Battery

Abstract

To provide a battery capable of reducing a pressure loss of a coolant and uniformly cooling a cell stack.SOLUTION: A battery includes: first and second cell stacks arranged side by side with each other; and first and second cooling pipes provided below the first and second cell stacks and configured to cool the first and second cell stacks, respectively. The first and second cooling pipes extend from the first end to the second end of each of the first and second cell stacks, and are connected to each other on the second end side. Both an inflow port and an outflow port of the coolant flowing through the first and second cooling pipes are provided on first end side, and the coolant flowing in from the inflow port passes through the first cooling pipe from the first end side, then passes through the second cooling pipe from the second end side, and flows out from the outflow port.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] In conventional batteries, terminals are provided on the top surface of each stacked prismatic cell. In recent years, as disclosed in Patent Document 1, batteries have been developed in which terminals are provided on the longitudinal end surfaces of each stacked prismatic cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2022 / 0302533 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have developed a battery in which cooling pipes extending longitudinally are provided for each of a plurality of parallelly arranged cell stacks for cooling. However, the inventors discovered that simply flowing refrigerant through all of the cooling pipes in parallel from one end to the other in such a battery results in a large pressure loss of the refrigerant, making it impossible to uniformly cool the cell stacks.

[0005] The present disclosure has been made in consideration of the above circumstances, and provides a battery that can reduce pressure loss of the refrigerant and uniformly cool the cell stack. [Means for solving the problem]

[0006] A battery according to one aspect of the present disclosure includes: first and second cell stacks arranged side by side; a first cooling pipe and a second cooling pipe provided below the first cell stack and the second cell stack, respectively, for cooling the first cell stack and the second cell stack; the first and second cooling pipes extend from first ends to second ends of the first and second cell stacks, respectively, and are connected to each other on the second end sides; an inlet and an outlet for the refrigerant flowing through the first and second cooling pipes are both provided on the first end side; The refrigerant that flows in from the inlet passes through the first cooling pipe from the first end side, then passes through the second cooling pipe from the second end side, and flows out from the outlet.

[0007] In the battery according to the present disclosure, the refrigerant that flows in through the inlet passes through the first cooling pipe from the first end, then passes through the second cooling pipe from the second end, and flows out through the outlet. Therefore, compared to a configuration in which the refrigerant flows in parallel through the first and second cooling pipes from the first end to the second end, the pressure loss of the refrigerant can be reduced, and the cell stack can be cooled more uniformly.

[0008] In each of the first and second cell stacks, a plurality of prismatic cells are stacked, terminals are provided on both longitudinal end faces of each of the plurality of prismatic cells, a pair of the first cooling pipes is provided at each widthwise end of the first cell stack, and a pair of the second cooling pipes is provided at each widthwise end of the second cell stack. With this configuration, the cell stack can be cooled efficiently and uniformly.

[0009] Each of the pair of first cooling pipes and the pair of second cooling pipes may be formed in a Z-shape so as to make one and a half round trips between the first end and the second end. Here, in each of the pair of first cooling pipes, the refrigerant may flow from the widthwise end side of the first cell stack toward the center, and in each of the pair of second cooling pipes, the refrigerant may flow from the widthwise end side of the second cell stack toward the center. This configuration enables more uniform cooling of the cell stack.

[0010] The first and second cell stacks may each be provided in plurality. Here, the first and second cell stacks may be provided in equal numbers. This configuration reduces pressure loss of the refrigerant, allowing the cell stacks to be cooled efficiently and uniformly.

[0011] The fuel cell may further include a case that houses the first and second cell stacks, and the first and second cooling pipes may be provided below a bottom plate of the case. [Effects of the Invention]

[0012] The present disclosure makes it possible to provide a battery that can reduce pressure loss of the refrigerant and uniformly cool the cell stack. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view showing a battery according to a first embodiment. [Figure 2] 1 is a schematic perspective view showing a cell stack CS1 in a battery according to a first embodiment. [Figure 3] 1 is a schematic perspective view showing a cell stack CS1 in a battery according to a first embodiment. [Figure 4] FIG. 2 is an enlarged cross-sectional view of region IV in FIG. [Figure 5] FIG. 2 is a schematic plan view showing the planar configuration of cooling pipes CP1 and CP2 according to the first embodiment. [Figure 6] FIG. 10 is a schematic plan view showing the planar configuration of cooling pipes CP1 and CP2 according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, specific embodiments of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings have been simplified appropriately for clarity of explanation.

[0015] (First embodiment) <Battery configuration> First, the configuration of the battery according to the first embodiment will be described with reference to Figures 1 to 4. Figure 1 is a schematic cross-sectional view showing the battery according to the first embodiment. Figures 2 and 3 are both schematic perspective views showing a cell stack CS1 in the battery according to the first embodiment. Figure 4 is an enlarged cross-sectional view of region IV in Figure 1.

[0016] The battery according to the present embodiment is used, for example, in a vehicle. The vehicle in which the battery according to the present embodiment is mounted is not particularly limited, but examples thereof include electric vehicles, hybrid vehicles, fuel cell vehicles, and the like that can be driven by power supplied from the battery. Naturally, the right-handed XYZ Cartesian coordinate system shown in Figures 1 to 4 and other figures is for the convenience of explaining the positional relationships of the components. In Figure 1 and other figures, the positive direction of the Z axis is normally vertically upward, and the XY plane is the horizontal plane, which is common to all figures.

[0017] 1, the battery according to the first embodiment includes cell stacks CS1 and CS2, an upper case UC, a lower case LC, and cooling pipes CP1 and CP2. As shown in Fig. 1, the cooling pipe CP1 includes a pair of cooling pipes CP11 and CP12, and the cooling pipe CP2 includes a pair of cooling pipes CP21 and CP22.

[0018] In Fig. 1, the cell stacks CS1 and CS2 extend in the X-axis direction. As shown in Fig. 1, the cell stacks CS1 and CS2 are arranged side by side in the Y-axis direction inside the cases (upper case UC and lower case LC). In FIG. 1, the cell stacks CS1 and CS2 are shown in a side view rather than a cross-sectional view.

[0019] Here, since the cell stacks CS1 and CS2 have the same configuration, the configuration of the cell stack CS1 will be described with reference to Figures 2 to 4. As shown in Figures 2 and 3, the cell stack CS1 includes prismatic cells C1 to C6, bus bars B1 to B5, and metal bands MB1 and MB2, and also includes insulating plates IP1 and IP2 as shown in Figure 4. In FIG. 4, the prismatic cell C1 is shown in a side view rather than a cross-sectional view.

[0020] 2 and 3, the prismatic cells C1 to C6 are rectangular parallelepiped cells extending in the Y-axis direction. The prismatic cells C1 to C6 are stacked in the thickness direction (X-axis direction) to form a cell stack CS1. The prismatic cells C1 to C6 are secondary batteries such as lithium-ion batteries or nickel-metal hydride batteries.

[0021] Note that the cell stack CS1 is shown in a simplified form in Figures 2 and 3. The cell stack CS1 shown in Figures 2 and 3 is composed of six prismatic cells C1 to C6, but is usually composed of more prismatic cells. On the other hand, the number of prismatic cells that make up the cell stack CS1 is not particularly limited, as long as it is plural.

[0022] Furthermore, a heat insulating plate or a spacer for adjusting the gap (not shown) may be inserted between adjacent rectangular cells. Furthermore, end plates (not shown) may be provided on both ends of the cell stack CS1 in the stacking direction (X-axis direction).

[0023] As shown in Fig. 2, a positive electrode terminal PT1 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of the prismatic cell C1. Although not particularly limited, the positive electrode terminal PT1 shown in Fig. 2 has a rectangular shape when viewed in the XZ plane and is provided so as to protrude outward from the end face of the prismatic cell C1. The positive electrode terminal PT1 shown in Fig. 2 is provided on the upper side (the positive Z-axis direction) of the end face of the prismatic cell C1. The positive electrode terminal PT1 is made of a metal material such as copper, which has excellent conductivity.

[0024] Similarly, as shown in FIG. 2, a negative electrode terminal NT2 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C2 adjacent to prismatic cell C1. A positive electrode terminal PT3 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C3 adjacent to prismatic cell C2. A negative electrode terminal NT4 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C4 adjacent to prismatic cell C3. A positive electrode terminal PT5 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C5 adjacent to prismatic cell C4. A negative electrode terminal NT6 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C6 adjacent to prismatic cell C5.

[0025] As shown in FIG. 2, the negative electrode terminal NT2 of the prismatic cell C2, the positive electrode terminal PT3 of the prismatic cell C3, the negative electrode terminal NT4 of the prismatic cell C4, the positive electrode terminal PT5 of the prismatic cell C5, and the negative electrode terminal NT6 of the prismatic cell C6 have the same shape as the positive electrode terminal PT1 of the prismatic cell C1 and are arranged in the same manner.

[0026] 2, the positive electrode terminal PT1 of adjacent prismatic cell C1 and the negative electrode terminal NT2 of adjacent prismatic cell C2 are electrically connected by a plate-shaped bus bar B1. Similarly, the positive electrode terminal PT3 of adjacent prismatic cell C3 and the negative electrode terminal NT4 of adjacent prismatic cell C4 are electrically connected by a plate-shaped bus bar B3. Similarly, the positive electrode terminal PT5 of adjacent prismatic cell C5 and the negative electrode terminal NT6 of adjacent prismatic cell C6 are electrically connected by a plate-shaped bus bar B5.

[0027] On the other hand, as shown in Fig. 3, a negative electrode terminal NT1 is provided on the other longitudinal end surface (the end surface on the Y-axis positive side) of the prismatic cell C1. Although not particularly limited, the negative electrode terminal NT1 shown in Fig. 3 has a rectangular shape in the XZ plane, similar to the positive electrode terminal PT1 shown in Fig. 2, and is provided so as to protrude outward from the end surface of the prismatic cell C1. Furthermore, similar to the positive electrode terminal PT1 shown in Fig. 2, the negative electrode terminal NT1 shown in Fig. 3 is provided on the upper side (the Z-axis positive side) of the end surface of the prismatic cell C1. Similar to the positive electrode terminal PT1, the negative electrode terminal NT1 is made of a metal material such as copper, which has excellent conductivity.

[0028] Similarly, as shown in FIG. 3, a positive electrode terminal PT2 is provided on the other longitudinal end surface (the end surface facing the positive Y-axis direction) of prismatic cell C2 adjacent to prismatic cell C1. A negative electrode terminal NT3 is provided on the other longitudinal end surface (the end surface facing the positive Y-axis direction) of prismatic cell C3 adjacent to prismatic cell C2. A positive electrode terminal PT4 is provided on the other longitudinal end surface (the end surface facing the positive Y-axis direction) of prismatic cell C4 adjacent to prismatic cell C3. A negative electrode terminal NT5 is provided on the other longitudinal end surface (the end surface facing the positive Y-axis direction) of prismatic cell C5 adjacent to prismatic cell C4. A positive electrode terminal PT6 is provided on the other longitudinal end surface (the end surface facing the positive Y-axis direction) of prismatic cell C6 adjacent to prismatic cell C5.

[0029] As shown in FIG. 3, the positive electrode terminal PT2 of the prismatic cell C2, the negative electrode terminal NT3 of the prismatic cell C3, the positive electrode terminal PT4 of the prismatic cell C4, the negative electrode terminal NT5 of the prismatic cell C5, and the positive electrode terminal PT6 of the prismatic cell C6 have the same shape as the negative electrode terminal NT1 of the prismatic cell C1 and are arranged in the same manner.

[0030] 3, the positive electrode terminal PT2 of adjacent prismatic cell C2 and the negative electrode terminal NT3 of adjacent prismatic cell C3 are electrically connected by a plate-shaped bus bar B2. Similarly, the positive electrode terminal PT4 of adjacent prismatic cell C4 and the negative electrode terminal NT5 of adjacent prismatic cell C5 are electrically connected by a plate-shaped bus bar B4. In this way, in the cell stack CS1 shown in FIGS. 2 and 3, the prismatic cells C1 to C6 are connected in series by the bus bars B1 to B5.

[0031] The negative electrode terminal NT1 of the prismatic cell C1 shown in Fig. 3 is connected to the positive electrode terminal of another cell stack via, for example, a bus bar (not shown), although this is not a limitation. The positive electrode terminal PT6 of the prismatic cell C6 shown in Fig. 3 is connected to the negative electrode terminal of yet another cell stack via, for example, a bus bar (not shown). This configuration allows, for example, multiple cell stacks to be connected in series.

[0032] The bus bars B1 to B5 shown in FIGS. 2 and 3 have the same configuration, so only the bus bar B1 will be described. 2, the busbar B1 is a plate-shaped member that electrically connects the positive terminal PT1 of the adjacent prismatic cell C1 and the negative terminal NT2 of the adjacent prismatic cell C2. The busbar B1 is made of a metal material such as copper, which has excellent electrical conductivity.

[0033] 2, the busbar B1 is, for example, a plate-like member having a rectangular shape when viewed in the XZ plane. The busbar B1 is provided so as to cover substantially the entire positive electrode terminal PT1 of the prismatic cell C1 and the negative electrode terminal NT2 of the prismatic cell C2. The busbar B1 has a pair of welds WP1 and WP2 welded to the positive electrode terminal PT1 of the prismatic cell C1 and the negative electrode terminal NT2 of the prismatic cell C2, respectively, which are arranged adjacent to each other.

[0034] Although not particularly limited, the welded portions WP1 and WP2 shown in FIG. 2 are provided on both ends in the X-axis direction on the lower side (negative Z-axis side) of the bus bar B1. Here, FIG. 2 shows the welded portions WP1 and WP2 before welding. The welded portions WP1 and WP2 shown in FIG. 2 are countersunk and have a thinner plate thickness than other regions. Furthermore, the welded portions WP1 and WP2 shown in FIG. 2 have a circular shape when viewed in the XZ plane and have a through hole in the center.

[0035] The welding method is not particularly limited, but for example, by irradiating a laser beam onto welded portion WP1 from the negative Y-axis direction side, the bus bar B1 is welded to the positive electrode terminal PT1 of prismatic cell C1 at welded portion WP1. Similarly, by irradiating a laser beam onto welded portion WP2 from the negative Y-axis direction side, the bus bar B1 is welded to the negative electrode terminal NT2 of prismatic cell C2 at welded portion WP2.

[0036] 2 and 3, the metal bands MB1 and MB2 are metal members with an L-shaped YZ cross section that extend in the stacking direction over the entire length of the cell stack CS1. The metal bands MB1 and MB2 restrain both lower longitudinal ends of the prismatic cells C1 to C6 (i.e., the cell stack CS1). The metal bands MB1 and MB2 may be divided into a plurality of bands and provided over the entire length of the cell stack CS1.

[0037] 4, metal band MB1 is provided along the lower corners of prismatic cells C1-C6 on the negative Y-axis side, and has an L-shaped YZ cross section. It includes a bottom plate that supports the bottom surfaces of prismatic cells C1-C6 and a side plate that supports the end surfaces of prismatic cells C1-C6. Similarly, metal band MB2 is provided along the lower corners of prismatic cells C1-C6 on the positive Y-axis side, and has an L-shaped YZ cross section. It includes a bottom plate that supports the bottom surfaces of prismatic cells C1-C6 and a side plate that supports the end surfaces of prismatic cells C1-C6.

[0038] 4, the insulating plate IP1 is provided between the prismatic cells C1 to C6 and the metal band MB1 at the lower corners of the prismatic cells C1 to C6 on the negative Y-axis direction side, and electrically insulates the prismatic cells C1 to C6 from the metal band MB1. That is, the insulating plate IP1 is an insulating member with an L-shaped YZ cross section that extends in the stacking direction over the entire length of the cell stack CS1.

[0039] Similarly, insulating plates IP2 are provided between the prismatic cells C1 to C6 and the metal band MB2 at the lower corners of the prismatic cells C1 to C6 on the positive Y-axis side, electrically insulating the prismatic cells C1 to C6 from the metal band MB2. That is, the insulating plate IP2 is an insulating member with an L-shaped YZ cross section that extends in the stacking direction over the entire length of the cell stack CS1.

[0040] The insulating plates IP1 and IP2 are made of, for example, resin. Although not particularly limited, the insulating plates IP1 and IP2 shown in Fig. 4 have an L-shaped YZ cross section corresponding to the metal bands MB1 and MB2, and are slightly larger than the metal bands MB1 and MB2 so as to protrude beyond the metal bands MB1 and MB2. Note that the insulating plates IP1 and IP2 are not essential as long as they can insulate the prismatic cells C1 to C6 from the metal bands MB1 and MB2.

[0041] Returning to Figure 1, the explanation will continue. As shown in Fig. 1, an upper case UC and a lower case LC constitute a case that houses the cell stacks CS1 and CS2. The upper case UC is a metal plate that covers the top surfaces of the cell stacks CS1 and CS2, and the lower case LC is a metal plate that supports the bottom surfaces of the cell stacks CS1 and CS2. The bottom surfaces of the cell stacks CS1 and CS2 (i.e., prismatic cells C1 to C6) and the top surface of the lower case LC are electrically insulated by, for example, an insulating heat-conducting layer (not shown).

[0042] As shown in Fig. 1, a cooling pipe (first cooling pipe) CP1 cools a cell stack (first cell stack) CS1. A cooling pipe (second cooling pipe) CP2 cools a cell stack (second cell stack) CS2. As shown in Fig. 1, the cooling pipes CP1 and CP2 are in contact with the bottom surface of the lower case LC and extend in the stacking direction (X-axis direction) over the entire length of the cell stacks CS1 and CS2. The cooling pipes CP1 and CP2 may be provided above the bottom surface of the lower case LC, that is, inside the case, as long as they can cool the cell stacks CS1 and CS2 from below.

[0043] The refrigerant flowing inside the cooling pipes CP1 and CP2 is, for example, water. Although details will be described later, the inlet and outlet of the refrigerant flowing through the cooling pipes CP1 and CP2 shown in Fig. 1 are both provided on the first ends (ends on the negative X-axis direction) of the cell stacks CS1 and CS2. The cooling pipes CP1 and CP2 are connected to each other on the second ends (ends on the positive X-axis direction) of the cell stacks CS1 and CS2.

[0044] The refrigerant that flows in through the inlet provided at the first end passes through the cooling pipe CP1 from the first end side, then passes through the cooling pipe CP2 from the second end side, and flows out through the outlet provided at the first end. As will be described in detail later, the battery of this embodiment can reduce the pressure loss of the refrigerant and can cool the cell stacks CS1 and CS2 more uniformly than a configuration in which the refrigerant flows in parallel from the first end to the second end of both cooling pipes CP1 and CP2.

[0045] <Detailed configuration of cooling pipes CP1 and CP2> The detailed configuration of the cooling pipes CP1 and CP2 will be described below. 1, the cooling pipe CP1 has a pair of cooling pipes CP11 and CP12 provided at both ends of the cell stack CS1 in the width direction. Similarly, the cooling pipe CP2 has a pair of cooling pipes CP21 and CP22 provided at both ends of the cell stack CS2 in the width direction.

[0046] Although not particularly limited, each of the cooling pipes CP11, CP12, CP21, and CP22 shown in Fig. 1 is formed by bonding two metal plates having irregularities. For example, metal plates made of aluminum, aluminum alloy, copper, copper alloy, or the like, which have excellent thermal conductivity, are used. For vehicle applications, an aluminum alloy plate is suitable from the viewpoint of weight reduction.

[0047] As shown in Fig. 4, terminals (positive terminal PT1 and negative terminal NT1 in Fig. 4) are provided on both end faces of the prismatic cells C1 to C6 that make up the cell stack CS1, and so heat is easily generated when current is applied. Therefore, by providing a pair of cooling pipes CP11 and CP12 at both widthwise ends of the cell stack CS1, the cell stack CS1 can be cooled efficiently and uniformly. Similarly, by providing a pair of cooling pipes CP21 and CP22 at both widthwise ends of the cell stack CS2, the cell stack CS2 can be cooled efficiently and uniformly.

[0048] 1 and 4 includes three cooling pipes CP11a, CP11b, and CP11c extending in the X-axis direction. The three cooling pipes CP11a, CP11b, and CP11c are arranged in order from the end of the cell stack CS1 (i.e., rectangular cells C1 to C6) on the negative Y-axis direction side toward the center.

[0049] 1 and 4 includes three cooling pipes CP12a, CP12b, and CP12c extending in the X-axis direction. The three cooling pipes CP12a, CP12b, and CP12c are arranged in order from the end of the cell stack CS1 (i.e., rectangular cells C1 to C6) on the positive side of the Y-axis toward the center.

[0050] 1 and 4, the cross-sectional shape of the cooling pipes CP11a, CP11b, and CP11c is a parallelogram or trapezoid, i.e., a rectangle. Therefore, the contact area between the cooling pipe CP11 and the lower case LC is large, allowing the cell stack CS1 to be cooled efficiently. Similarly, the cross-sectional shape of the cooling pipes CP12a, CP12b, and CP12c is also a parallelogram or trapezoid, i.e., a rectangle. Therefore, the contact area between the cooling pipe CP12 and the lower case LC is large, allowing the cell stack CS1 to be cooled efficiently.

[0051] 1 includes three cooling pipes CP21a, CP21b, and CP21c extending in the X-axis direction. The three cooling pipes CP21a, CP21b, and CP21c are arranged in order from the end of the cell stack CS2 (i.e., rectangular cells C1 to C6) on the negative Y-axis direction side toward the center.

[0052] 1 includes three cooling pipes CP22a, CP22b, and CP22c extending in the X-axis direction. The three cooling pipes CP22a, CP22b, and CP22c are arranged in order from the end of the cell stack CS2 (i.e., rectangular cells C1 to C6) on the positive side of the Y-axis toward the center.

[0053] As shown in Figure 1, the cross-sectional shape of the cooling pipes CP21a, CP21b, and CP21c is a parallelogram or trapezoid, i.e., a rectangle. This increases the contact area between the cooling pipe CP21 and the lower case LC, allowing the cell stack CS2 to be cooled efficiently. Similarly, the cross-sectional shape of the cooling pipes CP22a, CP22b, and CP22c is also a parallelogram or trapezoid, i.e., a rectangle. This increases the contact area between the cooling pipe CP22 and the lower case LC, allowing the cell stack CS1 to be cooled efficiently.

[0054] <Plane configuration of cooling pipes CP1 and CP2> Next, the planar configuration of the cooling pipes CP1 and CP2 will be described with reference to Fig. 5. Fig. 5 is a schematic plan view showing the planar configuration of the cooling pipes CP1 and CP2 according to the first embodiment. That is, Fig. 5 shows the piping paths of the cooling pipes CP1 and CP2. In Fig. 5, the cell stacks CS1 and CS2 are indicated by two-dot chain lines. Also, the arrows shown inside the cooling pipes CP1 and CP2 in Fig. 5 indicate the flow of the refrigerant. Although FIG. 5 is a plan view, the cooling pipes CP1 and CP2 are displayed as dots to facilitate understanding.

[0055] 5, the inlet IN and outlet OUT of the refrigerant flowing through the cooling pipes CP1 and CP2 are both provided on the first ends (ends on the negative X-axis direction) of the cell stacks CS1 and CS2. The cooling pipes CP1 and CP2 are connected to each other at the second ends (ends on the positive X-axis direction) of the cell stacks CS1 and CS2.

[0056] As shown in FIG. 5, the refrigerant that flows in from the inlet IN passes through the cooling pipes CP11 and CP12 (cooling pipe CP1) from the first end side, then passes through the cooling pipes CP21 and CP22 (cooling pipe CP2) from the second end side, and flows out from the outlet OUT.

[0057] That is, the cooling pipe CP1 for cooling the cell stack CS1 and the cooling pipe CP2 for cooling the cell stack CS2 are connected in series, and after cooling the cell stack CS1, the cell stack CS2 is cooled. The cooling pipes CP11 and CP12 constituting the cooling pipe CP1 are connected in parallel between the first end and the second end. Similarly, the cooling pipes CP21 and CP22 constituting the cooling pipe CP2 are connected in parallel between the first end and the second end.

[0058] More specifically, as shown in Fig. 5, the cooling pipe CP11 that cools the cell stack CS1 includes the cooling pipes CP11a, CP11b, and CP11c shown in Fig. 1 and Fig. 4, and is formed in a Z shape so as to make one and a half round trips between a first end and a second end. That is, the cooling pipe CP11 has two U-turn portions. The Z shape can also be considered an N shape.

[0059] 5, the refrigerant that flows in from the inlet passes through the cooling pipes CP11a, CP11b, and CP11c shown in Figures 1 and 4 in that order from the first end side, and reaches the second end. In this way, by flowing the refrigerant in the cooling pipe CP11 from the end side in the width direction of the cell stack CS1 toward the center side, the cell stack CS1 can be cooled uniformly and efficiently.

[0060] Similarly, as shown in Figure 5, the cooling pipe CP12 that cools the cell stack CS1 includes the cooling pipes CP12a, CP12b, and CP12c shown in Figures 1 and 4, and is formed in a Z shape so as to make one and a half round trips between the first end and the second end.

[0061] 5, the refrigerant that flows in from the inlet passes through the cooling pipes CP12a, CP12b, and CP12c shown in Figures 1 and 4 in that order from the first end side, and reaches the second end. In this way, by flowing the refrigerant in the cooling pipe CP12 from the end side in the width direction of the cell stack CS1 toward the center side, the cell stack CS1 can be cooled uniformly and efficiently.

[0062] On the other hand, as shown in Figure 5, the cooling pipe CP21 that cools the cell stack CS2 includes the cooling pipes CP21a, CP21b, and CP21c shown in Figure 1, and is formed in a Z shape so as to make one and a half round trips between the second end and the first end.

[0063] 5, the refrigerant that has passed through the cooling pipes CP11 and CP12 passes through the cooling pipes CP21a, CP21b, and CP21c shown in Fig. 1 in that order from the second end side, and flows out from the outlet OUT provided at the first end. In this way, by flowing the refrigerant in the cooling pipe CP21 from the width direction end side of the cell stack CS2 toward the center, the cell stack CS2 can be cooled uniformly and efficiently.

[0064] Similarly, as shown in Figure 5, the cooling pipe CP22 that cools the cell stack CS2 includes the cooling pipes CP22a, CP22b, and CP22c shown in Figure 1, and is formed in a Z shape so as to make one and a half round trips between the second end and the first end.

[0065] As shown in Fig. 5, the refrigerant that has passed through the cooling pipes CP11 and CP12 passes through the cooling pipes CP22a, CP22b, and CP22c shown in Fig. 1 in that order from the second end side, and flows out from the outlet OUT provided at the first end. In this way, by flowing the refrigerant in the cooling pipe CP22 from the end side in the width direction of the cell stack CS2 toward the center, the cell stack CS2 can be cooled uniformly and efficiently.

[0066] <Planar configuration of cooling pipes CP1 and CP2 according to the comparative example> Next, the planar configuration of cooling pipes CP1 and CP2 according to a comparative example will be described with reference to Fig. 6. Fig. 6 is a schematic plan view showing the planar configuration of cooling pipes CP1 and CP2 according to a comparative example. That is, Fig. 6 shows the piping paths of cooling pipes CP1 and CP2 in the comparative example. In Fig. 6, cell stacks CS1 and CS2 are indicated by two-dot chain lines. Also, arrows shown inside cooling pipes CP1 and CP2 in Fig. 6 indicate the flow of refrigerant. Although FIG. 6 is a plan view, the cooling pipes CP1 and CP2 are displayed as dots to facilitate understanding.

[0067] As shown in Fig. 6, the inlet IN and outlet OUT of the refrigerant flowing through the cooling pipes CP1 and CP2 are both located outside the side-by-side cell stacks CS1 and CS2, in the center in the negative X-axis direction. The cooling pipes CP1 and CP2 are connected to each other at both ends of the cell stacks CS1 and CS2 in the longitudinal direction (X-axis direction). Here, as shown in Fig. 6, the cooling pipes CP1 and CP2 according to the comparative example are provided with an inlet pipe PI connecting the inlet IN to a first end (the end on the negative X-axis side) and an outlet pipe PO connecting the outlet OUT to a second end (the end on the positive X-axis side).

[0068] 6, the inlet IN and outlet OUT are provided on the positive Y-axis side of cell stack CS2 as the outsides of the juxtaposed cell stacks CS1 and CS2, but they may also be provided on the negative Y-axis side of cell stack CS1. Alternatively, the inlet IN and outlet OUT may be provided on the first end side by extending the outlet piping PO to the first end side without providing the inlet piping PI. Alternatively, the inlet IN and outlet OUT may be provided on the second end side by extending the inlet piping PI to the second end side without providing the outlet piping PO.

[0069] 6, the refrigerant that flows in from the inlet IN flows from the first end through cooling pipes CP11 and CP12 (cooling pipe CP1) and cooling pipes CP21 and CP22 (cooling pipe CP2) to the second end and flows out from the outlet OUT. That is, in the comparative example shown in Fig. 6, the cooling pipe CP1 that cools the cell stack CS1 and the cooling pipe CP2 that cools the cell stack CS2 are connected in parallel, and the cell stacks CS1 and CS2 are cooled simultaneously.

[0070] 6, the cooling pipe CP11 according to the comparative example also includes the cooling pipes CP11a, CP11b, and CP11c shown in Figures 1 and 4, and is formed in a Z-shape so as to make one and a half round trips between the first end and the second end. As shown in Figure 6, the refrigerant that flows in from the inlet passes through the cooling pipes CP11a, CP11b, and CP11c in that order from the first end to the second end.

[0071] 6, the cooling pipe CP12 according to the comparative example also includes the cooling pipes CP12a, CP12b, and CP12c shown in Figures 1 and 4, and is formed in a Z-shape so as to make one and a half round trips between the first end and the second end. As shown in Figure 6, the refrigerant that flows in from the inlet passes through the cooling pipes CP12a, CP12b, and CP12c in that order from the first end to the second end.

[0072] Similarly, as shown in Fig. 6, the cooling pipe CP21 according to the comparative example also includes the cooling pipes CP21a, CP21b, and CP21c shown in Fig. 1, and is formed in a Z-shape so as to make one and a half round trips between the first end and the second end. On the other hand, as shown in Fig. 6, in the cooling pipe CP21 according to the comparative example, the refrigerant that flows in from the inlet passes through the cooling pipes CP21a, CP21b, and CP21c in that order from the first end side, and reaches the second end.

[0073] Similarly, as shown in Fig. 6, the cooling pipe CP22 according to the comparative example also includes the cooling pipes CP21a, CP21b, and CP21c shown in Fig. 1, and is formed in a Z-shape so as to make one and a half round trips between the first end and the second end. On the other hand, as shown in Fig. 6, in the cooling pipe CP22 according to the comparative example, the refrigerant that flows in from the inlet passes through the cooling pipes CP21a, CP21b, and CP21c in that order from the first end side, and reaches the second end.

[0074] 6, the cooling pipe CP1 that cools the cell stack CS1 and the cooling pipe CP2 that cools the cell stack CS2 are connected in parallel, and the cell stacks CS1 and CS2 are cooled simultaneously. Therefore, at first glance, it appears that the cell stacks CS1 and CS2 can be cooled uniformly, but in the comparative example, the refrigerant pressure loss increases, and in reality, the cell stacks CS1 and CS2 cannot be cooled uniformly. Furthermore, the more cell stacks that are installed side by side, the greater the refrigerant pressure loss, making it even more difficult to cool the cell stacks uniformly.

[0075] 5, the cooling pipe CP1 that cools the cell stack CS1 and the cooling pipe CP2 that cools the cell stack CS2 are connected in series, and the cell stack CS1 is cooled first, followed by the cell stack CS2. This reduces the pressure loss of the refrigerant compared to the comparative example, and allows the cell stacks CS1 and CS2 to be cooled more uniformly. In addition, in the present embodiment shown in FIG. 5, the inlet pipe PI and the outlet pipe PO shown in FIG. 6 are not necessary.

[0076] The battery according to this embodiment may include multiple cell stacks CS1, which are cooled first by the refrigerant flow, and multiple cell stacks CS2, which are cooled later by the refrigerant flow. In this case, if the battery according to this embodiment includes the same number of such cell stacks CS1 and cell stacks CS2, the cell stacks can be cooled efficiently and uniformly.

[0077] As described above, in the battery according to this embodiment, the refrigerant that flows in from the inlet IN passes through the cooling pipe CP1 that cools the cell stack CS1 from the first end side, then passes through the cooling pipe CP2 that cools the cell stack CS2 from the second end side, and flows out from the outlet OUT. Therefore, the battery according to this embodiment can reduce the pressure loss of the refrigerant and can cool the cell stack more uniformly than the comparative example in which the refrigerant flows in parallel from the first end side to the second end side through both the cooling pipe CP1 that cools the cell stack CS1 and the cooling pipe CP2 that cools the cell stack CS2.

[0078] The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0079] B1~B5 bus bar C1~C6 Prismatic cells CP1, CP11, CP12 First cooling pipe CP2, CP21, CP22 Second cooling pipe CS1 First cell stack CS2 Second Cell Stack IN inlet IP1, IP2 insulating plate LC Lower Case MB1, MB2 metal band NT1~NT6 Negative terminal OUT outlet PI inflow pipe PO Outlet Pipe PT1~PT6 Positive terminal UC Upper Case WP1, WP2 welds

Claims

1. first and second cell stacks arranged side by side; a first cooling pipe and a second cooling pipe provided below the first cell stack and the second cell stack, respectively, for cooling the first cell stack and the second cell stack, the first and second cooling pipes extend from first ends to second ends of the first and second cell stacks, respectively, and are connected to each other at the second ends; an inlet and an outlet for a refrigerant flowing through the first and second cooling pipes are both provided on the first end side; The refrigerant that flows in from the inlet passes through the first cooling pipe from the first end side, then passes through the second cooling pipe from the second end side, and flows out from the outlet. Battery.

2. Each of the first and second cell stacks includes a plurality of stacked rectangular cells, a terminal is provided on each of both longitudinal end surfaces of the plurality of rectangular cells; the first cooling pipes are provided in pairs at both ends of the first cell stack in the width direction, the second cooling pipes are provided in pairs at both ends of the second cell stack in the width direction; 10. The battery of claim 1.

3. Each of the pair of first cooling pipes and the pair of second cooling pipes is formed in a Z-shape so as to make one and a half round trips between the first end and the second end.

3. The battery of claim 2.

4. the refrigerant flows through each of the pair of first cooling pipes from an end side in a width direction of the first cell stack toward a center side thereof, In each of the pair of second cooling pipes, the refrigerant flows from an end side in the width direction of the second cell stack toward a center side.

4. The battery of claim 3.

5. a plurality of the first and second cell stacks; The battery according to any one of claims 1 to 4.

6. the first and second cell stacks are provided in equal numbers; 6. The battery of claim 5.

7. further comprising a case for accommodating the first and second cell stacks; the first and second cooling pipes are provided below the bottom plate of the case; The battery according to any one of claims 1 to 4.

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