Battery pack

Abstract

This battery pack (1) has a plurality of batteries (30) accommodated in a case (10). The plurality of batteries (30) have safety valves (37), which are opened by an increase in internal pressure and through which an internal gas is discharged, and are immersed in a cooling liquid (50) in the case (10). The case (10) includes: a case body (14) in which the plurality of batteries are accommodated; and a protruding part (12) that protrudes from a portion in the vertical direction of a terminal protruding side surface in the lateral direction of the case body (14) and has an exhaust hole (13) in the upper surface of same. A pack safety valve (82) is provided at a position above the protruding part (12) and covering the exhaust hole (13). The upper end of the pack safety valve (82) is disposed at a position lower than the uppermost end of the case (10).

Description

Battery pack

[0001] The present disclosure relates to a battery pack in which a plurality of batteries are housed in a case.

[0002] Secondary batteries such as lithium-ion batteries are used in the form of a battery pack in which a plurality of batteries are electrically connected and housed in a case. Patent Document 1 discloses a battery pack in which a plurality of batteries are housed in a space filled with a coolant having insulating properties and the plurality of batteries are cooled.

[0003] Japanese Unexamined Patent Application Publication No. 2014-60088

[0004] By the way, when there is an abnormality in the battery in the battery pack, heat generation occurs inside the battery, and the surface of the outer package of the battery becomes high temperature. And when the abnormality further progresses, eventually high-temperature gas is generated from inside the battery. In the battery pack disclosed in Patent Document 1, it is conceivable to provide a battery safety valve for the battery that opens when the internal pressure rises. In this case, an exhaust hole for exhausting the gas exhausted from the battery safety valve is provided on the side surface of the case of the battery pack, and a pack safety valve for exhausting when the internal pressure of the gas in the case rises to a predetermined value or more is provided at a position covering the exhaust hole.

[0005] However, in the configuration in which the pack safety valve is provided in this way, when the battery undergoes thermal runaway and the pack safety valve is opened, the coolant may flow out from the opened pack safety valve, and the liquid level of the coolant may drop to the position of the safety valve. In this case, the thermal runaway battery cannot be sufficiently immersed in the coolant, so the thermal runaway battery is not sufficiently cooled, and there is a possibility that thermal runaway may spread among the plurality of batteries in the battery pack.

[0006] On the other hand, to suppress the leakage of coolant due to the opening of the pack safety valve, it is conceivable to install the pack safety valve on the top surface of the case's top panel. However, if the pack safety valve is simply installed on the top surface of the top panel, the height of the battery pack will largely depend on the height of the pack safety valve. Also, if the pack safety valve is simply installed on the top surface of the top panel, it will be difficult to stack multiple battery packs vertically. In this case, outside the side of the case's lateral surface where the terminals protrude, the electrode terminals and coolant inflow / outflow ports are originally located outside this lateral surface, so components are not placed in the space other than where the electrode terminals and inflow / outflow ports are located, resulting in wasted space. Therefore, it is conceivable to make effective use of this space.

[0007] The purpose of this disclosure is to provide a battery pack that can suppress the outflow of coolant when the pack safety valve is opened, and that can make effective use of the space outside the case.

[0008] A first battery pack, which is one aspect of the present disclosure, is a battery pack in which a plurality of batteries are housed in a case, the plurality of batteries having battery safety valves that open when the internal pressure rises and exhaust the gas inside, and are immersed in a coolant in the case, the case including a case body in which the plurality of batteries are housed, and a protruding portion that protrudes from a part in the vertical direction of the terminal protruding side surface in the lateral direction of the case body and has an exhaust hole on its upper surface, a pack safety valve is provided above the protruding portion at a position covering the exhaust hole that opens when the internal pressure in the protruding portion rises and exhausts gas from the exhaust hole, and the upper end of the pack safety valve is positioned lower than the uppermost end of the case, the battery pack.

[0009] A second battery pack, which is one aspect of the present disclosure, is a battery pack in which a plurality of batteries are housed in a case, the plurality of batteries having battery safety valves that open when the internal pressure rises and exhaust the gas inside, and are immersed in a coolant in the case, the case including a case body in which the plurality of batteries are housed, and a protruding portion that protrudes from a part in the vertical direction of the terminal protruding side surface in the lateral direction of the case body and has an exhaust hole on its lower surface, a pack safety valve is provided below the protruding portion at a position covering the exhaust hole that opens when the internal pressure in the protruding portion rises and exhausts gas from the exhaust hole, and the upper end of the protruding portion is located at the uppermost end of the case, the battery pack.

[0010] According to one embodiment of the present disclosure, a battery pack can suppress the outflow of coolant when the pack safety valve is opened, and can also make effective use of the space outside the case. For example, according to the first battery pack, since an exhaust hole is provided on the upper surface of the protrusion, the exhaust hole can be placed at a high position. This suppresses the outflow of coolant when the pack safety valve is opened. According to the second battery pack, since it is not necessary to provide an exhaust hole on the lateral side of the protrusion, the vertical thickness of the protrusion can be reduced, and since the upper end of the protrusion is located at the top end of the case, the exhaust hole can be placed at a high position. This suppresses the outflow of coolant when the pack safety valve is opened.

[0011] This is a schematic perspective view of a battery pack, which is an example of an embodiment. This is a cross-sectional view taken along line A-A in Figure 1. This is an enlarged view showing the specific configuration of the battery block shown in Figure 2. This is a cross-sectional view of the batteries constituting the battery block shown in Figure 3. This is a diagram corresponding to Figure 2 in another example of an embodiment of a battery pack. This is a diagram corresponding to Figure 2 in another example of an embodiment of a battery pack, showing the pack safety valve closed. This is an enlarged cross-sectional view taken along line B-B in Figure 7. This is a diagram corresponding to Figure 7 in another example of an embodiment, showing the pack safety valve open.

[0012] The embodiments relating to this disclosure will be described in detail below with reference to the attached drawings. Note that the drawings include schematic diagrams, and the dimensional ratios such as length, width, and height of each component do not necessarily match between different drawings. Furthermore, among the components described below, those components that are not described in the independent claim representing the highest-level concept are optional components and not essential components.

[0013] Furthermore, in the following embodiments, the case in which the battery pack 1 has a substantially rectangular parallelepiped shape will be described as an example. In the drawings and the description of the embodiments, the X direction indicates the longitudinal direction of the battery pack 1 (case 10), the Y direction indicates the width direction of the battery pack 1 (case 10), and the Z direction indicates the vertical direction (height direction) of the battery pack 1 (case 10). The X, Y, and Z directions are orthogonal to each other. Also, in the Z direction, the side on which the cap 45 of the battery 30 shown in Figure 3 is provided is referred to as the "upper side," and the opposite side is referred to as the "lower side." The longitudinal direction, which is the X direction, corresponds to the first direction. The width direction, which is the Y direction, corresponds to the second direction. Battery pack 1 corresponds to the first battery pack.

[0014] The general outline of the battery pack 1 will be described with reference to Figures 1 to 3. Figure 1 is a schematic perspective view of the battery pack 1, which is an example of an embodiment. Figure 2 is a cross-sectional view taken along line A-A in Figure 1 (a cross-sectional view taken when the battery pack 1 is cut by the XZ plane passing through the center in the width direction).

[0015] The battery pack 1 comprises a battery block 20 having a plurality of batteries 30 (Figure 3) and a case 10 housing the battery block 20. The batteries 30 are, for example, non-aqueous electrolyte secondary batteries such as lithium-ion batteries, and are not particularly limited in shape or size, but cylindrical batteries are preferred. The following description will focus on the case where the batteries 30 are cylindrical batteries.

[0016] The case 10 is a box shape with a roughly rectangular parallelepiped exterior. An insulating coolant 50 is stored inside the case 10, and at least a portion of the outer surface of each battery 30 is immersed in the coolant 50. As a result, the coolant 50 is in direct contact with each battery 30, improving the cooling performance of each battery 30. Furthermore, as will be described later, when a malfunction occurs in the battery 30, the gas generated from inside the battery 30 passes through the coolant 50 storage area inside the case 10, thus lowering the gas temperature when the gas is exhausted outside the case 10.

[0017] Battery pack 1 is primarily used as a power source. For example, battery pack 1 is used as a power source for motor-driven electric equipment such as electric vehicles, power tools, electric assist bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the use of battery pack 1 is not limited, and it may also be used as a power source for various electrical equipment other than electric equipment, such as vacuum cleaners, wireless devices, lighting devices, digital cameras, and video cameras used both indoors and outdoors.

[0018] As shown in Figure 3, the battery block 20 includes a plurality of batteries 30 and a battery holder 60 that inserts and holds both ends of the plurality of batteries 30 in the vertical direction Z.

[0019] Each of the multiple batteries 30 has a battery safety valve 37 that opens when the internal pressure rises and exhausts the gas inside. As will be described in detail later, in this embodiment the battery safety valve 37 is provided at the upper end of the battery 30. The multiple batteries 30 are arranged vertically within the case 10 so that the battery safety valve 37 is located at the upper end. When a malfunction occurs in a battery 30 and the internal pressure of the battery 30 rises, gas is exhausted from the exhaust hole 45a (see Figure 4, described later) formed in the cap 45 that constitutes the battery safety valve 37.

[0020] The battery holder 60 includes an upper holder 61 that holds the upper part of the battery 30 and a lower holder 62 that holds the lower part of the battery 30. The upper holder 61 includes a holding portion 63 that holds the upper end of the battery 30 and an opening 64 into which the cap 45 of the battery 30 is inserted, exposing the cap 45 to the coolant reservoir in the case 10. The cap 45 constitutes the battery safety valve 37. The lower holder 62 includes a holding portion 65 that holds the lower end of the battery 30 and an opening 66 that connects to the inside of the holding portion 65 and exposes the lower end surface of the battery 30.

[0021] Case 10 will be explained in detail with reference to Figures 1 and 2.

[0022] The case 10 is made of a metal such as aluminum or resin and has a roughly rectangular parallelepiped shape. Specifically, the case 10 has a roughly rectangular parallelepiped shape and is composed of a case body 11 that houses a plurality of batteries 30, and a protruding portion 12 that is part of the vertical direction Z of one side of the case body 11 in the longitudinal direction X (front side in Figure 1, left side in Figure 2) and protrudes in the longitudinal direction X from a part of the width direction Y.

[0023] A positive terminal 71 and a negative terminal 72 protrude from both sides in the width direction of one longitudinal side of the case body 11, which is the lateral side. The positive terminal 71 and the negative terminal 72 correspond to electrode terminals. The positive terminal 71 is connected to a positive terminal plate described later inside the case 10. The negative terminal 72 is connected to a negative terminal plate described later inside the case 10. Thus, one longitudinal side of the case 10 corresponds to the terminal protruding side. On both sides in the width direction of one longitudinal side of the case body 11, an inlet port 73 for the inflow of coolant into the case 10 and an outlet port 74 for the outflow of coolant from the case 10 protrude from below the positive terminal 71 and the negative terminal 72, respectively. Coolant piping constituting a coolant path (not shown) is connected to the ends of each port 73 and 74. The coolant path is provided with a coolant storage section and a pump for supplying coolant from the storage section into the case body. The inlet port 73 may be located on the negative terminal 72 side, and the outlet port 74 on the positive terminal 71 side. Alternatively, the inlet port 73 may be located above the positive terminal 71 or the negative terminal 72, and the outlet port 74 may be located below the positive terminal 71 or the negative terminal 72. Conversely, the inlet port 73 may be located below the positive terminal 71 or the negative terminal 72, and the outlet port 74 may be located above the positive terminal 71 or the negative terminal 72. Furthermore, the inlet port 73 and the outlet port 74 may be located above the positive terminal 71 and the negative terminal 72, respectively. The case 10 is a roughly rectangular parallelepiped with an opening at its upper end and comprises a main body member 14 with a projection 12 protruding from one longitudinal side and a cover 15 that closes the opening at the upper end of the main body member 14. The cover 15 is a roughly rectangular plate.

[0024] The case body 11 has two first side walls 11a and 11b located at both ends in the longitudinal direction X, two second side walls 11c located at both ends in the width direction Y, and a bottom plate portion 11d provided at the lower end that closes the lower inner end of the case body 11. Each of the side walls 11a, 11b, and 11c corresponds to a wall portion. The case 10 has the function of protecting the battery 30 housed inside from dust and water.

[0025] As shown in Figures 2 and 3, a battery block 20 is housed inside the case 10, and the portion of the multiple batteries 30 constituting the battery block 20, including the middle portion in the vertical Z direction, is immersed in the coolant 50. From the viewpoint of efficiently cooling the batteries 30, it is preferable that the coolant 50 fills almost the entire interior of the case body 11. In this way, the batteries 30 are in contact with the coolant 50 and cooled directly, so the batteries 30 can be cooled efficiently. This improves the charging performance, durability, and safety of the batteries 30.

[0026] Furthermore, when multiple battery packs are combined to form a more advanced battery system, battery pack 1 may sometimes be referred to as a battery module.

[0027] The coolant 50 has insulating properties. This prevents battery 30 from leaking electricity to other batteries 30 via the coolant 50. Examples of coolant 50 include insulating oil, transformer oil, silicone oil, and fluorine-based inert liquids such as hydrofluoroether.

[0028] As shown in Figure 2, a gap is formed between the battery safety valve 37 of the battery 30 and the lower surface of the lid 15 at the upper end of the inside of the case 10. The cap 45 that constitutes the battery safety valve 37 is exposed in this gap. As a result, when a malfunction occurs in the battery 30 and the internal pressure of the battery 30 rises, the battery safety valve 37 opens, and the gas generated inside the battery 30 is exhausted through the exhaust hole 45a (see Figure 4) of the cap 45. The gas exhausted from the cap 45 of the battery safety valve 37 flows into the protruding portion 12, which will be described later.

[0029] The protruding portion 12 is a roughly rectangular box shape, with the other end in the longitudinal direction X (the right end in Figure 2), which is the entrance end, opening and communicating with the inside of the case body 11. Furthermore, an exhaust hole 13 is provided on the upper surface of the protruding portion 12 so as to penetrate vertically. The exhaust hole 13 exhausts the gas inside the case 10 to the outside of the case 10.

[0030] A pack safety valve 82 is provided above the protrusion 12, in a position that covers the exhaust hole 13, which opens when the internal pressure in the protrusion 12 rises, allowing gas to be exhausted through the exhaust hole 13. The pack safety valve 82 is configured such that, for example, the valve body is biased by a spring, causing the valve body to elastically close the exhaust hole 13. When the internal pressure in the protrusion 12 rises, the valve body moves against the force to open the exhaust hole 13, thus opening the pack safety valve 82. As a result, when a malfunction occurs in the battery 30, the gas exhausted from the battery safety valve 37 is exhausted to the outside of the case 10 through the exhaust hole 13 when the pack safety valve 82 opens. Also, under normal conditions when there is no malfunction in the battery 30, the pack safety valve 82 is closed, so the coolant inside the case 10 does not leak out of the case 10 through the exhaust hole 13.

[0031] Furthermore, the upper end of the pack safety valve 82 is positioned lower than the upper surface of the lid 15, which is the uppermost part of the case 10. Also, as described above, the pack safety valve 82 is located above the protrusion 12 and covers the exhaust hole 13. This suppresses the outflow of coolant when the pack safety valve 82 is opened, as will be described later, and allows for effective use of the space outside the case 10.

[0032] The battery block 20 will be described with reference to Figure 3. As described above, the battery block 20 has a battery holder 60 into which multiple batteries 30 are inserted and held at both axial ends.

[0033] The battery holder 60 is constructed by combining and fixing an upper holder 61 and a lower holder 62 in the vertical direction, with a plurality of batteries 30 sandwiched inside each other. The upper holder 61 has a holding portion 63 and an opening 64 as described above. The lower holder 62 has a holding portion 65 and an opening 66 as described above. The upper holder 61 and the lower holder 62 may be combined by a fitting portion (not shown) or locked together by a locking portion (not shown). The upper holder 61 and the lower holder 62 may be fixed together by fastening means including screws. The positive terminal plate 70 abuts against the upper surface of the upper holder 61. The negative terminal plate 80 abuts against the lower surface of the lower holder 62.

[0034] The battery holder 60 may be made of, for example, PC (polycarbonate) resin, high thermal conductivity PPS (polyphenylene sulfide) resin, resin containing a heat dissipation filler, or injection-molded thermosetting resin. More specifically, the battery holder 60 may be made of phenolic resin, unsaturated polyester, or unsaturated polyester mixed with a heat absorbent.

[0035] The holding portion 63 of the upper holder 61 is a circular hole formed on the lower surface of the upper holder 61. The upper end of the battery 30 is held by being fitted into the holding portion 63. The opening 64 is formed at the center of the holding portion 63 so as to penetrate the upper holder 61 in the vertical direction. The opening 64 is, for example, a hole with a circular cross-section. The cap 45 of the upper end of the battery 30 is exposed within the opening 64. The positive electrode terminal plate 70 and the cap 45 of the battery 30 are electrically connected via a positive electrode lead portion (not shown). The positive electrode lead portion may be a connecting lead portion formed integrally with the positive electrode terminal plate 70 and extending toward the cap 45. The positive electrode terminal plate 70 is electrically connected to a positive electrode terminal 71 that protrudes from one side surface in the longitudinal direction X of the case 10. When a malfunction occurs in the battery 30, the gas exhausted from the battery safety valve 37 is exhausted to the outside of the battery block 20 through the opening 64.

[0036] A vertical gap is formed between the positive electrode terminal plate 70 and the upper end of the inner surface of the case 10 to form a gas exhaust path, so that the gas exhausted to the outside of the battery block 20 is exhausted to the outside of the case 10 through the exhaust hole 13.

[0037] The holding portion 65 of the lower holder 62 is a circular hole formed on the upper surface of the lower holder 62. The lower end of the battery 30 is held by being fitted into the holding portion 65. The opening 66 is formed at the center of the holding portion 65 so as to penetrate the lower holder 62 in the vertical direction. The opening 66 is, for example, a hole with a circular cross-section. The lower end surface of the casing body of the battery 30, which will be described later, is exposed within the opening 66. The negative electrode terminal plate 80 and the lower end surface of the battery 30 are electrically connected via a negative electrode lead portion (not shown). The negative electrode lead portion may be a connecting lead portion formed integrally with the negative electrode terminal plate 80 and extending toward the lower end surface of the battery 30. The negative electrode terminal plate 80 is electrically connected to a negative electrode terminal 72 that protrudes from one side surface in the longitudinal direction X of the case 10.

[0038] The battery 30 will be described with reference to Figure 4. The battery 30 is a cylindrical battery and is a lithium-ion battery. The battery 30 is not limited to a cylindrical battery, but may also be a prismatic battery, a laminated battery, etc. The battery 30 is not limited to a non-aqueous battery, but may also be an aqueous battery.

[0039] The battery 30 comprises an electrode body 34, an electrolyte (not shown), and an outer casing 35 that houses the electrode body 34 and the electrolyte. The electrolyte is ionic conductive (for example, lithium ion conductive). The electrolyte includes, for example, a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The electrolyte is not limited to a liquid electrolyte and may be a solid electrolyte using a gel-like polymer or the like. The electrode body 34 has a positive electrode 31, a negative electrode 32, and a separator 33, and has a wound structure in which the positive electrode 31 and the negative electrode 32 are wound in a spiral shape via the separator 33. The outer casing 35 has a bottomed cylindrical shape with an open top, and the opening of the outer casing 35 is closed by a sealing body 36.

[0040] The battery 30 includes insulating plates 38a and 38b positioned above and below the electrode body 34, respectively. In the example shown in Figure 3, a positive electrode lead 39 attached to the positive electrode 31 extends towards the sealing body 36 through a through hole in insulating plate 38a, and a negative electrode lead 40 attached to the negative electrode 32 extends towards the bottom of the outer casing 35 through a through hole in insulating plate 38b. The positive electrode lead 39 is connected to the lower surface of the internal terminal plate 41, which is the bottom plate of the sealing body 36, by welding or the like. A cap 45, which is the top plate of the sealing body 36 and serves as the positive electrode external terminal, is electrically connected to the internal terminal plate 41. The negative electrode lead 40 is connected to the inner surface of the bottom of the outer casing 35 by welding or the like, so that the bottom of the outer casing 35 becomes the negative electrode external terminal.

[0041] The sealing body 36 has a structure in which an internal terminal plate 41, a first valve body 42, an insulating member 43, a second valve body 44, and a cap 45 are stacked in order from the electrode body 34 side. Each component constituting the sealing body 36 is, for example, disc-shaped or ring-shaped, and each component except the insulating member 43 is electrically connected to one another. The first valve body 42 and the second valve body 44 are connected to each other at their respective centers, with the insulating member 43 interposed between their respective peripheral edges.

[0042] In this embodiment, the battery safety valve 37 of the sealing body 36 is composed of a first valve body 42, a second valve body 44, and a cap 45. When an abnormality occurs in the battery 30 and the internal pressure rises to a predetermined value, the first valve body 42 deforms and breaks, pushing the second valve body 44 upward toward the cap 45, thereby interrupting the current path between the first valve body 42 and the second valve body 44. If the internal pressure rises further and reaches a predetermined value, the second valve body 44 breaks, and gas is exhausted from the battery exhaust hole 45a formed on the side surface of the protrusion of the cap 45.

[0043] The placement of the battery safety valve 37 is not limited to this embodiment. The battery safety valve may be provided at the bottom of the outer casing 35, which is below the battery 30, and may be configured to release gas from the battery safety valve when the internal pressure of the battery rises. In that case, a gas exhaust path is formed between the lower end of the battery 30 and the lower end of the inner surface of the case 10 so that the gas released from the bottom of the outer casing 35 is exhausted to the outside of the case 10 through the exhaust hole 13 of the case 10.

[0044] As shown in FIG. 3, the space between the holding portion 63 of the upper holder 61 and the holding portion 65 of the lower holder 62 and around each battery 30 communicates with the outer space of the battery holder 60 in the case 10. Thereby, the coolant 50 exists in the space around each battery 30 in the same manner as in the outer space of the battery holder in the case 10. It is preferable that the coolant 50 exists in the case 10 up to a position above the upper end of each battery 30. In this case, the gas exhausted from the battery safety valve 37 is sent to the exhaust hole 13 while contacting the coolant 50, and the temperature of the gas exhausted from the exhaust hole 13 to the outside is likely to decrease.

[0045] As described above, according to the battery pack 1 of the present embodiment, since the exhaust hole 13 is provided on the upper surface of the protruding portion 12, the exhaust hole 13 can be arranged at a high position. Thereby, the outflow of the coolant 50 when the pack safety valve 82 is opened can be suppressed. For this reason, when heat generation occurs inside the battery 30 during an abnormality of the battery 30 and the surface of the exterior body 35 of the battery 30 becomes high temperature, the expansion of thermal runaway between the plurality of batteries 30 can be suppressed.

[0046] Furthermore, since the upper end of the pack safety valve 82 is arranged at a position lower than the uppermost end of the case 10, the height of the battery pack 1 does not depend on the pack safety valve 82. Also, a plurality of battery packs 1 can be provided and stacked in the vertical direction. Further, since the pack safety valve 82 and the protruding portion 12 are provided on the side surface (the side surface on one side in the longitudinal direction X) of the case 10 on the side where the terminals 71 and 72 protrude in the lateral direction, a space that does not interfere with each terminal 71 and 72 and each port 73 and 74 can be effectively utilized outside this lateral side surface. Thereby, the effective use of the space outside the case 10 can be achieved.

[0047] Also, the exhaust hole 13 of the case 10 is provided at a position higher than the upper end of the battery 30. Thereby, when the pack safety valve 82 is opened and the gas and the coolant are exhausted outside the case 10 through the pack safety valve 82, it becomes easier to keep the battery 30 sufficiently immersed in the coolant 50. For this reason, the expansion of thermal runaway between the plurality of batteries 30 can be further suppressed.

[0048] Further, in this example, the protruding length of the protruding portion 12 from the terminal protruding side surface of the case 10 is smaller than the maximum length of the protruding lengths of the positive terminal 71, the negative terminal 72, the inflow port 73, and the outflow port 74 from the terminal protruding side surface of the case 10, and the pack safety valve 82 may be configured not to be arranged in the protruding direction from the tip of the protruding portion 12. According to this configuration, the length of the case 10 along the longitudinal direction in the lateral direction of the battery pack 1 does not depend on the protruding portion 12 and the pack safety valve 82. Therefore, when calculating the volume energy density of the battery pack 1, the lateral length of the battery pack 1 is not affected by the protruding portion 12 and the pack safety valve 82. Thus, a decrease in the volume energy density can be suppressed.

[0049] FIG. 5 is a diagram corresponding to FIG. 2 in the battery pack 1a of another example of the embodiment. In the configuration of this example, the protruding portion 12 is configured to include a case protruding portion 12a and a lid body protruding portion 15a1. The case protruding portion 12a protrudes in the longitudinal direction X from the middle portion in the width direction at the vertical middle portion of the terminal protruding side surface (one side surface in the longitudinal direction X) of the main body member 14a, and the upper end is open. The lid body protruding portion 15a1 is provided outside the longitudinal direction X from the middle portion in the width direction of the terminal protruding side end (the left end in FIG. 5) of the lid body 15a. The lid body protruding portion 15a1 is formed by bending the middle portion in the width direction at the end portion on the terminal protruding side of the lid body 15a downward at a right angle and then bending it at a right angle toward the protruding direction of the protruding portion 12 and extending in the protruding direction. The portion extending in the protruding direction closes the upper end opening of the case protruding portion 12a.

[0050] An exhaust hole 17 is formed in the portion of the lid body protruding portion 15a1 that closes the upper end opening of the case protruding portion 12a. Thereby, the protruding portion 12 is configured to include the lid body 15. A pack safety valve 82 is provided at a position covering the exhaust hole 17 above the protruding portion 12. Also in the case of this example, similar to the configuration of FIGS. 1 to 4, the upper end of the pack safety valve 82 is arranged at a position lower than the uppermost end of the case 10a.

[0051] In this example, since the protrusion 12 includes the lid 15a, it is not necessary to form a wall portion on the main body member 14a that forms the upper end of the protrusion 12. As a result, the main body member 14a can be formed in a shape where the entire upper end is open. For this reason, when the main body member 14a is made of metal, the main body member 14a can be formed by pressing the press molds onto the metal material from both sides in directions corresponding to the vertical direction. Also, when the main body member 14a is made of resin, the resin can be injection molded between two molds that are separable on both sides in directions corresponding to the vertical direction, and then the main body member 14a can be removed from between the molds. This facilitates the manufacturing of the case 10a. In this example, the other configurations and operations are the same as those in Figures 1 to 4.

[0052] Figure 6 is a diagram corresponding to Figure 2, showing a battery pack 1b of another embodiment. Battery pack 1b corresponds to the second battery pack. In the configuration of this example, the lid 15b is flat and has a plate-shaped lid projection 15b1 that protrudes in the direction of the terminal projection from the middle of the width direction of the terminal projection side end (left end in Figure 6). The main body member 14b has a roughly rectangular parallelepiped case projection 12b that protrudes from the middle of the width direction at the upper end including the upper end of the terminal projection side (one side in the longitudinal direction X), with the upper end being open. The case projection 12b and the lid projection 15b1 are combined such that the upper end opening of the case projection 12b is closed by the lid projection 15b1, thereby forming the projection 12. For this reason, the upper end of the projection 12 is located at the uppermost end of the case 10b.

[0053] Furthermore, an exhaust hole 13a is formed on the lower surface of the case protrusion 12b of the protrusion 12. The pack safety valve 82 is provided below the protrusion 12 and in a position that covers the exhaust hole 13a.

[0054] In this example, an exhaust hole 13a is provided on the lower surface of the protruding portion 12. This eliminates the need to provide an exhaust hole on the lateral side of the protruding portion 12, thus reducing the vertical thickness of the protruding portion 12. Furthermore, the upper end of the protruding portion 12 is located at the uppermost end of the case 10b. This allows the exhaust hole 13a to be positioned at a high location, even though it is provided on the lower surface of the protruding portion 12. As a result, the outflow of coolant 50 when the pack safety valve 82 is opened can be suppressed.

[0055] Furthermore, since the upper end of the pack safety valve 82 is positioned lower than the uppermost end of the case 10b, the height of the battery pack 1b does not depend on the pack safety valve 82. Also, multiple battery packs 1b can be provided and stacked vertically. Additionally, since the pack safety valve 82 and the protrusion 12 are provided on the side of the case 10b on the terminal protrusion side in the lateral direction, the space outside this lateral side can be effectively utilized without interfering with the terminals 71, 72 and ports 73, 74 (see Figure 1). This allows for effective use of the space outside the case 10b.

[0056] Furthermore, the protrusion 12 includes a lid 15b, and the lid 15b is formed in a flat plate shape. As a result, the main body member 14b can be formed with an open shape across its entire upper end, and since the case protrusion 12b is located at the uppermost end of the main body member 14b, the shape of the main body member 14b can be further simplified. Therefore, the manufacturing of the case 10b, including the lid 15b and the main body member 14b, can be further simplified. In this example, the other configurations and operations are the same as those in Figures 1 to 4, or the configuration in Figure 5.

[0057] Figure 7 is a diagram corresponding to Figure 2 in a battery pack 1c of another embodiment, showing the pack safety valve 82 in the closed position. Figure 8 is an enlarged cross-sectional view of Figure 7 along line B-B. Figure 9 is a diagram corresponding to Figure 7 in another example, showing the pack safety valve 82 in the open position.

[0058] In the configuration of this example, as shown in Figures 1 to 4, a roughly rectangular cylindrical pocket portion 84 is provided inside the case body 11, near the point where the internal space of the case body 11 and the internal space of the protruding portion 12 communicate. The pocket portion 84 has an opening P at its upper end and is closed at its lower end. The pocket portion 84 is provided so as to cover the entire opening of the protruding portion 12 on the case body 11 side. The lower end of the pocket portion 84 is located near the lower end of the protruding portion 12 on the inner surface of the first side wall 11a, which is located at one end in the longitudinal direction X of the case body 11. The inside of the pocket portion 84 communicates with the internal space of the protruding portion 12. The upper end of the opening P of the pocket portion 84 is located higher than the upper end of the battery of the battery block 20.

[0059] As shown in Figure 9, when the pack safety valve 82 is opened, a portion of the coolant 50 inside the case 10c is discharged outside the case 10c through the exhaust hole 13 along with the gas exhausted from the battery. At this time, there is a possibility that the coolant in the pocket portion 84 and the upper part of the internal space of the protruding portion 12 may be discharged outside the case 10c, but the coolant 50 flowing from inside the case body 11 toward the exhaust hole 13 can be blocked by the wall of the pocket portion 84. As a result, the height of the coolant 50 present in the space where the battery block 20 is arranged inside the case 10c can be kept at the height near the upper end of the pocket portion 84, and a significant decrease in the height of the coolant 50 can be suppressed. Therefore, the outflow of coolant 50 when the pack safety valve 82 is opened can be further suppressed. Consequently, the spread of thermal runaway between multiple batteries can be further suppressed. In this example, the other configurations and operations are the same as those in Figures 1 to 4.

[0060] In the above examples, the configuration described shows that the protruding portion 12 protrudes in the longitudinal direction X from a part of the width direction Y on one side of the case body 11 in the longitudinal direction X. On the other hand, in the above examples, the configuration may also be such that the protruding portion protrudes in the longitudinal direction X from substantially the entire width direction on one side of the case body 11 in the longitudinal direction X. Furthermore, in the above examples, the configuration described shows that the terminals 71, 72, ports 73, 74, and protruding portion 12 protrude from one side of the case body 11 in the longitudinal direction X, but the configuration may also be such that the terminals, ports, and protruding portion protrude from one side of the case body 11 in the width direction Y.

[0061] In the configurations of the examples above, multiple battery blocks can be housed inside the case, and these battery blocks can be electrically connected to each other in series, parallel, or a combination of series and parallel. Furthermore, multiple battery packs of the examples above can be arranged side-by-side and housed in a larger case, with these battery packs electrically connected to each other in series, parallel, or a combination of series and parallel.

[0062] This disclosure is further illustrated by the following embodiments. Configuration 1: A battery pack comprising a plurality of batteries housed in a case, wherein each plurality of batteries has a battery safety valve that opens when internal pressure rises to exhaust internal gas, and is immersed in a coolant within the case, the case comprising a case body housing the plurality of batteries, and a protruding portion that protrudes from a part in the vertical direction of the terminal protruding side surface in the lateral direction of the case body and has an exhaust hole on its upper surface, a pack safety valve is provided above the protruding portion at a position covering the exhaust hole, which opens when internal pressure rises within the protruding portion to exhaust the gas from the exhaust hole, and the upper end of the pack safety valve is positioned lower than the uppermost end of the case, the battery pack. Configuration 2: A battery pack in which a plurality of batteries are housed in a case, wherein each plurality of batteries has a battery safety valve that opens when the internal pressure rises and exhausts the internal gas, and is immersed in a coolant within the case, and the case includes a case body in which the plurality of batteries are housed, and a protruding portion that protrudes from a part in the vertical direction of the terminal protruding side surface in the lateral direction of the case body and has an exhaust hole on its lower surface, and a pack safety valve is provided below the protruding portion at a position covering the exhaust hole, which opens when the internal pressure in the protruding portion rises and exhausts the gas from the exhaust hole, and the upper end of the protruding portion is located at the uppermost end of the case, a battery pack. Configuration 3: The battery pack according to Configuration 1 or Configuration 2, wherein the exhaust hole is located at a position higher than the upper end of the battery, a battery pack according to any one of Configurations 1 to 3, wherein the case includes a main body member having an opening at its upper end and a lid that closes the opening of the main body member, and the protruding portion is composed of the lid, a battery pack according to any one of Configurations 1 to 3. Configuration 5: A battery pack according to any one of Configurations 1 to 4, wherein a cylindrical pocket portion is provided inside the case body, near the communication point between the internal space of the case body and the internal space of the protruding portion, with an opening at its upper end and a closed lower end, and the inside of the pocket portion communicates with the internal space of the protruding portion. Configuration 6: A battery pack according to Configuration 5, wherein the upper end of the opening is provided at a position higher than the upper end of the battery.Configuration 7: The battery pack according to any one of Configurations 1 to 6, wherein the length of the protrusion of the protrusion from the terminal protrusion side of the case is less than the maximum length of the protrusion of each port for the outflow or inflow of electrode terminals and coolant from the terminal protrusion side of the case, and the pack safety valve is not located outward in the protruding direction from the tip of the protrusion.

[0063] 1, 1a, 1b, 1c Battery pack, 10, 10a, 10b, 10c Case, 11 Case body, 11a, 11b First side wall, 11c Second side wall, 11d Bottom plate, 12 Protrusion, 13, 13a Exhaust hole, 14, 14a, 14b Main body component, 15, 15a, 15b Cover, 17 Exhaust hole, 20 Battery block, 30 Battery, 31 Positive electrode, 32 Negative electrode, 33 Separator, 34 Electrode body, 35 Outer casing, 36 Sealing body, 37 Battery safety valve, 38a, 38b Insulating plate, 39 Positive electrode lead, 40 Negative electrode lead, 41 Internal terminal plate, 42 First valve body, 43 Insulating member, 44 Second valve body, 45 Cap (Positive electrode external terminal), 45a Exhaust hole, 50 Coolant, 60, 60a, 60b Battery holder, 61 Upper holder, 62 Lower holder, 63 Holding part, 64 Opening, 65 Holding part, 66 Opening, 70 Positive terminal plate, 71 Positive terminal, 72 Negative terminal, 80 Negative terminal plate, 82 Pack safety valve, 84 Pocket part.

Claims

1. A battery pack comprising a case containing a plurality of batteries, wherein each plurality of batteries has a battery safety valve that opens when the internal pressure rises to release internal gas, and is immersed in a coolant within the case, the case comprising a case body containing the plurality of batteries, and a protruding portion that protrudes from a part in the vertical direction of the terminal protruding side surface of the case body in the lateral direction and has an exhaust hole on its upper surface, a pack safety valve is provided above the protruding portion at a position covering the exhaust hole, which opens when the internal pressure in the protruding portion rises to release the gas from the exhaust hole, and the upper end of the pack safety valve is positioned lower than the uppermost end of the case.

2. A battery pack comprising a case containing a plurality of batteries, wherein each plurality of batteries has a battery safety valve that opens when the internal pressure rises to release internal gas, and is immersed in a coolant within the case, the case comprising a case body containing the plurality of batteries, and a protruding portion that protrudes from a part in the vertical direction of the terminal protruding side surface in the lateral direction of the case body and has an exhaust hole on its lower surface, a pack safety valve is provided below the protruding portion at a position covering the exhaust hole, which opens when the internal pressure in the protruding portion rises to release the gas from the exhaust hole, and the upper end of the protruding portion is located at the uppermost end of the case.

3. The battery pack according to claim 1 or claim 2, wherein the exhaust port is located at a position higher than the upper end of the battery.

4. The battery pack according to claim 1 or claim 2, wherein the case includes a main body member having an opening at its upper end and a lid that closes the opening of the main body member, and the protruding portion is configured to include the lid.

5. The battery pack according to claim 1 or claim 2, wherein a cylindrical pocket portion is provided inside the case body, near the communication point between the internal space of the case body and the internal space of the protruding portion, with an opening at its upper end and a closed lower end, and the inside of the pocket portion communicates with the internal space of the protruding portion.

6. The battery pack according to claim 5, wherein the upper end of the opening is located higher than the upper end of the battery.

7. The battery pack according to claim 1 or 2, wherein the length of the protrusion from the terminal protrusion side of the case is less than the maximum length of the protrusion of each port for the outflow or inflow of electrode terminals and coolant from the terminal protrusion side of the case, and the pack safety valve is not located outward in the protruding direction from the tip of the protrusion.

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