Bus bar and power storage unit

Abstract

The invention relates to a bus bar and a power storage unit. According to the present disclosure, the stress applied to the joining portion of the bus bar and the terminal portion can be relaxed. A bus bar (1) disclosed herein has: a first bonding region (10) bonded to a terminal section (144) of a first electricity storage device (100A); a second joining region (20) to which a terminal part (144) of a second electricity storage device (100B) different from the first electricity storage device (100A) is joined; and a bridge region (30) connecting the first bonding region (10) and the second bonding region (20). Furthermore, the first bonding region (10) and / or the second bonding region (20) is provided with buffer sections (12, 22) that absorb stress (S) caused by fluctuations in the interval (G) between the first bonding region (10) and the second bonding region (20). The bus bar (1) of this configuration can alleviate the stress on the joining parts (W1, W2) between the bus bar (1) and the terminal parts (144).

Description

Technical Field

[0001] The present disclosure relates to a bus bar and a power storage unit. Background Art

[0002] Energy storage devices such as lithium-ion secondary batteries are used as power sources for various electrical products. In this case, an energy storage unit is sometimes constructed by connecting multiple energy storage devices using a busbar. An example of such a busbar is disclosed in Patent Document 1 (Japanese Application Publication No. 2020-021628). The busbar described in Patent Document 1 is a conductive member that connects multiple terminals. The busbar is stacked with multiple conductive plates, and has a bent portion that is bent along the stacking direction of the conductive plates between multiple connecting portions connected to the multiple terminals. Since the bent portion of the busbar with this structure deforms when stress is applied, it is possible to follow the changes in the distance between the terminals caused by the expansion and contraction of the single battery (energy storage device).

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-021628 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, a general busbar is joined to the terminal portion of the power storage device by laser welding, resistance welding, etc. Here, when the distance between the terminals changes due to the expansion and contraction of the power storage device, stress is sometimes applied not only to the busbar body but also to the joint between the busbar and the terminal portion. As described above, the busbar described in Patent Document 1 can use the bent portion between the two joints to alleviate the stress applied to the busbar body. However, in the busbar of this structure, it is difficult to alleviate the stress applied to the joint between the busbar and the terminal portion.

[0008] Means for solving problems

[0009] In order to solve the above-mentioned problems, a bus bar having the following structure is provided.

[0010] The bus bar disclosed herein comprises: a first joining region joined to a terminal portion of a first power storage device; a second joining region joined to a terminal portion of a second power storage device different from the first power storage device; and a bridging region connecting the first joining region and the second joining region. In addition, in the bus bar, a buffer portion is provided in at least one of the first joining region and the second joining region, and the buffer portion absorbs stress caused by a change in the interval between the first joining region and the second joining region.

[0011] In the busbar of the above structure, at least one of the first joint region and the second joint region is provided with a buffer portion for absorbing stress caused by the change in the interval between the first joint region and the second joint region. Thus, it is possible to suppress the stress generated by the change in the interval between the two joint regions from being applied to the joint between the busbar and the terminal portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a perspective view schematically showing the bus bar according to the first embodiment.

[0013] Figure 2 It is schematically shown Figure 1 A cross-sectional view showing the connection between a bus bar and a terminal portion of an electric storage device.

[0014] Figure 3 It is a perspective view schematically showing the power storage unit according to the first embodiment.

[0015] Figure 4 It is schematically shown Figure 3 A three-dimensional diagram of the power storage device in FIG.

[0016] Figure 5 It is schematically shown Figure 4 An enlarged cross-sectional view of the structure near the terminal mounting hole of the power storage device shown.

[0017] Figure 6 It is a description of the production Figure 5 An enlarged cross-sectional view of the step of the insulating member.

[0018] Figure 7 It is schematically shown Figure 3 An enlarged cross-sectional view of the connection structure of the power storage unit shown.

[0019] Figure 8 It is a cross-sectional view schematically showing the joining of a bus bar and a terminal portion of an electric storage device according to another embodiment.

[0020] Fig. 9 It is a plan view of a bus bar according to another embodiment.

[0021] Fig.10 It is a plan view of a bus bar according to another embodiment.

[0022] Fig.11 It is a plan view of a bus bar according to another embodiment.

[0023] Fig.12 This is an enlarged cross-sectional view schematically showing the structure of the vicinity of the terminal mounting hole of the electric storage device of the electric storage unit according to another embodiment.

[0024] Fig.13This is an enlarged cross-sectional view schematically showing the structure of the vicinity of the terminal mounting hole of the electric storage device of the electric storage unit according to another embodiment.

[0025] Fig.14 This is an enlarged cross-sectional view schematically showing the structure of the vicinity of the terminal mounting hole of the electric storage device of the electric storage unit according to another embodiment.

[0026] Fig.15 This is an enlarged cross-sectional view schematically showing a connection structure of an electric storage cell according to another embodiment.

[0027] Fig.16 This is an enlarged cross-sectional view schematically showing a connection structure of an electric storage cell according to another embodiment.

[0028] Description of Reference Numerals

[0029] 1 Busbar

[0030] 10 First bonding area

[0031] 11 First base

[0032] 12 Buffer

[0033] 13 Protrusion

[0034] 14 Contact Department

[0035] 17 Opening

[0036] 20 Second bonding area

[0037] 21 Second base

[0038] 22 Buffer

[0039] 23 Protrusion

[0040] 24 Contact Department

[0041] 30 Bridge Area

[0042] 31 Bridge base

[0043] 32. Fluctuation absorption unit

[0044] 33 Protrusion

[0045] 34 Connection

[0046] 100 Energy Storage Devices

[0047] 110 Electrode body

[0048] 120 Shell

[0049] 122 Shell body

[0050] 124 Sealing plate

[0051] 125 Terminal mounting hole

[0052] 130 Insulation

[0053] 140 Current Collector

[0054] 142 Joint

[0055] 144 Terminal

[0056] 500 Power storage unit. DETAILED DESCRIPTION

[0057] Hereinafter, with reference to the accompanying drawings, an implementation method of the technology disclosed herein will be described. In addition, for matters other than matters specifically mentioned in this specification, matters required for the implementation of the technology disclosed herein (such as the detailed structure of the electrode body, etc.) can be grasped as design matters for those skilled in the art based on the prior art in this field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in this field. In addition, the expression "A~B" indicating a range in this specification includes the meaning of more than A and less than B, and includes the meaning of "greater than A" and "less than B".

[0058] In addition, the term "electrical storage device" in this specification refers to a concept including a device that generates a charge-discharge reaction by moving charge carriers between a pair of electrodes (a positive electrode and a negative electrode). That is, the electrical storage device in the technology disclosed herein includes not only secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, but also capacitors such as lithium-ion capacitors and electric double-layer capacitors.

[0059] <First embodiment>

[0060] 1. Busbar structure

[0061] Below, refer to Figure 1 and Figure 2 , an embodiment of the bus bar disclosed herein is described. Figure 1 It is a perspective view schematically showing the bus bar according to the first embodiment. Figure 2 It is schematically shown Figure 1 A cross-sectional view of the connection between the busbar shown and the terminal portion of the power storage device. In addition, the reference numerals L, R, F, Rr, U, and D in the figure represent left, right, front, rear, top, and bottom, respectively. In addition, the reference numerals X, Y, and Z in the figure represent the width direction, depth direction, and height direction of the busbar, respectively. However, these directions are merely determined for the convenience of explanation and do not limit the use form of the busbar disclosed herein. In addition, for the convenience of explanation, in Figure 2 In FIG. 1 , regarding the first power storage device 100A and the second power storage device 100B, only the terminal portion 144 is shown and other portions are omitted.

[0062] like Figure 1 and Figure 2 As shown, the bus bar 1 of this embodiment includes: a first joint region 10, which is joined to the terminal portion 144 of the first power storage device 100A; a second joint region 20, which is joined to the terminal portion 144 of the second power storage device 100B different from the first power storage device 100A; and a bridge region 30, which connects the first joint region 10 and the second joint region 20. In addition, in the bus bar 1, buffer portions 12 and 22 are provided in the first joint region 10 and the second joint region 20, and the buffer portions 12 and 22 absorb the stress S caused by the change of the interval G between the first joint region 10 and the second joint region 20. As a result, the stress on the joint portions W1 and W2 of the bus bar 1 and the terminal portion 144 can be relieved. Hereinafter, the bus bar 1 of this structure will be described in detail.

[0063] (1) Overall structure

[0064] like Figure 2 As shown, the busbar 1 of the present embodiment is a conductive member that connects the terminal portions 144 of two power storage devices (the first power storage device 100A and the second power storage device 100B). The material of the busbar 1 only needs to have a certain conductivity, and conventionally known conductive materials can be used without particular limitation. As an example of the material of the busbar 1, metal materials such as aluminum, copper, iron, zinc, silver, and nickel can be cited. In addition, the material of the busbar 1 can also be an alloy of these metals. The busbar 1 can also be a clad material (clad material) formed by stacking multiple layers composed of different metal materials. In addition, if the bonding property with the terminal portion 144 of the power storage device is taken into consideration, the busbar 1 is preferably composed of the same type of metal material as the terminal portion 144. For example, the terminal portion 144 on the positive electrode side of the power storage device uses aluminum or the like. In this case, the busbar 1 is preferably composed of aluminum or an aluminum alloy.

[0065] Furthermore, the bus bar 1 of the present embodiment includes a first joint region 10, a second joint region 20, and a bridge region 30. Specifically, Figure 1 The bus bar 1 shown is a long plate-shaped member extending in the width direction X. In the bus bar 1, a first joint region 10, a bridge region 30, and a second joint region 20 are arranged in order from the left L to the right R in the width direction X. Each region will be described below.

[0066] (2) First bonding area 10

[0067] The first bonding region 10 is a region bonded to the terminal portion 144 of the first power storage device 100A. Figure 1 As shown in FIG. 1 , the first joint region 10 is formed at one end (left side L) of the bus bar 1 in the width direction X. Figure 2 As shown, a portion of the first bonding region 10 (contact portion 14 described later) is bonded to the terminal portion 144 of the first power storage device 100A. Conventionally known bonding processes (laser welding, resistance welding, ultrasonic bonding, etc.) are used to bond the first bonding region 10 to the terminal portion 144. Thus, a bonding portion W1 spanning the first bonding region 10 (contact portion 14) and the terminal portion 144 is formed. Although not shown in the figure, the bonding portion W1 is an annular bonding portion when viewed from above.

[0068] Here, in the bus bar 1 of the present embodiment, the buffer portion 12 is provided in the first joint region 10, and the buffer portion 12 absorbs the stress S caused by the change in the interval G between the first joint region 10 and the second joint region 20. Thus, the stress S applied to the joint portion W1 can be suppressed. An example of the structure of the buffer portion 12 is described below.

[0069] First, the first joining region 10 has a plate-shaped joining base. Hereinafter, the joining base in the first joining region 10 is referred to as the "first base 11". In addition, the buffer portion 12 in the present embodiment is composed of a step protruding from the first base 11. Specifically, the step-shaped buffer portion 12 protrudes from the first base 11 toward the terminal portion 144 of the first power storage device 100A (i.e., downward D in the height direction Z). Since the step-shaped buffer portion 12 deforms when the stress S along the width direction X is applied, it is possible to suppress the stress S from being directly applied to the joining portion W1.

[0070] More specifically, the step-shaped buffer portion 12 includes: a protrusion 13, which protrudes downward D from the first base portion 11; and a contact portion 14, which is provided at the front end (lower end) 13a of the protrusion 13 and contacts the terminal portion 144. The contact portion 14 is a plate-shaped member extending in the plane direction (width direction X and depth direction Y). The bonding portion W1 on the first bonding area 10 side extends in the height direction Z in a manner spanning the contact portion 14 and the terminal portion 144. In addition, the protrusion 13 extends in the height direction Z in a manner connecting the contact portion 14 to the first base portion 11. According to the buffer portion 12 of this structure, the stress S on the bonding portion W1 can be particularly appropriately relieved. Specifically, it is as follows. First, when the first power storage device 100A and the second power storage device 100B expand and contract, the interval G between the first bonding area 10 and the second bonding area 20 changes. As a result, the stress S in the plane direction (width direction X, depth direction Y) is applied to the first bonding area 10. However, the buffer portion 12 of this embodiment includes the protrusion 13 extending in the height direction Z. Since the protrusion 13 deforms preferentially when the stress S in the plane direction is applied, it can absorb the stress S. Thus, the stress S in the width direction X can be suppressed from being applied to the joining portion W1 extending in the height direction Z.

[0071] In addition, it is preferable that the thickness t1 of the protrusion 13 (the dimension of the protrusion 13 in the width direction X) is thinner than the thickness t2 of the contact portion 14 (the dimension of the contact portion 14 in the height direction Z). Thus, since the protrusion 13 is more likely to be deformed preferentially, the stress S on the joint portion W1 can be more appropriately relieved. Specifically, when the thickness t2 of the contact portion 14 is set to 100%, the thickness t1 of the protrusion 13 is preferably 90% or less, more preferably 85% or less, further preferably 80% or less, and particularly preferably 75% or less. Thus, the protrusion 13 is more likely to be deformed with respect to the stress S along the width direction X. On the other hand, the thickness t1 of the protrusion 13 is preferably 45% or more, more preferably 50% or more, further preferably 55% or more, and particularly preferably 60% or more relative to the thickness t2 of the contact portion 14. Thus, the strength of the protrusion 13 can be sufficiently ensured.

[0072] In addition, the specific value of the thickness t2 of the contact portion 14 is preferably 0.1 mm or more, more preferably 0.2 mm or more, further preferably 0.3 mm or more, and particularly preferably 0.5 mm or more. Thus, the strength of the contact portion 14 can be sufficiently ensured. On the other hand, the thickness t2 of the contact portion 14 is preferably 3.5 mm or less, more preferably 3.0 mm or less, further preferably 2.5 mm or less, and particularly preferably 2.0 mm or less. Thus, the junction W1 spanning the contact portion 14 and the terminal portion 144 can be easily formed.

[0073] In addition, the height h1 of the protrusion 13 is preferably 1.0 mm or more, more preferably 1.5 mm or more, and particularly preferably 2.0 mm or more. As a result, the protrusion 13 is easily deformed with respect to the stress S in the planar direction, and thus the stress S on the joint W1 can be more appropriately relieved. On the other hand, the storage cell 500 (see FIG. 1 ) when the bus bar 1 is mounted Figure 3 ), the height h1 of the protrusion 13 is preferably 3.0 mm or less, and more preferably 2.0 mm or less. This can improve the loading efficiency when the power storage unit is mounted on an electrical product (electric vehicle, etc.).

[0074] In addition, if Figure 1 As shown, the buffer portion 12 in this embodiment is a concave portion having a substantially circular planar shape. Figure 1 In the buffer portion 12 shown in the figure, a cylindrical protrusion 13 protrudes from the first base portion 11 toward the downward direction D. Figure 1 The contact portion 14 shown is a disk-shaped member that blocks the opening below D of the cylindrical protrusion 13. Since the buffer portion 12 having a substantially circular planar shape can deform the protrusion 13 in various directions in the planar direction, the stress S on the joint W1 can be more appropriately relieved.

[0075] In addition, the inner diameter d1 of the cylindrical protrusion 13 is preferably 10 mm or more, more preferably 15 mm or more, and particularly preferably 20 mm or more. As a result, the reliability of the joint W1 is improved because the welding area can be ensured. On the other hand, from the perspective of reducing the size of the bus bar 1 and achieving lightweight storage devices, the inner diameter d1 of the protrusion 13 is preferably 25 mm or less, and more preferably 20 mm or less.

[0076] (2) Second bonding area 20

[0077] The second bonding region 20 is a region bonded to the terminal portion 144 of the second power storage device 100B different from the first power storage device 100A. The second bonding region 20 is formed at the other end (rightward R) of the bus bar 1 in the width direction X. Also, similarly to the first bonding region 10, a bonding portion W2 is formed in a portion (contact portion 24) of the second bonding region 20 that spans the second bonding region 20 and the terminal portion 144.

[0078] Furthermore, in the bus bar 1 of the present embodiment, a buffer portion 22 is also provided in the second joining area 20. The buffer portion 22 of the second joining area 20 has a structure substantially the same as the buffer portion 12 of the first joining area 10 described above. Specifically, the second joining area 20 has a plate-shaped joining base (second base 21). Furthermore, the buffer portion 22 on the second joining area 20 side is also composed of a step protruding from the second base 21 toward the lower side D. More specifically, the buffer portion 22 has: a protrusion 23, the protrusion 23 protruding from the second base 21 toward the lower side D; and a contact portion 24, the contact portion 24 being provided at the lower end 23a of the protrusion 23 and contacting the terminal portion 144. Since the buffer portion 22 of this structure can appropriately absorb the stress S in the planar direction, it is possible to alleviate the stress S on the joining portion W2 of the second joining area 20.

[0079] In addition, as described above, the buffer portion 22 of the second bonding area 20 has a structure substantially the same as that of the buffer portion 12 of the first bonding area 10. Therefore, the dimensions of each component constituting the buffer portion 22 of the second bonding area 20 can be appropriately set based on the same concept as that of the buffer portion 12 of the first bonding area 10 described above. Therefore, in this specification, repeated descriptions are omitted. However, the dimensions of each of the buffer portions 12 and 22 can be appropriately changed according to the shape of the terminal portion 144 of the bonding object, etc., and do not need to be exactly the same. That is, the buffer portion 22 of the second bonding area 20 may also have a different size from the buffer portion 12 of the first bonding area 10.

[0080] (3) Bridging area

[0081] The bridge region 30 is a region connecting the first joint region 10 and the second joint region 20. The bridge region 30 is provided across the first joint region 10 and the second joint region 20 to electrically connect the first power storage device 100A and the second power storage device 100B.

[0082] In addition, the bridging area 30 in the present embodiment has a variation absorbing portion 32, and the variation absorbing portion 32 absorbs the variation of the interval G between the first bonding area 10 and the second bonding area 20. Thus, the stress applied to the bus bar 1 itself can be alleviated. Specifically, the bridging area 30 in the present embodiment has a plate-shaped bridging base 31. And the variation absorbing portion 32 is composed of a step protruding from the bridging base 31. More specifically, the variation absorbing portion 32 has a protrusion 33 protruding from the bridging base 31 toward the upper U and a flat plate-shaped connecting portion 34 provided at the upper end 33a of the protrusion 33. Since the variation absorbing portion 32 of this structure can cause the protrusion 33 to deform preferentially when the interval G between the first bonding area 10 and the second bonding area 20 varies, it is possible to alleviate the stress applied to the bus bar 1 itself.

[0083] In addition, the thickness (dimension in the width direction X) t3 of the protrusion 33 of the bridge region 30 is preferably thinner than the thickness (dimension in the height direction Z) t4 of the connecting portion 34. As a result, the protrusion 33 of the bridge region 30 is more easily deformed. Specifically, when the thickness t4 of the connecting portion 34 is set to 100%, the thickness t3 of the protrusion 33 is preferably 90% or less, more preferably 85% or less, further preferably 80% or less, and particularly preferably 75% or less. On the other hand, the ratio of the thickness t3 of the protrusion 33 to the thickness t4 of the connecting portion 34 is preferably 50% or more, more preferably 55% or more, and particularly preferably 60% or more. As a result, the strength of the protrusion 33 can be sufficiently ensured.

[0084] In addition, specifically, the thickness t4 of the connecting portion 34 is preferably 0.1 mm or more, more preferably 0.25 mm or more, and particularly preferably 0.5 mm or more. Thus, the strength of the connecting portion 34 can be sufficiently ensured. On the other hand, the upper limit of the thickness t4 of the connecting portion 34 is preferably 3.0 mm or less, more preferably 2.5 mm or less, and particularly preferably 2.0 mm or less. Thus, since the bridging region 30 (protrusion 33, connecting portion 34) is easily deformed, the stress S applied to the first joining region 10 and the second joining region 20 can be reduced.

[0085] In addition, the height h2 of the protrusion 33 of the bridge region 30 is preferably 1.0 mm or more, more preferably 1.5 mm or more, further preferably 2.0 mm or more, and particularly preferably 2.5 mm or more. As a result, the protrusion 33 of the bridge region 30 is easily deformed. On the other hand, the height h2 of the protrusion 33 of the bridge region 30 is preferably 5.0 mm or less, more preferably 4.0 mm or less, and particularly preferably 3.0 mm or less. As a result, the storage unit 500 (see Figure 3 ), thus, it is possible to improve the loading efficiency when the power storage unit 500 is mounted on an electrical product (such as an electric vehicle).

[0086] In addition, if Figure 1 As shown, the variation absorbing portion 32 in the present embodiment is a band-shaped step formed over the entire area in the depth direction Y of the bridging region 30. In other words, the variation absorbing portion 32 has a pair of protrusions 33 protruding toward the upper side U from the entire area in the depth direction Y of the bridging base 31. The pair of protrusions 33 face each other in the width direction X. In addition, a connecting portion 34 as a roughly rectangular plate-shaped member is provided in a manner that connects the upper ends 33a of the pair of protrusions 33. Since the variation absorbing portion 32 of this structure can fully absorb the large stress along the width direction X, it is possible to suppress the stress from spreading to the first joining region 10 and the second joining region 20.

[0087] In addition, the width dimension W1 of the connection portion 34 is not particularly limited, and can be appropriately adjusted in consideration of the size, installation position, etc. of the first power storage device 100A and the second power storage device 100B. For example, the lower limit value of the width dimension W1 of the connection portion 34 may be 10 mm or more, 15 mm or more, or 20 mm or more. On the other hand, the upper limit value of the width dimension W1 of the connection portion 34 may be 70 mm or less, 60 mm or less, or 50 mm or less.

[0088] The structure of the bus bar 1 of the present embodiment has been described above. As described above, the bus bar 1 of this structure includes the buffer portions 12 and 22 that absorb the stress S caused by the change in the interval G between the first joint region 10 and the second joint region 20. Thus, it is possible to suppress the stress S from being applied to the joint portions W1 and W2 between the bus bar 1 and the terminal portion 144.

[0089] 2. Structure of the power storage unit

[0090] Next, a description will be given of a power storage unit 500 using the bus bar 1 having the above-described structure. Figure 3 It is a perspective view schematically showing the power storage unit according to the first embodiment. Figure 4 It is schematically shown Figure 3 A three-dimensional diagram of the power storage device in FIG. Figure 5 It is schematically shown Figure 4 An enlarged cross-sectional view of the structure near the terminal mounting hole of the power storage device shown. Figure 6 It is a description of the production Figure 5 An enlarged cross-sectional view of the step of the insulating member. Figure 7 It is schematically shown Figure 3 An enlarged cross-sectional view of the connection structure of the power storage unit shown.

[0091] (1) Power storage device 100

[0092] Figure 3 The illustrated power storage unit 500 includes a plurality of power storage devices 100. Specifically, in the power storage unit 500, a flat square power storage device 100 is used. In addition, the plurality of power storage devices 100 are arranged along the width direction X so that the flat surfaces face each other. In addition, the number of power storage devices 100 included in the power storage unit 500 is not particularly limited and can be appropriately changed according to the purpose of the power storage unit 500 (required power, specifications, etc. of the electrical product to be used).

[0093] In addition, if Figure 4 and Figure 5 As shown, the electricity storage device 100 includes an electrode body 110, a case 120, an insulating member 130, and a current collector 140. An example of the structure of the electricity storage device 100 will be described below.

[0094] (1-1) Electrode body 110

[0095] The electrode body 110 is a power generation element of the power storage device 100 . Figure 5 The illustrated power storage device 100 includes an electrode body 110. However, the number of electrode bodies is not particularly limited and may be multiple. In addition, although detailed illustration is omitted, the electrode body 110 includes a positive electrode plate, a negative electrode plate and a separator. The positive electrode plate includes a positive electrode core body as a conductive metal foil (aluminum foil, etc.) and a positive electrode active material layer applied to the surface of the positive electrode core body. On the other hand, the negative electrode plate includes a negative electrode core body as a conductive metal foil (copper foil, etc.) and a negative electrode active material layer applied to the surface of the negative electrode core body. In addition, the separator is an insulating sheet between the positive electrode plate and the negative electrode plate. In addition, the raw materials of each component (positive electrode plate, negative electrode plate, separator, etc.) constituting the electrode body 110 can use materials that can be used in general power storage devices without particular limitation, and the technology disclosed herein is not limited, so the detailed description is omitted.

[0096] In addition, the specific structure of the electrode body 110 is not particularly limited. For example, the electrode body 110 may also be a wound electrode body formed by winding a stack including a positive electrode plate, a negative electrode plate and a separator. In addition, the electrode body 110 may also be a stacked electrode body formed by stacking a plurality of positive plates, negative plates and separators. However, regardless of the structure adopted, connecting tabs 112 are formed on both side edges of the electrode body 110 in the depth direction Y. The connecting tab 112 on one side is a positive electrode tab electrically connected to the positive electrode plate. The positive electrode tab is formed, for example, by bundling a positive electrode core body not coated with a positive electrode active material layer. In addition, the connecting tab 112 on the other side is a negative electrode tab electrically connected to the negative electrode plate. The negative electrode tab is formed by bundling a negative electrode core body not coated with a negative electrode active material layer. The details will be described later, but these connecting tabs 112 are electrically connected to the collector 140.

[0097] (1-2) Housing 120

[0098] The shell 120 is a container that accommodates the electrode body 110 and has a terminal assembly hole 125. Specifically, the shell 120 is a flat box-shaped container having an internal space. And the electrode body 110 is accommodated in the internal space of the shell 120. In addition, although the illustration is omitted, an electrolyte is also accommodated in the shell 120. The electrolyte can be used without particular limitation. The electrolyte that can be used in general power storage devices is not limited, and the technology disclosed herein is not limited, so a detailed description is omitted.

[0099] In addition, the housing 120 includes a housing body 122 and a sealing plate 124. The housing body 122 is a box-shaped body with an upper surface opening. Figure 4 As shown, the shell body 122 includes: a bottom 122b which is a long rectangular plate-like member, a pair of first side walls 122c extending upward D from the long sides (sides along the depth direction Y) of the bottom 122b, and a pair of second side walls 122d extending upward D from the short sides (sides along the width direction X) of the bottom 122b. In addition, an upper surface opening surrounded by the upper ends of the first side wall 122c and the second side wall 122d is formed on the upper surface of the shell body 122. On the other hand, the sealing plate 124 is a rectangular plate-like member that blocks the upper surface opening of the shell body 122. Specifically, as Figure 5 As shown, the sealing plate 124 is embedded in the upper surface opening of the shell body 122. In addition, the boundary between the shell body 122 and the sealing plate 124 is joined by laser welding or the like. In addition, the shell 120 (shell body 122 and sealing plate 124) is preferably a metal member having a certain strength or more. As an example of the raw material of the shell 120, metal materials such as aluminum and aluminum alloy can be listed.

[0100] In addition, as described above, the housing 120 is provided with a terminal assembly hole 125. The terminal assembly hole 125 is a through hole that penetrates the housing 120. The terminal assembly hole 125 is an opening for forming a conductive path from the electrode body 110 inside the housing 120 to the outside of the housing 120. Figure 4 As shown in FIG. 1 , the terminal assembly hole 125 is a circular opening in a plan view. However, the planar shape of the terminal assembly hole is not particularly limited and may also be a square. Figure 4 In the illustrated power storage device 100, two terminal assembly holes 125 are formed in the sealing plate 124 of the housing 120. Specifically, the terminal assembly holes 125 are formed at both ends of the sealing plate 124 in the depth direction Y. In addition, one terminal assembly hole 125 becomes a positive terminal assembly hole 125P, and the positive terminal assembly hole 125P forms a conductive path with the positive electrode of the electrode body 110. In addition, the other terminal assembly hole 125 becomes a negative terminal assembly hole 125N, and the negative terminal assembly hole 125N forms a conductive path with the negative electrode of the electrode body 110. Below, the structure around the negative terminal assembly hole 125N is listed as an example for explanation.

[0101] (1-3) Insulation 130

[0102] The insulating member 130 continuously covers the peripheral wall 125a of the terminal assembly hole 125 and the peripheral edge portions 120a1 and 120b1 of the terminal assembly hole 125 in the circumferential direction, and is joined to the peripheral edge portions 120a1 and 120b1 of the terminal assembly hole 125. The insulating member 130 is a member for preventing conduction to the housing 120. Specifically, a collector 140 is installed inside the housing 120 to form a conductive path from the electrode body 110 to the outside of the housing 120. In addition, as shown in FIG. Figure 3 As shown in FIG. 1 , the bus bar 1 is mounted on the outside of the housing 120. By interposing the insulating member 130 between these conductive members and the housing 120, conduction to the housing 120 can be prevented. In addition, the insulating member 130 is made of an insulating resin such as polypropylene resin, polyphenylene sulfide resin, polyamide resin, polyacetal resin, and polyimide resin. In addition, the insulating member 130 has an opening 138 that passes through the insulating member 130. The insulating member 130 is formed so that the opening 138 overlaps with the terminal assembly hole 125. That is, the insulating member 130 is configured so as not to block the terminal assembly hole 125 of the housing 120.

[0103] also, Figure 5 The insulating member 130 shown is manufactured by insert molding. In the insert molding, first, Figure 6 As shown, the current collector 140 and the mold M are installed on the sealing plate 124. At this time, the positional relationship of each component is adjusted to produce a cavity S1 of a shape corresponding to the predetermined insulating member 130. Next, the resin material is filled into the interior of the cavity S1 through the injection hole M1 of the mold M. Then, the insulating member 130 of a shape corresponding to the cavity S1 is produced by solidifying the resin material. In this way, when the insulating member 130 is produced by insert molding, the sealing plate 124 and the current collector 140 are integrated through the insulating member 130. As a result, the insulating member 130 continuously covers the peripheral wall 125a of the terminal assembly hole 125 and the peripheral edge portions 120a1 and 120b1 of the terminal assembly hole 125 in the circumferential direction, and is joined to the peripheral edge portions 120a1 and 120b1 of the terminal assembly hole 125. In addition, the insulating member 130 after insert molding has an external insulating portion 132, an internal insulating portion 134 and an in-hole insulating portion 136. The specific shape of each part will be described below.

[0104] The insulating member 130 includes an external insulating portion 132 that is joined to the peripheral portion 120a1 of the terminal mounting hole 125 in the outer surface 120a of the housing 120. The external insulating portion 132 is a member that prevents conduction between the bus bar 1 and the housing 120. Specifically, the external insulating portion 132 is a plate-shaped portion arranged along the outer surface 120a of the housing 120 (the upper surface 124a of the sealing plate 124). In addition, the lower surface 132a of the external insulating portion 132 is joined to the outer surface 120a of the housing 120 by insert molding. Figure 7 As shown, by providing the external insulating portion 132, the bus bar 1 can be prevented from contacting the housing 120 (sealing plate 124). In addition, the thickness of the external insulating portion 132 is preferably 0.5 mm or more, more preferably 1.0 mm or more, and particularly preferably 2.0 mm or more. Thus, conduction between the bus bar 1 and the housing 120 can be more appropriately prevented. On the other hand, the thickness of the external insulating portion 132 is preferably 4.0 mm or less, more preferably 3.0 mm or less. Thus, since the height dimension of the storage device 100 can be further reduced, the loading efficiency of the storage device in the electrical product can be further improved.

[0105] In addition, the insulating member 130 has an internal insulating portion 134, which is joined to the peripheral portion 120b1 of the terminal assembly hole 125 in the inner surface 120b of the housing 120. The internal insulating portion 134 is a member that prevents the conduction between the collector 140 and the housing 120 described later. Specifically, the internal insulating portion 134 is a plate-shaped portion between the inner surface 120b of the housing 120 (the lower surface 124b of the sealing plate 124) and the joint 142 of the collector 140. In addition, the upper surface 134a of the internal insulating portion 134 is joined to the inner surface 120b of the housing 120 by insert molding. In addition, the thickness of the internal insulating portion 134 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more. As a result, the conduction between the collector 140 and the sealing plate 124 can be more appropriately prevented. On the other hand, the thickness of the internal insulating portion 134 is preferably 2.0 mm or less, and more preferably 1.0 mm or less. This increases the space for housing the electrode body 110 in the case 120 , thereby contributing to improved performance of the power storage device 100 .

[0106] Furthermore, the insulating member 130 includes an in-hole insulating portion 136 that is joined to the peripheral wall 125a of the terminal mounting hole 125. Although the details will be described later, in the storage cell 500, the buffer portions 12 and 22 of the bus bar 1 are inserted into the terminal mounting hole 125, and the contact portions 14 and 24 of the bus bar 1 are joined to the terminal portion 144. The in-hole insulating portion 136 prevents the buffer portions 12 and 22 inserted into the terminal mounting hole 125 from directly contacting the housing 120 (sealing plate 124). Specifically, the in-hole insulating portion 136 is a cylindrical portion extending along the height direction Z. The in-hole insulating portion 136 is arranged inside the terminal mounting hole 125 of the housing 120. Furthermore, the outer periphery 136a of the in-hole insulating portion 136 is joined to the peripheral wall 125a of the terminal mounting hole 125. In addition, in the insulating member 130, the external insulating portion 132 and the internal insulating portion 134 are continuous via the in-hole insulating portion 136. In other words, the external insulating portion 132, the internal insulating portion 134 and the in-hole insulating portion 136 are integrally formed. In addition, the thickness of the in-hole insulating portion 136 is preferably 0.5 mm or more, more preferably 1.0 mm or more, and particularly preferably 2.0 mm or more. Thus, it is possible to prevent the in-hole insulating portion 136 from being damaged due to friction and heat when the buffer portions 12 and 22 are inserted. On the other hand, the thickness of the in-hole insulating portion 136 is preferably 4.0 mm or less, more preferably 3.0 mm or less. Thus, since the size of the terminal assembly hole 125 can be sufficiently ensured, the insertion of the buffer portions 12 and 22 becomes easy.

[0107] In addition, the insulating member 130 has a protrusion 134c protruding from a portion of the internal insulating portion 134 (the portion on the inner side of the depth direction Y) toward the lower side D. Thus, the up and down movement of the electrode body 110 in the shell 120 can be restricted. As a result, the contact between the electrode body 110 and the sealing plate 124, the damage to the connecting tab 112, etc. can be prevented. In addition, the thickness (protrusion amount) of the protrusion 134c is preferably greater than 2.0 mm, and more preferably greater than 3.0 mm. Thus, the up and down movement of the electrode body 110 can be more appropriately restricted. On the other hand, the thickness of the protrusion 134c is preferably less than 5.0 mm, and more preferably less than 4.0 mm. Thus, the accommodation space for the electrode body 110 in the shell 120 can be fully ensured.

[0108] In addition, although not shown in the figure, it is preferred to perform rough surface processing on the surface of the metal component (sealing plate 124, collector 140) in contact with the insulating member 130. Specifically, the portion to be roughened is the peripheral portion 120a1 of the terminal assembly hole 125 in the outer surface 120a of the housing 120, the peripheral portion 120b1 of the terminal assembly hole 125 in the inner surface 120b of the housing 120, the peripheral wall 125a of the terminal assembly hole 125, and the surface of the collector 140 joined to the insulating member 130 (the upper surface 142a of the joint 142). Thus, when insert molding is performed, the resin material enters the concave and convex surfaces of each metal component. As a result, an anchoring effect is generated, so that the insulating member 130 can be more firmly joined to the metal component. In addition, the rough surface processing only needs to be performed on at least one of the above-mentioned surfaces. In this case, the joining strength between the insulating member 130 and the metal component can also be appropriately improved. In addition, the rough surface processing does not limit the technology disclosed herein. That is, even when the roughening process is not performed, the insulating member 130 and the metal member can be fully integrated by insert molding.

[0109] (1-4) Current collector 140

[0110] The collector 140 is a conductive member electrically connected to the electrode body 110 inside the shell 120. Specifically, the collector 140 has an internal collector portion 146 extending along the height direction Z. The internal collector portion 146 is a plate-shaped portion connected to the connecting tab 112 of the electrode body 110. In addition, the internal collector portion 146 is preferably composed of the same type of metal material as the connecting tab 112 as the connection object. For example, as described above, the negative electrode tab is composed of a negative electrode core as a copper foil. In this case, the internal collector portion 146 is preferably composed of a copper-based material (copper, copper alloy, etc.). As a result, the collector 140 can be firmly connected to the electrode body 110 with low resistance.

[0111] In addition, the current collector 140 is configured to block the terminal mounting hole 125 via the insulating member 130. In addition, the current collector 140 is joined to the insulating member 130. In addition, the current collector 140 has a terminal portion 144. The terminal portion 144 is exposed to the outside of the housing 120 through the terminal mounting hole 125 and can be electrically connected to the bus bar 1. The current collector having this structure is described in detail below.

[0112] First, the collector 140 has a joint portion 142 as a plate-shaped member joined to the insulating member 130. The joint portion 142 is joined to the lower surface 134b of the internal insulating portion 134 in a manner that blocks the terminal assembly hole 125 inside the housing 120. More specifically, the joint portion 142 is formed by bending the upper end of the internal collector portion 146 in a manner facing the sealing plate 124. As a result, the joint portion 142 faces the inner surface 120b of the housing 120 with the internal insulating portion 134 sandwiched therebetween. In addition, the upper surface 142a of the joint portion 142 is joined to the lower surface 134b of the internal insulating portion 134 by insert molding. As a result, the lower end of the terminal assembly hole 125 is blocked by the joint portion 142.

[0113] The terminal portion 144 is exposed to the outside of the housing 120 through the terminal mounting hole 125. Thus, the bus bar 1 and the terminal portion 144 can be electrically connected. Figure 5 In the structure shown, the upper end of the terminal assembly hole 125 is open. As a result, a portion of the collector 140 (terminal portion 144) is exposed to the outside of the housing 120. Thus, the buffer portions 12 and 22 of the bus bar 1 can be inserted into the terminal assembly hole 125 from the outside of the housing 120 (see Figure 7 ). Then, laser welding or other joining process is performed while the contact portions 14 and 24 of the bus bar 1 are in contact with the terminal portion 144. Thus, since joining portions W1 and W2 are formed across the contact portions 14 and 24 and the terminal portion 144, the bus bar 1 and the current collector 140 can be electrically connected.

[0114] in addition, Figure 5 The terminal portion 144 of the power storage device 100 shown in FIG. 1 is located inwardly of the outer surface 120a of the housing 120. In other words, Figure 5 As shown, the upper surface 144a of the terminal portion 144 is arranged at a position D below the outline L1 along the outer surface 120a of the shell 120. This prevents a portion of the collector 140 from protruding outside the shell 120. In addition, in the power storage device 100, the terminal assembly hole 125 is sealed by the insulating member 130 and the collector 140 (the joint 142 and the terminal portion 144). This prevents the outflow of the electrolyte, the intrusion of foreign matter, etc. As described above, according to Figure 5 The power storage device 100 of the structure shown in FIG. 1 can form a conductive path to the outside of the housing 120 and seal the inside of the housing 120 even without providing an external connection portion. Figure 5 The structure shown can eliminate the conductive member protruding outside the case 120, so that the height of the power storage device 100 can be reduced. As a result, the efficiency of loading the power storage device 100 in the electric product can be improved.

[0115] also, Figure 5 The terminal portion 144 shown is a convex terminal portion inserted into the terminal assembly hole 125 from the inner side of the housing 120. As a result, since the position of the upper surface 144a of the terminal portion 144 in the terminal assembly hole 125 is raised, the connection between the terminal portion 144 and the bus bar 1 (i.e., the insertion of the buffer portion 12, 22 from the upper side U) becomes easy. In addition, when the convex terminal portion 144 is inserted from the lower side D of the terminal assembly hole 125, the movement of the collector 140 in the horizontal direction (depth direction Y and width direction X) is restricted. As a result, it is also possible to suppress the peeling of the joint interface between the joint portion 142 and the internal insulating portion 134. In addition, as the position of the upper surface 144a of the terminal portion 144 in the terminal assembly hole 125 is raised, there is a tendency that the connection between the terminal portion 144 and the bus bar 1 becomes easier. From this point of view, the distance H3 from the outer surface 120a of the housing 120 to the upper surface 144a of the terminal portion 144 is preferably 2.0 mm or less, more preferably 1.0 mm or less, and further preferably 0.5 mm or less. In addition, the upper surface 144a of the terminal portion 144 may be substantially the same height as the outer surface 120a of the housing 120 (i.e., the distance H3 is 0 mm). In this case, the connection between the terminal portion 144 and the bus bar 1 becomes easier.

[0116] In addition, as mentioned above, Figure 5 The current collector 140 shown in the figure has a joint portion 142 as a plate-shaped member joined to the insulating member 130. In this case, Figure 5 The convex terminal portion 144 shown is a columnar member that is joined to the upper surface 142a of the joint portion 142. As a result, the thickness of the terminal portion 144 can be sufficiently ensured. As a result, an appropriate welding depth can be ensured when forming the joint portions W1 and W2. In addition, when such a structure is adopted, the raw material of the terminal portion 144 can be freely selected without being affected by the raw materials of other parts (joint portion 142, internal collector portion 146).

[0117] For example, Figure 5As shown, as the terminal portion 144, a cladding material having a first layer 147 and a second layer 145 can be used. The first layer 147 of the terminal portion 144 is bonded to the upper surface 142a of the joint portion 142, and is a layer composed of the same type of metal as the joint portion 142. Thus, the terminal portion 144 can be firmly bonded to the joint portion 142. On the other hand, the second layer 145 is exposed to the outside of the housing 120 through the terminal assembly hole 125, and is a layer composed of a metal different from the first layer 147. Thus, a metal that is easy to connect to the bus bar 1 can be arranged on the upper surface 144a of the terminal portion 144. For example, in the collector 140 on the negative electrode side, copper-based materials are used for the internal collector portion 146 and the joint portion 142 in consideration of connectivity with the negative electrode tab. On the other hand, in the collector on the positive electrode side, aluminum-based materials are used in consideration of connectivity with the positive electrode tab. At this time, considering the connectivity with the terminal portion 144 on the positive electrode side, the busbar 1 connecting the collector on the positive electrode side and the collector on the negative electrode side mostly uses an aluminum-based material. In this case, the collector 140 on the negative electrode side can make the first layer 147 of the terminal portion 144 consist of copper and the second layer 145 consist of aluminum. Thus, a copper bonding interface can be formed between the terminal portion 144 and the bonding portion 142, and an aluminum bonding interface can be formed between the terminal portion 144 and the busbar 1. As a result, a conductive path from the electrode body 110 to the busbar 1 can be formed firmly and with low resistance.

[0118] In the above, an example of the power storage device 100 used in the power storage unit 500 is described. Figure 5 The power storage device 100 of the structure shown does not have a conductive member (terminal portion 144) protruding outside the housing 120, so the height dimension is reduced. As a result, the loading efficiency of the power storage device 100 in the electrical product can be improved. In addition, in the power storage unit 500 of the present embodiment, it is not necessary for all of the multiple power storage devices 100 to have the above-mentioned structure. For example, when the power storage unit is mounted on an electrical product, since only a part of the multiple power storage devices interferes with other components, it is sometimes necessary to reduce the overall height dimension of the power storage unit. In such a case, the above-mentioned structure can be adopted only for the power storage device that interferes with other components. As a result, the loading efficiency of the power storage device can be improved.

[0119] (2) Constraint components

[0120] Next, Figure 3The illustrated power storage unit 500 includes a restraining member for restraining a plurality of power storage devices 100. Specifically, a pair of end plates 220 are arranged on both outer sides of the arrangement direction (width direction X) of the power storage unit 500. The pair of end plates 220 are bridged by a restraining beam member 230. Thus, restraining pressure along the arrangement direction can be applied to each power storage device 100. In addition, a resin buffer member 250 is arranged between each of the arranged power storage devices 100. Thus, the restraining pressure applied to the power storage device 100 can be made uniform.

[0121] (3) Bus bar

[0122] Furthermore, the power storage unit 500 of the present embodiment uses the bus bar 1 having the above-mentioned structure. The bus bar 1 is electrically connected to the plurality of power storage devices 100. Specifically, Figure 3 In the illustrated power storage unit 500, a plurality of power storage devices 100 are arranged so that a positive terminal mounting hole 125P of one power storage device 100 is adjacent to a negative terminal mounting hole 125N of another power storage device 100. Bus bar 1 is connected to terminal portions 144 located within each of a pair of adjacent terminal mounting holes 125.

[0123] Here, the bus bar 1 in the present embodiment includes step-shaped buffer portions 12 and 22 protruding downward D (see Figure 1 and Figure 2 ). As described above, the buffer portions 12 and 22 are inserted into the terminal assembly hole 125 from the outside of the housing 120. Furthermore, the contact portions 14 and 24, which are the bottom surfaces of the buffer portions 12 and 22, are engaged with the terminal portion 144. Thus, even when the terminal portion 144 is arranged at a position inward (downward D) relative to the outer surface 120a of the housing 120, the terminal portion 144 can be easily connected to the bus bar 1.

[0124] Furthermore, when the buffering parts 12 and 22 are inserted into the terminal mounting hole 125, it is preferable to set the inner dimension of the terminal mounting hole 125 and the outer dimension of the buffering parts 12 and 22 to be substantially equal. Thus, since the outer peripheral wall of the protrusions 13 and 23 contacts the inner peripheral wall of the in-hole insulating part 136, the movement (vibration, etc.) of the contact parts 14 and 24 in the plane direction can be restricted. As a result, it is possible to more appropriately prevent the stress S in the plane direction from being applied to the joints W1 and W2 of the contact parts 14 and 24 and the terminal part 144.

[0125] <Other embodiments>

[0126] An embodiment of the technology disclosed herein has been described above. However, the technology disclosed herein is not limited to the above embodiment. Other embodiments of the technology disclosed herein will be described below.

[0127] 1. Buffering part with groove

[0128] like Figure 2 As shown in FIG. 1 , the buffer portions 12 and 22 in the first embodiment include contact portions 14 and 24 with flat upper surfaces. Figure 8 As shown, grooves 14a and 24a may be formed on the upper surfaces of the contact portions 14 and 24. The grooves 14a and 24a are annular grooves when viewed from above. Since the thickness of the portion where the grooves 14a and 24a are formed is thinner than other regions, it is possible to easily form the joints W1 and W2 that penetrate the contact portions 14 and 24. In addition, when the grooves 14a and 24a are formed, the joints W1 and W2 can be easily formed even if the other portions are made thicker. Therefore, it can also contribute to improving the overall strength of the busbar 1.

[0129] 2. Plane shape of the buffer

[0130] like Figure 1 As shown in FIG. 1 , in the first embodiment, the buffer portions 12 and 22 are provided with a substantially circular planar shape. However, the planar shape of the buffer portion is not particularly limited, and various shapes can be adopted. For example, Fig. 9 As shown in FIG. 1 , the bus bar 1 may also include buffer portions 12 and 22 having a substantially rectangular planar shape. In this case, stresses in the width direction X and the depth direction Y can also be appropriately relieved. Fig.10 As shown in FIG. 1 , the bus bar 1 may also include a strip-shaped buffer portion 12, 22 extending over the entire area in the depth direction Y when viewed from above. In this case, the stress along the width direction X can also be relieved. As described above, since the stress S caused by the change in the interval G between the first joint area 10 and the second joint area 20 is mainly the stress along the width direction X, even if the stress S is reduced by using Fig.10 The band-shaped buffer portions 12 and 22 shown can also provide sufficient buffering.

[0131] 3. Buffering parts other than step shapes

[0132] In addition, in the above-mentioned embodiments, the step-shaped buffer portions 12 and 22 having the protruding portions 13 and 23 and the contact portions 14 and 24 are formed (see Figure 1 , 9 , 10). However, the buffer portion is not limited to a step-shaped buffer portion as long as it can absorb the stress caused by the change in the interval between the first bonding area and the second bonding area. For example, Fig.11The bus bar 1 shown in the figure is formed with a pair of openings 17 and 27 extending in the depth direction Y. Furthermore, in the bus bar 1, joints W1 and W2 are formed between the pair of openings 17 and 27. In the bus bar 1 of this structure, when a stress S is generated along the width direction X, the bus bar 1 is deformed in such a way that the openings 17 and 27 are flattened. Thus, the stress S along the width direction X can be fully absorbed. That is, the buffer portion in the bus bar disclosed here is not limited to the above-mentioned step-shaped buffer portion, and can also be composed of Fig.11 The openings 17 and 27 are configured as shown.

[0133] 4. Number of joint areas with buffers

[0134] In addition, if Figure 1 and Figure 2 As shown, in the bus bar 1 of the first embodiment, the buffer portions 12 and 22 are provided in both the first joint region 10 and the second joint region 20. However, the buffer portion may be formed in only one of the first joint region and the second joint region. In this case, it is also possible to prevent a large stress from being applied to the joint region in the joint region where the buffer portion is formed. In particular, Figure 3 As shown, the terminal portions 144 of the storage devices 100 arranged at both ends of the arrangement direction (width direction X) are not connected to the adjacent storage devices 100. In addition, the open terminal portions 144 are connected to external devices (motor, etc.) as the total positive terminal (or total negative terminal). The busbar used in the connection portion only needs to form a buffer portion in the joint area on the side that is joined to the total positive terminal (or total negative terminal). As a result, stress can be suppressed from being applied to the joint between the terminal portion and the busbar.

[0135] 5. Construction of the bridging area

[0136] In addition, the bus bar 1 of the first embodiment is provided with a fluctuation absorbing portion 32 in the bridge region 30 (see Figure 1 and Figure 2 ). However, the bus bar disclosed herein may not be provided with a fluctuation absorbing portion in the bridging region. As described above, as long as the buffer portion 12, 22 is provided in at least one of the first joining region 10 and the second joining region 20, the stress on the joining portion W1, W2 between the terminal portion 144 and the bus bar 1 can be relieved.

[0137] 6. Structure of the terminal portion of the power storage device

[0138] In addition, as described above, the power storage unit disclosed herein is not limited to the use Figure 4 and Figure 5 In particular, even without using Figure 4 and Figure 5In the case of the structure shown, the terminal portion can also be arranged at a position closer to the inside of the housing and the loading efficiency of the power storage device can be improved. Figure 5 The terminal portion 144 of the power storage device 100 of the structure shown is a columnar cladding material having a first layer 147 and a second layer 145. However, the terminal portion 144 is not limited to a columnar cladding material. For example, the terminal portion 144 may also be a columnar member made of a single metal material (see Fig.12 Even when this structure is adopted, the loading efficiency of the power storage device 100 can be improved as long as the upper surface 144 a of the terminal portion 144 is arranged inward (downward D) relative to the outer surface 120 a of the case 120 .

[0139] In addition, when the joint 142 and the bus bar 1 are made of the same material, it is particularly suitable to use a terminal portion 144 composed of a single metal material. For example, in the collector 140 on the positive electrode side, considering the connectivity with the positive electrode tab (aluminum foil), the internal collector 146 and the joint 142 use aluminum-based materials. On the other hand, as described above, the bus bar 1 when constructing the storage cell 500 also uses aluminum-based materials. In the case of this structure, even if the terminal portion 144 does not use a cladding material, it is possible to use an aluminum-based material to construct a conductive path from the electrode body 110 to the bus bar 1, thereby forming a strong and low-resistance conductive path.

[0140] In the first embodiment, a columnar terminal portion 144 is bonded to the upper surface 142a of the bonding portion 142 (see Figure 5 However, the convex terminal portion 144 is not limited to this structure. For example, when the joint portion 142 of the collector 140 is a plate-shaped member, the convex terminal portion 144 can be formed by bending the joint portion 142 (see Fig.13 ). The convex terminal portion 144 can be formed by stamping the plate-shaped joint portion 142. Even when the terminal portion 144 of this structure is inserted into the terminal assembly hole 125, the connection between the terminal portion 144 and the bus bar 1 becomes easy, and the movement of the collector 140 in the horizontal direction can be restricted. In addition, according to this embodiment, since the number of components of the collector 140 can be reduced, it can contribute to the reduction of material costs.

[0141] In the first embodiment, the convex terminal portion 144 is inserted into the terminal assembly hole 125. However, the current collector of the power storage device may not have a convex terminal portion. Fig.14As shown, the joint portion 142 and the terminal portion 144 may also form a continuous flat surface. Even in the case of adopting such a structure, the terminal assembly hole 125 can be sealed by the insulating member 130 and the terminal portion 144. Furthermore, even in the case of adopting such a structure, since the terminal portion 144 is exposed to the outside of the housing 120 through the terminal assembly hole 125, the bus bar 1 and the collector 140 can be electrically connected. Furthermore, even in this case, the terminal portion 144 is arranged at a position closer to the inside (lower D) than the outer surface 120a of the housing 120, so that the loading efficiency of the storage device in the electrical product can be improved.

[0142] In the first embodiment, the storage unit 500 uses the storage device 100 having the terminal portion 144 disposed inside the housing 120. In the first embodiment, the buffer portions 12 and 22 of the bus bar 1 are inserted into the terminal assembly hole 125. However, the structure of the bus bar disclosed herein is not affected by the structure of the terminal portion of the storage device. In other words, the structure of the storage device 100 does not limit the technology disclosed herein. For example, Fig.15 As shown, even when the power storage device 100 having the terminal portion 144 protruding to the outside of the housing 120 is used, the buffer portions 12 and 22 of the bus bar 1 can be properly joined to the terminal portion 144. Furthermore, even when this structure is adopted, since the buffer portions 12 and 22 of the bus bar 1 can absorb the stress along the width direction X, the stress on the joint portions W1 and W2 can be relieved.

[0143] In the first embodiment, the outer wall of the protrusions 13 and 23 of the bus bar 1 is brought into contact with the inner wall of the in-hole insulating portion 136 of the insulating member 130 (see Figure 7 ). Thus, since the movement of the contact portions 14 and 24 in the planar direction can be restricted, the stress applied to the joint portions W1 and W2 can be more appropriately suppressed. However, the means for restricting the movement of the contact portions 14 and 24 in the planar direction is not limited to the above-mentioned structure. For example, Fig.16 As shown, when using the power storage device 100 having the terminal portion 144 protruding to the outside of the housing 120, a movement restriction portion 144a protruding toward the upper U can be provided on the outer peripheral edge of the terminal portion 144. And the bus bar 1 and the terminal portion 144 are joined in such a manner that the outer walls of the protruding portions 13 and 23 of the bus bar 1 are in contact with the movement restriction portion 144a. Thus, the movement of the contact portions 14 and 24 in the planar direction can be appropriately restricted. That is, in order to restrict the movement of the contact portions 14 and 24 in the planar direction, it is sufficient to make the outer walls of the protruding portions 13 and 23 of the bus bar 1 contact with a part of the power storage device 500.

[0144] The above is a detailed description of the technology disclosed herein. However, these are only examples and do not limit the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above. That is, the technology disclosed herein includes the forms described in the following items 1 to 10.

[0145] [Project 1]

[0146] A bus bar, wherein the bus bar has:

[0147] a first bonding region bonded to a terminal portion of a first power storage device;

[0148] a second bonding region bonded to a terminal portion of a second power storage device different from the first power storage device; and

[0149] a bridging region connecting the first joining region and the second joining region,

[0150] A buffer portion is provided in at least one of the first joining region and the second joining region, and the buffer portion absorbs stress caused by a change in the interval between the first joining region and the second joining region.

[0151] [Project 2]

[0152] The bus bar according to item 1, wherein:

[0153] At least one of the first bonding region and the second bonding region has a plate-shaped bonding base.

[0154] The buffer portion is constituted by a step protruding from the engagement base.

[0155] [Item 3]

[0156] The bus bar according to item 2, wherein:

[0157] The buffer portion has:

[0158] a protrusion protruding from the engagement base; and

[0159] A contact portion is provided at a front end of the protruding portion and contacts the terminal portion.

[0160] [Item 4]

[0161] The bus bar according to item 3, wherein:

[0162] The thickness of the protruding portion is thinner than the thickness of the contact portion.

[0163] [Item 5]

[0164] The bus bar according to item 4, wherein:

[0165] When the thickness of the contact portion is set to 100%, the thickness of the protruding portion is 50% to 90%.

[0166] [Item 6]

[0167] The bus bar according to any one of items 1 to 5, wherein:

[0168] The buffer portion is provided in both the first joining region and the second joining region.

[0169] [Item 7]

[0170] The bus bar according to any one of items 1 to 6, wherein:

[0171] The bridge region includes a fluctuation absorbing portion configured to absorb fluctuations in the interval between the first joining region and the second joining region.

[0172] [Item 8]

[0173] The bus bar according to item 7, wherein:

[0174] The bridging region has a plate-shaped bridging base,

[0175] The fluctuation absorbing portion is constituted by a step protruding from the bridging base portion.

[0176] [Item 9]

[0177] A power storage unit, wherein the power storage unit comprises:

[0178] a plurality of power storage devices; and

[0179] a plurality of bus bars electrically connecting the respective terminal portions of the plurality of power storage devices;

[0180] At least one of the plurality of bus bars is the bus bar according to any one of items 1 to 8.

[0181] [Item 10]

[0182] The power storage unit according to item 9, wherein:

[0183] At least one of the plurality of power storage devices comprises:

[0184] Electrode body;

[0185] A shell, the shell accommodates the electrode body and has a terminal assembly hole;

[0186] an insulating member that continuously covers a peripheral wall of the terminal mounting hole and a peripheral edge portion of the terminal mounting hole in a circumferential direction and is joined to the peripheral edge portion of the terminal mounting hole; and

[0187] a current collector electrically connected to the electrode body inside the casing,

[0188] The current collector is configured to block the terminal assembly hole via the insulating member,

[0189] The current collector is joined to the insulating member,

[0190] The current collector has a terminal portion, which is exposed to the outside of the case through the terminal assembly hole and can be electrically connected to the bus bar.

[0191] The terminal portion is located inwardly of the outer surface of the housing, and the terminal assembly hole is sealed by the insulating member and the collector.

[0192] The buffer portion of the bus bar is inserted into the terminal mounting hole from the outside of the case and connected to the terminal portion.

Claims

1. A bus bar, wherein: The bus bar has: a first bonding region bonded to a terminal portion of a first power storage device; a second bonding region bonded to a terminal portion of a second power storage device different from the first power storage device; as well as a bridging region connecting the first joining region and the second joining region, A buffer portion is provided in at least one of the first joining region and the second joining region, and the buffer portion absorbs stress caused by a change in the interval between the first joining region and the second joining region.

2. The bus bar according to claim 1, wherein: At least one of the first bonding region and the second bonding region has a plate-shaped bonding base. The buffer portion is constituted by a step protruding from the engagement base.

3. The bus bar according to claim 2, wherein: The buffer portion has: a protrusion protruding from the engagement base; as well as A contact portion is provided at a front end of the protruding portion and contacts the terminal portion.

4. The bus bar according to claim 3, wherein: The thickness of the protruding portion is thinner than the thickness of the contact portion.

5. The bus bar according to claim 4, wherein: When the thickness of the contact portion is set to 100%, the thickness of the protruding portion is 50% to 90%.

6. The bus bar according to claim 1, wherein: The buffer portion is provided in both the first joining region and the second joining region.

7. The bus bar according to claim 1, wherein: The bridge region includes a fluctuation absorbing portion configured to absorb fluctuations in the interval between the first joining region and the second joining region.

8. The bus bar according to claim 7, wherein: The bridging region has a plate-shaped bridging base, The fluctuation absorbing portion is constituted by a step protruding from the bridging base portion.

9. A power storage unit, wherein: The power storage unit comprises: a plurality of power storage devices; and a plurality of bus bars electrically connecting the respective terminal portions of the plurality of power storage devices; At least one of the plurality of bus bars is the bus bar according to any one of claims 1 to 8.

10. The power storage unit according to claim 9, wherein: At least one of the plurality of power storage devices comprises: Electrode body; A shell, the shell accommodates the electrode body and has a terminal assembly hole; an insulating member, the insulating member continuously covers the peripheral wall of the terminal assembly hole and the peripheral edge of the terminal assembly hole in the circumferential direction and is engaged with the peripheral edge of the terminal assembly hole; as well as a current collector electrically connected to the electrode body inside the casing, The current collector is configured to block the terminal assembly hole via the insulating member, The current collector is joined to the insulating member, The current collector has a terminal portion, which is exposed to the outside of the case through the terminal assembly hole and can be electrically connected to the bus bar. The terminal portion is located inwardly of the outer surface of the housing, and the terminal assembly hole is sealed by the insulating member and the collector. The buffer portion of the bus bar is inserted into the terminal fitting hole from the outside side of the case and engaged with the terminal portion.

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