Inter-device conductive member

Abstract

To provide an inter-device conduction member capable of breaking the inter-device conduction member itself to cut off electrical connection between power storage devices conducted via the inter-device conduction member.SOLUTION: The inter-device conduction member 1 includes the conducting portion 10 having the first connection portion 15 connected to the electrode terminal 120 of one electricity storage device 100, the second connection portion 25 connected to the electrode terminal 130 of another electricity storage device 100, and the breakable portion 35 located between the first connection portion 15 and the second connection portion 25 and electrically connected to the first connection portion 15 and the second connection portion 25. And a breakage induction part 40 for making the first connection part 15 and the second connection part 25 non-conductive.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an inter-device conductive member that establishes electrical continuity between an electrode terminal of one electricity storage device (such as a battery or capacitor) and an electrode terminal of another electricity storage device. [Background technology]

[0002] Hybrid cars, plug-in hybrid cars, and electric vehicles are equipped with battery packs that include multiple batteries. To enhance safety, each battery in such battery packs is provided with a safety valve and a current interrupt device (CID). In the battery packs described above, the electrode terminals of adjacent batteries are electrically connected to each other using a bus bar made of, for example, a rectangular metal plate. Patent Document 1, for example, discloses such a bus bar and battery pack (see, for example, Figures 2 and 3 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-085447 Summary of the Invention [Problem to be solved by the invention]

[0004] However, it is desirable to further improve the safety of battery packs. Because the conventional bus bars described above are simply metal plates, even if the temperature of the bus bars rises to a high level due to, for example, a large current flowing through the bus bars, it is not possible to cut off the current flowing through the bus bars and thereby cut off the electrical connection between the batteries.

[0005] The present invention has been made in consideration of the current situation, and provides an inter-device conductive member that provides electrical conduction between power storage devices such as batteries, and that, when the temperature of the inter-device conductive member rises to a high temperature, breaks the inter-device conductive member itself, thereby severing the electrical connection between the power storage devices that are electrically connected via the inter-device conductive member. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problem is an inter-device conductive member that provides electrical continuity between an electrode terminal of one power storage device and an electrode terminal of another power storage device, the inter-device conductive member comprising: a first connection portion connected to the electrode terminal of the one power storage device; a second connection portion connected to the electrode terminal of the other power storage device; a conductive portion located between the first connection portion and the second connection portion and having a portion intended to break that is conductive to the first connection portion and the second connection portion; and a break inducing portion that deforms when the temperature rises above an operating temperature, causing the portion intended to break in the conductive portion to break, thereby preventing electrical continuity between the first connection portion and the second connection portion.

[0007] In the inter-device conductive member described above, when the temperature of the break inducement portion rises to or above the activation temperature, the break inducement portion deforms, causing the breakage-intended portion of the conductive portion to break, thereby discontinuing electrical connection between the first connection portion and the second connection portion of the conductive portion. Therefore, the inter-device conductive member itself can cut off the electrical connection between the power storage devices that are electrically connected via the inter-device conductive member.

[0008] (2) Furthermore, in the inter-device conductive member described in (1), the conductive portion may be an inter-device conductive member having: a first member made of a first metal and consisting of the first connection portion and a first non-connection portion other than the first connection portion; a second member made of a second metal different from the first metal and consisting of the second connection portion and a second non-connection portion other than the second connection portion; and a junction portion where the first non-connection portion and the second non-connection portion are joined and electrically connected to each other.

[0009] (3) The inter-device conductive member according to (2) may further include a resin sealing member that hermetically seals the joint portion of the conductive portion.

[0010] (4) Furthermore, in the inter-device conductive member described in (3), the first non-connecting portion of the first member has a first roughened sealing surface on which first nanopillars, each having a height of 50 nm or more, are formed by first particles derived from the first metal constituting the first member and linked together in a string of beads; the second non-connecting portion of the second member has a second roughened sealing surface on which second nanopillars, each having a height of 50 nm or more, are formed by second particles derived from the second metal constituting the second member and linked together in a string of beads; and the resin sealing member has a resin material constituting the resin sealing member filled between the first nanopillars on the first roughened sealing surface to airtightly bond them to the first roughened sealing surface, and the resin material filled between the second nanopillars on the second roughened sealing surface to airtightly bond them to the second roughened sealing surface, thereby airtightly sealing the joint.

[0011] (5) Furthermore, in the inter-device conductive member described in any one of (1) to (4), the breakage inducing portion may be made of a bimetal, and may have a bimetal member that undergoes click reversal deformation when the temperature rises above the operating temperature, thereby breaking the intended breakage portion of the conductive portion.

[0012] The inter-device conductive member according to any one of (6) or (1) to (4) may preferably be an inter-device conductive member having a shape memory alloy member that is made of a shape memory alloy and that deforms when the temperature rises above the operating temperature, which is the transformation point, to cause the breakage-inducing portion of the conductive portion to break.

[0013] In the inter-device conductive member described in (7) or any one of (1) to (4), the breakage inducing portion includes a fixing member made of a thermoplastic resin or a low-melting-point metal, and an elastic member held in a biased state by the fixing member, and the inter-device conductive member preferably has a temperature-sensitive structure configured to release the holding of the elastic member by the fixing member and break the intended break portion of the conductive portion when the temperature rises above the operating temperature, which is the softening temperature of the thermoplastic resin or the melting point of the low-melting-point metal. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a top view of a battery module configured using the bus bars according to the first to fourth embodiments. [Figure 2] FIG. 2 is a top view of the bus bar according to the first embodiment. [Figure 3] 3 is a cross-sectional view of the bus bar according to the first embodiment taken along the arrow in FIG. 2. [Figure 4] 4 is an enlarged cross-sectional view of the bus bar according to the first embodiment, showing the vicinity of a breakage induction portion and a resin sealing member in FIG. 3. [Figure 5] 4 is an explanatory view showing an enlarged view of a joint portion between a first roughened sealing surface of a first member (or a second roughened sealing surface of a second member) and a resin sealing member in the bus bar according to the first embodiment. FIG. [Figure 6] 10 is an explanatory view showing how the breakage inducement portion is deformed by a temperature rise and breaks the intended breakage portion of the conductive portion according to the first embodiment. FIG. [Figure 7] FIG. 10 is an explanatory diagram showing a method for manufacturing a busbar according to the first embodiment, in which a pulsed laser beam is scanned to form a plurality of first cup-shaped recesses and first nanopillars standing in each of the first cup-shaped recesses (or a plurality of second cup-shaped recesses and second nanopillars standing in each of the second cup-shaped recesses) in the first seal portion of the first member (or the second seal portion of the second member). [Figure 8] 5 is an enlarged cross-sectional view of a bus bar according to a second embodiment, corresponding to FIG. 4. FIG. [Figure 9] 7 is an explanatory diagram corresponding to FIG. 6, illustrating a bus bar according to a second embodiment. [Figure 10]5 is an enlarged cross-sectional view of a bus bar according to a third embodiment, corresponding to FIG. 4. FIG. [Figure 11] 7 is an explanatory diagram corresponding to FIG. 6, illustrating a bus bar according to a third embodiment. [Figure 12] 10 is an enlarged cross-sectional view of a bus bar according to a fourth embodiment, corresponding to FIG. 4. FIG. [Figure 13] 10 is an explanatory diagram corresponding to FIG. 6, illustrating a bus bar according to a fourth embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] (Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings. A busbar (inter-device conductive member) 1 (see FIGS. 1 to 5) of this first embodiment is a member that provides electrical continuity between adjacent rectangular (rectangular) batteries (electricity storage devices) 100 in a battery module 200 (see FIG. 1) that is mounted on vehicles such as hybrid cars, plug-in hybrid cars, and electric cars. In the following description, the height direction AH, longitudinal direction BH, and lateral direction CH of the busbar 1 are defined as the directions shown in FIGS. 1 to 5.

[0016] The battery module 200 includes a plurality of batteries 100 (see FIG. 1). The batteries 100 constituting the battery module 200 are housed in a module case (not shown) with their orientations alternately stacked in a row in the battery thickness direction, and are constrained in the battery stacking direction SH by the module case. The positive terminal (electrode terminal) 120 of one adjacent battery 100 and the negative terminal (electrode terminal) 130 of another adjacent battery 100 are aligned in the battery stacking direction SH and are electrically connected (connected in series) via a bus bar 1. The bus bar 1 is joined to the positive terminal 120 and the negative terminal 130 by welding.

[0017] Each battery 100 is composed of a rectangular box-shaped case 110, an electrode assembly (not shown) including positive and negative electrode plates and an electrolyte (not shown) housed in the case 110, a positive terminal 120 and a negative terminal 130 each supported by the case 110, etc. A safety valve 113 is provided in the upper wall 111 of the case 110, which ruptures to open when the internal pressure of the case 110 exceeds a valve opening pressure. A liquid inlet (not shown) is also provided in the upper wall 111 of the case 110, and this liquid inlet is airtightly sealed with a disk-shaped sealing member 115.

[0018] A positive electrode terminal 120 and a negative electrode terminal 130 are fixed to the upper wall portion 111 of the case 110. Specifically, a pair of insertion holes (not shown) are provided in the upper wall portion 111 of the case 110. The positive electrode terminal 120 made of a first metal (aluminum in the first embodiment) is inserted into one of the insertion holes, and the negative electrode terminal 130 made of a second metal (copper in the first embodiment) different from the first metal is inserted into the other insertion hole. The positive electrode terminal 120 is fixed to the upper wall portion 111 of the case 110 via an insert-molded resin insulating member 125, and the negative electrode terminal 130 is fixed to the upper wall portion 111 of the case 110 via an insert-molded resin insulating member 135. The positive electrode terminal 120 has a rectangular plate-shaped positive electrode top plate portion 121 arranged outside the case 110, and the bus bar 1 is welded to this positive electrode top plate portion 121. The positive electrode terminal 120 is electrically connected to the positive electrode current collector of the electrode body inside the case 110. The negative electrode terminal 130 has a rectangular plate-shaped negative electrode top plate portion 131 that is arranged outside the case 110, and the bus bar 1 is welded to this negative electrode top plate portion 131. The negative electrode terminal 130 is electrically connected to the negative electrode current collector of the electrode body inside the case 110.

[0019] Next, the busbar 1 will be described (see FIGS. 1 to 5). The busbar 1 is composed of a conductive portion 10 that provides electrical continuity between the positive electrode terminals 120 and negative electrode terminals 130 of adjacent batteries 100, a breakage inducing portion 40 that causes breakage in the conductive portion 10, and a resin sealing member 50. Of these, the conductive portion 10 is formed by joining a first member 11 made of the same first metal as the positive electrode terminal 120 (aluminum in the first embodiment) and a second member 21 made of the same second metal as the negative electrode terminal 130 (copper in the first embodiment).

[0020] The first member 11 is formed by pressing an aluminum plate and includes a flat plate portion 14 and a first housing portion 13. The flat plate portion 14 is flat and extends in the longitudinal direction BH and the transverse direction CH, and has a rectangular outer shape. The first housing portion 13 protrudes from the flat plate portion 14 to an upper side AH1 in the height direction AH on the other side BH2 in the longitudinal direction BH. The first housing portion 13 has a bottomed rectangular cylindrical shape with an open lower side AH2 and a closed upper side AH1. A rectangular housing space SA is formed between the first housing portion 13 and a second housing portion 23 of the second member 21 (described later). The breakage inducement portion 40 is housed within the housing space SA. The rectangular annular portion of the first housing portion 13 located on the lower side AH2 in the height direction AH forms a first seal portion 18 that is airtightly bonded to the resin sealing member 50. Details of the first seal portion 18 will be described later.

[0021] The flat plate portion 14 has a first connecting portion 15, a first sealing portion 16, and a first joining portion 17. In the first embodiment, the portions of the first member 11 other than the first connecting portion 15, i.e., the first accommodating portion 13, the first sealing portion 16, and the first joining portion 17, are the first non-connecting portion 12. The first connection portion 15 is located on one side BH1 in the longitudinal direction BH and has a rectangular plate shape extending in the longitudinal direction BH and the lateral direction CH. The first connection portion 15 is a portion to be welded to a positive electrode top plate portion 121 of a positive electrode terminal 120 of the battery 100.

[0022] The first joint portion 17 is a rectangular annular portion located on the other side BH2 in the longitudinal direction BH. The first joint portion 17 is welded to a second joint portion 27 of the second member 21 (described later) to form a joint portion 37 consisting of the first joint portion 17 and the second joint portion 27. This joint portion 37 provides electrical continuity between the first non-connecting portion 12 of the first member 11 and the second non-connecting portion 22 of the second member 21 (described later). In the first embodiment, the joint portion 37 serves as a breakable portion 35. This breakable portion 35 (joint portion 37) is located in the conductive portion 10 between the first connecting portion 15 of the first member 11 and the second connecting portion 25 of the second member 21, and electrical continuity is established between the first connecting portion 15 and the second connecting portion 25 via the breakable portion 35. Therefore, as described later, when the breakable portion 35 breaks, electrical continuity is broken between the first connecting portion 15 and the second connecting portion 25.

[0023] The first seal portion 16 is located between the first connection portion 15 and the first joint portion 17 and is a rectangular plate-shaped portion whose dimension in the short direction CH is longer than its dimension in the long direction BH. The first seal portion 16 of the flat plate portion 14 and the first seal portion 18 of the first accommodating portion 13 described above are each covered with a resin sealing member 50 and are airtightly joined to the resin sealing member 50. The first seal portion 16 of the flat plate portion 14 has an annular first roughened seal surface 16m (see FIGS. 4 and 5) extending along its entire periphery perpendicular to the long direction BH. Meanwhile, the first seal portion 18 of the first accommodating portion 13 has an annular first roughened seal surface 18m (see FIGS. 4 and 5) extending along its entire periphery perpendicular to the height direction AH.

[0024] These first roughened sealing surfaces 16m, 18m are roughened surfaces at the nano level (nano order), and as shown in Fig. 5, are composed of a forest of nano-level first nanopillars 33, each of which has a height ha of 50 nm or more and less than 1000 nm and is formed by first particles 33p derived from the metal constituting the first member 11 being linked together in a string of beads. In this embodiment 1, the height ha of each first nanopillar 33 is approximately 200 nm. As mentioned above, the metal constituting the first member 11 is aluminum, and the first nanopillars 33 are made of first particles 33p made of aluminum and aluminum oxide.

[0025] The second member 21 is made of a copper plate and has a rectangular plate shape extending in the longitudinal direction BH and the lateral direction CH. The second member 21 has a second accommodating portion 23, a second connecting portion 25, a second sealing portion 26, and a second bonding portion 27. In the second embodiment, the portions of the second member 21 other than the second connecting portion 25, i.e., the second accommodating portion 23, the second sealing portion 26, and the second bonding portion 27, are the second non-connecting portion 22. The second storage section 23 is a rectangular plate extending in the longitudinal direction BH and the transverse direction CH, and as described above, a storage space SA for accommodating the breakage induction section 40 is formed between the second storage section 23 and the first storage section 13 of the first member 11.

[0026] The second connection portion 25 is located on the other side BH2 in the longitudinal direction BH and has a rectangular plate shape extending in the longitudinal direction BH and the lateral direction CH. The second connection portion 25 is a portion to be welded to the negative electrode top plate portion 131 of the negative electrode terminal 130 of the battery 100. The second joint 27 is a rectangular annular portion located on the other side BH2 of the longitudinal direction BH, and as described above, is welded to the first joint 17 of the first member 11 to form the joint 37 (which is also the intended fracture portion 35 in this embodiment 1).

[0027] The second seal portion 26 is located between the second connection portion 25 and the second bonding portion 27 and is a rectangular plate-shaped portion whose dimension in the short direction CH is longer than its dimension in the long direction BH. The second seal portion 26 is covered with a resin sealing member 50 and is airtightly bonded to the resin sealing member 50. The second seal portion 26 has an annular second roughened seal surface 26m (see FIGS. 4 and 5) extending along the entire circumference perpendicular to the long direction BH. The second roughened seal surface 26m is also a nano-level roughened surface. As shown in FIG. 5, second particles 34p derived from the metal constituting the second member 21 are linked together in a string-like pattern to form columnar shapes, forming nano-level second nanopillars 34 with a height ha of 50 nm or more and less than 1000 nm. In the first embodiment, the height ha of each second nanopillar 34 is approximately 200 nm. The metal forming the second member 21 is copper as described above, and the second nanopillars 34 are made of second particles 34p made of copper and copper oxide.

[0028] Next, the fracture inducing portion 40 will be described. In the present embodiment 1, the fracture inducing portion 40 is made of a bimetal member 41. This bimetal member 41 is made of a clad material in which two types of metal plates (a first metal plate 42 and a second metal plate 43) with different thermal expansion coefficients are bonded together in the thickness direction. Specifically, the bimetal member 41 has the first metal plate 42 with a small thermal expansion coefficient arranged on the outer side (upper side AH1) and the second metal plate 43 with a large thermal expansion coefficient arranged on the inner side (lower side AH2). In the present embodiment 1, a metal plate made of a Ni-Fe alloy is used as the first metal plate 42, and a metal plate made of a Ni-Mn-Fe alloy is used as the second metal plate 43.

[0029] The bimetal member 41 has a semi-cylindrical shape with an axis extending in the short direction CH. The semi-cylindrical portion 45 undergoes click reversal deformation, and includes a pair of ears 46 extending in the short direction CH, located on one side BH1 and the other side BH2 in the longitudinal direction BH of the semi-cylindrical portion 45 (see FIG. 4). These ears 46 are sandwiched between the first member 11 and the second member 21 and fixed to the conductive portion 10. This fixes the bimetal member 41 (breakage inducement portion 40) to the conductive portion 10. Note that an insulating member 48 made of insulating ceramic (e.g., alumina) may be interposed between the bimetal member 41 and the second member 21, as shown by the dashed line in FIG. 6, to insulate the bimetal member 41 from the second member 21. Furthermore, an insulating member (not shown) may be interposed between the ears 46 of the bimetal member 41 and the first member 11 to insulate the bimetal member 41 from the first member 11.

[0030] The bimetal member 41 undergoes click reversal deformation when its temperature rises above the activation temperature Ta (Ta=130°C in the first embodiment) (see FIG. 6). This causes the breakable portion 35 of the conductive portion 10 to break, thereby disconnecting the first connecting portion 15 and the second connecting portion 25 of the conductive portion 10. Specifically, the semi-cylindrical portion 45, which protrudes outward (upper side AH1) in a semi-cylindrical shape, deforms to protrude inward (lower side AH2) due to the temperature rise. The semi-cylindrical portion 45 then presses the second member 21 toward the lower side AH2. Meanwhile, the pair of ears 46 of the bimetal member 41 press the first member 11 toward the upper side AH1. This causes the breakable portion 35 (joint 37) to break. This breakage creates a gap between the first joint portion 17 and the second joint portion 27, resulting in a discontinuity between the first non-connection portion 12 and the second non-connection portion 22, and also a discontinuity between the first connection portion 15 and the second connection portion 25.

[0031] Next, the resin sealing member 50 will be described. The resin sealing member 50 has a roughly rectangular parallelepiped outer shape, and airtightly covers a portion of the conductive portion 10 to airtightly seal the joint portion 37 of the conductive portion 10. The resin sealing member 50 is made of a resin material 51 containing a thermoplastic resin, a thermoplastic elastomer, and a fibrous filler. In the first embodiment, the thermoplastic resin is polyphenylene sulfide (PPS), the thermoplastic elastomer is a thermoplastic polyurethane elastomer, and the fibrous filler is glass fiber. The resin sealing member 50 is insert-molded as described below.

[0032] The resin sealing member 50 covers only the first seal portion 16 and the first joining portion 17 of the first non-connection portion 12 of the first member 11 and the first seal portion 18 of the first accommodating portion 13, and is airtightly joined to the first seal portions 16, 18. The resin sealing member 50 also covers the second seal portion 26, the second joining portion 27 of the second non-connection portion 22 of the second member 21, and the entire second accommodating portion 23, and is airtightly joined to the second seal portion 26.

[0033] Specifically, the resin sealing member 50 is airtightly bonded to the first roughened sealing surfaces 16m and 18m by filling the spaces between the first nanopillars 33 standing tall on the first roughened sealing surfaces 16m and 18m of the first sealing portions 16 and 18 with a resin material 51 constituting the resin sealing member 50. This effectively prevents air and moisture from entering the interior of the resin sealing member 50 from the boundary between the first member 11 and the resin sealing member 50 and coming into contact with the joint 37. Furthermore, the resin sealing member 50 is airtightly bonded to the second roughened sealing surface 26m by filling the spaces between the second nanopillars 34 standing tall on the second roughened sealing surface 26m of the second sealing portion 26 with the resin material 51 constituting the resin sealing member 50. This effectively prevents air and moisture from entering the interior of the resin sealing member 50 from the boundary between the second member 21 and the resin sealing member 50 and coming into contact with the joint 37.

[0034] In the busbar 1 of the first embodiment, when the temperature of the break induction portion 40 rises to or above the operating temperature Ta, the break induction portion 40 deforms, causing the break portion 35 of the conductive portion 10 to break, thereby discontinuing conduction between the first connection portion 15 and the second connection portion 25 of the conductive portion 10. This allows the busbar 1 itself to cut off the electrical connection between the batteries 100 that are electrically connected via the busbar 1. Furthermore, in the first embodiment, the break induction portion 40 has a bimetal member 41, and therefore, when the temperature of the bimetal member 41 rises to or above the operating temperature Ta, the bimetal member 41 undergoes click reversal deformation, causing the break portion 35 of the conductive portion 10 to break.

[0035] In the first embodiment, the positive electrode terminal 120 of one battery 100, which is made of a first metal (aluminum in the first embodiment), and the negative electrode terminal 130 of another battery 100, which is made of a second metal (copper in the first embodiment), are connected by the busbar 1. In contrast, the conductive portion 10 of the busbar 1 is formed by joining a first member 11 made of the same first metal as the positive electrode terminal 120 and a second member 21 made of the same second metal as the negative electrode terminal 130. Therefore, the first member 11 of the busbar 1 can be connected to the positive electrode terminal 120 of one battery 100, and the second member 21 of the busbar 1 can be connected to the negative electrode terminal 130 of the other battery 100.

[0036] In addition, in the first embodiment, the first member 11 and the second member 21 are made of dissimilar metals, and therefore galvanic corrosion may occur between the first joint portion 17 and the second joint portion 27 of the joint portion 37 where the first member 11 and the second member 21 are joined. In contrast, in the busbar 1, the joint portion 37 is airtightly sealed with a resin sealing member 50. This prevents air and moisture from coming into contact with the joint portion 37, and can suppress corrosion between the first joint portion 17 and the second joint portion 27.

[0037] Furthermore, in this embodiment 1, the first non-connected portion 12 of the first member 11 is formed with the nano-level first roughened sealing surfaces 16m, 18m, on which the aforementioned first nanopillars 33 stand, and the second non-connected portion 22 of the second member 21 is formed with the nano-level second roughened sealing surface 26m, on which the aforementioned second nanopillars 34 stand. A resin material 51 is filled between the adjacent first nanopillars 33 on the first roughened sealing surfaces 16m, 18m to airtightly bond a resin sealing member 50 to the first roughened sealing surfaces 16m, 18m. Furthermore, a resin material 51 is filled between the adjacent second nanopillars 34 on the second roughened sealing surface 26m to airtightly bond a resin sealing member 50 to the second roughened sealing surface 26m, thereby airtightly sealing the joint 37. This allows the joint 37 to be sealed with particularly high airtightness, thereby more effectively suppressing corrosion at the joint 37.

[0038] Next, a method for manufacturing the busbar 1 will be described. First, the first member 11, the second member 21, and the bimetal member 41 are prepared. Then, while the bimetal member 41 is accommodated between the first housing portion 13 of the first member 11 and the second housing portion 23 of the second member 21, the first joint portion 17 of the first member 11 and the second joint portion 27 of the second member 21 are overlapped and welded together around their entire peripheries. This forms the conductive portion 10 that accommodates the fracture inducement portion 40 therein.

[0039] Next, the conductive portion 10 is subjected to a surface roughening treatment to form nano-level first roughened seal surfaces 16m, 18m on the first seal portions 16, 18 of the first member 11, and a nano-level second roughened seal surface 26m on the second seal portion 26 of the second member 21 (see FIG. 7). Specifically, pulsed laser light LB is intermittently irradiated onto the first seal portions 16, 18 of the first member 11 while shifting the irradiation position, forming the first roughened seal surfaces 16m, 18m in which a large number of first bowl-shaped recesses 31 each containing a forest of first nanopillars 33 are arranged in a partially overlapping manner. The laser irradiation conditions were a wavelength of 1064 nm, a peak output of 5 kW, a pulse width of 150 ns, a pitch pb of 75 μm, and a spot diameter of 80 μm.

[0040] In the first sealing portions 16, 18, at the portions irradiated with the pulsed laser beam LB, the first metal (aluminum in the first embodiment) forming the vicinity of the surface melts and turns into vapor. Thereafter, as the temperature of the vapor drops, it turns into first particles 33p of aluminum and aluminum oxide and accumulates in the first bowl-shaped recess 31. By intermittently irradiating the surface with the pulsed laser beam LB while shifting the irradiation position, the first particles 33p accumulate in a string of beads and combine to form columns, forming a forest of first nanopillars 33.

[0041] The second sealing portion 26 of the second member 21 is also irradiated intermittently with pulsed laser light LB while shifting the irradiation position, forming a second roughened sealing surface 26m in which a large number of second cup-shaped recesses 32 with standing second nanopillars 34 are arranged in a partially overlapping manner (see FIG. 7). The laser irradiation conditions were a wavelength of 1064 nm, a peak output of 20 kW, a pulse width of 50 ns, a pitch pb of 60 μm, and a spot diameter of 75 μm. In the portion of the second sealing portion 26 irradiated with the pulsed laser beam LB, the second metal (copper in the first embodiment) near the surface melts and turns into vapor. Thereafter, as the temperature of the vapor drops, it turns into second particles 34p of copper and copper oxide and accumulates in the second bowl-shaped recess 32. By intermittently irradiating the portion with the pulsed laser beam LB while shifting the irradiation position, the second particles 34p accumulate in a string of beads and combine to form columns, forming a forest of second nanopillars 34.

[0042] Next, the resin sealing member 50 is insert-molded. Specifically, using a molding die (not shown) having upper and lower dies, the roughened conductive portion 10 and other components are placed at predetermined positions in the lower die, and then the molding die is closed. Next, molten resin of the resin material 51 is injected into the cavity to fill the cavity. At this time, the molten resin of the resin material 51 also fills the spaces between the first nanopillars 33 standing on the first roughened seal surfaces 16m and 18m of the first seal portions 16 and 18 of the first member 11, and the spaces between the second nanopillars 34 standing on the second roughened seal surface 26m of the second seal portion 26 of the second member 21 (see FIG. 5). The resin sealing member 50 is then molded to hermetically bond the first roughened seal surfaces 16m and 18m of the first member 11 and the second roughened seal surface 26m of the second member 21, hermetically sealing the joint portion 37 of the conductive portion 10. In this way, the bus bar 1 is completed.

[0043] (Embodiment 2) Next, a second embodiment will be described (see FIGS. 8 and 9). Descriptions of parts similar to those of the first embodiment will be omitted or simplified. In the busbar 1 of the first embodiment, the joint portion 37 of the conductive portion 10 is configured as the planned fracture portion 35 that fractures when the busbar 1 becomes hot. In contrast, the busbar (inter-device conductive member) 300 of the second embodiment differs in that a notch portion provided in the first member 311 of the conductive portion 310 is configured as the planned fracture portion 335.

[0044] The busbar 300 of the second embodiment is configured with a conductive portion 310 having a first member 311 and a second member 21, a breakage inducement portion 40 made of a bimetal member 41, and a resin sealing member 350 (see FIG. 8). The first member 311 of the conductive portion 310 is formed of a first metal (specifically, aluminum) like the first member 11 of the first embodiment, but has a different form from the first member 11. On the other hand, the second member 21 is the same as in the first embodiment. The first member 311 of the second embodiment is configured with a first connecting portion 315 and a first non-connecting portion 312, and the first non-connecting portion 312 has an extending portion 314, a first accommodating portion 313, a notch portion (prospective breaking portion) 335, and a first joining portion 317.

[0045] The first connection portion 315 is similar to the first connection portion 15 of the first embodiment and is connected to the positive electrode terminal 120 of the battery 100. The first housing portion 313 is similar to the first housing portion 13 of the first embodiment and accommodates the break induction portion 40 in an accommodation space SA defined between the first housing portion 313 and the second housing portion 23 of the second member 21. The first housing portion 313 also has a first seal portion 318 including a nano-level first roughened seal surface 318m (see FIG. 5 ), similar to the first seal portion 18 of the first embodiment. The first roughened seal surface 318m is airtightly joined to the resin sealing member 350. The extension portion 314 extends from the first connection portion 315 to the first housing portion 313 and connects the first connection portion 315 and the first housing portion 313.

[0046] The first joint portion 317 is a rectangular annular portion similar to the first joint portion 17 of the first embodiment, and is welded to the second joint portion 27 of the second member 21 to form a joint portion 337 consisting of the first joint portion 317 and the second joint portion 27. However, in the second embodiment, this joint portion 337 is not a portion that is expected to break, and will not break even when the busbar 300 becomes hot. In the second embodiment, the planned breaking portion 335 is a notch portion (a portion where a V-shaped recessed groove is formed) provided between the first accommodating portion 313 and the first joint portion 317, and is a portion that is thinner and more easily broken than other portions of the first member 311. The planned breaking portion 335 is also located in the conductive portion 310, between the first connecting portion 315 of the first member 311 and the second connecting portion 25 of the second member 21, and is electrically connected to the first connecting portion 315 and the second connecting portion 25.

[0047] The breakage inducement portion 40 is the same as in the first embodiment and is made of a bimetal member 41. As described above, the bimetal member 41 undergoes click reversal deformation when its own temperature rises above the activation temperature Ta (specifically, Ta = 130°C) (see FIG. 9). In the second embodiment, the notch portion (proposed break portion 335) of the conductive portion 310 has lower strength and is more likely to break than the joint portion 337, so breakage occurs at the notch portion (proposed break portion 335). This causes non-conduction between the first connecting portion 315 and the second connecting portion 25 of the conductive portion 310.

[0048] The resin sealing member 350 is made of the resin material 51 of the first embodiment described above, has a generally rectangular parallelepiped outer shape, and airtightly covers a portion of the conductive portion 310 to airtightly seal the joint portion 337. Specifically, the resin sealing member 350 covers the first joint portion 317, the planned rupture portion 335 consisting of a notch portion, and the first seal portion 318 of the first member 311, and is airtightly joined to the first seal portion 318. The resin sealing member 350 also covers the second seal portion 26, the second joint portion 27, and the second accommodating portion 23 of the second member 21, and is airtightly joined to the second seal portion 26.

[0049] In the busbar 300 of the second embodiment, when the temperature of the breakage induction portion 40 rises to or above the activation temperature Ta, the breakage induction portion 40 deforms, causing the breakage planned portion 335 of the conductive portion 310 to break, thereby causing non-conduction between the first connection portion 315 and the second connection portion 25 of the conductive portion 310. Therefore, the busbar 300 itself can cut the electrical connection between the batteries 100 that are electrically connected via the busbar 300. Other parts similar to those of the first embodiment provide the same effects as those of the first embodiment.

[0050] (Embodiment 3) Next, a third embodiment will be described (see FIGS. 10 and 11). Descriptions of parts similar to those of the first or second embodiment will be omitted or simplified. In the busbars 1, 300 of the first and second embodiments, the breakage induction portion 40 is formed using a bimetal member 41. In contrast, the busbar (inter-device conductive member) 400 of the third embodiment differs in that the breakage induction portion 440 is formed using a shape memory alloy member 441.

[0051] The busbar 400 of the third embodiment is composed of a conductive portion 10, a breakage inducement portion 440, and a resin sealing member 50 (see FIG. 10). The conductive portion 10 and the resin sealing member 50 are the same as those of the first embodiment. Meanwhile, in the third embodiment, the breakage inducement portion 440 has a shape memory alloy member 441 made of a shape memory alloy. The original form of the shape memory alloy member 441 (see FIG. 11) is composed of a semi-cylindrical portion 445 having an axis extending in the short-side direction CH, and a pair of ears 446 located on one side BH1 and the other side BH2 of the longitudinal direction BH of the semi-cylindrical portion 445 and extending in the short-side direction CH. In the busbar 400 (see FIG. 10), the shape memory alloy member 441 is accommodated in the accommodation space SA of the conductive portion 10 in a state where it is crushed in the height direction AH. The pair of ears 446 are sandwiched between the first member 11 and the second member 21 and fixed to the conductive part 10.

[0052] When the temperature of the shape memory alloy member 441 rises above the operating temperature Ta (Ta = 130°C in the third embodiment), which is the transformation point, the shape memory alloy member 441 deforms to return to its original shape (see FIG. 11). Then, the breakable portion 35 of the conductive portion 10 breaks, causing electrical discontinuity between the first connecting portion 15 and the second connecting portion 25 of the conductive portion 10. Specifically, the semi-cylindrical portion 445, which has been crushed in the height direction AH, deforms to its original semi-cylindrical shape due to the temperature rise. Then, the semi-cylindrical portion 445 presses the first member 11 upward AH1. Meanwhile, the pair of ears 446 of the shape memory alloy member 441 press the second member 21 downward AH2. As a result, the joint portion 37 (the breakable portion 35) breaks in the same manner as in the first embodiment, causing electrical discontinuity between the first connecting portion 15 and the second connecting portion 25.

[0053] In the busbar 400 of the third embodiment, when the temperature of the break induction portion 440 rises to or above the activation temperature Ta, the break induction portion 440 deforms, causing the break portion 35 of the conductive portion 10 to break, thereby discontinuing electrical connection between the first connection portion 15 and the second connection portion 25 of the conductive portion 10. This allows the busbar 400 itself to cut off the electrical connection between the batteries 100 that are electrically connected via the busbar 400. In particular, in the third embodiment, the break induction portion 440 includes a shape memory alloy member 441. Therefore, when the temperature of the shape memory alloy member 441 rises to or above the activation temperature Ta, the shape memory alloy member 441 deforms to return to its original shape, thereby breaking the break portion 35 of the conductive portion 10. Other parts similar to those of the first or second embodiment provide the same functions and effects as those of the first or second embodiment.

[0054] (Embodiment 4) Next, a fourth embodiment will be described (see FIGS. 12 and 13). Note that descriptions of parts similar to those of any of the first to third embodiments will be omitted or simplified. In the busbars 1, 300 of the first and second embodiments, the breakage induction portion 40 is formed using a bimetal member 41, while in the busbar 400 of the third embodiment, the breakage induction portion 440 is formed using a shape memory alloy member 441. In contrast, the busbar (inter-device conductive member) 500 of the fourth embodiment differs in that the breakage induction portion 540 is formed using a temperature-sensitive structure 541 having an elastic member 545 and a fixing member 543 that fixes the elastic member 545.

[0055] The bus bar 500 of the fourth embodiment is composed of a conductive portion 10, a breakage induction portion 540, and a resin sealing member 50 (see FIG. 12). Of these, the conductive portion 10 and the resin sealing member 50 are the same as those of the first embodiment. Meanwhile, in the fourth embodiment, the breakage induction portion 540 has a temperature-sensitive structure 541 made up of an elastic member 545 and a fixing member 543. The breakage induction portion 540 is accommodated in the accommodation space SA of the conductive portion 10. The elastic member 545 is a coil spring, and its axis extends in the height direction AH, and is biased (contracted) in the height direction AH, and is maintained in the biased state by the fixing member 543. In the fourth embodiment, the fixing member 543 is made of a thermoplastic resin. The fixing member 543 may also be made of a low-melting-point metal. The fixing member 543 is cylindrical with an outer diameter larger than that of the elastic member 545, and covers the entire radially outer side of the elastic member 545. The fixing member 543 is joined at its lower end to the second housing portion 23 of the second member 21 of the conductive portion 10. This fixes the temperature-sensitive structure 541 (breakage inducement portion 540) made up of the fixing member 543 and the elastic member 545 to the conductive portion 10.

[0056] When the temperature of the fixing member 543 rises above its softening temperature, that is, the operating temperature Ta (Ta=130°C in the fourth embodiment), the fixing member 543 softens and releases the holding of the elastic member 545 by the fixing member 543 (see FIG. 13 ). Then, the elastic member 545 breaks the breakable portion 35 of the conductive portion 10, thereby discontinuing electrical continuity between the first connecting portion 15 and the second connecting portion 25 of the conductive portion 10. Specifically, when the fixing member 543 softens, the elastic member 545, which is a compressed coil spring, expands in the height direction AH. Then, the elastic member 545 presses the first member 11 upward AH1 and presses the second member 21 downward AH2. As a result, the joint portion 37 (the breakable portion 35) breaks in the same manner as in the first embodiment, thereby discontinuing electrical continuity between the first connecting portion 15 and the second connecting portion 25.

[0057] The busbar 500 of the fourth embodiment is formed by the following method. Specifically, the second member 21 is prepared, the elastic member 545 is placed at a predetermined position in the second housing portion 23 of the second member 21, and the elastic member 545 is then biased. Insert molding is then performed in this state to form a fixing member 543 that fixes the elastic member 545 in a biased state. This forms the break induction portion 540 on the second housing portion 23 of the second member 21. Then, the first joint portion 17 of the first member 11, which is separately prepared, is placed on the second joint portion 27 of the second member 21, and these portions are welded to form the conductive portion 10 that accommodates the break induction portion 540 therein. The busbar 400 is then manufactured in the same manner as in the first embodiment.

[0058] In the busbar 500 of the fourth embodiment, when the temperature of the break induction portion 540 rises to or above the actuation temperature Ta, the break induction portion 540 deforms, causing the break portion 35 of the conductive portion 10 to break, thereby discontinuing electrical continuity between the first connection portion 15 and the second connection portion 25 of the conductive portion 10. This allows the busbar 500 itself to cut off electrical connection between the batteries 100 that are electrically connected via the busbar 500. In particular, in the fourth embodiment, the break induction portion 540 includes a temperature-sensitive structure 541 made up of an elastic member 545 and a fixing member 543. Therefore, when the temperature of the fixing member 543 rises to or above the actuation temperature Ta, the fixing member 543 releases the elastic member 545 from its hold, causing the elastic member 545 to deform in an attempt to return to its original shape, thereby breaking the break portion 35 of the conductive portion 10. Other components similar to those of any of the first to third embodiments provide similar functions and effects to those of any of the first to third embodiments.

[0059] The present invention has been described above in accordance with embodiments 1 to 4, but it goes without saying that the present invention is not limited to embodiments 1 to 4 and can be modified and applied as appropriate within the scope of the gist of the present invention. For example, although lithium ion secondary batteries have been exemplified as the power storage device in the first to fourth embodiments, the present invention is not limited to this. Examples of the power storage device include secondary batteries such as sodium ion secondary batteries and calcium ion secondary batteries, and capacitors such as lithium ion capacitors.

[0060] In addition, in the first to fourth embodiments, the first member 11, 311 and the second member 21 are welded to form the conductive portion 10, 310, but the method for joining the first member and the second member is not limited to this. Methods for joining the first member and the second member include fastening using bolts and nuts, FSW (friction stir welding), caulking, riveting, etc. In addition, in the first, third, and fourth embodiments, the joint portion 37 of the conductive portion 10 is the portion to be broken 35, and in the second embodiment, the notch portion provided in the first member 311 of the conductive portion 310 is the portion to be broken 335, but this is not limited to these. For example, a notch portion or a thin-walled portion may be provided in the second member of the conductive portion, and this may be used as the portion to be broken. Furthermore, a notch portion or a thin-walled portion may be provided in each of the first member and the second member, and each of these may be used as the portion to be broken (multiple portions to be broken may be provided).

[0061] Although the first to fourth embodiments illustrate bus bars 1, 300, 400, and 500 that connect adjacent batteries 100 in series, the present invention may also be applied to bus bars that connect batteries in parallel. In this case, the bus bar that connects the positive terminals 120 of the batteries 100 preferably has first and second members made of aluminum, the same as the positive terminals 120, and the bus bar that connects the negative terminals 130 of the batteries 100 preferably has first and second members made of copper, the same as the negative terminals 130. In addition, in embodiments 1 to 4, the resin sealing member 50, 350 is configured to cover only a portion of the lower side AH2 of the first accommodating portion 13, 313 of the first member 11, 311, but this is not limited to this and the resin sealing member 50, 350 may be configured to cover the entire first accommodating portion 13, 313. [Explanation of symbols]

[0062] 1,300,400,500 Busbar (conductive member between devices) 10,310 Conductive part 11,311 First member 12,312 First non-connected part 15,315 First connection 16,18,318 First seal part 16m, 18m, 318m First roughened seal surface 17,317 1st joint 21 Second member 22 First non-connected part 25 Second connection part 26 Second seal part 26m Second roughened seal surface 27 Second joint 33 First Nano Pillar 33p 1st particle 34 Second nano pillar 34p 2nd particle 35 Expected fracture area (joint) 335 Breaking section (notch section) 37,337 joints 40,440,540 Break induction section 41 Bimetallic member 441 Shape memory alloy components 541 Temperature sensitive structure 543 Fixing member 545 Elastic Members 50,350 Resin sealing material 51 Resin material 100 Batteries (energy storage devices) 120 Positive terminal (electrode terminal) 130 Negative terminal (electrode terminal) Ta operating temperature ha height

Claims

1. An inter-device conductive member that electrically connects an electrode terminal of one power storage device to an electrode terminal of another power storage device, a first connection portion connected to an electrode terminal of the one power storage device; a second connection portion connected to an electrode terminal of the other power storage device; and a breakable portion located between the first connection portion and the second connection portion and electrically connected to the first connection portion and the second connection portion; A conductive portion; a break inducing portion that deforms when the temperature rises to an operating temperature or higher, thereby breaking the breakable portion of the conductive portion and discontinuing electrical continuity between the first connecting portion and the second connecting portion. Conductive material between devices.

2. The inter-device conductive member according to claim 1 , The conductive portion is a first member made of a first metal and including the first connection portion and a first non-connection portion other than the first connection portion; a second member made of a second metal different from the first metal and including the second connection portion and a second non-connection portion other than the second connection portion; a joint portion at which the first non-connecting portion and the second non-connecting portion are joined and electrically connected to each other, Conductive material between devices.

3. The inter-device conductive member according to claim 2, The conductive member further includes a resin sealing member that hermetically seals the joint portion of the conductive portion. Conductive material between devices.

4. The inter-device conductive member according to claim 3 , The first non-connected portion of the first member is a first roughened sealing surface on which first particles derived from the first metal constituting the first member are linked in a string to form columnar shapes, each having a height of 50 nm or more; The second non-connected portion of the second member is a second roughened sealing surface on which second particles derived from the second metal constituting the second member are linked in a string to form columnar shapes, each having a height of 50 nm or more; The resin sealing member is A resin material constituting the resin sealing member is filled between the first nanopillars standing on the first roughened sealing surface, and the resin material is airtightly bonded to the first roughened sealing surface, The resin material is filled between the second nanopillars standing on the second roughened sealing surface, and the second nanopillars are airtightly bonded to the second roughened sealing surface, The joint is sealed airtightly. Conductive material between devices.

5. The inter-device conductive member according to any one of claims 1 to 4, The breakage induction portion is The bimetal member is made of a bimetal and undergoes click reversal deformation when the temperature rises above the operating temperature, causing the breakable portion of the conductive portion to break. Conductive material between devices.

6. The inter-device conductive member according to any one of claims 1 to 4, The breakage induction portion is a shape memory alloy member that is made of a shape memory alloy and that deforms when the temperature rises above the operating temperature, which is a transformation point, to break the intended break portion of the conductive portion; Conductive material between devices.

7. The inter-device conductive member according to any one of claims 1 to 4, The breakage induction portion is a fixing member made of a thermoplastic resin or a low-melting-point metal; an elastic member held in a biased state by the fixing member, When the temperature rises to the operating temperature or higher, which is the softening temperature of the thermoplastic resin or the melting point of the low-melting-point metal, the holding of the elastic member by the fixing member is released, and the breakable portion of the conductive portion is broken. Has a temperature-sensitive structure Conductive material between devices.

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