Battery pack

Abstract

To improve the heat absorption efficiency of a heat absorption agent in a battery pack when a battery generates abnormal heat.SOLUTION: A battery pack 1 includes a plurality of batteries 50, a heat absorbing agent 71, a heat absorbing member 70 that accommodates the heat absorbing agent 71, and a holder 80 that holds the plurality of batteries 50 and the heat absorbing member 70. The holder 80 includes a holder member 90 having an opposing surface So that faces the outer surface of the heat absorbing member 70. The holder member 90 is a porous body having continuous pores Hs in which a plurality of pores H are connected, and at least one pore H1 of the plurality of pores H that constitute the continuous pores Hs is open to the opposing surface So.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack. [Background technology]

[0002] Patent Document 1 discloses, as an example of a battery pack, a battery module including a heat-absorbing member and a plurality of cells. The heat-absorbing member includes a heat-absorbing agent and an exterior film that contains the heat-absorbing agent. When the secondary battery generates abnormal heat, the exterior film tears, and the temperature of the secondary battery drops due to the leaked heat-absorbing agent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2010 / 098067 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the heat-absorbing agent that has flowed out from the exterior film may remain in one place. In this case, the contact area between the outer surface of the secondary battery and the heat-absorbing agent is relatively small, and the heat-absorbing efficiency is relatively low.

[0005] The present disclosure has been made in view of the above, and has an object to improve the heat absorption efficiency of a heat-absorbing agent in a battery pack when the battery generates abnormal heat. [Means for solving the problem]

[0006] The battery pack of the present disclosure comprises a plurality of batteries, a heat-absorbing agent, a heat-absorbing member that accommodates the heat-absorbing agent, and a holder that holds the plurality of batteries and the heat-absorbing member, wherein the holder comprises a holder member having an opposing surface that faces the outer surface of the heat-absorbing member, the holder member being a porous body having continuous pores in which a plurality of pores are connected, and at least one pore of the plurality of pores that make up the continuous pores is open to the opposing surface. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to improve the heat absorption efficiency of the heat absorbing agent in a battery pack when the battery generates abnormal heat. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an exploded perspective view of a battery pack according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an exploded perspective view of the battery unit shown in FIG. [Figure 3] FIG. 3 is a diagram showing a cross-sectional shape of the battery unit shown in FIG. 1 when cut along a plane perpendicular to the central axis of the battery. [Figure 4] FIG. 4 is a partially enlarged view of the cross-sectional shape of the battery unit shown in FIG. [Figure 5] FIG. 5 is a partially enlarged view of the cross-sectional shape of the battery unit shown in FIG. [Figure 6] FIG. 6 is a partial enlarged view of the cross-sectional shape of a battery unit in a battery pack according to a first modified example of the first embodiment of the present disclosure. [Figure 7] FIG. 7 is a partial enlarged view of the cross-sectional shape of a battery unit in a battery pack according to a second modified example of the first embodiment of the present disclosure. [Figure 8] FIG. 8 is a partial enlarged view of the cross-sectional shape of the battery unit shown in FIG. 4 in a battery pack according to a third modified example of the first embodiment of the present disclosure. [Figure 9] FIG. 9 is a partial enlarged view of the cross-sectional shape of a battery unit in a battery pack according to a second embodiment of the present disclosure. [Figure 10] FIG. 10 is a partial enlarged view of the cross-sectional shape of a battery unit in a battery pack according to a third embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram showing a cross-sectional shape of a battery unit in a battery pack according to a fourth embodiment of the present disclosure. [Figure 12]FIG. 12 is a partial enlarged view of the cross-sectional shape of a battery unit in a battery pack according to a fifth embodiment of the present disclosure. [Figure 13] FIG. 13 is a perspective view of a battery unit in a battery pack according to a sixth embodiment of the present disclosure. [Figure 14] FIG. 14 is a diagram showing a cross-sectional shape of the battery unit shown in FIG. 13 taken along a plane perpendicular to the X direction. [Figure 15] FIG. 15 is a plan view of the battery shown in FIG. [Figure 16] FIG. 16 is a perspective view of a battery unit according to a seventh embodiment of the present disclosure. [Figure 17] FIG. 17 is a diagram showing a cross-sectional shape of the battery unit shown in FIG. 16 when cut along a plane perpendicular to the X direction. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the drawings. Note that the present disclosure is not limited to these embodiments. Each embodiment is an example, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible.

[0010] The X direction shown in the drawings corresponds to the width direction of the battery pack 1, the Y direction corresponds to the depth direction of the battery pack 1, and the Z direction corresponds to the height direction of the battery pack 1. The X direction, Y direction, and Z direction are perpendicular to each other. In the X direction, the side indicated by the arrow is the +X side, and the side opposite the +X side is the -X side. In the Y direction, the side indicated by the arrow is the +Y side, and the side opposite the +Y side is the -Y side. In the Z direction, the side indicated by the arrow is the +Z side, and the side opposite the +Z side is the -Z side. Note that the X, Y, and Z directions are merely examples, and the present disclosure is not limited to these directions.

[0011] First Embodiment 1 is an exploded perspective view of a battery pack 1 according to a first embodiment of the present disclosure. The battery pack 1 can be used as a power source for external devices (not shown), such as electronic devices, electric vehicles, and power tools. The battery pack 1 includes an outer case 10, a connector 20, a control board 30, and a battery unit 40.

[0012] The exterior case 10 is box-shaped and houses the control board 30 and the battery unit 40. The exterior case 10 has a first case portion 11 and a second case portion 12.

[0013] The connector 20 is attached to the exterior case 10. The connector 20 electrically connects an external device and the battery unit 40 via the control board 30, and supplies (discharges) power from the battery unit 40 to the external device. The connector 20 also electrically connects a power source (e.g., a commercial power source) and the battery unit 40 via the control board 30, and supplies (charges) power from the power source to the battery unit 40. The control board 30 controls charging and discharging of the battery unit 40.

[0014] Fig. 2 is an exploded perspective view of the battery unit 40 shown in Fig. 1. The battery unit 40 includes a plurality of batteries 50, a plurality of lead plates 60, a plurality of heat-absorbing members 70, and a holder 80.

[0015] The batteries 50 are secondary batteries. The batteries 50 are, for example, lithium ion batteries. The batteries 50 have a cylindrical shape. In the first embodiment, the number of batteries 50 is eight, but it goes without saying that the number is not limited to eight.

[0016] The plurality of batteries 50 are arranged in parallel and spaced apart from one another. The central axes CL of the plurality of batteries 50 are parallel to one another. In the first embodiment, the central axes CL of the plurality of batteries 50 are aligned along the Y direction. The plurality of batteries 50 are also arranged so that the positive electrode terminal 51 and the negative electrode terminal 52 are oriented in predetermined directions.

[0017] The plurality of batteries 50 are arranged in two rows. Specifically, four batteries 50 are arranged along the X direction, and two batteries 50 are arranged along the Y direction. It goes without saying that the arrangement of the plurality of batteries 50 is not limited to two rows.

[0018] The lead-plates 60 electrically connect the multiple batteries 50 in series or parallel. The lead-plates 60 also electrically connect the multiple batteries 50 to the control board 30. The lead-plates 60 include a first lead-plate 61 and a second lead-plate 62. The first lead-plate 61 electrically connects two batteries 50. The second lead-plate 62 electrically connects four batteries 50. It goes without saying that the number of batteries 50 electrically connected to the first lead-plate 61 and the second lead-plate 62 is not limited to the above numbers.

[0019] FIG. 3 is a diagram showing a cross-sectional shape of the battery unit 40 shown in FIG. 1 taken along a plane perpendicular to the central axis CL of the battery 50. As shown in FIG.

[0020] 2 and 3, the heat absorption member 70 is columnar. The cross-sectional shape of the heat absorption member 70 shown in FIG. 3 is substantially rectangular. The cross-sectional shape of the heat absorption member 70 may also be rectangular. The heat absorption member 70 is disposed so as to extend along the Y direction. The heat absorption member 70 includes a heat absorption agent 71 and an exterior member 72.

[0021] The heat-absorbing agent 71 contains a substance that absorbs heat generated by the battery 50. The main component of the heat-absorbing agent 71 is a liquid such as water. The heat-absorbing agent 71 may also contain a gelling agent, a surfactant, and an antifreeze agent. The heat-absorbing agent 71 has fluidity.

[0022] The exterior member 72 houses the heat absorbing member 70. The outer surface of the exterior member 72 corresponds to the outer surface of the heat absorbing member 70. The material of the exterior member 72 is, for example, polyethylene terephthalate alone. However, the material of the exterior member 72 may also be a synthetic resin containing at least one of polyethylene terephthalate, polypropylene, polyethylene, and polystyrene.

[0023] In this embodiment, the number of heat absorbing members 70 is three. It goes without saying that the number of heat absorbing members 70 is not limited to three. The multiple heat absorbing members 70 are arranged in parallel along the X direction.

[0024] In the cross-sectional shape shown in Fig. 3, each of the multiple heat absorption members 70 is surrounded by four of the multiple batteries 50. For ease of explanation, the three heat absorption members 70 will be referred to as the first heat absorption member 70a, the second heat absorption member 70b, and the third heat absorption member 70c, in that order, from the +X side to the -X side. Note that when the first heat absorption member 70a, the second heat absorption member 70b, and the third heat absorption member 70c are described without distinction, they will be simply referred to as "heat absorption members 70."

[0025] 3, the four batteries 50 surrounding the first heat-absorbing member 70a are referred to as the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d. When the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d are described without distinction, they are simply referred to as "batteries 50."

[0026] The first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d are arranged in pairs along the X direction and in pairs along the Z direction. Specifically, of the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d, the first battery 50a is arranged furthest from the +Z side and furthest from the +X side, and the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d are arranged clockwise in this order in Figure 3, surrounding the first heat absorption member 70a. The first heat absorption member 70a is located between the first battery 50a and the third battery 50c, and between the second battery 50b and the fourth battery 50d.

[0027] In the cross-sectional shape shown in Fig. 3, the outer surface of the first heat-absorbing member 70a is in contact with the outer peripheral surface of the first battery 50a, the outer peripheral surface of the second battery 50b, the outer peripheral surface of the third battery 50c, and the outer peripheral surface of the fourth battery 50d. Specifically, the outer surface of the first heat-absorbing member 70a has a first arc-shaped surface Sc1 that is in contact with the outer peripheral surface of the first battery 50a, a second arc-shaped surface Sc2 that is in contact with the outer peripheral surface of the second battery 50b, a third arc-shaped surface Sc3 that is in contact with the outer peripheral surface of the third battery 50c, and a fourth arc-shaped surface Sc4 that is in contact with the outer peripheral surface of the fourth battery 50d. Hereinafter, when the first arc-shaped surface Sc1, the second arc-shaped surface Sc2, the third arc-shaped surface Sc3, and the fourth arc-shaped surface Sc4 are described without distinction, they will be simply referred to as "arcuate surfaces Sc." In this specification, the arc surface Sc is the surface that actually comes into contact with the outer peripheral surface of the battery 50, and the portion of the outer surface of the heat absorption member 70 that is separated from the outer peripheral surface of the battery 50 is not included in the arc surface Sc.

[0028] The outer surface of the heat absorption member 70 also has an opposed surface Sa that faces an opposing surface So, which will be described later. Specifically, the outer surface of the first heat absorption member 70a has a first opposed surface Sa1 between the first arcuate surface Sc1 and the second arcuate surface Sc2, a second opposed surface Sa2 between the second arcuate surface Sc2 and the third arcuate surface Sc3, and a third opposed surface Sa3 between the fourth arcuate surface Sc4 and the first arcuate surface Sc1. Hereinafter, when the first opposed surface Sa1, the second opposed surface Sa2, and the third opposed surface Sa3 are not to be distinguished from one another, they will be simply referred to as "opposed surfaces Sa."

[0029] The outer surfaces of the second heat absorption member 70b and the third heat absorption member 70c each have four arcuate surfaces Sc, similar to the first heat absorption member 70a. The outer surface of the second heat absorption member 70b has two opposed surfaces Sa, and the outer surface of the third heat absorption member 70c has three opposed surfaces Sa, similar to the first heat absorption member 70a. The positions and numbers of the arcuate surfaces Sc and opposed surfaces Sa on the outer surface of the heat absorption member 70 vary depending on the number and arrangement of the batteries 50 and heat absorption members 70 in the battery unit 40.

[0030] 2 and 3, the holder 80 holds a plurality of batteries 50 and a plurality of heat absorption members 70. The holder 80 includes a first holder member 90a and a second holder member 90b.

[0031] The first holder member 90a holds the -Y sides of the plurality of batteries 50 and the plurality of heat absorption members 70. The second holder member 90b holds the +Y sides of the plurality of batteries 50 and the plurality of heat absorption members 70. The first holder member 90a and the second holder member 90b have the same shape. Hereinafter, when the first holder member 90a and the second holder member 90b are described without distinction, they will be simply referred to as "holder members 90."

[0032] 3, the holder member 90 is in contact with the plurality of batteries 50 and holds the plurality of batteries 50 and the plurality of heat absorption members 70. First, the relationship between the holder member 90 and the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d will be described.

[0033] The inner surface of the holder member 90 has a first contact surface St1, a second contact surface St2, a third contact surface St3, and a fourth contact surface St4 that contact the outer surfaces of the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d. In the cross-sectional shape shown in FIG. 3, the first contact surface St1 contacts the outer peripheral surface of the first battery 50a, the second contact surface St2 contacts the outer peripheral surface of the second battery 50b, the third contact surface St3 contacts the outer peripheral surface of the third battery 50c, and the fourth contact surface St4 contacts the outer peripheral surface of the fourth battery 50d. Hereinafter, when the first contact surface St1, the second contact surface St2, the third contact surface St3, and the fourth contact surface St4 are described without distinction, they will be simply referred to as the "contact surface St." In this specification, the contact surface St is the surface that actually comes into contact with the outer peripheral surface of the battery 50, and the portion of the inner surface of the holder member 90 that is separated from the outer peripheral surface of the battery 50 is not included in the contact surface St.

[0034] The holder member 90 also has a portion that overlaps with a first imaginary line L1 that connects the central axes CL of the first battery 50a and the second battery 50b, a portion that overlaps with a second imaginary line L2 that connects the central axes CL of the second battery 50b and the third battery 50c, and a portion that overlaps with a third imaginary line L3 that connects the central axes CL of the fourth battery 50d and the first battery 50a.

[0035] Fig. 4 is a partially enlarged view of the cross-sectional shape of the battery unit 40 shown in Fig. 3. The inner surface of the holder member 90 further has an opposing surface So that faces the outer surface of the heat absorption member 70 (specifically, the opposed surface Sa). The opposing surface So is spaced apart from the outer surface of the heat absorption member 70. There are multiple opposing surfaces So.

[0036] The opposing surface So is located between any two adjacent batteries 50 among the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d in the cross-sectional shape shown in Fig. 4. In the first embodiment, the inner surface of the holder member 90 has a first opposing surface So1 located between the first battery 50a and the second battery 50b, a second opposing surface So2 located between the second battery 50b and the third battery 50c, and a third opposing surface So3 located between the fourth battery 50d and the first battery 50a in the cross-sectional shape shown in Fig. 4.

[0037] In other words, in the cross-sectional shape shown in FIG. 4, the first opposing surface So1 is located between the first contact surface St1 and the second contact surface St2. The second opposing surface So2 is located between the second contact surface St2 and the third contact surface St3. The third opposing surface So3 is located between the fourth contact surface St4 and the first contact surface St1. The first opposing surface So1 faces the first opposed surface Sa1. The second opposing surface So2 faces the second opposed surface Sa2. The third opposing surface So3 faces the third opposed surface Sa3. Hereinafter, when the first opposing surface So1, the second opposing surface So2, and the third opposing surface So3 are described without distinction, they will be simply referred to as "opposing surfaces So."

[0038] 3, the inner surface of the holder member 90 further has a contact surface St that comes into contact with batteries 50 other than the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d. The inner surface of the holder member 90 also has an opposing surface So that faces the second heat absorption member 70b and the third heat absorption member 70c. The positions and numbers of the contact surface St and the opposing surfaces So on the inner surface of the holder member 90 vary depending on the number and arrangement of the batteries 50 and heat absorption members 70 in the battery unit 40.

[0039] Fig. 5 is a partially enlarged view of the cross-sectional shape of the battery unit 40 shown in Fig. 4. For ease of explanation, the thickness of the holder member 90 is shown to be larger in Fig. 5 than in Fig. 4.

[0040] The holder member 90 is a porous body with interconnected pores. That is, the holder member 90 has interconnected pores Hs, in which a plurality of pores H are connected to one another. The material of the holder member 90 is a foamed resin, such as polyurethane or polystyrene. The material of the holder member 90 may also be ceramic or metal. The presence of a plurality of pores H gives the holder member 90 heat insulation properties.

[0041] Furthermore, the pores H and the interconnected pores Hs are present throughout the holder member 90. As shown in FIG. 5, the pores H and the interconnected pores Hs are provided in the holder member 90 so as to surround the battery 50 (the first battery 50a in FIG. 5). Note that FIG. 5 is a cross-sectional view of a predetermined location of the battery unit 40, and even pores H that are discontinuous in FIG. 5 may be interconnected with pores not shown in FIG. 5. The interconnected pores Hs are formed when two or more pores H that are adjacent to each other in the radial or circumferential direction of the battery 50 in the cross-sectional shape shown in FIG. 5 are connected to each other, or when two or more pores H that are adjacent to each other in the direction along the central axis CL of the battery 50 are connected to each other.

[0042] At least one pore H of the pores H that make up the continuous pores Hs opens to the opposing surface So1. Fig. 5 shows pores H1 and H2 that open to the first opposing surface So1 and make up the continuous pores Hs.

[0043] The holder member 90 also has a first communication passage W1 and a second communication passage W2. The first communication passage W1 and the second communication passage W2 are formed by continuous pores Hs, and are flow paths through which the heat-absorbing agent 71 can flow.

[0044] The first communication passage W1 is a flow path having a first end that opens to the opposing surface So and a second end that opens to the contact surface St. There are multiple first communication passages W1. In the first communication passage W1 shown in FIG. 5, the first end opens to the first opposing surface So1 and the second end opens to the first contact surface St1. Pores H1 that open to the first opposing surface So1 are included in the first communication passage W1. Note that pores H2 are not included in the first communication passage W1.

[0045] It goes without saying that the opposing surface So where the first end of the first communication passage W1 opens is not limited to the first opposing surface So1, and the contact surface St where the second end of the first communication passage W1 opens is not limited to the first contact surface St1. Furthermore, the first communication passage W1 branches between the first and second ends and may have a third end that opens on the same opposing surface So as the opposing surface So where the first end opens, or a fourth end that opens on a different opposing surface So from the opposing surface So where the first end opens. Furthermore, the first communication passage W1 may have a fifth end that opens on the same contact surface St as the contact surface St where the second end opens, or a sixth end that opens on a different contact surface St from the contact surface St where the second end opens.

[0046] The second communication passage W2 is a flow path in which the first end and the second end open at different positions on the same contact surface St. There are multiple second communication passages W2. In the second communication passage W2 shown in Figure 5, the first end and the second end open at different positions on the first contact surface St1.

[0047] It goes without saying that the contact surface St at which the first and second ends of the second communication passage W2 open is not limited to the first contact surface St1. Furthermore, the first and second ends of the second communication passage W2 may open at different contact surfaces St. Furthermore, the second communication passage W2 may branch between the first and second ends and have a third end that opens at the same contact surface St as the contact surface St at which the first and second ends open, or a fourth end that opens at a different contact surface St from the contact surface St at which the first and second ends open.

[0048] Furthermore, the outer surface of the holder member 90 is subjected to a sealing treatment. The sealing treatment is, for example, painting. The paint is, for example, a urethane-based or acrylic-based paint. By the sealing treatment, a paint layer is formed on the outer surface of the holder member 90. The paint layer covers the pores H that open in the outer surface of the holder member 90. In other words, the pores H do not open in the outer surface of the holder member 90.

[0049] Next, the operation of the battery pack 1 when the battery 50 generates abnormal heat will be described. Abnormal heat generation in the battery 50 occurs, for example, due to a short circuit in the battery 50 or external heating. For simplicity of explanation, the following describes the case where the first battery 50a generates abnormal heat, using FIG. 5.

[0050] When the first battery 50a generates abnormal heat, the heat insulating property of the holder member 90 prevents the heat from the first battery 50a from being transferred to batteries 50 other than the first battery 50a. This prevents the batteries 50 other than the first battery 50a from generating abnormal heat.

[0051] Furthermore, due to abnormal heat generation in the first battery 50a, the heat of the first battery 50a is transferred to the first heat absorption member 70a, which causes the temperature of the exterior member 72 of the first heat absorption member 70a to rise, causing the exterior member 72 to crack and leak the heat absorption agent 71.

[0052] When the first arc-shaped surface Sc1 is torn, the heat-absorbing agent 71 leaking from the first arc-shaped surface Sc1 comes into contact with the outer peripheral surface of the first battery 50a to absorb the heat of the first battery 50a, and flows between the first arc-shaped surface Sc1 and the outer surface of the first battery 50a to reach the first opposing surface So1 and the third opposing surface So3.

[0053] Furthermore, when the first opposed surface Sa1 is torn, it comes into contact with the outer peripheral surface of the first battery 50a, absorbs heat, and reaches the first opposed surface So1. Similarly, when the second opposed surface Sa2 and the third opposed surface Sa3 are torn, it comes into contact with the outer peripheral surface of the first battery 50a, absorbs heat, and reaches the second opposed surface So2 and the third opposed surface So3.

[0054] The heat-absorbing agent 71 that reaches the first opposing surface So1 flows into the holder member 90 through pores H1 that open to the first opposing surface So1. The heat-absorbing agent 71 spreads through the continuous pores Hs to the portion of the holder member 90 that covers the first battery 50a. Therefore, the heat-absorbing agent 71 does not remain in one place, but spreads around the first battery 50a and absorbs the heat of the first battery 50a. This improves the heat absorption efficiency of the heat-absorbing agent 71.

[0055] The heat-absorbing agent 71 that has flowed into the pores H1 flows through the first communication passages W1, leaks from the first contact surface St1 where the second end of the first communication passages W1 opens, and reaches the outer surface of the first battery 50a. That is, the heat-absorbing agent 71 reaches a portion of the outer surface of the first battery 50a that is away from the portion that contacts the first heat-absorbing member 70a, and absorbs heat from the first battery 50a. This further improves the heat-absorbing efficiency of the heat-absorbing agent 71.

[0056] Furthermore, the heat-absorbing agent 71 that reaches the outer surface of the first battery 50a via the first communication passage W1 reaches the first end of the second communication passage W2 that opens at the first contact surface St1. The heat-absorbing agent 71 then leaks out through the second end of the second communication passage W2 that opens at the first contact surface St1. At the first contact surface St1, the second end of the second communication passage W2 is spaced apart from the second end of the first communication passage W1. Therefore, the heat-absorbing agent 71 reaches a relatively wide area on the outer surface of the first battery 50a and absorbs heat from the first battery 50a. This further improves the heat absorption efficiency of the heat-absorbing agent 71.

[0057] The heat-absorbing agent 71 that has reached the second opposing surface So2 and the third opposing surface So3 also absorbs heat from the first battery 50a, similar to the heat-absorbing agent 71 that has reached the first opposing surface So1. Furthermore, even when a battery 50 other than the first battery 50a generates abnormal heat, the heat of the battery 50 is absorbed by the heat-absorbing agent 71 leaking from the heat-absorbing member 70, similar to the case where the first battery 50a generates abnormal heat. Therefore, the heat absorption efficiency of the heat-absorbing agent 71 in the battery pack 1 can be improved when a battery 50 generates abnormal heat.

[0058] <Modification of the first embodiment> Next, a battery pack 1 according to a modified example of the first embodiment of the present disclosure will be described, focusing mainly on the parts that differ from the first embodiment described above.

[0059] Figure 6 is a partially enlarged view of the cross-sectional shape of the battery unit 40 in the battery pack 1 according to a first modification of the first embodiment of the present disclosure. The cross-sectional shape of the battery unit 40 shown in Figure 6 is the cross-sectional shape when cut along a plane perpendicular to the central axis CL of the battery 50. The battery unit 40 of this first modification has a different shape of the holder member 190 from the battery unit 40 of the above-described first embodiment.

[0060] The holder member 190 of this first modified example does not have a portion that overlaps with the first imaginary line L1 that connects the central axes CL of the first battery 50a and the second battery 50b in the cross-sectional shape shown in Fig. 6. In other words, the holder member 190 is located at a position that is off the first imaginary line L1 in the cross-sectional shape shown in Fig. 6.

[0061] In the first modified example, when the first battery 50a generates abnormal heat, the heat-absorbing agent 71 leaking from the first opposed surface Sa1 reaches the point where the distance between the outer peripheral surface of the first battery 50a and the outer peripheral surface of the second battery 50b is shortest (the point where the distance overlaps with the first imaginary line L1 in the space surrounded by the heat-absorbing member 70, the first battery 50a, the second battery 50b, and the holder member 190 shown in FIG. 6) earlier than when the holder member 90 has a portion that overlaps with the first imaginary line L1. The heat-absorbing agent 71 then fills the space between the first battery 50a and the second battery 50b. The point where the distance between the outer peripheral surface of the first battery 50a and the outer peripheral surface of the second battery 50b is shortest is where heat is most easily transferred between the batteries 50a and 50b. Therefore, by allowing the heat-absorbing agent 71 to quickly reach and fill the location where the distance between the outer circumferential surface of the first battery 50a and the outer circumferential surface of the second battery 50b is shortest, it is possible to further suppress the transfer of heat from the first battery 50a to the second battery 50b. Also, since the holder member 190 is positioned away from the first imaginary line L1, part of the outer surface of the first battery 50a is exposed from the holder member 190 (see FIG. 6). This allows the heat-absorbing agent 71 to quickly transfer to the outer surface of the first battery 50a and quickly absorb the heat of the first battery 50a.

[0062] Furthermore, the heat-absorbing agent 71 leaking from the first opposed surface Sa1 quickly reaches the first opposed surface So1 and quickly spreads throughout the holder member 190 via the continuous pores Hs, absorbing the heat of the first battery 50a in the same manner as in the first embodiment. Therefore, the heat-absorbing agent 71 quickly absorbs the heat of the first battery 50a. This further improves the heat absorption efficiency of the heat-absorbing agent 71.

[0063] Furthermore, even if the holder member 190 does not have a portion that overlaps with the imaginary line connecting the central axes CL of two of the multiple batteries 50, the heat absorption efficiency of the heat absorption agent 71 can be further improved, just as in the case where the holder member 190 has a portion that overlaps with the above-mentioned first imaginary line L1.

[0064] 7 is a partially enlarged view of the cross-sectional shape of the battery unit 40 in the battery pack 1 according to the second modified example of the first embodiment of the present disclosure. The cross-sectional shape of the battery unit 40 shown in FIG. 7 is the cross-sectional shape when cut along a plane perpendicular to the central axis CL of the battery 50.

[0065] 7, the battery unit 40 of the second modified example differs from the first embodiment in that the opposing surface So of the holder member 290 contacts the outer surface of the heat absorption member 70. Specifically, the opposing surface So contacts the opposed surface Sa.

[0066] As a result, the heat-absorbing agent 71 leaking from the first opposed surface Sa1 quickly reaches the first opposed surface So1 and quickly spreads throughout the holder member 290 via the continuous pores Hs, absorbing the heat of the first battery 50a in the same manner as in the first embodiment. Therefore, the heat-absorbing agent 71 quickly absorbs the heat of the first battery 50a. This further improves the heat-absorbing efficiency of the heat-absorbing agent 71.

[0067] Fig. 8 is a partially enlarged view of the cross-sectional shape of the battery unit 40 shown in Fig. 4 in the battery pack 1 according to the third modified example of the first embodiment of the present disclosure. For ease of explanation, Fig. 8 illustrates the thickness of the holder member 90 to be larger than that in Fig. 4.

[0068] In this third modified example, the holder member 90 does not have a first communication passage W1 or a second communication passage W2. Meanwhile, in this third modified example, like the holder member 90 of the first embodiment, the pores H and the continuous pores Hs are present throughout the holder member 90. The pores H2 that open to the first opposing surface So1 shown in FIG. 8 constitute continuous pores Hs, but do not constitute the first communication passage W1. In other words, even if one traces the continuous pores Hs from the pore H2, one does not reach the outer surface of the battery 50. Furthermore, in this third modified example, since there are no pores H that constitute the second communication passage W2, even if one traces the pores H that open to the contact surface St that contacts the outer surface of the battery 50, one does not reach other pores H that open to the contact surface St. In the third modified example, when the battery 50 generates abnormal heat, the heat-absorbing agent 71 leaks from the heat-absorbing member 70 and reaches the opposing surface So. The heat-absorbing agent 71 flows into the holder member 90 through the pores H2 that open to the opposing surface So, and spreads through the continuous pores Hs to the portion of the holder member 90 that covers the battery 50. Therefore, the heat-absorbing agent 71 does not remain in one place, but spreads around the battery 50 and absorbs the heat of the battery 50. In this way, in the third modified example, the heat-absorbing agent 71 absorbs the heat of the battery 50 by spreading around the battery 50, even if it does not reach the outer surface of the battery 50. Therefore, the heat-absorbing efficiency of the heat-absorbing agent 71 can be improved.

[0069] Second Embodiment Next, a battery pack 1 according to a second embodiment of the present disclosure will be described, focusing mainly on the differences from the first embodiment described above.

[0070] 9 is a partially enlarged view of the cross-sectional shape of the battery unit 40 in the battery pack 1 according to the second embodiment of the present disclosure. The cross-sectional shape of the battery unit 40 shown in FIG. 9 is the cross-sectional shape when cut along a plane perpendicular to the central axis CL of the battery 50.

[0071] 9, the battery unit 40 of the second embodiment differs from the first embodiment in that the inner surface of the holder member 390 is in contact with the outer periphery of the plurality of batteries 50, including the first battery 50a, the second battery 50b, the third battery 50c, and the fourth battery 50d, and with the outer periphery of the plurality of heat absorption members 70. The thickness of the holder member 390 is also substantially constant.

[0072] Specifically, the battery 50 and the heat absorption member 70 are not in contact with each other, and the holder member 390 is also located between the battery 50 and the heat absorption member 70. The contact surface St is in contact with the outer periphery of the battery 50 over the entire circumference. That is, the first contact surface St1 is in contact with the outer periphery of the first battery 50a over the entire circumference. The second contact surface St2 is in contact with the outer periphery of the second battery 50b over the entire circumference. The third contact surface St3 is in contact with the outer periphery of the third battery 50c over the entire circumference. The fourth contact surface St4 is in contact with the outer periphery of the fourth battery 50d over the entire circumference.

[0073] 9, the opposing surface So is in contact with the entire outer circumferential surface of the heat absorption member 70. In the cross-sectional shape shown in FIG. 9, the outer circumferential surface of the heat absorption member 70 in contact with the opposing surface So corresponds to the opposed surface Sa.

[0074] As a result, the heat-absorbing agent 71 leaking from the outer surface of the heat-absorbing member 70 quickly reaches the opposing surface So and spreads throughout the holder member 390 via the continuous pores Hs, absorbing the heat of the battery 50 in the same manner as in the first embodiment. Therefore, the heat-absorbing agent 71 quickly absorbs the heat of the battery 50. This further improves the heat absorption efficiency of the heat-absorbing agent 71.

[0075] Furthermore, the holder member 90 holds the plurality of batteries 50 by contacting the entire outer periphery of the batteries 50. Therefore, when one battery 50 generates abnormal heat, the heat can be further prevented from being transferred to the other batteries 50.

[0076] Furthermore, in the second embodiment, the holder member 90 individually holds the plurality of batteries 50 and the plurality of heat absorption members 70. This improves the rigidity of the holder 80. This improves the vibration resistance and impact resistance of the battery unit 40.

[0077] <Third embodiment> Next, a battery pack 1 according to a third embodiment of the present disclosure will be described, focusing mainly on the differences from the first embodiment described above.

[0078] 10 is a partially enlarged view of the cross-sectional shape of the battery unit 40 in the battery pack 1 according to the third embodiment of the present disclosure. The cross-sectional shape of the battery unit 40 shown in FIG. 10 is the cross-sectional shape when cut along a plane perpendicular to the central axis CL of the battery 50.

[0079] In the battery unit 40 of the third embodiment, the holder 80 further includes an outer layer 491 disposed on the outer surface of the holder member 90. Note that the outer surface of the holder member 90 of the third embodiment is not subjected to a pore-sealing treatment.

[0080] The outer layer 491 covers the pores H that open to the outer surface of the holder member 90, and has a rigidity higher than that of the holder member 90. The material of the outer layer 491 is a thermoplastic resin, such as polyurethane, polystyrene, polycarbonate, and polyamide. The material of the outer layer 491 may also be ceramic or metal.

[0081] This reliably improves the rigidity of the holder 80, thereby reliably improving the vibration resistance and impact resistance of the battery unit 40. Furthermore, because rigidity can be ensured even when the holder member 90 is thin, the battery unit 40 can be made smaller and lighter.

[0082] <Fourth embodiment> Next, a battery pack 1 according to a fourth embodiment of the present disclosure will be described, focusing mainly on the differences from the first embodiment described above.

[0083] 11 is a diagram showing a cross-sectional shape of a battery unit 540 in a battery pack 1 according to a fourth embodiment of the present disclosure. The cross-sectional shape of the battery unit 540 shown in FIG. 11 is a cross-sectional shape when cut along a plane perpendicular to the central axis CL of the battery 50.

[0084] The battery unit 540 of the fourth embodiment differs from the first embodiment in that the plurality of batteries 50 are arranged in a row along a direction perpendicular to the central axis CL (specifically, the X direction). In the fourth embodiment, the plurality of batteries 50 are referred to as a first battery 50a, a second battery 50b, a third battery 50c, and a fourth battery 50d, in order from the +X side to the -X side. The shapes of the holder 580 (holder member 590) and the heat-absorbing member 570 also differ from those of the first embodiment. The heat-absorbing member 570 includes a heat-absorbing agent 571 and an exterior member 572.

[0085] 11, the first contact surface St1 contacts the outer peripheral surface of the first battery 50a over the entire circumference, the second contact surface St2 contacts the outer peripheral surface of the second battery 50b over the entire circumference, the third contact surface St3 contacts the outer peripheral surface of the third battery 50c over the entire circumference, and the fourth contact surface St4 contacts the outer peripheral surface of the fourth battery 50d over the entire circumference. The thickness of the holder member 590 is also substantially constant.

[0086] Additionally, the heat absorption member 570 is on the -Z side of the multiple batteries 50. When the battery unit 540 is viewed from the +Z side along the Z direction, the first heat absorption member 570a overlaps with the first battery 50a and the second battery 50b, the second heat absorption member 570b overlaps with the second battery 50b and the third battery 50c, and the third heat absorption member 570c overlaps with the third battery 50c and the fourth battery 50d.

[0087] In the cross-sectional shape shown in FIG. 11, the outer surface on the +Z side of the first heat absorption member 570a has a first curved surface Sb1 that contacts the outer surface of the holder member 590. When the battery unit 540 is viewed from the +Z side along the Z direction, the first curved surface Sb1 overlaps with the first battery 50a and the second battery 50b. The portion of the outer surface of the holder member 590 that contacts the first curved surface Sb1 corresponds to the opposing surface So. The opposing surface So that contacts the first curved surface Sb1 is on the opposite side of the holder member 590 from the first contact surface St1 and the second contact surface St2. The outer surface on the -Z side of the first heat absorption member 570a is a plane that is perpendicular to the Z direction.

[0088] 11, the outer surface on the +Z side of the second heat absorption member 570b has a second curved surface Sb2 that contacts the outer surface of the holder member 590. When the battery unit 540 is viewed along the Z direction from the +Z side, the second curved surface Sb2 overlaps with the second battery 50b and the third battery 50c. The portion of the outer surface of the holder member 590 that contacts the second curved surface Sb2 corresponds to the facing surface So. The facing surface So that contacts the second curved surface Sb2 is on the opposite side of the holder member 590 from the second contact surface St2 and the third contact surface St3. The outer surface on the -Z side of the second heat absorption member 570b is a plane that is perpendicular to the Z direction.

[0089] 11, the outer surface on the +Z side of the third heat absorption member 570c has a third curved surface Sb3 that contacts the outer surface of the holder member 590. When the battery unit 540 is viewed along the Z direction from the +Z side, the third curved surface Sb3 overlaps with the third battery 50c and the fourth battery 50d. The portion of the outer surface of the holder member 590 that contacts the third curved surface Sb3 corresponds to the facing surface So. The facing surface So that contacts the third curved surface Sb3 is on the opposite side of the holder member 590 from the third contact surface St3 and the fourth contact surface St4. The outer surface on the -Z side of the third heat absorption member 570c is a plane that is perpendicular to the Z direction.

[0090] In the battery unit 540 of the fourth embodiment, the heat-absorbing agent 571 leaking from the first curved surface Sb1, the second curved surface Sb2, and the third curved surface Sb3 quickly reaches the opposing surface So and quickly spreads throughout the holder member 590 via the continuous pores Hs, absorbing the heat of the batteries 50 in the same manner as in the first embodiment. Therefore, the heat-absorbing agent 571 quickly absorbs the heat of the batteries 50. This further improves the heat absorption efficiency of the heat-absorbing agent 571.

[0091] Fifth Embodiment Next, the battery pack 1 according to the fifth embodiment of the present disclosure will be described, mainly focusing on the differences from the first embodiment described above.

[0092] 12 is a partially enlarged view of the cross-sectional shape of the battery unit 40 in the battery pack 1 according to the fifth embodiment of the present disclosure. The cross-sectional shape of the battery unit 40 shown in FIG. 12 is the cross-sectional shape when cut along a plane perpendicular to the central axis CL of the battery 50.

[0093] The battery unit 40 of the fifth embodiment differs from the first embodiment in that, in the cross-sectional shape shown in Fig. 12, four batteries 50 surround two heat-absorbing members 670. The two heat-absorbing members 670 are aligned in contact with each other along the Z direction.

[0094] Furthermore, in the heat-absorbing member 670 of the fifth embodiment, the shape of the exterior member 672 that houses the heat-absorbing agent 671 differs from that of the exterior member 72 of the first embodiment. Specifically, the outer surface of the exterior member 672 (i.e., the outer surface of the heat-absorbing member 670) has a first surface S1, a second surface S2, and a third surface S3. The first surface S1 and the second surface S2 are curved surfaces. The third surface S3 is flat. The outer surface of the exterior member 672 has a substantially triangular shape in cross section as shown in FIG. 12.

[0095] Of the two heat absorption members 670, the heat absorption member 670 on the +Z side contacts the outer peripheral surface of the first battery 50a on a first surface S1 and contacts the outer peripheral surface of the fourth battery 50d on a second surface S2. Furthermore, of the two heat absorption members 670, the heat absorption member 670 on the -Z side contacts the outer peripheral surface of the second battery 50b on a second surface S2 and contacts the outer peripheral surface of the third battery 50c on a first surface S1. In other words, the first surface S1 and the second surface S2 correspond to the arc surface Sc. Furthermore, the two heat absorption members 670 contact each other on their third surfaces S3.

[0096] In the heat-absorbing member 670 of the fifth embodiment, the heat-absorbing agent 671 leaking from the opposed surface Sa absorbs heat from the battery 50, similar to the first embodiment. Therefore, the heat-absorbing efficiency of the heat-absorbing agent 671 can be improved.

[0097] Sixth Embodiment Next, a battery pack 1 according to a sixth embodiment of the present disclosure will be described, mainly focusing on the differences from the first embodiment described above.

[0098] Fig. 13 is a perspective view of a battery unit 740 in a battery pack 1 according to a sixth embodiment of the present disclosure. Fig. 14 is a diagram showing a cross-sectional shape of the battery unit 740 shown in Fig. 13 taken along a plane perpendicular to the X direction.

[0099] The battery unit 740 of the sixth embodiment differs from the first embodiment mainly in the type of batteries 750, the shape of the heat absorption members 770, and the shape of the holder 780. The battery unit 740 of the sixth embodiment includes a plurality of batteries 750, a plurality of heat absorption members 770, and a holder 780. In the sixth embodiment, the number of batteries 750 is five, and the number of heat absorption members 770 is five. It goes without saying that the number of batteries 750 and the number of heat absorption members 770 are not limited to the above numbers.

[0100] Fig. 15 is a plan view of the battery 750 shown in Fig. 14. The battery 750 has a rectangular shape in plan view. The battery 750 includes a positive terminal 751, a negative terminal 752, a laminate 753, and an exterior body 754 that houses the laminate 753.

[0101] The laminate 753 has a plurality of sheet-like positive electrodes (not shown) and negative electrodes (not shown), which are alternately laminated with separators (not shown) interposed therebetween.

[0102] Positive electrode terminal 751 is electrically connected to a plurality of positive electrodes. A portion of positive electrode terminal 751 is located outside exterior body 754. Negative electrode terminal 752 is electrically connected to a plurality of negative electrodes. A portion of negative electrode terminal 752 is located outside exterior body 754.

[0103] Exterior body 754 is formed by folding a single film. Exterior body 754 integrally includes a storage portion 754a and a flange portion 754b. Storage portion 754a stores laminate 753 and an electrolyte (e.g., a non-aqueous electrolyte solution). Storage portion 754a is a substantially rectangular parallelepiped. Flange portion 754b is located around storage portion 754a.

[0104] 14 has a substantially rectangular parallelepiped shape. The heat absorbing member 770 includes a heat absorbing agent 771 and an exterior member 772.

[0105] 13 and 14 includes one holder member 790. The outer shape of the holder member 790 is a rectangular parallelepiped. The holder member 790 has five spaces R inside that are aligned along the Z direction. The spaces R are spaces that are open on the -Y side.

[0106] Each of the five spaces R accommodates one battery 750 and one heat absorption member 770, with the first battery surface Se1 of the battery 750 in contact with the first heat absorption surface Sh1 of the heat absorption member 770. The first battery surface Se1 is the +Z side surface of the outer surface of the battery 650 accommodated in the space R, and corresponds to part of the outer surface of the accommodation section 754a. The first heat absorption surface Sh1 is the -Z side surface of the outer surface of the heat absorption member 770 accommodated in the space R.

[0107] The flange portion 754b is bent in the space R. An inner surface 791a of the holder member 790 on the -Z side of the space R contacts the second battery surface Se2 of the battery 750. The second battery surface Se2 is the surface opposite to the first battery surface Se1 on the outer surface of the battery 650 housed in the space R. The inner surface 791a of the holder member 790 on the -Z side of the space R corresponds to the contact surface St.

[0108] Additionally, the inner surface 791b of the holder member 790 on the +Z side of the space R comes into contact with the second heat absorption surface Sh2 of the heat absorption member 770. The second heat absorption surface Sh2 is the +Z side surface of the outer surface of the heat absorption member 770 housed in the space R, and is the surface opposite to the first heat absorption surface Sh1.

[0109] Additionally, an inner surface 791c of the holder member 790 on the +Y side of the space R comes into contact with the third heat absorption surface Sh3 of the heat absorption member 770. The third heat absorption surface Sh3 is the +Y side surface of the outer surface of the heat absorption member 770 housed in the space R, and is the surface that connects the first heat absorption surface Sh1 and the second heat absorption surface Sh2. The inner surface 791b of the holder member 790 on the +Z side of the space R and the inner surface 791c of the holder member 790 on the +Y side of the space R correspond to the opposing surface So that faces the heat absorption member 770.

[0110] Note that one of the inner surface 791b of the holder member 790 on the +Z side of the space R and the inner surface 791c of the holder member 790 on the +Y side of the space R may be in contact with one heat absorption member 770. The space R may also be a space that is open on both sides in the Y direction. In this case, the holder member 790 does not have an inner surface 791c on the +Y side of the space R.

[0111] In the battery pack 1 of the sixth embodiment, the heat-absorbing agent 771 leaking from the heat-absorbing member 770 reaches the opposing surface So, spreads throughout the holder member 790 via the continuous pores Hs, and absorbs the heat of the battery 750, similar to the first embodiment. Therefore, the heat-absorbing efficiency of the heat-absorbing agent 771 can be improved.

[0112] Seventh Embodiment Next, a battery pack 1 according to a seventh embodiment of the present disclosure will be described, mainly focusing on the differences from the sixth embodiment described above.

[0113] Fig. 16 is a perspective view of a battery unit 740 according to a seventh embodiment of the present disclosure. Fig. 17 is a diagram showing a cross-sectional shape of the battery unit 840 shown in Fig. 16 taken along a plane perpendicular to the X direction.

[0114] The battery unit 840 of the seventh embodiment differs from the sixth embodiment mainly in the number and arrangement of the heat absorption members 870 and the shape of the holder 880. The battery unit 840 of the seventh embodiment includes a plurality of batteries 750, one heat absorption member 870, and a holder 880. In the seventh embodiment, the number of batteries 750 is five. It goes without saying that the number of batteries 750 and the number of heat absorption members 870 are not limited to the above numbers.

[0115] The holder member 890 has five spaces R arranged inside along the Z direction. The spaces R are spaces that are open on both sides in the Y direction. The space R closest to the +Z side is also open on the +Z side.

[0116] Each of the five spaces R houses one battery 750. Specifically, the inner surface 891a of the holder member 890 on the -Z side of the space R contacts the second battery surface Se2 of the battery 750. In other words, the inner surface 891a of the holder member 890 on the -Z side of the space R corresponds to the contact surface St.

[0117] The heat absorption member 870 includes a heat absorption agent 871 and an exterior member 872. The shape of the heat absorption member 870 is a substantially rectangular parallelepiped. The heat absorption member 870 is disposed on a predetermined surface Sd on the +Y side of the outer surface of the holder member 890. A fourth heat absorption surface Sh4 on the -Y side of the outer surface of the heat absorption member 870 contacts the entire predetermined surface Sd. In other words, the predetermined surface Sd corresponds to the opposing surface So that faces the outer surface of the heat absorption member 870. The five spaces R open on the predetermined surface Sd. Therefore, the heat absorption member 870 faces each of the multiple batteries 750. The heat absorption member 870 and the multiple batteries 750 are separated from each other. The predetermined surface Sd is not subjected to a sealing treatment. In other words, pores H are open on the predetermined surface Sd.

[0118] In the battery pack 1 of the seventh embodiment, the heat-absorbing agent 871 leaking from the heat-absorbing member 870 reaches the opposing surface So, spreads throughout the holder member 890 via the continuous pores Hs, and absorbs the heat of the battery 750, similar to the sixth embodiment. Therefore, the heat-absorbing efficiency of the heat-absorbing agent 871 can be improved.

[0119] The heat-absorbing member 870 may be in contact with the plurality of batteries 750. In this case, when the batteries 750 generate abnormal heat, the heat from the batteries 750 is easily transferred to the heat-absorbing member 870, causing the heat-absorbing member 870 to split open quickly. This allows the heat from the batteries 750 to be absorbed quickly.

[0120] The above-described embodiments and modifications are intended to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. The present disclosure may be modified or improved without departing from the spirit thereof, and equivalents thereof are also included in the present disclosure.

[0121] <Configuration Example of the Present Disclosure> The present disclosure may also be implemented as a combination of the following configurations.

[0122] (1) Multiple batteries and An endothermic agent; a heat absorbing member that accommodates the heat absorbing agent; a holder that holds the plurality of batteries and the heat absorption member, the holder includes a holder member having an opposing surface facing an outer surface of the heat absorption member, the holder member is a porous body having continuous pores in which a plurality of pores are connected to one another, At least one pore among the plurality of pores constituting the continuous pores is open on the opposing surface. Battery pack.

[0123] (2) The holder member is a contact surface that comes into contact with an outer surface of one of the plurality of batteries; a first communication passage formed by the continuous pores, the first end of which opens into the opposing surface and the second end of which opens into the contact surface; The battery pack described in (1).

[0124] (3) The holder member is the first end and the second end open at different positions on the contact surface, and a second communication passage formed by the continuous pores. A battery pack according to (1) or (2).

[0125] (4) the plurality of batteries include a first battery, a second battery, a third battery, and a fourth battery, each of which has a cylindrical shape and has a central axis that is parallel to one another; In a cross-sectional shape when cut along a plane perpendicular to the central axis, the first battery, the second battery, the third battery, and the fourth battery surround the heat absorption member; the holder member further has a first contact surface in contact with an outer peripheral surface of the first battery, a second contact surface in contact with an outer peripheral surface of the second battery, a third contact surface in contact with an outer peripheral surface of the third battery, and a fourth contact surface in contact with the fourth battery; the opposing surface is located between two adjacent batteries among the first battery, the second battery, the third battery, and the fourth battery; A battery pack according to any one of (1) to (3).

[0126] (5) the outer surface of the heat absorption member is in contact with the outer peripheral surface of the first battery, the outer peripheral surface of the second battery, the outer peripheral surface of the third battery, and the outer peripheral surface of the fourth battery, (4) The battery pack described in (4).

[0127] (6) In the cross-sectional shape, the first contact surface contacts the outer peripheral surface of the first battery over the entire periphery; the second contact surface contacts the outer circumferential surface of the second battery over the entire periphery; the third contact surface contacts the outer peripheral surface of the third battery over the entire periphery; the fourth contact surface contacts the outer peripheral surface of the fourth battery over the entire periphery; the opposing surface is in contact with the outer circumferential surface of the heat absorbing member over the entire periphery; (4) The battery pack described in (4).

[0128] (7) the outer surface of the heat absorption member has a first surface, a second surface, and a third surface; In the cross-sectional shape, the first battery, the second battery, the third battery, and the fourth battery surround two of the heat absorption members; one of the two heat absorption members contacts the outer peripheral surface of the fourth battery at the first surface and contacts the outer peripheral surface of the first battery at the second surface; the other of the two heat absorption members is in contact with the outer peripheral surface of the second battery at the first surface and in contact with the outer peripheral surface of the third battery at the second surface; the third surfaces of the two heat absorption members are in contact with each other; (4) The battery pack described in (4).

[0129] (8) The material of the holder member is a foamed resin. A battery pack according to any one of (1) to (7).

[0130] (9) the holder further comprises an outer layer disposed on an outer surface of the holder member; the outer layer covers pores that open to the outer surface of the holder member among the plurality of pores, and has rigidity higher than rigidity of the holder member. A battery pack according to any one of (1) to (8).

[0131] (10) The facing surface is in contact with the outer surface of the heat absorption member. A battery pack according to any one of (1) to (9).

[0132] (11) the plurality of batteries are each cylindrical, arranged in a row along a direction perpendicular to a central axis of the battery, and include a first battery and a second battery adjacent to each other; In a cross-sectional shape when cut along a plane perpendicular to the central axis, the holder member has a first contact surface that contacts the outer peripheral surface of the first battery over the entire periphery, and a second contact surface that contacts the outer peripheral surface of the second battery over the entire periphery; the opposing surface is located opposite the first contact surface and the second contact surface and is in contact with the outer surface of the heat absorption member; A battery pack according to any one of (1) to (3).

[0133] (12) A plurality of the heat absorption members are provided, each of the outer surfaces of the plurality of batteries has a first battery surface; Each of the outer surfaces of the heat absorption members has a first heat absorption surface and a second heat absorption surface opposite to the first heat absorption surface; The holder member has a plurality of spaces therein, one battery among the plurality of batteries and one heat absorption member among the plurality of heat absorption members are accommodated in the space portion in a state where the first battery surface of the one battery and the first heat absorption surface of the one heat absorption member are in contact with each other; the opposing surface is in contact with the second heat absorption surface of the one heat absorption member; A battery pack according to any one of (1) to (3).

[0134] (13) The holder member has a plurality of spaces therein, One battery among the plurality of batteries is accommodated in the space portion, the space portion opens to a predetermined surface of the outer surface of the holder member, the heat absorption member is disposed on the predetermined surface and faces the one battery; A battery pack according to any one of (1) to (3). [Explanation of symbols]

[0135] 1 battery pack 50 batteries 50a First Battery 50b Second Battery 50c Third Battery 50d 4th battery 70 Heat absorption member 71 Endothermic agent 80 Holder 90 Holder member 491 Outer layer CL center axis H stomata Hs continuous pores R space part S1 1st page S2 side 2 S3 3rd page Sd specified surface Se1 1st battery side Sh1 1st endothermic surface Sh2 2nd endothermic surface So opposing surface St contact surface St1 1st contact surface St2 Second contact surface St3 3rd contact surface St4 4th contact surface W1 1st communication path W2 2nd connecting road

Claims

1. A number of batteries; A heat absorbing agent; a heat absorbing member that accommodates the heat absorbing agent; a holder for holding the plurality of batteries and the heat absorbing member, the holder includes a holder member having a facing surface facing an outer surface of the heat absorbing member, the holder member is a porous body having continuous pores in which a plurality of pores are connected to each other, At least one pore among the plurality of pores constituting the continuous pores is opened on the opposing surface. Battery pack.

2. The holder member includes: a contact surface that comes into contact with an outer surface of one of the plurality of batteries; a first communication passage having a first end opening at the opposing surface and a second end opening at the contact surface, the first communication passage being formed by the continuous pores. The battery pack according to claim 1 .

3. The holder member includes: the first end and the second end open at different positions on the contact surface, and a second communication passage is formed by the continuous pore. The battery pack according to claim 2 .

4. the plurality of batteries include a first battery, a second battery, a third battery, and a fourth battery each having a cylindrical shape and having central axes parallel to each other; In a cross-sectional shape when cut along a plane perpendicular to the central axis, the first battery, the second battery, the third battery, and the fourth battery surround the heat absorption member; the holder member further has a first contact surface in contact with an outer circumferential surface of the first battery, a second contact surface in contact with an outer circumferential surface of the second battery, a third contact surface in contact with an outer circumferential surface of the third battery, and a fourth contact surface in contact with the fourth battery; the opposing surface is between two adjacent batteries among the first battery, the second battery, the third battery, and the fourth battery; The battery pack according to claim 1 .

5. an outer surface of the heat absorption member contacts an outer peripheral surface of the first battery, an outer peripheral surface of the second battery, an outer peripheral surface of the third battery, and an outer peripheral surface of the fourth battery; The battery pack according to claim 4.

6. In the cross-sectional shape, the first contact surface is in contact with an outer circumferential surface of the first battery over the entire periphery; the second contact surface is in contact with an outer circumferential surface of the second battery over the entire periphery; the third contact surface is in contact with an outer circumferential surface of the third battery over the entire periphery; the fourth contact surface contacts an outer circumferential surface of the fourth battery over an entire periphery; The facing surface is in contact with the outer circumferential surface of the heat absorbing member over the entire circumference. The battery pack according to claim 4.

7. the outer surface of the heat absorbing member has a first surface, a second surface, and a third surface; In the cross-sectional shape, the first battery, the second battery, the third battery, and the fourth battery surround two of the heat absorption members; One of the two heat absorption members contacts an outer peripheral surface of the fourth battery at the first surface and contacts an outer peripheral surface of the first battery at the second surface, the other of the two heat absorption members is in contact with an outer peripheral surface of the second battery at the first surface and in contact with an outer peripheral surface of the third battery at the second surface; The third surfaces of the two heat absorption members are in contact with each other. The battery pack according to claim 4.

8. The material of the holder member is a foamed resin. The battery pack according to claim 1 .

9. the holder further comprises an outer layer disposed on an outer surface of the holder member; the outer layer covers pores that open to an outer surface of the holder member among the plurality of pores and has a rigidity higher than a rigidity of the holder member. The battery pack according to claim 1 .

10. The facing surface is in contact with an outer surface of the heat absorbing member. The battery pack according to claim 1 .

11. The plurality of batteries each have a cylindrical shape, are arranged in a row along a direction perpendicular to a central axis of the battery, and include a first battery and a second battery adjacent to each other, In a cross-sectional shape when cut along a plane perpendicular to the central axis, the holder member has a first contact surface that contacts an outer circumferential surface of the first battery over an entire periphery, and a second contact surface that contacts an outer circumferential surface of the second battery over an entire periphery, the facing surface is located opposite the first contact surface and the second contact surface and is in contact with an outer surface of the heat absorbing member; The battery pack according to claim 1 .

12. A plurality of the heat absorbing members are provided, each of the outer surfaces of the plurality of batteries has a first battery surface; Each of the outer surfaces of the heat absorption members has a first heat absorption surface and a second heat absorption surface opposite to the first heat absorption surface; The holder member has a plurality of spaces therein, one battery of the plurality of batteries and one heat absorption member of the plurality of heat absorption members are accommodated in the space portion in a state in which the first battery surface of the one battery and the first heat absorption surface of the one heat absorption member are in contact with each other; The facing surface is in contact with the second heat absorbing surface of the one heat absorbing member. The battery pack according to claim 1 .

13. The holder member has a plurality of spaces therein, One battery among the plurality of batteries is accommodated in the space portion, The space portion opens to a predetermined surface of the outer surface of the holder member, the heat absorbing member is disposed on the predetermined surface and faces the one battery; The battery pack according to claim 1 .

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