Busbar and energy storage device module

Abstract

To provide a busbar that can be cooled by circulating a cooling medium through it, and that can also reduce the weight of the busbar. [Solution] The busbar 1 comprises a conductive member 10 made of metal and a resin member 20 made of resin. The conductive member 10 has a first connection part 11 connected to the electrode terminal 220 of one energy storage device 200, a second connection part 12 connected to the electrode terminal 230 of another energy storage device 200, and a conductive part 13 located between them and conductive to them. The resin member 20 is fixed to the conductive part 13 of the conductive member 10. The conductive member 10 and the resin member 20, or the resin member alone, constitute a refrigerant flow path 30 through which a cooling medium RB flows to cool the conductive part 13.

Description

Technical Field

[0001] The present invention relates to a bus bar for electrically connecting an electrode terminal of one power storage device (such as a battery or a capacitor) to an electrode terminal of another power storage device, and a power storage device module in which a plurality of power storage devices are connected using this bus bar.

Background Art

[0002] For example, in a battery module including a plurality of batteries, an electrode terminal (for example, a positive electrode terminal) of one battery and an electrode terminal (for example, a negative electrode terminal) of another battery are electrically connected via a bus bar. Further, it is known to provide a refrigerant flow path in such a bus bar and circulate a cooling medium in the refrigerant flow path to cool the bus bar itself. Thereby, for example, in a situation where the temperature of each battery rises with rapid charging, it is possible to suppress the temperature rise of the bus bar and each electrode terminal connected thereto, and suppress the temperature rise of each battery. For example, such a bus bar is disclosed in Patent Document 1 (see FIGS. 1, 2, etc. of Patent Document 1). The bus bar described in Patent Document 1 is made of a metal tube having a rectangular cross section, and the bus bar (metal tube) is cooled by circulating a cooling medium inside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the above-described bus bar is entirely made of metal, the weight of the bus bar becomes heavy. Therefore, the battery module using this bus bar also becomes heavy in weight.

[0005] This invention has been made in view of the current situation, and provides a busbar that can be cooled by circulating a cooling medium through the busbar and can also be made lighter, and an energy storage device module that electrically connects energy storage devices using this busbar. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problems is a busbar for providing electrical conductivity between the electrode terminals of one energy storage device and the electrode terminals of another energy storage device, comprising: a conductive member made of metal, having a first connection portion connected to the electrode terminals of the one energy storage device, a second connection portion connected to the electrode terminals of the other energy storage device, and a conductive portion located between the first connection portion and the second connection portion and providing electrical conductivity to them; and a resin member made of resin and fixed to the resin-fixed surface of the conductive portion of the conductive member, wherein the conductive member and the resin member, or the resin member alone, constitute a refrigerant flow path for circulating a cooling medium to cool the conductive portion.

[0007] The aforementioned busbar has a refrigerant channel through which a cooling medium flows, and therefore the busbar itself can be cooled. Furthermore, since the aforementioned busbar is made of a conductive member made of metal and a resin member made of resin fixed together, it can be made lighter than a busbar made entirely of metal.

[0008] (2) The busbar described in (1) is further provided, wherein the resin member has a grooved wall portion that forms a recessed groove opening toward the conductive portion of the conductive member, and the refrigerant flow path is formed by the conductive portion of the conductive member and the grooved wall portion of the resin member.

[0009] (3) or (1) is a busbar, wherein the resin member is a busbar having the refrigerant flow path that penetrates the inside of the resin member.

[0010] (4) A busbar according to any one of (1) to (3), wherein the resin-fixed surface of the conductive member is a nanoroughened surface in which nano-columns with a height of 50 nm or more are lined up, formed by linking particles derived from the metal that makes up the conductive member in a chain-like manner, and the resin member is a busbar in which the resin material that makes up the resin member is filled between the nano-columns that line up on the resin-fixed surface and fixed to the resin-fixed surface.

[0011] (5) Another embodiment is an energy storage device module comprising a plurality of energy storage devices and a busbar as described in any of (1) to (4), wherein adjacent energy storage devices are connected to each other via the busbar. [Brief explanation of the drawing]

[0012] [Figure 1] This is a top view of the battery module according to Embodiment 1. [Figure 2] This is a top view of the busbar according to Embodiment 1. [Figure 3] This is a cross-sectional view of the busbar according to Embodiment 1, taken along the line 3-3 in Figure 2. [Figure 4] This is a cross-sectional view of the busbar according to Embodiment 1, taken along the line 4-4 in Figure 2. [Figure 5] This is an explanatory diagram showing an enlarged view of the bonded portion between the resin-bonded surface of the conductive member and the resin member of the busbar according to Embodiment 1. [Figure 6] This is an explanatory diagram illustrating the process of manufacturing a busbar according to Embodiment 1, in which a pulsed laser beam is scanned to form a plurality of bowl-shaped recesses and nano-pillars standing in each bowl-shaped recess on the resin-bonded surface of a conductive member. [Figure 7] This is a top view of the busbar according to Embodiment 2. [Figure 8] This is a cross-sectional view of the busbar according to Embodiment 2, taken along the line 8-8 in Figure 7. [Figure 9] This is a cross-sectional view of the busbar according to Embodiment 2, taken along the line 9-9 in Figure 7. [Modes for carrying out the invention]

[0013] (Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The busbar 1 of this embodiment 1 (see Figures 2 to 4) provides electrical conductivity between adjacent batteries 200 in a battery module 300 (see Figure 1) which has multiple rectangular (rectangular) batteries (energy storage devices) 200 (two in this embodiment 1). The height direction AH, the longitudinal direction BH, and the short direction CH of the busbar 1 will be defined as the directions shown in Figures 2 to 4.

[0014] Each battery 200 constituting the battery module 300 (see Figure 1) is stacked in the battery thickness direction with its orientation reversed, and is constrained in the same battery stacking direction SH as the battery thickness direction by a restraining member (not shown). The positive electrode terminal 220 of one battery 200 (left side in Figure 1) and the negative electrode terminal 230 of the other battery 200 (right side in Figure 1) are aligned in the battery stacking direction SH and are electrically connected (series connected) via a busbar 1. The busbar 1 and the positive electrode terminal 220 and negative electrode terminal 230 are joined by welding. Alternatively, the busbar 100 of Embodiment 2 (see Figures 7 to 9), which will be described later, can be used instead of busbar 1.

[0015] Each battery 200 consists of a rectangular box-shaped case 210, an electrode body (not shown) including positive and negative electrode plates and an electrolyte (not shown) housed within the case 210, and positive electrode terminals 220 and negative electrode terminals 230, respectively, supported by the case 210. The upper wall portion 211 of the case 210 is provided with a safety valve 213 that ruptures and opens when the internal pressure of the case 210 exceeds the opening pressure. The upper wall portion 211 of the case is also provided with an electrolyte injection hole (not shown), which is airtightly sealed with a disc-shaped sealing member 215.

[0016] Also, a positive electrode terminal 220 and a negative electrode terminal 230 are fixed to the upper wall portion 211 of the case. Specifically, a pair of insertion holes (not shown) are provided in the upper wall portion 211 of the case. A positive electrode terminal 220 made of aluminum is inserted into one of the insertion holes, and a negative electrode terminal 230 made of copper is inserted into the other insertion hole. The positive electrode terminal 220 is fixed to the upper wall portion 211 of the case via an insert-molded resin insulating member 225, and the negative electrode terminal 230 is fixed to the upper wall portion 211 of the case via an insert-molded resin insulating member 235. The positive electrode terminal 220 has a rectangular plate-shaped positive electrode top plate portion 221 disposed outside the case 210, and the bus bar 1 is welded to this positive electrode top plate portion 221. Also, the positive electrode terminal 220 is conductively connected to a positive electrode current collecting portion (not shown) of the electrode body within the case 210. The negative electrode terminal 230 has a rectangular plate-shaped negative electrode top plate portion 231 disposed outside the case 210, and the bus bar 1 is welded to this negative electrode top plate portion 231. Also, the negative electrode terminal 230 is conductively connected to a negative electrode current collecting portion (not shown) of the electrode body within the case 210.

[0017] Next, the bus bar 1 will be described (see FIGS. 1 to 4). The bus bar 1 is composed of a conductive member 10 made of metal and a resin member 20 made of resin fixed to the conductive member 110. Among these, the conductive member 10 is made of aluminum and has a rectangular plate shape that extends in the longitudinal direction BH and the short-side direction CH. The conductive member 10 includes a first connection portion 11 connected (welded in Embodiment 1) to the positive electrode terminal 220 of one battery 200 (the left side in FIG. 1), a second connection portion 12 connected (welded in Embodiment 1) to the negative electrode terminal 230 of the other battery 200 (the right side in FIG. 1), and a conductive portion 13 located between the first connection portion 11 and the second connection portion 12 and conducting to them.

[0018] Specifically, the first connection part 11 is a rectangular plate-shaped part located on one side BH1 of the longitudinal direction BH of the conduction member 10, and the second connection part 12 is a rectangular plate-shaped part located on the other side BH2 of the longitudinal direction BH of the conduction member 10. The conduction part 13 is a rectangular plate-shaped part located at the center of the longitudinal direction BH of the conduction member 10, is located between the first connection part 11 and the second connection part 12, is connected to the first connection part 11 and the second connection part 12, and is integrated with them.

[0019] Among the conduction parts 13 of the conduction member 10, the main surface 14 located on the resin member 20 side (the upper side AH1 in the height direction AH in the first embodiment) has three resin fixing surfaces 15 that are fixed to the resin member 20. Specifically, on these resin fixing surfaces 15, the tip 25k of the second wall part 25 and the tips 26k of the two third wall parts 26 of the main body part 22 of the resin member 20 to be described later are respectively fixed. Each resin fixing surface 15 is a nano roughened surface roughened at the nano level. Specifically, on the resin fixing surface 15, nano columns 17 with a height ha of 50 nm or more and less than 1000 nm, in which particles 17p derived from the metal forming the conduction member 10 are connected in a bead-like shape and become columnar, stand upright (see FIG. 5). In the first embodiment, the height ha of each nano column 17 is approximately 200 nm. The metal forming the conduction member 10 is aluminum as described above, and the nano columns 17 are made of particles 17p composed of aluminum and aluminum oxide.

[0020] Next, the resin member 20 will be described. The resin member 20 is made of a thermoplastic resin material 21 (in the first embodiment, a resin material mainly composed of polyphenylene sulfide (PPS)). The resin member 20 has a main body part 22 having a concave groove 23, an introduction part 28 for introducing a cooling medium RB (water in the first embodiment) into the main body part 22, and a discharge part 29 for discharging the cooling medium RB in the main body part 22 to the outside of the main body part 22.

[0021] Specifically, the main body portion 22 consists of a first wall portion 24, a second wall portion 25, and two third wall portions 26. The first wall portion 24 is located on the upper side AH1 in the height direction AH and is a rectangular plate-shaped portion that extends in the longitudinal direction BH and the short direction CH. The second wall portion 25 is a rectangular tubular portion that extends from the peripheral edge of the first wall portion 24 to the lower side AH2 in the height direction AH towards the conductive portion 13 along its entire circumference. The second wall portion 25 is fixed to the resin fixing surface 15 of the conductive portion 13 of the conductive member 10 along its entire circumference at its tip portion (lower end portion) 25k. The two third wall portions 26 are rectangular plate-shaped portions that extend from the central portion of the first wall portion 24, excluding the peripheral portion, downward AH2 towards the conductive portion 13 and extend in the height direction AH and the longitudinal direction BH. Each third wall portion 26 is fixed at its tip (lower end) 26k to the resin fixing surface 15 of the conductive portion 13 of the conductive member 10. Specifically, the tip 25k of the second wall portion 25 of the resin member 20 and the tip 26k of each of the two third wall portions 26 are hermetically fixed to the resin fixing surface 15 of the conductive member 10 by filling the spaces between the aforementioned nano-pillars 17 that are densely arranged on the resin fixing surface 15 of the conductive member 10 with the resin material 21 that makes up the resin member 20 (see Figure 5).

[0022] The groove 23 of the main body 22 is composed of a groove wall 27 consisting of a first wall 24, a second wall 25, and two third wall 26. The groove 23 opens toward the conductive portion 13 of the conductive member 10 (towards the lower AH2 in this embodiment 1). A space is formed between the groove wall 27 of the resin member 20 and the conductive portion 13 of the conductive member 10, and this space is a refrigerant flow path 30 through which the cooling medium RB flows. In this embodiment 1, the cooling medium RB flows through the refrigerant flow path 30 while in contact with the conductive portion 13, so the conductive portion 13 can be directly cooled by the cooling medium RB.

[0023] The inlet section 28 and the outlet section 29 are cylindrical in shape, each projecting upward AH1 from the first wall section 24 of the main body section 22, and are in communication with the refrigerant flow path 30 of the main body section 22. The inlet section 28 is located in the center of the short-width CH direction on one side BH1 in the longitudinal direction BH of the first wall section 24 of the main body section 22, and the outlet section 29 is located in the center of the short-width CH direction on the other side BH2 in the longitudinal direction BH of the first wall section 24 of the main body section 22.

[0024] The busbar 1 of this embodiment 1 has a refrigerant flow path 30 through which a cooling medium RB that cools the conductive portion 13 flows, so the busbar 1 itself can be cooled. Furthermore, since the busbar 1 is made of a conductive member 10 made of metal and a resin member 20 made of resin fixed together, the busbar 1 can be made lighter compared to a busbar made entirely of metal. Furthermore, in the battery module 300 of this embodiment 1, the busbar 1 itself can be cooled, so even in situations where the temperature of each battery 200 tends to rise, such as when each battery 200 is rapidly charged, the temperature rise of the busbar 1 and the positive terminal 220 and negative terminal 230 connected thereto can be suppressed, thereby suppressing the temperature rise of each battery 200. Moreover, since the busbar 1 can be made lighter, the battery module 300 can also be made lighter.

[0025] Furthermore, in the busbar 1 of this embodiment 1, the refrigerant flow path 30 is formed by the conductive portion 13 of the conductive member 10 and the grooved wall portion 27 of the resin member 20. Therefore, the cooling medium RB can be brought into contact with the conductive portion 13, allowing the conductive portion 13 to be cooled directly and efficiently cooled. In addition, in busbar 1, the resin bonding surface 15 of the conductive member 10 is made into a nano-level nano-roughened surface with numerous nano-pillars 17, and resin material 21 is filled between the nano-pillars 17 to bond the resin member 20 to the conductive portion 13. In this way, the bonding strength and sealing performance of the conductive member 10 and the resin member 20 can be increased.

[0026] Next, the manufacturing method of the busbar 1 described above will be explained. First, a conductive member 10Z is prepared before surface roughening treatment, and each resin-bonded surface 15 of the main surface 14 of this conductive member 10Z is subjected to surface roughening treatment to make each resin-bonded surface 15 a nano-level nano-roughened surface (see Figure 6). Specifically, the resin-bonded surface 15 of the conductive member 10Z is intermittently irradiated with pulsed laser light LB while shifting the irradiation position to form a nano-roughened surface in which numerous bowl-shaped recesses 18, where nano-pillars 17 stand in a forest, are arranged with some overlap. In this embodiment 1, the laser irradiation conditions were a wavelength of 1064 nm, a peak power of 5 kW, a pulse width of 150 ns, a pitch pb of 75 μm, and a spot diameter of 80 μm.

[0027] In the resin-bonded surface 15, the metal (aluminum in this embodiment 1) near the surface melts and turns into vapor in the area irradiated with pulsed laser light LB. Subsequently, as the temperature of the vapor decreases, it becomes aluminum and aluminum oxide particles 17p, which are deposited in the bowl-shaped recess 18. By intermittently irradiating with pulsed laser light LB while shifting the irradiation position, the particles 17p are deposited and bonded in a chain-like manner to form columnar structures, creating a forest of nano-columns 17.

[0028] Next, a separate resin member 20 is prepared and joined to the conductive member 10 by heat welding. Specifically, the tip 25k of the second wall portion 25 and the tip 26k of the third wall portion 26 of the main body portion 22 of the resin member 20 are melted by heat and joined to the resin fixing surface 15 of the conductive portion 13 of the conductive member 10. At this time, the molten resin of the resin material 21 also fills the spaces between the nano-pillars 17 that are lined up on the resin fixing surface 15 (see Figure 5), so that each tip 25k, 26k of the resin member 20 is airtightly joined to each resin fixing surface 15 with high bonding strength and high sealing performance. In addition, the refrigerant flow path 30 is formed when the conductive portion 13 of the conductive member 10 and the grooved wall portion 27 of the resin member 20 are joined. Thus, the busbar 1 is completed.

[0029] (Embodiment 2) Next, a second embodiment will be described (see Figures 7 to 9). Note that descriptions of parts similar to those in Embodiment 1 will be omitted or simplified. In the busbar 1 of Embodiment 1, the refrigerant flow path 30 was formed by the conductive portion 13 of the conductive member 10 and the grooved wall portion 27 of the resin member 20. In contrast, the busbar 100 of this second embodiment differs in that the refrigerant flow path 130 is formed solely by the resin member 120.

[0030] The busbar 100 of this second embodiment comprises a conductive member 110 and a resin member 120. Of these, the conductive member 110 is the same as the conductive member 10 of the first embodiment except for the area of ​​the resin fixing surface 115 to which the resin member 120 is fixed, and has a first connecting portion 11, a second connecting portion 12 and a conductive portion 13, similar to the first embodiment. In this second embodiment, the resin fixing surface 115 is rectangular, and almost the entire surface of the main surface 14 of the conductive portion 13, excluding the peripheral edge, is the resin fixing surface 115. This resin fixing surface 115, like the resin fixing surface 15 of the first embodiment, is a nano-roughened surface that is roughened at the nano level, and nano-columns 17 are densely arranged (see Figure 5).

[0031] The resin member 120 is formed by fixing the first resin member 20 and the second resin member 122 together. The first resin member 20 and the second resin member 122 are made of the same resin material 21 as in Embodiment 1. The first resin member 20 is also the same as the resin member 20 of Embodiment 1. On the other hand, the second resin member 122 is a rectangular plate shape that extends in the longitudinal direction BH and the transverse direction CH, and has the same size as the first wall portion 24 of the main body portion 22 of the first resin member 20. The first resin member 20 and the second resin member 122 are joined together by the tip portion 25k of the second wall portion 25 and the tip portion 26k of each third wall portion 26 of the first resin member 20 being joined (specifically, joined by heat welding) to the first main surface 123 located on the upper side AH1 of the second resin member 122.

[0032] In this second embodiment, the grooved wall portion 27 of the first resin member 20 and the first main surface 123 of the second resin member 122 form a refrigerant flow path 130 that penetrates the interior of the resin member 120. In this second embodiment, since the cooling medium RB flows inside the resin member 120, the conductive portion 13 of the conductive member 110 is indirectly cooled by the cooling medium RB. Furthermore, in this embodiment 2, the resin member 120 is fixed to the resin fixing surface 115 of the conductive member 110 with respect to the entire surface of the second main surface 124 located at the lower AH2 of the second resin member 122. Specifically, the second resin member 122 of the resin member 120 is fixed to the resin fixing surface 115 of the conductive member 10 by filling the spaces between the nano-pillars 17 that are densely packed on the resin fixing surface 115 of the conductive member 10 with resin material 21 that makes up the second resin member 122 (see Figure 5).

[0033] The busbar 100 of this second embodiment is manufactured as follows. Specifically, a first resin member 20 and a second resin member 122 are prepared and joined together by heat welding to form a resin member 120. This forms a refrigerant flow path 130 that penetrates the inside of the resin member 120. Separately, a conductive member 110Z before surface roughening treatment is prepared, and the resin-fixed surface 115 of this conductive member 110Z is subjected to surface roughening treatment in the same manner as in the first embodiment, so that the resin-fixed surface 115 becomes a nano-roughened surface in which nano-columns 17 are densely arranged (see Figure 6). Next, the resin member 120 is joined to the conductive member 110 by heat welding. Specifically, the second main surface 124 of the second resin member 122 of the resin member 120 is melted by heat, and the second resin member 122 is joined to the resin bonding surface 115 of the conductive member 110. At this time, the molten resin of the resin material 21 also fills the spaces between the nano-pillars 17 that are densely packed on the resin bonding surface 115 (see Figure 5), so the second resin member 122 is joined to the resin bonding surface 115 with high bonding strength. Thus, the busbar 100 is completed.

[0034] The busbar 100 of this second embodiment also has a refrigerant flow path 130 through which a cooling medium RB that cools the conductive portion 13 flows, so the busbar 1 itself can be cooled. Furthermore, since the busbar 100 is made of a conductive member 110 made of metal and a resin member 120 made of resin fixed together, the busbar 100 can be made lighter compared to a busbar made entirely of metal. Furthermore, in this second embodiment, the busbar 100 has a configuration in which the refrigerant flow path 130 penetrates the interior of the resin member 120, and since the refrigerant flow path 130 is composed solely of the resin member 120, it is not necessary to consider the sealing performance (leakage of the cooling medium RB) at the fixed portion between the conductive member 110 and the resin member 120. Other parts that are the same as in the first embodiment provide the same effects and advantages as in the first embodiment.

[0035] Although the present invention has been described above in reference to Embodiments 1 and 2, it goes without saying that the present invention is not limited to Embodiments 1 and 2, and can be applied with appropriate modifications without departing from the spirit of the invention. For example, in Embodiments 1 and 2, lithium-ion secondary batteries were used as examples of energy storage devices, but the invention is not limited to these. Examples of energy storage devices include secondary batteries such as sodium-ion secondary batteries and calcium-ion secondary batteries, and capacitors such as lithium-ion capacitors. In addition, while the battery module 300 connects the batteries 200 in series via busbar 1 (or busbar 100), the batteries 200 may also be connected in parallel via busbar 1 (or busbar 100). [Explanation of symbols]

[0036] 1,100 Busba 10,110 Conductive members 11. First connection section 12. Second connection section 13 Conductive section 15,115 Resin adhesion surface 17 nanopillars 17p particles 20 Resin component (first resin component) 120 Resin component 21 Resin materials 23 grooves 24 1st wall 25 2nd wall section 26 Third wall 27 Recessed groove wall section 30,130 Refrigerant flow path 200 Batteries (energy storage devices) 220 Positive terminal (electrode terminal) 230 Negative terminal (electrode terminal) 300 Battery Modules (Energy Storage Device Modules) RB cooling medium ha (height of nano-columns)

Claims

1. A busbar that provides electrical conductivity between the electrode terminals of one energy storage device and the electrode terminals of another energy storage device, A conductive member made of metal, A first connection part connected to the electrode terminal of the aforementioned energy storage device, A second connection part connected to the electrode terminals of the other energy storage device, and It has a conductive portion located between the first connecting portion and the second connecting portion, which is electrically connected to them. Conductive member and It comprises a resin member made of resin, which is fixed to the resin fixing surface of the conductive portion of the conductive member, The conductive member and the resin member, or the resin member alone, constitute a refrigerant flow path through which a cooling medium for cooling the conductive portion is circulated. Bassba.

2. A bus bar according to claim 1, The resin member has a groove wall portion that forms a groove opening toward the conductive portion of the conductive member, The conductive portion of the conductive member and the grooved wall portion of the resin member constitute the refrigerant flow path. Bassba.

3. A bus bar according to claim 1, The resin member has a refrigerant flow path that penetrates the interior of the resin member. Bassba.

4. A bus bar according to any one of claims 1 to 3, Of the conductive members, the resin-bonded surface is, The aforementioned conductive material is composed of nano-roughened surfaces in which particles derived from the metal are linked together in a chain-like manner, forming columnar structures with a height of 50 nm or more, creating a dense network of nano-columns. The aforementioned resin member is The resin material forming the resin member is filled between the nano-pillars that are standing in a forest on the resin bonding surface, and is then fixed to the resin bonding surface. Bassba.

5. Multiple energy storage devices, A bus bar according to any one of claims 1 to 3, comprising: Adjacent energy storage devices are connected to each other via the busbar. Energy storage device module.

Images