electrical storage element is provided with the gasket arrange | positioned along the inner surface and outer surface of a case. In this type of power storage element, the connection body penetrates the case and the gasket, and electrically connects the power generation element in the case and the external terminal outside the case. A gasket seals the hole which penetrates the connection body formed in the case. Thereby, the inside of the case is kept airtight and liquid-tight.

  There are various types of bus bars, and one of them is welded to an external terminal of a power storage element. The bus bar has a main body portion and a connection portion, and is connected to an external terminal at the connection portion.

  More specifically, the bus bar is made of a metal plate having a substantially uniform thickness. And a bus bar has a connection part in at least any one edge part. That is, the bus bar has a main body portion and a connection portion, and there are a bus bar in which the connection portion is connected to one end of the main body portion and a connection portion that is connected to both ends of the main body portion. Note that the bus bar having the connection portion connected to one end of the main body portion connects the external terminal of the power storage element and an external electrical load, and the bus bar having the connection portion connected to both ends of the main body portion has two The external terminals of the two storage elements are connected to each other.

  In any bus bar, the connection portion is superimposed on the upper surface of the external terminal of the power storage element, and the connection portion and the external terminal (upper surface) are welded. Accordingly, the bus bar is mechanically and electrically connected to the external terminal of the power storage element.

  By the way, when the bus bar (connecting portion) and the external terminal are welded, a large amount of heat is required to melt the entire thickness of the bus bar. Therefore, in the conventional power storage device, the gasket may be softened or melted when the bus bar is welded. As a result, the gasket cannot sufficiently seal the case, and the inside of the case cannot be kept airtight and liquid tight. The external terminal is connected to the power generation element via the connection conductor. Therefore, the heat at the time of welding a bus bar may be transmitted to the inside of the case (for example, a power generation element or the like) via an external terminal. Therefore, the power generation element in the case may be affected by heat and the performance may be reduced.

JP 2010-160931 A (see paragraph 0025)

  Therefore, the present invention provides a power storage device and a method for manufacturing the power storage device that can suppress the deterioration of the quality of the power storage device due to the thermal effect caused by the welding of the bus bar to the external terminal of the power storage device.

  Moreover, this invention provides the bus bar which can suppress that the quality of an electrical storage element falls by the thermal influence at the time of the welding with respect to the external terminal of an electrical storage element.

The power storage device according to the present invention includes:
A storage element having an external terminal;
A bus bar connected to the external terminal,
The bus bar has a thin portion,
The thin portion and the external terminal are welded.

  According to this structure, the thin part of a bus bar and the external terminal of an electrical storage element are welded. Therefore, compared with the case where a thin part is not provided, the output energy required for welding can be reduced. Thereby, it can prevent that the periphery of the external terminal in an electrical storage element and the inside of an electrical storage element are damaged by the influence of the heat of welding.

Here, as one embodiment of the present invention,
At least two storage elements,
The thin portion is provided in at least two places,
Welded to the external terminals of the two storage elements,
Can be.

  According to such a configuration, one thin portion is connected to the external terminal of one power storage element, and the other thin portion is connected to the external terminal of the other power storage element. The external terminals of the electricity storage elements are connected to each other. Thereby, two electrical storage elements electrically comprise one electrical storage element.

As another aspect of the present invention,
The thin-walled portion is formed on at least a portion of the bus bar that contacts the external terminal.
Can be.

  According to this configuration, the thin portion of the bus bar and the external terminal are welded. Therefore, compared with the case where a thin part is not provided, the output energy required for welding can be reduced. Thereby, it can prevent that the periphery of the external terminal in an electrical storage element and the inside of an electrical storage element are damaged by the influence of the heat of welding.

As another aspect of the present invention,
The thin portion is formed along the outer edge of the bus bar,
Can be.

  According to such a configuration, the thin portion is formed along the outer edge of the bus bar. Therefore, it is possible to weld spot-like to an arbitrary portion of the thin-walled portion, or to continuously weld the thin-walled portion along the longitudinal direction in order to further increase the welding strength. Therefore, various welding modes can be freely selected.

in this case,
The outer edge of the bus bar has a shape having no discontinuity,
Can be.

  According to such a configuration, since the outer edge of the thin portion has a shape that does not have a discontinuous portion, the outer edge of the thin portion has no corners. When welding at least a partial region of the outer edge of the thin portion and the external terminal along the outer edge, if there is a corner, the welding speed is reduced and the homogeneity of the welded portion is impaired. However, if there is no corner, welding can be performed continuously at a constant speed, so that a weld having a uniform constant length can be formed.

As still another aspect of the present invention,
The thin part is formed at the center of the bus bar,
Can be.

  According to this structure, the thin part is formed in the center part of the bus bar. Therefore, it is possible to weld spot-like to an arbitrary portion of the thin-walled portion, or to continuously weld the thin-walled portion along the longitudinal direction in order to further increase the welding strength. Therefore, various welding modes can be freely selected.

in this case,
The outer edge of the thin part is a closed shape without discontinuities,
Can be.

  According to such a configuration, since the outer edge of the thin portion has a closed shape without discontinuous portions, the outer edge of the thin portion has no corners. When welding at least a partial region of the outer edge of the thin portion and the external terminal along the outer edge, if there is a corner, the welding speed is reduced and the homogeneity of the welded portion is impaired. However, if there is no corner, welding can be performed continuously at a constant speed, so that a weld having a uniform constant length can be formed.

As another aspect of the present invention,
The bus bar has a main body portion and a connection portion continuous with the main body portion and connected to an external terminal.
The thin part is formed in the connection part,
Can be.

  According to this structure, the thin part is formed in the connection part. Therefore, it is possible to weld spot-like to an arbitrary portion of the thin-walled portion, or to continuously weld the thin-walled portion along the longitudinal direction in order to further increase the welding strength. Therefore, various welding modes can be freely selected.

in this case,
The width of the connection part is narrower than the width of the main body part,
Can be.

  According to such a configuration, in the bus bar, the width of the connection portion is narrower than the width of the main body portion. Therefore, compared with the case where the width of a connection part is not narrower than the width | variety of a main-body part, a welding range can be decreased. The fact that the welding range can be reduced means that the output energy required for welding can be further reduced. Therefore, it is possible to prevent the periphery of the external terminal in the power storage element and the inside of the power storage element from being damaged by the heat of welding. Further, since the width of the main body does not become narrow, an appropriate current capacity can be obtained as the entire bus bar.

In this case,
At least two storage elements,
A pair of connecting portions are provided at both ends of the main body, and connect the external terminals of the two power storage elements.
Can be.

  According to this configuration, in the bus bar, one connection portion is connected to the external terminal of one power storage element, and the other connection portion is connected to the external terminal of the other power storage element. The external terminals of the element are connected. Thereby, two electrical storage elements electrically comprise one electrical storage element.

Furthermore, in this case
The electricity storage element includes a case, and is a flat rectangular shape in which one surface on which the external terminal in the case is arranged is rectangular, and at least two electricity storage elements are arranged so that the one surface is aligned in the longitudinal direction,
The main body is formed according to the width of one side,
The connecting portion is formed in accordance with the width of the external terminal that is narrower than one surface.
Can be.

  According to such a configuration, at least two power storage elements are disposed so that one surface on which the external terminals are disposed is aligned in the longitudinal direction, and the bus bar connects the external terminals of the two power storage elements. The connection portion is formed in accordance with the width of one surface, and the connection portion is formed in accordance with the width of the external terminal having a width smaller than that of the one surface. For this reason, it is possible to alleviate layout restrictions or arrangement space restrictions when arranging the connection portions on the external terminals. Further, since the width of the main body does not become narrow, an appropriate current capacity can be obtained as the entire bus bar.

Or
The power storage element is provided with a case, and has a rectangular shape with one surface on which external terminals are arranged in the case having a rectangular shape, and a plurality of power storage elements are arranged in a line so that the one surface is aligned in the longitudinal direction and the short direction. Arranged in a shape,
Among the bus bars, the main body of the bus bar that connects the external terminals of the two power storage elements arranged in the longitudinal direction is formed in accordance with the width of one surface,
The connecting portion of the bus bar is formed in accordance with the width of the external terminal that is narrower than one surface.
Can be.

  According to such a configuration, the plurality of power storage elements are arranged so that one surface on which the external terminals are arranged is aligned in the longitudinal direction and the short direction, and the external terminals of the two power storage elements aligned in the longitudinal direction are connected to each other. In the above, the main body portion is formed in accordance with the width of one surface, and the connection portion is formed in accordance with the width of the external terminal that is narrower than the one surface. For this reason, it is possible to alleviate layout restrictions or arrangement space restrictions when arranging the connection portions on the external terminals. Further, since the width of the main body does not become narrow, an appropriate current capacity can be obtained as the entire bus bar. Further, the width of the main body does not exceed or greatly exceed the width of one surface. Therefore, it can prevent interfering with the bus bar connected to the power storage element adjacent in the short direction.

As still another aspect of the present invention,
The thin part is formed in a stepped shape,
Can be.

As another aspect of the present invention,
The thin part is formed in a shape with a thickness that decreases toward the outer edge side,
Can be.

In this case,
The end of the connection part is a semicircular arc shape,
Can be.

  According to such a configuration, since the end portion of the connection portion has a semicircular arc shape, there is no corner portion on the outer edge of the connection portion. When welding at least a partial region of the outer edge of the connecting portion and the external terminal along the outer edge of the connecting portion, if there is a corner, the welding speed is reduced at that point, and the uniformity of the welded portion is impaired. However, if there is no corner, welding can be performed continuously at a constant speed, so that a weld having a uniform constant length can be formed.

A method for manufacturing a power storage device according to the present invention includes:
A method of manufacturing a power storage device including a power storage element having an external terminal and a bus bar connected to the external terminal,
A step of welding the thin portion formed on the bus bar and the external terminal.

  According to this structure, the thin part formed in a bus bar and the external terminal of an electrical storage element are welded. Therefore, compared with the case where a thin part is not provided, the output energy required for welding can be reduced. Thereby, it can prevent that the periphery of the external terminal in an electrical storage element and the inside of an electrical storage element are damaged by the influence of the heat of welding.

Here, as one aspect of the method for manufacturing the power storage device according to the present invention,
Welding is laser welding,
It is preferable.

  According to such a configuration, the external terminal and the bus bar are directly connected. That is, if the external terminal and the bus bar are welded by laser welding, they are melted together and connected. Accordingly, the bus bar is connected to the external terminal in a mechanically and electrically preferable state.

in this case,
Laser welding is to irradiate a laser beam perpendicular to the bus bar.
Can be.

  According to such a configuration, the thin-walled portion can be appropriately welded even if the welding equipment is not equipped with a mechanism for changing / adjusting the tilt angle of the welding head that emits laser light, and thus the welding equipment is large-scale. Not necessary.

The bus bar according to the present invention is
A bus bar connected to the external terminal of the electricity storage device having an external terminal,
It has a thin part welded to the external terminal.

  According to this structure, the thin part which a bus-bar has, and the external terminal of an electrical storage element are welded. Therefore, compared with the case where a thin part is not provided, the output energy required for welding can be reduced. Thereby, it can prevent that the periphery of the external terminal in an electrical storage element and the inside of an electrical storage element are damaged by the influence of the heat of welding.

The bus bar according to the present invention is
A bus bar for connecting the external terminals of two power storage elements each having an external terminal,
At least two locations have thin portions that are welded to the external terminals of the two power storage elements.

  According to such a configuration, the thin portion and the external terminal of the power storage element are welded. Therefore, compared with the case where a thin part is not provided, the output energy required for welding can be suppressed. Thereby, it can prevent that the periphery of the external terminal in an electrical storage element and the inside of an electrical storage element are damaged by the influence of the heat of welding. In the bus bar, one thin portion is connected to the external terminal of one power storage element, and the other thin portion is connected to the external terminal of the other power storage element. Connect the external terminals of the element. Thereby, two electrical storage elements electrically comprise one electrical storage element.

  As described above, according to the present invention, it is possible to provide a power storage device and a method for manufacturing the power storage device that can suppress the deterioration of the quality of the power storage device due to the heat effect caused by the welding of the bus bar to the external terminal of the power storage device.

  Moreover, according to this invention, the bus bar which can suppress that the quality of an electrical storage element falls by the heat influence at the time of the welding with respect to the external terminal of an electrical storage element can be provided.

FIG. 1 is a perspective view of a battery module according to an embodiment of the present invention. FIG. 2 shows a plan view of the battery module. FIG. 3 shows a perspective view of each battery cell constituting the battery module. 4A is a first bus bar for connecting battery cells, FIG. 4A is a perspective view, FIG. 4B is a cross-sectional view taken along line II of FIG. 4A, and FIG. 4C is II- II sectional drawing is shown. 5 is a second bus bar for connecting battery cells, FIG. 5A is a perspective view, FIG. 5B is a cross-sectional view taken along line III-III in FIG. 5A, and FIG. IV sectional drawing is shown. 6A is a partially enlarged cross-sectional view of a state where the first bus bar is placed across two external terminals of adjacent battery cells, and FIG. 6B is a state where the first bus bar is welded to the external terminals. A partially enlarged sectional view is shown. FIG. 7A is a partially enlarged cross-sectional view of a state in which the second bus bar is placed across two external terminals of adjacent battery cells, and FIG. 7B is a state in which the second bus bar is welded to the external terminals. A partially enlarged sectional view is shown. FIG. 8A is a first variation of the thin portion, and is a cross-sectional view of the thin portion where the thickness decreases toward the outer edge so that the center is convex, and FIG. 8B is a second variation of the thin portion. FIG. 8C shows a cross-sectional view of a thin-walled portion having a thickness that decreases toward the outer edge so that the center is concave. 9A and 9B show a first modification of the bus bar, in which FIG. 9A is a perspective view, and FIG. 9B is a cross-sectional view taken along line VV in FIG. 9A. FIG. 10 shows a second modification of the bus bar, in which FIG. 10A is a perspective view, and FIG. 10B is a cross-sectional view taken along the line VI-VI in FIG. 10A. FIG. 11A is a plan view of a third modification of the bus bar, and FIG. 11B is a plan view of a fourth modification of the bus bar.

  Hereinafter, a battery module which is an embodiment of a power storage device according to the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the battery module according to the present embodiment includes a plurality of battery cells 1 and a housing 7 that houses the plurality of battery cells 1.

  As shown in FIG. 3, the battery cell 1 includes a case 2 including a case main body 2a having an opening and a lid plate 2b that closes and seals the opening of the case main body 2a. A power generation element (not shown) is accommodated in the case 2.

  As the battery cell 1, a rectangular battery having an outer appearance rectangular parallelepiped or a round battery having an outer appearance cylindrical shape can be adopted. The battery cell 1 which concerns on this embodiment is a square battery. Therefore, the case main body 2a has a bottomed rectangular tube shape that is flat in the width direction, and the cover plate 2b is a rectangular plate material corresponding to the opening of the case main body 2a.

  An external gasket 3 is disposed on the outer surface of the case 2, more specifically on the outer surface of the cover plate 2 b. An external terminal 4 is disposed on the outer surface of the external gasket 3. In the present embodiment, the external gasket 3 has a recess, and the external terminal 4 is disposed in the recess. The external terminal 4 is made of an aluminum-based metal material such as aluminum or an aluminum alloy. Here, a through hole (not shown) is formed in the cover plate 2b, and a through hole (not shown) is also formed in the external gasket 3. The external gasket 3 is arranged on the outer surface of the cover plate 2b so that the through hole thereof coincides with the through hole of the cover plate 2b. The external terminal 4 has a shaft portion (not shown) that passes through these through holes. A shaft portion of the external terminal 4 penetrating the external gasket 3 and the cover plate 2b through two through holes is connected to a current collector (not shown) connected to the power generation element. Thereby, the external terminal 4 is electrically connected to the power generation element.

  The external gasket 3 and the external terminal 4 are provided for a positive electrode and a negative electrode. The external gasket 3 and the external terminal 4 for the positive electrode are disposed at one end in the longitudinal direction of the lid plate 2b. The external gasket 3 and the external terminal 4 for the negative electrode are disposed at the other end in the longitudinal direction of the lid plate 2b. The external gasket 3 and the external terminal 4 for the positive electrode, and the external gasket 3 and the external terminal 4 for the negative electrode are arranged at equal positions on the left and right with the intermediate position in the longitudinal direction of the lid plate 2b as the center.

  The external gasket 3 and the external terminal 4 have a rectangular shape in plan view. The external gasket 3 and the external terminal 4 have a rectangular shape in which the longitudinal direction of the lid plate 2b is long and the short direction of the lid plate 2b (the width direction of the lid plate 2b) is short. In the present embodiment, the “rectangular shape” is a concept including a rounded shape and a shape close to a rectangular shape (a shape that can be considered as a whole shape), etc. is there.

  The upper part of the external terminal 4 is a flat surface 4a. Since the external terminal 4 is rectangular in plan view, the flat surface 4a is also rectangular. Needless to say, the flat surface 4a of the external terminal 4 has a rectangular shape in which the longitudinal direction of the cover plate 2b is long and the short direction of the cover plate 2b (the width direction of the cover plate 2b) is short. The flat surface 4a of the external terminal 4 is located at a position away from the outer surface of the lid plate 2b. The flat surface 4 a of the external terminal 4 protrudes from the external gasket 3. The flat surface 4a of the external terminal 4 for positive electrode and the flat surface 4a of the external terminal 4 for negative electrode are at the same height level with respect to the outer surface of the cover plate 2b.

  1 and 2, the plurality of battery cells 1,... Are arranged in rows and columns so that the cover plates 2 b are arranged in the longitudinal direction and the short direction. In this embodiment, when the longitudinal direction of the cover plate 2b is a row and the short direction of the cover plate 2b is a column, 10 battery cells 1,... Are arranged in 2 rows and 5 columns. In addition, the battery cells 1 in the adjacent rows are opposite in polarity so that all the battery cells 1,... It is arranged to be.

  External terminals 4, 4 of battery cells 1, 1 arranged in the row direction (longitudinal direction of battery cell 1 or cover plate 2 b) are connected by a first bus bar 10. The external terminals 4, 4 of the battery cells 1, 1 arranged in the row direction (the battery cell 1 or the short direction of the cover plate 2 b) are connected by a second bus bar 15. More specifically, in the battery cells 1 and 1 that are adjacent in the row direction, the external terminal 4 for the positive electrode of one battery cell 1 and the external terminal 4 for the negative electrode of the other battery cell 1 are close to each other, These external terminals 4 and 4 are connected by the first bus bar 10. Further, in the battery cells 1 and 1 adjacent in the column direction, the external terminal 4 for the positive electrode of one battery cell 1 and the external terminal 4 for the negative electrode of the other battery cell 1 are close to each other. External terminals 4 and 4 are connected by a second bus bar 15.

  Of the battery cells 1,... Connected in series, a third bus bar 20 is connected to the external terminal 4 at one end and the external terminal 4 at the other end. In the present embodiment, the third bus bar 20A for positive electrode and the third bus bar 20B for negative electrode are different. These third bus bars 20 are external connection bus bars connected to another battery module, another device, a load, or a power source.

  As shown in FIG. 4, the first bus bar 10 (hereinafter, also simply referred to as “bus bar 10”) has a main body portion 11 and a pair of connection portions 12 and 12 provided at both ends of the main body portion 11. Yes. The connection portion 12 is a portion that is placed on the flat surface 4 a of the external terminal 4 and connected to the external terminal 4. The main body 11 connects the pair of connection parts 12, 12.

  The connecting portion 12 is narrower than the main body portion 11. More specifically, the main body portion 11 is formed in accordance with the width of the cover plate 2b, that is, the width of the battery cell 1, and the tip portion 12 has the width of the external terminal 4 (the width of the external terminal 4 in the width direction of the cover plate 2b). It is formed according to the outer dimensions. Note that the term “match” refers to an aspect in which the width of the main body portion 11 is within a range of 50 to 150% of the width of the battery cell 1, and the width of the tip portion 12 is the width of the external terminal 4. The aspect which is settled in the range of 50 to 100%.

  In the present embodiment, the main body 11 has a rectangular shape in plan view. The connecting portion 12 has a rectangular shape in plan view with the tip end rounded into a semicircular arc. Both the main body 11 and the connecting part 12 are formed of a plate material made of aluminum or an aluminum-based metal material of an aluminum alloy.

  The connection part 12 has a thin part 13. The thin portion 13 is formed in a stepped shape. That is, the connection part 12 includes a thin part 13 and a part (thick part) which is a part other than the thin part 13 in the connection part 12 and is thicker than the thin part 13. Accordingly, the thin portion 13 is thinner than the portion (thick portion) other than the thin portion 13 in the connection portion 12. The part (thick part) other than the thin part 13 of the connection part 12 has the same thickness as the main body part 11, and the thickness of the thin part 13 is the thickness of the other part (thick part) of the connection part 12. And it is thinner than the thickness of the main body 11. The thin portion 13 is formed along the outer edge of the connecting portion 12. More specifically, the thin-walled portion 13 is formed in a strip shape over three continuous sides of two opposing sides along the longitudinal direction of the first bus bar 10 and one side connected to the two opposing sides.

  The thin portion 13 is formed so as to protrude outward from the lower region of the outer end surface of the connecting portion 12. The thin portion 13 is formed by removing the outer edge portion of the upper surface of the connection portion 12 (the surface opposite to the joint surface with the external terminal 4 (the lower surface of the connection portion 12)). That is, the thin part 13 is a step part. The thin-walled portion 13 is formed by machining such as press molding, extrusion molding, cutting, and electric discharge machining.

  The upper surface of the thin portion 13 is parallel to the lower surface of the thin portion 13 and the lower surface of the connection portion 12. That is, the thickness of the thin portion 13 is constant. However, the upper surface of the thin portion 13 may be an inclined surface in which the thickness of the thin portion 13 becomes smaller toward the outer edge side (see FIGS. 8A to 8C).

  A hole 14 is formed in the main body 11. This hole 14 is a hole into which a terminal (not shown) of a voltage measurement line and a terminal (not shown) of a temperature measurement line connected to a cell monitoring circuit (CMU: Cell Monitor Unit) are mounted. These terminals are rivets that are inserted into the holes 14 and crimped. Alternatively, a screw is cut in the hole 14, the terminal is a male screw, and the hole 14 is attached by screwing. Alternatively, the terminal is mounted by being press-fitted into the hole 14. However, the mounting mode is not limited to these. In the present embodiment, two holes 14 and 14 are formed: a hole 14 to which a voltage measurement line terminal is attached and a hole 14 to which a temperature measurement line is attached. The hole 14 may be a through-hole penetrating the front and back of the main body 11 or a non-through hole that does not penetrate.

  As shown in FIG. 5, the second bus bar 15 (hereinafter also simply referred to as “bus bar 15”) has a main body portion 16 and a pair of connecting portions 17 and 17 provided at both ends of the main body portion 16. Yes. The connection portion 17 is a portion that is placed on the flat surface 4 a of the external terminal 4 and connected to the external terminal 4. The main body portion 16 couples a pair of connection portions 17 and 17.

  In the present embodiment, the main body portion 16 has a rectangular shape in plan view. The connecting portion 17 has a rectangular shape in plan view with rounded corners. The main body portion 16 and the connection portion 17 are each formed of a plate material made of an aluminum-based metal material of aluminum or an aluminum alloy.

  The connecting portion 17 has a thin portion 18. The thin portion 18 is formed in a stepped shape. That is, the connection part 17 includes a thin part 18 and a part (thick part) which is a part other than the thin part 18 in the connection part 17 and is thicker than the thin part 18. Therefore, the thin portion 18 is thinner than the portion (thick portion) other than the thin portion 18 in the connection portion 17. The part (thick part) other than the thin part 18 of the connection part 17 has the same thickness as the main body part 16, and the thickness of the thin part 18 is the thickness of the other part (thick part) of the connection part 17. And it is thinner than the thickness of the main body 16. The thin portion 18 is formed along the outer edge of the connection portion 17. More specifically, the thin-walled portion 18 is formed in a band shape over three continuous sides of two opposing sides along the longitudinal direction of the second bus bar 15 and one side connected to the two opposing sides.

  However, in the present embodiment, the thin portion 18 is also formed along the outer edge of the main body portion 16. More specifically, the thin-walled portion 18 is formed in a band shape on two opposite sides of the main body portion 16 along the longitudinal direction of the second bus bar 15. And the thin part 18 formed in the connection part 17 and the thin part 18 formed in the main-body part 16 are connected. Therefore, the thin portion 18 is formed in an annular shape so as to go around the outer edge of the second bus bar 15. Therefore, in the second bus bar 15, the thickness of the main body portion 16 means the maximum thickness (plate thickness).

  The thin portion 18 is formed so as to protrude outward from the lower region of the outer end surface of the connection portion 17 (or the main body portion 16). The thin-walled portion 18 is removed from the outer edge portion of the upper surface of the connection portion 17 (or the main body portion 16) (the surface opposite to the joint surface with the external terminal 4 (the surface opposite to the lower surface of the connection portion 12 (or the main body portion 16)). It is formed by. That is, the thin portion 18 is a step portion. The thin portion 18 is formed by machining such as press molding, cutting, electric discharge machining, or the like.

  The upper surface of the thin portion 18 is parallel to the lower surface of the thin portion 18 and the lower surface of the connection portion 17. That is, the thickness of the thin portion 18 is constant. However, the upper surface of the thin portion 18 may be an inclined surface in which the thickness of the thin portion 18 becomes smaller toward the outer edge side (see FIGS. 8A to 8C).

  A hole 19 is formed in the main body 16. This hole 19 is a hole in which a terminal (not shown) of a voltage measurement line and a terminal (not shown) of a temperature measurement line connected to the cell monitoring circuit are mounted. These terminals are rivets, and are inserted into the holes 19 and crimped. Alternatively, a screw is cut in the hole 19 and the terminal is a male screw, and is attached by screwing. Alternatively, the terminal is mounted by being press-fitted into the hole 19. However, the mounting mode is not limited to these. In the present embodiment, two holes 19 and 19 are formed, which are a hole 19 in which a voltage measurement line terminal is mounted and a hole 19 in which a temperature measurement line is mounted. The hole 19 may be a through-hole penetrating the front and back of the main body 16 or may be a non-through hole that does not penetrate.

  Here, a method of connecting the bus bars 10 and 15 to the battery cell 1 will be described.

  First, a plurality of battery cells 1,... Are arranged in a matrix and then conveyed into an operation region (hereinafter referred to as “welding area”) of the welding apparatus. Specifically, the plurality of batteries 1,... Are arranged in the same matrix state as when completed on a conveying device such as a belt conveyor, and then conveyed to the welding area by the conveying device. When the plurality of battery cells 1 reach the welding area, the bus bars 10 and 15 are arranged so as to straddle the external terminals 4 and 4 of the adjacent battery cells 1 as shown in FIGS. 6A and 7A. That is, as shown in FIG. 6A, the first bus bar 10 is disposed so as to straddle the external terminals 4 and 4 of the two battery cells 1 and 1 arranged in the row direction, and the second bus bar 15 is arranged in FIG. 7A. As shown, the battery cells 1 and 1 are arranged so as to straddle the external terminals 4 and 4 of the two battery cells 1 and 1 aligned in the column direction. In this state, the thin-walled portions 13 and 18 of the connecting portions 12 and 17 of the bus bars 10 and 15 and the external terminals 4 overlapping therewith are welded by the welding device.

  If demonstrating it more concretely, the automatic supply apparatus which arrange | positions the bus-bars 10 and 15 on the battery cell 1 will be arrange | positioned adjacent to a welding apparatus in a welding area. The automatic supply device includes a holding body configured to hold the bus bars 10 and 15, a first position for receiving the bus bars 10 and 15, and external terminals of the battery cells 1 and so on in which the bus bars 10 and 15 are arranged in a matrix. Teaching is performed so as to move between the second position and the second position that can be arranged in a state of straddling 4 and 4. In order to handle a plurality of types of bus bars 10 and 15, an automatic supply device corresponding to each bus bar 10 and 15 may be arranged. Teaching is performed so that the bus bar 10 and the second bus bar 15 can be arranged on the battery cell 1. The holding body is provided with protrusions (tapered protrusions) that can be inserted into holes 14 and 19 provided in the main body portions 11 and 16 of the bus bars 10 and 15. That is, the holding body is configured such that the protrusions are fitted into the holes 14 and 19 of the bus bars 10 and 15 so that the bus bars 10 and 15 are in a fixed arrangement (aligned state). Further, as the two holes 14 and 19 are provided in the main body portions 11 and 16 of the bus bars 10 and 15, two protrusions are provided on the holding body. Thereby, the holding body can also prevent the displacement (rotation) of the held bus bars 10 and 15.

  As described above, since the first bus bar 10 and the second bus bar 15 are arranged by one automatic supply device, the automatic supply device changes the arrangement of the protrusions of the holding body to the bus bar 10, The state in which the first bus bar 10 is arranged on the battery cell 1 and the second bus bar 15 are rotated by rotating the holding body 90 degrees around a predetermined axis so as to correspond to the arrangement of the 15 holes 14 and 19. It switches to the state arrange | positioned on the battery cell 1. FIG.

  And as a 2nd position, the protrusion of a holding body respond | corresponds between battery cells 1 and 1, and the holding body is set to the position which will be in the state which pressed the bus-bars 10 and 15 against the external terminal 4. FIG. Thereby, in a state where the holding body has reached the second position, the bus bars 10 and 15 are always pressed against the external terminals 4 and 4 in a fixed arrangement with respect to the external terminals 4 and 4 of the two battery cells 1 and 1. It is like that. The automatic supply device is set differently from the first position and the second position when the first bus bar 10 is supplied, and the first position and the second position when the second bus bar 15 is supplied. Has been.

  The transport device transports the plurality of battery cells 1 in a direction corresponding to the longitudinal direction of the battery cell 1. Along with this, first, one of the battery cells 1,. Then, the automatic supply device moves the holding body from the first position to the second position, and as shown in FIG. 7A, the second bus bar 15 is connected to the external terminals 4, 4 of the battery cells 1, 1 adjacent in the column direction. It arranges so that it may straddle. In addition, by holding one bus bar 10, 15 with the holding body and reciprocating the holding body a plurality of times, the bus bars 10, ..., 15,... According to the number of battery cells 1,. In this embodiment, the holding body is configured to hold a number of bus bars 10,..., 15,... According to the number of battery cells 1,. Yes. Therefore, the second bus bar 15 is arranged in each of the adjacent battery cells 1 of the plurality of battery cells 1 arranged in a row.

  And a welding apparatus welds the connection part 17 of the 2nd bus-bar 15, and the external terminal 4 which overlapped this, maintaining the holding body located in the 2nd position. That is, the connection part 17 of the second bus bar 15 is welded to the external terminal 4 of the battery cell 1 in a state in which the displacement of the battery cell 1 with respect to the external terminal 4 is prevented by the holding body. A laser welding apparatus is employed as the welding apparatus, and a welding head that emits laser light is moved along the outer edge (thin wall portion 18) of the connection portion 17 of the second bus bar 15. In addition, since the thin portion 18 provided along the outer edge of the connection portion 17 is welded to the external terminal 4, the welding head emits laser light in a state of being perpendicular to the upper surface of the thin portion 18.

  Thus, the thin head 18 of the second bus bar 15 positioned by the holding body and the flat surface 4a of the external terminal 4 are welded by moving the welding head while emitting laser light. That is, the thin-walled portion 18 of the connecting portion 17 and the external terminal 4 are welded by laser welding, so that the welded thin-walled portion 18 merges with the external terminal 4 and extends along the connecting portion 17 as shown in FIG. 7B. The weld line W becomes. Thereby, the second bus bar 15 is electrically and mechanically connected to the external terminal 4 of the battery cell 1.

  Then, the automatic supply device moves the holding body to the first position, holds the first bus bar 10 on the holding body, and the transfer device moves the plurality of battery cells 1. When both the battery cells 1 and 1 arranged in two rows reach the welding area, the automatic supply device moves the holding body from the first position to the second position, and as shown in FIG. 6A, the first bus bar 10 Is arranged so as to straddle the external terminals 4 and 4 of the battery cells 1 and 1 adjacent in the row direction. And a welding apparatus welds the connection part 12 of the 1st bus bar 10, and the external terminal 4 which overlapped with this, maintaining the state which has arrange | positioned the bus bar 15 in the 2nd position. That is, the connection part 12 of the first bus bar 10 is welded to the external terminal 4 of the battery cell 1 in a state in which the positional deviation from the external terminal 4 of the battery cell 1 is prevented by the holding body. That is, when the welding head moves while emitting laser light, the thin portion 13 of the bus bar 10 positioned by the holding body and the flat surface 4a of the external terminal 4 are welded. Also in this case, the welded thin portion 13 is melted into the external terminal 4 and becomes a weld line W along the connecting portion 12 as shown in FIG. 6B. Thereby, the first bus bar 10 is electrically and mechanically connected to the external terminal 4 of the battery cell 1.

  Then, the automatic supply device moves the holding body to the first position, holds the second bus bar 15 on the holding body, and the transfer device moves the plurality of battery cells 1. Then, when the remaining one row of battery cells 1, 1 arranged in two rows reaches the welding area, the automatic supply device moves the holding body from the first position to the second position, and as shown in FIG. The bus bars 15 are arranged so as to straddle the external terminals 4 and 4 of the battery cells 1 and 1 adjacent in the column direction. Then, similarly to the connection of the bus bar 15 to the external terminal 4 of the previous example, the thin portion 18 of the bus bar 15 and the flat surface 4a of the external terminal 4 are welded by the welding device (see FIG. 7B). Thereby, the second bus bar 15 is electrically and mechanically connected to the external terminal 4 of the battery cell 1.

  A plurality of battery cells 1,... Electrically connected via the bus bars 10 and 15 are accommodated in the housing 7, thereby completing a large capacity battery module.

  As described above, according to the battery module and the method for manufacturing the battery module according to the present embodiment, the thin portions 13 and 18 of the bus bars 10 and 15 and the external terminals 4 of the battery cell 1 are welded. Therefore, compared with the case where the thin parts 13 and 18 are not provided, the output energy required for welding can be reduced. Thereby, the periphery of the external terminal 4 in the battery cell 1 and the inside of the battery cell 1, specifically, the external gasket 3 in which the external terminal 4 in the battery cell 1 is arranged and the power generation element connected to the external terminal 4 are welded. It is possible to prevent damage due to the influence of heat.

  Instead of irradiating the laser beam downward from the upper side and welding, the laser beam is emitted obliquely downward and irradiated to the lower part of the bus bars 10 and 15 so that the thin portions 13 and 18 are not provided. It is possible to reduce the output energy required for However, this requires a mechanism for changing and adjusting the tilt angle of the welding head that emits laser light (the tilt angle with respect to the Z axis when the bus bars 10 and 15 are placed on the XY plane). It will become something. In addition, for example, when the arc portions of the bus bars 10 and 15 are laser-welded, the welding head moves around the Z axis while moving on the XY plane, so a machining program for controlling the movement is provided. There is a problem that it becomes complicated and it takes time and cost to create a machining program. Furthermore, compared to welding by irradiating laser light downward from above, the method of emitting laser light obliquely downward and welding scatters laser light over a wide area, affecting other parts of the battery module. There is a risk of giving. However, if the thin-walled portions 13 and 18 are used, welding can be performed simply by emitting a laser beam from the top to the bottom and irradiating the thin-walled portions 13 and 18. Becomes simple, and the problem of scattering of laser light is eliminated.

  In the bus bars 10 and 15, one thin portion 13 and 18 is connected to the external terminal 4 of one battery cell 1, and the other thin portion 13 and 18 is connected to the external terminal 4 of the other battery cell 1. The bus bars 10 and 15 connect the external terminals 4 and 4 of the two battery cells 1 and 1 to each other. Thereby, the two battery cells 1 and 1 electrically constitute one battery.

  Further, in the bus bars 10 and 15, thin portions 13 and 18 are formed along the outer edges of the connection portions 12 and 17. Therefore, the thin-walled portions 13 and 18 can be spot-welded to an arbitrary portion, or the thin-walled portions 13 and 18 can be continuously welded along the longitudinal direction in order to further increase the welding strength. . Therefore, various welding modes can be freely selected.

  In particular, in the first bus bar 10, the connection portion 12 is narrower than the main body portion 11. Therefore, compared with the case where the width of the connection part 12 is not narrower than the width | variety of the main-body part 11, a welding range can be decreased. The fact that the welding range can be reduced means that the output energy required for welding can be reduced. Therefore, it is possible to suitably prevent thermal damage to the bus bar 10, the external terminal 4, the external gasket 3 in which the external terminal 4 is disposed, or the power generation element connected to the external terminal 4. Moreover, since the width | variety of the main-body part 11 does not become narrow, appropriate current capacity can be obtained as the bus bar 10 whole.

  Further, in the first bus bar 10, the end of the connecting portion 12 has a semicircular arc shape, that is, the outer edge of the end of the connecting portion 12 does not have a discontinuous portion. There are no corners. When at least a partial region of the outer edge of the connecting portion 12 and the external terminal 4 are welded along the outer edge of the connecting portion 12, if there is a corner, the welding speed is reduced and the homogeneity of the welded portion is impaired. End up. However, if there is no corner portion, welding can be performed continuously at a constant speed, so that a weld portion W having a uniform constant length can be formed.

  In the first bus bar 10, the cross-sectional area of the connecting portion 12 is smaller than the cross-sectional area of the main body portion 11. If the bus bar is formed with a certain width, the size of the bus bar is not limited from the viewpoint of the current capacity of the bus bar, but also from the viewpoint of layout restrictions or arrangement space restrictions when arranging the connection parts on the external terminals. Determined by For example, when the width size of the bus bar is determined in view of layout restrictions or arrangement space restrictions when arranging the connection portions on the external terminals, the entire bus bar width is reduced. Therefore, the current capacity of the entire bus bar is reduced. On the other hand, if the width size of the bus bar is determined in order to obtain an appropriate current capacity for the entire bus bar, the width of the connection portion is also increased. For this reason, the connection portion may not be properly disposed on the external terminal. However, if the cross-sectional area of the connection part 12 is smaller than the cross-sectional area of the main body part 11, it is possible to relax the restrictions on layout or arrangement space when the connection part 12 is arranged on the external terminal 4. it can. That is, the connection part 12 can be appropriately arranged on the external terminal 4. Further, since the cross-sectional area of the main body 11 is not reduced, an appropriate current capacity can be obtained for the first bus bar 10 as a whole.

  Specifically, the first bus bar 10 is plate-shaped, and in the first bus bar 10, the width of the connection portion 12 is narrower than the width of the main body portion 11. The cross-sectional area of the connection part 12 is smaller than the cross-sectional area of the main body part 11. Therefore, layout restrictions or arrangement space restrictions when arranging the connecting portion 12 on the external terminal 4 can be relaxed. Further, since the cross-sectional area of the main body 11 is not reduced, an appropriate current capacity can be obtained for the first bus bar 10 as a whole.

  In addition, at least two battery cells 1 and 1 are arranged such that one surface (outer surface of the cover plate 2b) on which the external terminals 4 are arranged is arranged in the longitudinal direction, and the first bus bar 10 has two battery cells 1 and 1. When the external terminals 4 and 4 are connected to each other, the main body portion 11 is formed according to the width of one surface, and the connection portion 12 is formed according to the width of the external terminal 4 narrower than the one surface. Yes. Therefore, layout restrictions or arrangement space restrictions when arranging the connecting portion 12 on the external terminal 4 can be relaxed. Moreover, since the width | variety of the main-body part 11 is not narrowed, suitable electric current capacity can be obtained as the 1st bus bar 10 whole.

  Further, the plurality of battery cells 1,... Are arranged so that one surface (the outer surface of the cover plate 2b) on which the external terminals 4 are arranged is arranged in the longitudinal direction and the short direction, and the first bus bar 10 is arranged in the longitudinal direction. In connecting the external terminals 4, 4 of the two battery cells 1, 1, the main body portion 11 is formed in accordance with the width of one surface, and the connection portion 12 of the external terminal 4 is narrower than the one surface. It is formed according to the width. Therefore, layout restrictions or arrangement space restrictions when arranging the connecting portion 12 on the external terminal 4 can be relaxed. Moreover, since the width | variety of the main-body part 11 is not narrowed, suitable electric current capacity can be obtained as the 1st bus bar 10 whole. Further, the width of the main body 11 does not exceed or greatly exceed the width of one surface. Therefore, it can prevent interfering with the 1st bus bar 10 connected to the battery cell 1 adjacent in a transversal direction.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

  In the said embodiment, although the connection parts 12 and 17 (thick part) and the main-body parts 11 and 16 of the 1st bus bar 10 and the 2nd bus bar 15 were made into the same thickness, it is not limited to this. For example, assuming that the thickness of the thin portion is thinner than the thickness of the connection portion (more preferably, the thickness of the connection portion and the main body portion), the thickness of the connection portion (thick portion) is larger than the thickness of the main body portion. It may be thicker.

  In the above embodiment, in the first bus bar 10, the width of the connection portion 12 is constant (ignoring the point of the semicircular arc at the tip portion), and the width of the main body portion 11 is also constant. It is constant. Therefore, the width of the first bus bar 10 changes discontinuously from the connection portion 12 to the main body portion 11. However, it is not limited to such a form. For example, the width may continuously change from the connecting portion to the main body, that is, the width may gradually increase.

  Moreover, in the said embodiment, only the 1st bus-bar 10 is made to give the difference of a cross-sectional area between the main-body part 11 and the connection part 12. FIG. However, similarly to the first bus bar 10, the second bus bar 15 may have a cross-sectional area difference between the main body portion 16 and the connection portion 17.

  Further, the present invention does not include only the first bus bar 10 and the second bus bar 15 in the technical scope. For example, the third bus bar 20 having a connection portion only on one side is also included in the technical scope. Actually, as shown in FIGS. 1 and 2, the third bus bar 20 (the positive third bus bar 20A and the negative third bus bar 20B) employs such a configuration.

  In the above embodiment, the thin portion 13 is formed along the outer edge of the connection portion 12 of the first bus bar 10, and the thin portion 18 is formed along the outer edge of the connection portion 17 of the second bus bar 15. Has been. However, the location where the thin portion is formed is not limited to the outer edge of the connecting portion. For example, an opening penetrating the front and back and an opening cut out inward from a part of the outer edge of the connection part may be formed in the connection part, and a thin part may be formed at the inner edge of the opening. . Moreover, the whole connection part 12 and 17 may be sufficient as a thin part.

  Alternatively, a non-penetrating recess is formed on the upper surface or the lower surface (preferably the upper surface) of the central portion of the connection portions 12 and 17 as shown in FIGS. 9 and 10 instead of the opening penetrating the front and back of the connection portion. Thus, the thin portions 21 and 22 may be formed. In this case, the thin portions 21 and 22 may be formed with a uniform thickness, but may be formed with a non-uniform thickness. For example, the thin portions 21 and 22 are formed with a non-uniform thickness, so that the thickness decreases toward the center in the width direction, the inner edge, or the outer edge of the thin portions 21 and 22 (for example, FIG. It may have an inclined top surface (as in FIG. 8C). 9 and 10, the thin portions 21 and 22 are annular, and the non-thin portion that is not the thin portion remains in the inner region, but the entire inner region is a thin portion. There may be.

  That is, the thin wall portion only needs to be thinner than the original plate thickness of the plate material constituting the bus bars 10 and 15.

  In addition, when the thin parts 21 and 22 are formed in the center part of the connection parts 12 and 17, from the viewpoint of forming the welded part W having a uniform and constant length as described above, the thin parts 21 and 22 are A shape such as a circular shape, an elliptical shape, or an oval shape is preferable. That is, the outer edges of the thin portions 21 and 22 have a closed shape having no discontinuous portions, and therefore it is preferable that the outer edges of the thin portions 21 and 22 have no corners.

  For the same reason, the bus bar may have an oval shape, an oval shape, or a semicircular arc shape at the end, as shown in FIG.

  Moreover, in the said embodiment, the thin parts 13 and 18 are continuously formed with predetermined length. However, the present invention is not limited to this. For example, if the arbitrary portions of the connecting portions 12 and 17 of the bus bars 10 and 15 are spot-welded, it is only necessary that the thin-walled portion is formed at least at the portions.

  Moreover, in the said embodiment, although the external terminal 4 and the bus-bars 10 and 15 were comprised with the aluminum-type metal material, it is not limited to this. For example, the external terminals 4 and the bus bars 10 and 15 may be made of a metal material such as copper, SUS, or steel. That is, the external terminals 4 and the bus bars 10 and 15 may be metal materials that are conductive and can be welded to each other.

  In the said embodiment, although the bus-bars 10 and 15 were welded to the external terminal 4 of the battery cell 1 by laser welding, it is not limited to this. For example, general arc welding may be used.

  Moreover, in the said embodiment, the lithium ion secondary battery was demonstrated. However, the type and size (capacity) of the battery are arbitrary.

  Further, the present invention is not limited to the lithium ion secondary battery. The present invention is also applicable to various secondary batteries, other primary batteries, and capacitors such as electric double layer capacitors.

  By the way, in the said embodiment, the thin part 13 is formed in the connection part 12, and the thin part 13 and the external terminal 4 are welded. However, even if the connection part 12 is narrower than the main body part 11, the welding range can be reduced, and the output energy required for welding can be reduced. From this point of view, it can be technically established that the thin portion 13 is not provided in the connecting portion 12. That is, the invention has a power storage element having an external terminal, a main body portion and a connection portion, and a bus bar connected to the external terminal at the connection portion, wherein the connection portion has a smaller cross-sectional area than the main body portion. Can hold.

  In this case, in the above embodiment, in the first bus bar 10, the width of the connection portion 12 is narrower than the width of the main body portion 11, so that the cross-sectional area of the connection portion 12 is larger than the cross-sectional area of the main body portion 11. It is getting smaller. However, it is not limited to this. For example, the thickness of the connection part 12 may be made smaller than the thickness of the main body part 11. Or you may make it provide the difference of a cross-sectional area between the connection part 12 and the main-body part 11 with the combination of thickness and width. In short, it is only necessary to provide a difference in cross-sectional area between the connection portion 12 and the main body portion 11 by changing the shape and dimensions of the corresponding portions of the first bus bar 10 including the thickness and width.

  Further, in this case, the bus bars 10 and 15 and the external terminals 4 are not welded. For example, the external terminals are bolt terminals, and a hole through which the bolt terminal is inserted is formed in the bus bar. It is also possible to connect the bus bar and the external terminal by fastening the nut.

DESCRIPTION OF SYMBOLS 1 ... Battery cell, 2 ... Case, 2a ... Case main body, 2b ... Cover plate, 3 ... External gasket, 4 ... External terminal, 4a ... Flat surface, 7 ... Housing, 10 ... 1st bus bar, 11 ... Main-body part, DESCRIPTION OF SYMBOLS 12 ... Connection part, 13 ... Thin part, 14 ... Hole, 15 ... Second bus bar, 16 ... Main part, 17 ... Connection part, 18 ... Thin part, 19 ... Hole, 20 ... Third bus bar (20A ... Positive electrode 3rd bus bar, 20B ... 3rd bus bar for negative electrode), 21 ... thin wall part, 22 ... thin wall part, W ... welding line (weld part)

Claims (13)

A storage element having an external terminal;
A bus bar connected to the external terminal,
The bus bar has a thin portion formed along an outer edge of the bus bar ,
A power storage device in which the thin portion and the external terminal are welded. The power storage device according to claim 1 , wherein the outer edge of the bus bar has a shape having no discontinuous portion. A storage element having an external terminal;
A bus bar connected to the external terminal,
The bus bar has a thin portion,
The thin portion and the external terminal are welded,
The thin-walled portion is a concave portion formed in an annular shape in the central portion of the bus bar.
Power storage device. Comprising at least two power storage elements,
The thin portion is
At least two places,
The power storage device according to any one of claims 1 to 3 , wherein the power storage device is welded to the external terminals of two power storage elements. The power storage device according to any one of claims 1 to 4, wherein the thin portion is formed in at least a portion of the bus bar that is in contact with the external terminal. The power storage device according to claim 3 , wherein an outer edge of the thin portion has a closed shape without a discontinuous portion. The bus bar has a main body part and a connection part that is continuous with the main body part and connected to the external terminal;
The power storage device according to any one of claims 1 to 6 , wherein the thin portion is formed in the connection portion. The power storage device according to claim 7 , wherein a width of the connection portion is narrower than a width of the main body portion. Comprising at least two power storage elements,
The power storage device according to claim 7 or 8 , wherein a pair of the connection parts are provided at both ends of the main body part and connect the external terminals of two power storage elements. The power storage element includes a case, and is flattened in a rectangular shape with one surface on which the external terminal is disposed in the case, and at least two power storage elements are disposed so that the one surface is aligned in the longitudinal direction. ,
The main body is formed in accordance with the width of the one surface,
The power storage device according to claim 9 , wherein the connection portion is formed according to the width of the external terminal that is narrower than the one surface. The power storage element includes a case, and a plurality of power storage elements are arranged such that one surface of the case on which the external terminals are arranged is a flat rectangular shape having a rectangular shape, and the one surface is aligned in the longitudinal direction and the short direction. Are arranged in a matrix,
Among the bus bars, the main body portion of the bus bar that connects the external terminals of two power storage elements arranged in the longitudinal direction is formed according to the width of the one surface,
The power storage device according to claim 9 , wherein the connection portion of the bus bar is formed in accordance with the width of the external terminal that is narrower than the one surface. The power storage device according to any one of claims 1 to 11 , wherein the thin portion is formed in a stepped shape. The power storage device according to any one of claims 1 to 11 , wherein the thin portion is formed in a shape that decreases in thickness toward an outer edge side.

Images