Battery pack

Abstract

Even if high-temperature and high-pressure gas is discharged from a secondary battery cell inside a battery pack, the high-temperature and high-pressure gas can be smoothly discharged to the outside. A battery pack (100) is provided with: a plurality of secondary battery cells (1); and an exterior case (10) that houses the plurality of secondary battery cells (1). The exterior case (10) opens a gas discharge hole (13) in one part of the surface thereof, and the exterior case (10) is internally provided with: a discharge guide (6) that defines a gas guide path (34) that guides a gas to the gas discharge hole (13) when the gas is discharged from any one of the plurality of secondary battery cells (1), and that guides the gas to the gas discharge hole (13) when the gas is discharged from any one of the plurality of secondary battery cells (1); the discharge guide (6) includes an inclined wall (18) inclined from a posture facing the discharge direction of the gas.

Description

Technical Field

[0001] The present disclosure relates to battery packs. Background Art

[0002] In electrical equipment using rechargeable secondary batteries such as lithium-ion secondary batteries, Fig.14 As shown in the cross-sectional view of FIG. 7 , a battery pack is used in which a plurality of secondary battery cells 701 are housed in an outer casing 710 so that the secondary battery can be replaced. Examples of electrical equipment driven by the battery pack include various equipment such as an electric cart and an electric tool.

[0003] On the other hand, secondary battery cells sometimes generate heat due to some abnormality. At this time, the structure is such that the interior of the outer can of the secondary battery cell becomes high pressure, so the safety valve provided in the outer can is opened to discharge the high-temperature, high-pressure gas from the outer can. In the previous battery pack, a discharge path 734 is defined in the outer shell 710 so that when the gas is discharged from any secondary battery cell to the outer shell 710, it can be safely discharged to the outside of the battery pack. The discharge path 734 is formed by the wall 735.

[0004] However, the inventors of the present application have found that if the high-temperature and high-pressure gas collides with the wall 735 while being guided by the exhaust path 734, Fig.15 As shown, a cyclone VX may be generated in the exhaust path 734 of the combustion gas, and the combustion gas may be stagnant. As a result, the outer casing 710 may be heated and melted by the stagnant combustion gas, and the combustion gas may leak out of the outer casing 710.

[0005] Prior Art Literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-084558 Summary of the invention

[0008] -Problems that the invention aims to solve-

[0009] One of the objects of the present disclosure is to provide a battery pack that can smoothly discharge high-temperature and high-pressure gas to the outside even if the gas is discharged from a secondary battery cell inside the battery pack.

[0010] -Methods used to solve the problem-

[0011] A battery pack according to one embodiment of the present invention comprises: a plurality of secondary battery cells; and an outer casing for accommodating the plurality of secondary battery cells, the outer casing having a gas discharge hole opened on a portion of its surface, the outer casing comprising: a discharge guide member inside thereof, defining a gas guide path, wherein the gas guide path guides the gas to the gas discharge hole when gas is released from any one of the plurality of secondary battery cells, and the discharge guide member includes an inclined wall inclined in a posture opposite to the discharge direction of the gas.

[0012] -Effects of the Invention-

[0013] According to the battery pack according to one aspect of the present invention, when high-temperature and high-pressure gas is released from any of the secondary battery cells, the inclined wall can prevent the gas from colliding with a part of the discharge guide to generate cyclones and stagnate, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a perspective view showing the battery pack according to the first embodiment.

[0015] Figure 2 yes Figure 1 A longitudinal cross-sectional view of a battery pack taken along line II-II.

[0016] Figure 3 yes Figure 1 A cross-sectional view of a battery pack taken along line III-III.

[0017] Figure 4 Yes Figure 1 Exploded perspective view of the battery pack with the label removed.

[0018] Figure 5 Yes Figure 1 An exploded perspective view of a battery pack with its outer casing disassembled.

[0019] Figure 6 It is viewed from the bottom. Figure 5 An exploded perspective view of a battery pack in a state where the outer casing is disassembled.

[0020] Figure 7 yes Figure 5 An exploded perspective view of a battery module.

[0021] Figure 8 It is shown in Figure 2 A cross-sectional view of a path for discharging high-pressure gas from an outer casing in a battery pack.

[0022] Fig. 9 yes Figure 6 Exploded perspective view of the upper housing.

[0023] Fig.10 It is shown from Fig. 9 An exploded perspective view of the state where the gas cooling plate is removed from the upper shell.

[0024] Fig.11 yes Figure 1 A horizontal cross-sectional view of a battery pack taken along line XI-XI.

[0025] Fig.12 yes Figure 2 An enlarged cross-sectional view of the main parts of the battery pack.

[0026] Fig.13 yes Fig.10 An enlarged perspective view of the upper shell.

[0027] Fig.14 It is a cross-sectional view showing a battery pack according to a comparative example.

[0028] Fig.15 yes Fig.14 An enlarged view of the main parts of the battery pack. DETAILED DESCRIPTION

[0029] The aspects of the present invention can also be identified by the following structures and features.

[0030] In the battery pack according to another aspect of the present invention, in the above aspect, when gas is released from any of the plurality of secondary battery cells, the inclined wall extends in a posture intersecting with a discharge direction of the gas in a plan view.

[0031] In addition, in a battery pack according to another aspect of the present invention, in any of the above aspects, the inclined wall is integrally provided on the inner surface of the outer case.

[0032] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the gas guide path has a pressure reducing structure for reducing the pressure of the high-pressure gas. The pressure reducing structure is provided in front of the gas discharge hole inside the outer case. The inclined wall is formed at a height difference portion of the gas guide path formed by the pressure reducing structure.

[0033] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the outer casing is formed into an outer shape extending in one direction.

[0034] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the inclined wall is inclined along the extension direction of the outer case.

[0035] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, a plurality of the inclined walls are formed along the extension direction of the outer case.

[0036] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the inclined walls are formed in a staggered pattern along an extension direction of the outer case.

[0037] Furthermore, in addition, a battery pack according to another aspect of the present invention, in any of the above aspects, further comprises: a battery holder for holding the plurality of secondary battery cells.

[0038] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the gas guide path is formed in a region where one surface of the battery holder faces the inner surface of the outer case.

[0039] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the outer case is made of resin.

[0040] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the inclined wall includes a curved surface.

[0041] Hereinafter, the embodiments of the present invention will be described based on the accompanying drawings. However, the embodiments shown below are examples for concretizing the technical ideas of the present invention, and the present invention is not defined as the following methods. In addition, this specification does not define the components shown in the claims as the components of the embodiments. In particular, the size, material, shape, relative configuration, etc. of the structural components described in the embodiments are not intended to limit the scope of the present invention to this, as long as there is no particularly specific description, but are simply illustrative examples. In addition, in order to make the description clear, the size, positional relationship, etc. of the components shown in the drawings are sometimes exaggerated. Further, in the following description, the same name and figure mark represent the same or homogeneous components, and detailed description is appropriately omitted. Further, the various elements constituting the present invention can be set to constitute multiple elements with the same components to use multiple elements by one component, and on the contrary, it can also be realized by multiple components sharing the function of one component.

[0042] The battery pack of the present invention can be used as a driving power source for mobile bodies such as electric carts, electric scooters, and power-assisted bicycles, or as a power source for portable electrical equipment such as radio equipment, electric cleaners, and electric tools, or as a backup power source for stationary power storage mid-way servers, power supply devices for home use, office use, and factory use, and further as a driving power source for vehicles such as hybrid vehicles and electric vehicles, etc. Hereinafter, as one embodiment of the present invention, a battery pack used as a driving power source for an electric cart will be described.

[0043] [Implementation Method 1]

[0044] The battery pack 100 according to the first embodiment of the present invention is shown in FIG. Figure 1 to Figure 7 . These figures show respectively: Figure 1 is a perspective view showing a battery pack 100 according to Embodiment 1. Figure 2 yes Figure 1 A longitudinal cross-sectional view of the battery pack 100 taken along line II-II, Figure 3 yes Figure 1 A cross-sectional view of the battery pack 100 at line III-III, Figure 4 Yes Figure 1 An exploded perspective view of the battery pack 100 with the label 40 removed, Figure 5 Yes Figure 1 An exploded perspective view of the battery pack 100 in which the outer casing 10 is decomposed. Figure 6 It is viewed from the bottom. Figure 5 An exploded perspective view of a battery pack 100 in a disassembled state of the outer casing 10 , Figure 7 yes Figure 5 1 and 2 are exploded perspective views of a battery module 2. The battery pack 100 shown in these figures includes an outer casing 10, a battery module 2, and a circuit board 3.

[0045] (External casing 10)

[0046] The outer casing 10 accommodates the battery module 2 and the circuit board 3. Figure 1 , Figure 4 As shown in FIG. 1 , the outer casing 10 is formed into a box shape. Figure 2-3 , Figure 5-6 As shown in FIG. 1 , the outer casing 10 is divided into an upper casing 11 and a lower casing 12. The outer casing 10 is preferably made of a member having excellent insulation properties, such as a resin such as polycarbonate or PC-ABS alloy, but may also be made of a metal member such as aluminum or aluminum alloy. Figure 2-3 , Figure 5-6 As shown in FIG. 1 and FIG. 2 , an internal space for accommodating the battery module 2 and the circuit board 3 is provided inside the outer casing 10 .

[0047] (Battery module 2)

[0048] The battery module 2 is also called a core pack, etc., and is composed of a plurality of battery blocks 20. Figure 2-3 , Figure 5 to Figure 7 In the example shown, the battery module 2 is composed of a first battery block 20A and a second battery block 20B. The first battery block 20A and the second battery block 20B are respectively composed of a plurality of secondary battery cells 1. The plurality of secondary battery cells 1 are connected in series and in parallel via lead plates. The number of series connections and the number of parallel connections can be arbitrarily set according to the required specifications. It is preferred that the first battery block 20A and the second battery block 20B use the same number of secondary battery cells 1. In addition, the number of series connections and the number of parallel connections are also preferably the same in the first battery block 20A and the second battery block 20B. Figure 2-3 In the example shown in FIG. 1 , each battery block 20 uses a total of 90 secondary battery cells 1 , which are connected in series and in parallel, but the present invention is not limited to this structure.

[0049] Each battery block 20 includes a plurality of secondary battery cells 1. For example, the battery block 20 includes a battery holder that accommodates the secondary battery cells 1. The battery holder is provided with a plurality of accommodating tubes that independently accommodate the secondary battery cells 1. Such a battery holder can be made of a resin such as polycarbonate having excellent insulation properties. Figure 7 In the example, each battery block 20 is formed by 90 secondary battery cells 1, but the number of secondary battery cells forming each battery block is not limited thereto and can be set to any number. In addition, the number of secondary battery cells can be changed in some battery blocks.

[0050] In addition, Figure 2-3 , Figure 7 In the examples, the example of the battery block 20 consisting of the first battery block 20A and the second battery block 20B is described, but the present invention does not limit the number of battery blocks to 2, and it can be set to 3 or more, which is self-evident.

[0051] (Secondary battery cell 1)

[0052] The one or more secondary battery cells 1 can be cylindrical or square. Figure 2-3 , Figure 7 In the example shown, cylindrical secondary battery cells 1 are arranged in a staggered manner in a longitudinal position for use. In addition, the number and configuration of the secondary battery cells 1 are not limited to this example, and any number and configuration can be appropriately adopted. Each secondary battery cell 1 has a positive and negative electrode. The positive and negative electrodes are preferably provided on one end surface of the secondary battery cell 1. Among the secondary battery cells 1, known secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries can be appropriately used.

[0053] (Safety valve)

[0054] In addition, a safety valve is provided in the outer can of the secondary battery cell 1. The safety valve opens in response to an increase in the internal pressure of the outer can, and releases the gas inside the outer can to the outside.

[0055] (Gas discharge hole 13)

[0056] On the other hand, Figure 2 to Figure 5 As shown in FIG. 1 and FIG. 2 , a gas discharge hole 13 is formed in a part of the outer casing 10. The gas discharge hole 13 is used to discharge high-pressure gas to the outside when the safety valve of the secondary battery cell 1 is opened and the high-pressure gas is discharged. Here, the gas discharge hole 13 is formed in the label pasting area 13a to which the label 40 is pasted, and the gas discharge hole 13 is blocked by pasting the label 40. In addition, when high-temperature and high-pressure gas is ejected from the gas discharge hole 13, the label 10 that blocks the gas discharge hole 13 is broken due to the pressure and heat of the gas, and the gas discharge hole 13 is opened.

[0057] The gas discharge hole 13 is disposed on one side of the top surface 14 of the outer shell 10. In addition, the gas discharge hole 13 is not limited to the top surface 14 of the outer shell 10, and can also be disposed on the bottom surface 15, the side surface 16, etc. In addition, the gas discharge hole 13 can also be opened in multiple locations. The gas discharge hole 13 is designed according to the volume of the outer shell 10, the battery capacity of the secondary battery cell 1, etc., and is, for example, set to a width of 12 mm. Figure 4 In the example of , the gas discharge hole 13 is a cross shape obtained by dividing a circle into four. Thus, when a thin label is attached, the effect of preventing the central portion from being dented or damaged by external force can be obtained.

[0058] (Tag 40)

[0059] The label 40 is adhered to the periphery of the gas exhaust hole 13 of the outer shell 10 and is pasted to the label pasting area 13a of the outer shell 10. The label pasting area 13a is formed in a height difference portion that is one layer lower than other areas of the outer shell 10 in a manner that is almost flush with the surface of the label 20. The label 40 is pre-printed with specifications of the battery pack 100, such as model number, manufacturer name, battery capacity, rating and other information. The label 40 is made of a resin such as polycarbonate, polypropylene, or a member impregnated or coated with a resin on a paper substrate. In addition, the thickness of the label 40 is set to 0.5 mm, for example. The outer shape of the label 40 is rectangular. Figure 4 In the examples, the outer shape of the label 40 is a horizontally long rectangular shape with chamfered corners, but the shape is not limited to this shape and may be a vertically long, square, octagonal or other polygonal shape.

[0060] (Double-sided tape 30)

[0061] In addition, in order to attach the label 40, at least a portion of the back side of the label 40 has an attachment surface. Figures 4 to 6 As shown, a double-sided tape 30 is attached around the label 40, and an attachment surface is attached to the label 40. The double-sided tape 30 is a member for fixing the label 40 at a position for blocking the gas discharge hole 13. In addition, the label 40 is not limited to the double-sided tape 30, and an adhesive or the like may be used for bonding.

[0062] In addition, Figure 4 In the example of FIG. 1 , a second label 42 is attached to an area on the upper surface of the outer casing 10 parallel to the label 40. In addition, a second label attachment area 13b is provided on the upper casing 11 to attach the second label 42. A checkered slit is formed in the second label attachment area 13b to prevent air bubbles from entering when attaching the second label 42.

[0063] (Circuit board 3)

[0064] Each of the first battery block 20A and the second battery block 20B is connected to the circuit board 3 via a lead plate. The circuit board 3 is mounted with a charge and discharge circuit for charging and discharging the secondary battery cell 1, a protection circuit for monitoring the voltage and temperature of the secondary battery cell 1 and blocking the current in the event of an abnormality, etc. The circuit board 3 is composed of a glass epoxy substrate or the like.

[0065] (Spacer 30)

[0066] like Figure 2-3 , Figure 7 As shown, the spacer 30 is interposed between the first battery block 20A and the second battery block 20B. The spacer 30 is made of a member having excellent insulating properties, for example, a resin such as polycarbonate or PC-ABS alloy.

[0067] (Separator 32)

[0068] The spacer 30 includes a partition plate 32 that divides a first space 31A facing the first battery block 20A and a second space 31B facing the second battery block 20B. The partition plate 32 is preferably formed so that the height of the first space 31A and the height of the second space 31B are substantially equal. The partition plate 32 is preferably formed integrally with the spacer 30.

[0069] (Gas guide path 34)

[0070] The outer case 10 defines a gas guide path 34 therein. If gas is released from any of the secondary battery cells 1, the gas guide path 34 guides the gas to the gas discharge hole 13. Figure 8In the example shown in the cross-sectional view of , the gas guide path 34 includes a first space 31A and a second space 31B formed between the first battery block 20A and the second battery block 20B, a third space 31C formed between the bottom surface of the second battery block 20B and the inner surface of the bottom surface 15 of the lower shell 12, and a fourth space 31D formed between the top surface of the first battery block 20A and the circuit substrate 3 arranged on the inner surface of the top surface 14 of the upper shell 11, and each space is extended to cross the interior along the long side direction of the outer shell 10. In addition, on the inner surface of the side surface 16 of the outer shell 10, these first space 31A, second space 31B, third space 31C, and fourth space 31D are connected to a surface along the short side direction of the outer shell 10 (at Figure 8 The fifth space 31E is connected to the fifth space 31E extending in the vertical direction of the left side surface 16. Furthermore, the fifth space 31E is connected to the sixth space 31F formed on the inner surface side of the top surface 14 of the outer casing 10. The sixth space 31F extends along the long side direction to the gas discharge hole 13 on the back side of the upper casing 11. With this structure, Figure 8 As shown, when high-temperature and high-pressure gas is discharged from any secondary battery cell 1, the gas is discharged to any one of the first space 31A, the second space 31B, the third space 31C, and the fourth space 31D according to its discharge position, that is, the position of the safety valve provided in the secondary battery cell, and is guided to the sixth space 31F through the fifth space 31E, and finally discharged to the outside of the outer casing 10 from the gas discharge hole 13. In addition, in this structure, Figure 8 In the description, an example is described in which the fifth space 31E is provided on the left side of the inner surface of the outer casing, but the present disclosure is not limited to this structure, and a gas guide path may be separately formed on the right side of the inner surface of the outer casing.

[0071] In addition, the end faces of each secondary battery cell 1 constituting the first battery block 20A and the end faces of each secondary battery cell 1 constituting the second battery block 20B are preferably arranged in a posture opposing each other with a spacer 30 therebetween. Furthermore, it is desirable that a safety valve be provided in any one of the end faces of the secondary battery cells 1 of the first battery block 20A and the end faces of the secondary battery cells 1 of the second battery block 20B in a posture opposing each other with a spacer 30 therebetween. For example, it is desirable that any one of the end faces of the secondary battery cells of the first battery block 20A and the end faces of the secondary battery cells of the second battery block 20B opposing each other be the positive electrode and the other be the negative electrode. Since a safety valve is generally provided at either the positive electrode or the negative electrode, by configuring a safety valve only at either of the surfaces where the electrodes are opposed, it is possible to exclude the situation where high-temperature and high-pressure gas is ejected from the end faces of both sides, thereby ensuring safety.

[0072] (Gas cooling structure)

[0073] A gas cooling structure for cooling the high-temperature gas may be added in the middle of the gas guide path 34. Figure 9-10 In the example of FIG. 1 , as a gas cooling structure, a first cooling plate 51, a second cooling plate 52, and an insulating plate 53 are fixed to the inner surface of the upper housing 11. The first cooling plate 51 and the second cooling plate 52 are made of a material having excellent thermal conductivity and heat resistance, such as metal such as aluminum. In addition, the insulating plate 53 is made of a sheet of a material having excellent insulation and heat resistance, such as mica, Nomex (registered trademark), etc.

[0074] like Fig.12 As shown in the cross-sectional view of FIG, the second cooling plate 52 and the insulating plate 53 overlap and are in close contact, and insulation is achieved between the circuit substrate 3 that is separated from the lower surface of the insulating plate 53. On the other hand, the second cooling plate 52 is separated from the first cooling plate 51, and a gas guide path 34 for guiding high-temperature gas is constructed therebetween. With this structure, by passing high-temperature gas between the first cooling plate 51 and the second cooling plate 52, the gas can be brought into contact with the first cooling plate 51 and the second cooling plate 52, and the heat of the gas can be taken away to cool it down.

[0075] In order to separate the first cooling plate 51 from the second cooling plate 52, a spacer may be provided. For example, when the first cooling plate 51 and the second cooling plate 52 are screwed together, a nut may be interposed between the first cooling plate 51 and the second cooling plate 52. Fig.12 In the example of , in order to separate the second cooling plate 52 from the inner surface of the upper shell 11, the buffer member 54 is interposed between the second cooling plate 52 and the inner surface of the upper shell 11. The buffer member 54 is formed in an annular shape along the contour of the second cooling plate 52. Such a buffer member 54 can utilize polyurethane, rubber, silicone, etc. In addition, in order to fix the annular buffer member 54 at a fixed position on the inner surface of the upper shell 11, a buffer guide wall 17 for holding the buffer member 54 is formed on the inner surface of the top surface 14 of the upper shell 11. The buffer guide wall 17 is formed integrally with the inner surface of the upper shell 11. The material constituting the buffer guide wall 17 is the same as that of the upper shell 11, and resins such as polycarbonate and PC-ABS alloy can be utilized.

[0076] In addition, Fig. 9 In the example of FIG. 5 , the first cooling plate 51 is formed to overlap a portion of the second cooling plate 52. In other words, the first cooling plate 51 is formed smaller than the second cooling plate 52. This is to provide a labyrinth structure to be described later adjacent to the first cooling plate 51. However, it is self-evident that the first cooling plate 51 may be formed to be the same size as the second cooling plate 52. For example, the labyrinth structure may be omitted, or a labyrinth structure may be provided on the surface of the first cooling plate.

[0077] (Pressure reduction structure)

[0078] Furthermore, a pressure reducing structure for reducing the pressure of the high-pressure gas may be added in the middle of the gas guide path 34. In addition, the pressure reducing structure and the gas cooling structure may be integrated. Fig. 9 , Fig.11 In the example of FIG. 5 , an opening region 53a is provided at a portion of the insulating plate 53, and a hole region 52a having a plurality of holes is provided at a position corresponding to the opening region 53a of the insulating plate 53 of the second cooling plate 52. In such a second cooling plate 52, a punched metal plate in which the hole region 52a is formed by punching can be used. Fig.12 As shown in the cross-sectional view of FIG. 5 , the pressure reduction structure of this structure allows the high-temperature and high-pressure gas guided to the sixth space 31F to pass through the hole area 52a of the second cooling plate 52 exposed through the opening area 53a of the insulating plate 53. The high-pressure gas reduces its pressure by using the resistance when passing through the hole area 52a. In addition, by passing through the hole area 52a of the metal second cooling plate 52, heat is also taken away and the temperature is reduced. In this way, the hole area 52a of the second cooling plate 52 functions as a pressure reduction structure and also functions as a gas cooling structure.

[0079] (Maze structure)

[0080] In addition, as part of the pressure reduction structure, a labyrinth structure that hinders the flow of high-pressure gas may be added. Figures 9 to 11 In the example, as a labyrinth structure, an obstruction wall 60 is formed adjacent to the first cooling plate 51. The obstruction wall 60 is arranged to be in a cross posture with respect to the direction of travel of the high-pressure gas, that is, the long side direction of the outer shell 10. It is preferred to arrange a plurality of obstruction walls 60 in multiple layers. In addition, the obstruction wall 60 is not completely blocked with respect to the direction of travel of the gas, but a passing area 64 with a portion of the opening is provided, thereby achieving the goal of guiding the gas to the passing area 64 and finally guiding the gas to the gas discharge hole 13. However, by not configuring the passing area 64 continuously with respect to the long side direction but discontinuously in a staggered manner, etc., the travel of the gas can be obstructed each time, the momentum of the gas can be gradually reduced, the pressure can be reduced, and it can be guided to the gas discharge hole 13. In this way, when the obstruction wall 60 is arranged in multiple layers, it is preferably formed in a staggered shape along the extension direction of the outer shell 10.

[0081] exist Figure 9-10In the example of , for the gas guided to the sixth space 31F and passing through the first cooling plate 51, the first barrier wall 61 is provided at the center in the width direction relative to the sixth space 31F, and the left and right sides of the first barrier wall 61 are used as the passing area 64. As a result, the high-pressure gas is divided to the left and right by the first barrier wall 61. Then, the second barrier wall 62 of the second layer is oppositely arranged at both ends of the width direction of the sixth space 31F, and the center is used as the passing area 64. As a result, the high-pressure gas temporarily divided to the left and right is concentrated to the center again, and passes through the passing area 64 in a state where the high-pressure gases collide with each other and the pressure is reduced. Furthermore, the third barrier wall 63 of the third layer is arranged again in the center in the width direction of the sixth space 31F, and the left and right sides are used as the passing area 64. As a result, the high-pressure gas is divided to the left and right again and passes, and the pressure is further reduced. In this way, by alternately arranging the obstruction walls 60 in multiple layers in the main direction of gas travel, i.e., the long side direction of the outer shell 10 , the gas bends left and right and moves in a zigzag manner, causing the gas to move with significantly reduced pressure, and is finally discharged from the gas discharge hole 13 to the outside of the outer shell 10 .

[0082] (Discharge guide 6)

[0083] A portion of the gas guide path 34 is defined by the exhaust guide 6. Figure 9-10 In the example of FIG. 1 , the discharge guide 6 defining the sixth space 31F in the gas guide path 34 is fixed to the inner surface of the upper housing 11. In this example, the discharge guide 6 is formed integrally with the inner surface of the upper housing 11. However, the discharge guide 6 is not limited to this structure, and for example, it may be composed of a member independent of the upper housing. In addition, the discharge guide may also be provided in other members such as the upper surface of the circuit substrate.

[0084] (Inclined wall 18)

[0085] The discharge guide 6 includes an inclined wall 18 inclined in a posture facing the discharge direction of the gas. Fig.13 In the example, an inclined wall 18 is formed on the inner surface of the upper shell 11 in front of the buffer guide wall 17. In addition, it can also be understood that in the discharge guide 6, a height difference portion 19 is formed as a pressure reduction structure formed on the inner surface of the top surface 14 of the upper shell 11 of the outer shell 10, and the inclined wall 18 is formed in the height difference portion 19. By providing such an inclined wall 18, when high-temperature and high-pressure gas is discharged from the secondary battery cell 1, the inclined wall 18 can be used to avoid the situation in which the gas collides with a part of the discharge guide 6 and generates a cyclone and is retained, thereby improving safety.

[0086] Here, for comparison, Figure 14-15 The battery pack 700 shown in the cross-sectional view of FIG. 1 is described in comparison. Figure 14-15The battery pack 700 is provided with a wall between the upper surface of the battery module 702 and the inner surface of the top surface 714 of the upper shell 711 in order to define the discharge path 734. The wall is made of resin, the same as the outer shell 710. In the battery pack 700, a situation is considered in which a safety valve of a secondary battery cell 701 is opened due to thermal runaway, etc., and a high-temperature and high-pressure gas is ejected into the outer shell 710. The inventor of the present application found that in the process of high-temperature and high-pressure gas being guided along the discharge path 734 in the outer shell 710, if the high-temperature and high-pressure gas collides violently with the wall, the gas generates a cyclone VX, which can produce a situation in which the high temperature and high-pressure gas is retained. Sometimes, the high-temperature and high-pressure gas ignites combustibles and generates flames. When the outer shell 710 is partially melted by the retained combustion gas, it will break, and the combustion gas will leak from here to the outside of the outer shell 710, and it is considered that there is a possibility of fire leakage.

[0087] In this regard, the inventors of the present application conducted in-depth research and found a structure that is difficult to generate gas retention, that is, a structure that is set to a state where it is difficult to generate a cyclone of gas and can be guided to a desired path, thereby forming the battery pack involved in the present embodiment. Specifically, it was found that when the wall is perpendicular to the direction of gas travel, cyclones are easy to generate. For this reason, the following understanding was obtained: by forming an inclined wall 18 inclined along the direction of gas travel in an area that is easy to generate a thin area and an area close to the surface of the outer shell 10 in the discharge guide 6 that specifies the gas guide path 34, instead of setting a wall at right angles to the direction of gas travel, the risk of cyclone generation can be reduced without hindering the progress of the gas, thereby suppressing fire leakage caused by local heating and melting.

[0088] For example, in the sixth space 31F provided inside the top surface 14 of the outer casing 10, as shown in FIG. Fig.15 As shown, at right angles, the wall is prone to produce cyclone VX when it collides with the gas, so Fig.12 As shown in the cross-sectional view of , by providing the inclined wall 18 on the discharge guide 6, the high-temperature and high-pressure gas can be smoothly guided to the gap between the insulating plate 53 and the circuit substrate 3, reducing the risk of gas stagnation.

[0089] When constructing the gas guide path 34 in the outer shell 10, it is desirable to suppress the pressure and temperature of the gas to a certain extent at the stage of discharging the gas to the outside of the outer shell 10. Therefore, it is desirable to make the gas ejected from the safety valve in the outer shell 10 travel a certain distance inside the outer shell 10, during which the momentum is reduced. Therefore, in the case where the outer shell 10 is a shape that is long in one direction, it is preferred to construct the gas guide path 34 along the long side direction of the outer shell 10 to obtain the travel distance of the gas. Therefore, since the guiding direction of the gas is along the extension direction of the outer shell 10, the inclined wall 18 is preferably inclined along the extension direction of the outer shell 10.

[0090] In addition, the inclined wall 18 is not limited to being provided at one location, and a plurality of inclined walls 18 may be formed along the extending direction of the outer case 10 .

[0091] Furthermore, the inclined wall 18 is preferably provided on the discharge guide 6 which is extended in a posture intersecting the gas discharge direction in a plan view. Since there is a high possibility of generating cyclones when the gas collides with the intersecting wall, the risk of gas stagnation can be reduced by providing the inclined wall 18 on such a surface.

[0092] For example, an inclined wall may be provided in front of the first obstruction wall 61, the second obstruction wall 62, and the third obstruction wall 63 of the above-mentioned labyrinth structure. However, when the momentum and pressure of the gas are sufficiently reduced, the risk of cyclone generation is also reduced, so in the area close to the gas discharge hole 13, even if it is a wall intersecting with the gas discharge direction, it is not necessarily necessary to provide an inclined wall.

[0093] Furthermore, the inclined wall 18 does not necessarily need to be flat, and may include a curved surface. In the present disclosure, the inclined wall 18 also includes a state where the inclined surface is curved.

[0094] In the above examples, the battery pack is mounted on the electrical device to be driven, and supplies power to the electrical device. In the case where the remaining capacity of the battery pack decreases or the battery pack deteriorates over the years, the battery pack can be replaced and the electrical device can continue to be used. However, the present invention is not limited to replaceable battery packs in which the battery pack mainly accommodates secondary battery cells, but can also be applied to a method in which secondary battery cells are accommodated in the housing of the electrical device. In the present disclosure, the battery pack only needs to accommodate secondary battery cells in the housing, and the method in which secondary battery cells for driving are built into the housing of the electrical device itself is also included in the battery pack. That is, the present invention is not limited to replaceable battery packs, but can also be applied to electrical devices with built-in secondary battery cells.

[0095] Industrial Applicability

[0096] The battery pack of the present invention can be suitably used as a driving power source for mobile bodies such as electric carts and electric scooters, and can also be suitably used as a power source for radio equipment, and a power source for portable electric equipment such as electric cleaners and electric tools.

[0097] -Description of Reference Numerals-

[0098] 100, 700…Battery pack

[0099] 1…Secondary battery cell

[0100] 1…Secondary battery cell

[0101] 2…Battery Module

[0102] 3…Circuit board

[0103] 6…Discharge guide

[0104] 10…External housing

[0105] 11…Upper housing

[0106] 12…Lower housing

[0107] 13...gas discharge hole; 13a...label pasting area; 13b...second label pasting area

[0108] 14…Top

[0109] 15…Bottom

[0110] 16…Side

[0111] 17…Buffer guide wall

[0112] 18…Sloped wall

[0113] 19…Height difference

[0114] 20…battery block; 20A…first battery block; 20B…second battery block

[0115] 30…Spacer

[0116] 31A…first space; 31B…second space; 31C…third space; 31D…fourth space; 31E…fifth space; 31F…sixth space

[0117] 32…Separator

[0118] 34…Gas guide path

[0119] 40… Tags

[0120] 51…First cooling plate

[0121] 52 ... second cooling plate; 52a ... hole area

[0122] 53 ... insulating plate; 53a ... opening area

[0123] 54…Buffer

[0124] 60…Obstacle wall

[0125] 61…The first barrier

[0126] 62…Second barrier

[0127] 63…The Third Obstacle

[0128] 64…through area

[0129] 701…Secondary battery cell

[0130] 702…Battery module

[0131] 710…External housing

[0132] 711…Upper housing

[0133] 714…Top surface of upper shell

[0134] 734…Discharge path

[0135] 735…wall

[0136] VX…cyclone.

Claims

1. A battery pack comprising: a plurality of secondary battery cells; and an outer casing accommodating the plurality of secondary battery cells, The outer casing has a gas discharge hole opened on a portion of its surface. The outer casing includes a discharge guide member inside thereof, which defines a gas guide path, wherein: The gas guide path guides the gas to the gas discharge hole when the gas is released from any one of the plurality of secondary battery cells. The exhaust guide includes an inclined wall that is inclined in a posture facing the exhaust direction of the gas.

2. The battery pack according to claim 1, wherein: When gas is released from any one of the plurality of secondary battery cells in a plan view, the inclined wall extends in a posture intersecting with a discharge direction of the gas.

3. The battery pack according to claim 2, wherein: The inclined wall is integrally provided on the inner surface of the outer casing.

4. The battery pack according to claim 1, wherein: The gas guide path includes a pressure reducing structure for reducing the pressure of the high-pressure gas. The pressure reducing structure is provided in front of the gas discharge hole inside the outer casing. The inclined wall is formed at a height difference portion of the gas guide path formed by the pressure reducing structure.

5. The battery pack according to claim 4, wherein: The outer casing is formed into an outer shape extending in one direction. The inclined wall is inclined along an extension direction of the outer casing.

6. The battery pack according to claim 5, wherein: The inclined walls are formed in a plurality of lines along the extension direction of the outer casing.

7. The battery pack according to claim 6, wherein: The inclined walls are formed in a staggered shape along an extension direction of the outer casing.

8. The battery pack according to any one of claims 1 to 7, wherein: The battery pack further comprises: a battery holder for holding the plurality of secondary battery cells; The gas guide path is formed in a region where one surface of the battery holder faces the inner surface of the outer case.

9. The battery pack according to any one of claims 1 to 7, wherein: The outer casing is made of resin.

10. The battery pack according to any one of claims 1 to 7, wherein: The inclined wall includes a curved surface.

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