Battery pack

Abstract

A battery pack is provided with: a battery in which a lid, which is the top surface of a sealing body as an external terminal, is provided on one side in the Z direction, and in which internal gas is discharged from one side in the Z direction when internal pressure rises; a first holder that holds one side in the Z direction of the plurality of batteries arranged side by side, and that has an opening that exposes the lid; and a collector plate which is provided on one side of the first holder, closes a part of the opening, and is connected to the cover, a first protrusion is formed on a surface on one side of the first holder in the Z direction, and a gap is formed between the surface on one side of the first holder in the Z direction and the collector plate by being provided on the first holder in contact with the first protrusion by the collector plate.

Description

Technical Field

[0001] The present invention relates to a battery pack accommodating a plurality of batteries. Background Art

[0002] In a battery pack, a plurality of batteries are housed in an outer casing in a manner corresponding to a device in which the batteries are used. In a battery pack, a plurality of batteries arranged in a row are held by a holder, and the plurality of batteries are electrically connected to each other by a current collector plate (for example, Patent Document 1).

[0003] When a battery stored in a battery pack goes into thermal runaway due to some abnormality, the high-temperature internal gas discharged from the battery in thermal runaway comes into contact with the batteries held in the same holder (hereinafter referred to as peripheral batteries), which may cause the peripheral batteries to go into thermal runaway and cause a chain reaction of thermal runaway. Therefore, it is necessary to reliably discharge the internal gas discharged from the battery in thermal runaway to the outside of the holder without contacting the peripheral batteries.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-002199 Summary of the invention

[0007] In addition, in the battery, a gas discharge valve is provided on one side in the longitudinal direction. With this structure, when thermal runaway occurs, the internal pressure of the battery rises and the gas discharge valve operates to discharge the internal gas from one side in the longitudinal direction. On the other hand, there is a case where an external terminal is provided on one side in the longitudinal direction of the battery. Therefore, an opening for exposing the external terminal is provided in a retaining frame that holds one side in the longitudinal direction of the battery, and a collector lead of a collector plate is connected to the external terminal exposed from the opening.

[0008] In the above structure, when the internal gas of the battery is exhausted, the internal gas is exhausted from the opening of the holder. However, since the collector lead of the collector plate blocks part of the opening, there is a case where part of the exhaust gas is blocked by the collector lead. In recent years, due to the large-scale and high-output batteries, the wide-width collector leads have increased, and the above tendency has become more obvious.

[0009] When the discharge of internal gas is blocked by the current collecting lead, the discharge of internal gas to the outside of the holder is hindered, and the high-temperature internal gas flows into the inside of the holder and contacts the surrounding batteries, which may cause thermal runaway of the surrounding batteries, thereby causing a chain reaction of thermal runaway.

[0010] Therefore, an object of the present invention is to provide a battery pack capable of reliably discharging high-temperature internal gas discharged from a battery to the outside of a holder when the battery thermally runs away.

[0011] The battery pack of the present invention is characterized in that it comprises: a battery having an external terminal on one side in the longitudinal direction, and the battery discharges internal gas from one side in the longitudinal direction when the internal pressure rises; a retaining frame having an opening on one side in the longitudinal direction for exposing the external terminal for retaining a plurality of batteries arranged in an arranged manner; and a collector plate provided on one side of the retaining frame, sealing a portion of the opening and connected to the external terminal, a first protrusion being formed on a surface on one side in the longitudinal direction of the retaining frame, and the collector plate being provided on the retaining frame so as to abut against the first protrusion, thereby forming a gap between the surface on one side in the longitudinal direction of the retaining frame and the collector plate.

[0012] According to the battery pack of the present invention, when the battery thermally runs away, the high-temperature internal gas exhausted from the battery can be reliably exhausted to the outside of the holder. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing a battery pack as an example of an embodiment.

[0014] Figure 2 It is a cross-sectional view showing a battery pack as an example of an embodiment.

[0015] Figure 3 It is a cross-sectional view showing a battery as an example of an embodiment.

[0016] Figure 4 It is a plan view showing a retainer and a current collector plate as an example of an embodiment.

[0017] Figure 5 It is a plan view showing a retainer and a current collector plate as another example of the embodiment. DETAILED DESCRIPTION

[0018] In the following description, specific shapes, materials, directions, numerical values, etc. are given for easy understanding of the present invention and can be appropriately changed according to the application, purpose, specification, etc.

[0019] <Battery Pack>

[0020] use Figure 1 A battery pack 10 as an example of the embodiment will be described.

[0021] In the battery pack 10, a plurality of battery modules 20 are housed in an outer casing 11 in a manner corresponding to the device to be used. In each battery module 20, a plurality of (in Figure 1 In the example shown, two batteries 30 are fixed to each other by a holder and housed in an outer casing 11. With the battery pack 10, when the battery 30 thermally runs away, the high-temperature internal gas discharged from the battery 30 can be reliably discharged to the outside of the holder, as will be described in detail later.

[0022] Hereinafter, the components will be described with the longitudinal direction of the battery 30 being the Z direction, the direction perpendicular to the Z direction and in which the battery 30 is arranged in the battery module 20 being the X direction, and the direction perpendicular to the Z direction and the X direction being the Y direction. Figure 3 ) of the top plate, that is, the cover 45 (refer to Figure 3 ) is set as one side, and the side opposite thereto is set as the other side.

[0023] The battery pack 10 is mainly used as a power source for power. For example, the battery pack 10 is used as a power source for electric devices driven by motors, such as electric vehicles, electric tools, electric power-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the use of the battery pack 10 is not specific, and it can also be used as a power source for various electric devices used indoors and outdoors, such as cleaners, wireless devices, lighting devices, digital cameras, and video cameras, etc., other than electric devices.

[0024] The battery pack 10 has a plurality of Figure 1 In the example shown, there are two battery modules 20 each including a battery 30 and an outer casing 11 that accommodates the plurality of battery modules 20 .

[0025] The battery module 20 has a plurality of batteries 30 which will be described in detail later and arranged in an array. Figure 1 In the example shown, three battery modules 20 are connected in series, and a voltage corresponding to the device used is output. In the battery module 20, a plurality of batteries 30 are connected in parallel. The battery module 20 will be described in detail later.

[0026] The outer casing 11 is made of a metal such as aluminum and is cylindrical. However, the outer casing 11 is not limited to being made of metal and may be made of resin. A battery pack external terminal 12 electrically connected to the battery module 20 is provided at the end on the other side of the outer casing 11 in the Z direction. When the battery pack 10 is assembled in a device that carries the battery pack 10 and is used, the battery pack external terminal 12 is used as a terminal for supplying a DC voltage. The battery pack external terminal 12 is also used when charging the battery pack 10. In addition, an exhaust hole 13 is provided on the side of the outer casing 11 (see Figure 2 ), the exhaust hole 13 discharges the high-temperature internal gas discharged from the battery 30 in thermal runaway to the outside of the battery pack 10.

[0027] <Battery Module>

[0028] use Figure 2 A battery module 20 as an example of the embodiment will be described.

[0029] The battery module 20 includes: two batteries 30; a first holder 50, which is a holder on one side of the Z direction for holding the two batteries 30; a collector plate 60, which is in contact with a surface of one side of the first holder 50 and is in contact with a sealing body 36 (see Figure 3 ) is connected to the top plate, that is, the cover 45; a second holder 55, which holds the other side of the two batteries 30 in the Z direction; and a collector lead 65, which is connected to the outer can 35 (reference Figure 3 ) is connected to the bottom of the battery 30. The battery 30, the first holder 50 and the collector plate 60 will be described in detail later. Among the plurality of battery modules 20 connected in series in the battery pack 10, the collector plate 60 of the battery module 20 closest to one side in the Z direction corresponds to the total positive, and the collector lead 65 of the battery module 20 closest to the other side in the Z direction corresponds to the total negative, and is electrically connected to the battery pack external terminal 12 (not shown).

[0030] <Battery>

[0031] use Figure 2 and Figure 3 A battery 30 as an example of an embodiment will be described.

[0032] The battery 30 is a cylindrical battery and a lithium ion battery. However, the battery 30 is not limited to a cylindrical battery, and may be a square battery, a stacked battery, etc. In addition, the battery 30 may be an aqueous battery or a non-aqueous battery. As an example of a non-aqueous battery, a lithium ion battery is preferably used.

[0033] like Figure 3 As shown, the battery 30 is provided with a top plate of the sealing body 36, i.e., a cover 45, which serves as a positive electrode external terminal, on one side in the Z direction. When the internal pressure rises during thermal runaway, the internal gas is discharged from the exhaust hole 45A of the cover 45, which will be described in detail later. In other words, in the battery 30, the internal gas is discharged from one side in the Z direction when the internal pressure rises.

[0034] The battery 30 includes an electrode body 34, an electrolyte (not shown), and an outer can 35 for storing the electrode body 34 and the electrolyte. The electrode body 34 includes a positive electrode 31, a negative electrode 32, and a separator 33, and has a winding structure in which the positive electrode 31 and the negative electrode 32 are wound in a spiral shape with the separator 33 interposed therebetween. The outer can 35 has a bottomed cylindrical shape with one side open in the Z direction, and the opening of the outer can 35 is sealed by a sealing body 36.

[0035] The battery 30 includes insulating plates 37 and 38 disposed above and below the electrode body 34, respectively. Figure 3In the example shown, the positive electrode lead 39 attached to the positive electrode 31 extends to the sealing body 36 side through the through hole of the insulating plate 37, and the negative electrode lead 40 attached to the negative electrode 32 extends from the outside of the insulating plate 38 to the bottom side of the outer can 35. The positive electrode lead 39 is connected to the bottom plate of the sealing body 36, that is, the lower surface of the internal terminal plate 41, by welding or the like, and the top plate of the sealing body 36, that is, the cover 45, which is electrically connected to the internal terminal plate 41, serves as the positive electrode external terminal. The negative electrode lead 40 is connected to the bottom inner surface of the outer can 35 by welding or the like, and the bottom of the outer can 35 serves as the negative electrode external terminal.

[0036] The sealing body 36 has a structure in which an internal terminal plate 41, a lower valve body 42, an insulating member 43, an upper valve body 44, and a cover 45 are stacked in order from the electrode body 34 side. The components constituting the sealing body 36 are, for example, disc-shaped or ring-shaped, and the components except the insulating member 43 are electrically connected to each other. The lower valve body 42 and the upper valve body 44 constituting the so-called gas exhaust valve are connected to each other at their respective central portions, and the insulating member 43 is interposed between their respective peripheral portions.

[0037] In the gas discharge valve, if the internal pressure rises when the battery 30 thermally runs away, the lower valve body 42 is deformed and broken in a manner that pushes the upper valve body 44 toward the cover 45 side, and the current path between the lower valve body 42 and the upper valve body 44 is cut off. If the internal pressure rises further, the upper valve body 44 breaks, and the internal gas is discharged from the exhaust hole 45A formed on the side of the convex part of the cover 45. However, this embodiment is not limited to this, and a structure in which a gas discharge valve is provided on the other side in the Z direction, that is, the bottom of the outer tank 35, and the internal gas is discharged from the other side in the Z direction when the internal pressure rises.

[0038] <Retainer>

[0039] use Figure 2 and Figure 4 The first holder 50 as an example of the embodiment will be described.

[0040] As described above, the first holding frame 50 holds one side in the Z direction of the two batteries 30. However, the number of batteries held by the first holding frame 50 is not limited to the present embodiment.

[0041] The first holder 50 may be made of, for example, a highly thermally conductive PPS (polyphenylene sulfide) resin, a resin containing a heat dissipating filler, a thermosetting resin capable of injection molding, etc. More specifically, the first holder 50 may be made of a phenolic resin, an unsaturated polyester, or an unsaturated polyester mixed with a heat absorbent, etc. The first holder 50 may also be made of an inorganic mineral such as mica, or a material obtained by mixing an inorganic mineral such as mica into a resin material.

[0042] like Figure 2 and Figure 4As shown, the first holder 50 is formed into a rounded shape when viewed from the Z direction, and has a predetermined thickness in the Z direction. The first holder 50 has a storage portion 51 (see FIG. 5 ) for storing the battery 30. Figure 2 ), an opening 52 for exposing the cover 45 serving as the positive external terminal of the battery 30, and a plurality of first protrusions 53 formed on the surface on one side in the Z direction.

[0043] like Figure 2 As shown, the storage portion 51 is formed on the surface of the other side in the Z direction of the first holding frame 50. The storage portion 51 is formed to be circular when viewed from the other side in the Z direction and to be a recessed portion when viewed from the X direction or the Y direction. The end of one side in the Z direction of the battery 30 is fitted into the storage portion 51, and one side of the battery 30 is held.

[0044] like Figure 2 and Figure 4 As shown, the opening 52 is formed to penetrate the storage portion 51. More specifically, the opening 52 is formed as a circular hole with a diameter smaller than the diameter of the circular shape of the storage portion 51 when viewed from the other side in the Z direction. However, the center of the storage portion 51 and the center of the opening 52 are formed to be the same center.

[0045] The opening 52 can expose the lid 45, which is the top plate of the sealing body 36 and serves as the positive terminal of the battery 30, and connect the lid 45 to the collector plate 60. In addition, the opening 52 can discharge the internal gas discharged from the battery 30 to the outside of the first holder 50 when the battery 30 thermally runs away.

[0046] like Figure 4 As shown, as described above, the first protrusion 53 is formed on the surface of one side in the Z direction. The surface of one side in the Z direction of the first protrusion 53 is formed flat for abutment by the main body 61 of the collector plate 60 described later. The area where the first protrusion 53 is formed in the overall area of ​​the XY plane of the first retainer 50 is preferably 50% or less. In the present embodiment, the shape of the first protrusion 53 is set to a cylindrical shape, but there is no particular limitation. In addition, the number of the first protrusions 53 is not particularly limited.

[0047] Here, when the internal pressure of the battery 30 increases when the battery 30 thermally runs away, the gas is discharged from the vent hole 45A (see Figure 3 ) to discharge the internal gas, and discharge the internal gas from the opening 52 of the first retainer 50. However, since a part of the opening 52 is blocked by the collector lead 62 of the collector plate 60 described later, there is a case where a part of the discharged internal gas is blocked by the collector lead 62.

[0048] In the portion where the discharge of internal gas is blocked by the collector lead 62, the internal gas flows into the interior of the first retaining frame 50, and the high-temperature internal gas contacts the battery 30 retained inside the first retaining frame 50, which may cause thermal runaway of the battery 30 retained inside the first retaining frame 50, thereby causing a chain reaction of thermal runaway.

[0049] By using the first protrusion 53, a gap is formed between the first holder 50 and the collector plate 60, and the portion of the opening 52 of the first holder 50 blocked by the collector lead 62 of the collector plate 60 can reliably discharge the internal gas discharged from the battery 30 from the above gap to the outside of the first holder 50. Thus, it is possible to avoid a situation in which, when one battery 30 of the battery module 20 thermally runs away, the internal gas flows into the inside of the first holder 50, causing the battery 30 held inside the first holder 50 to thermally run away, thereby preventing a chain reaction of thermal runaway.

[0050] In addition, not limited to the present embodiment, in the case of a structure in which a gas exhaust valve is provided on the other side in the Z direction, i.e., at the bottom of the outer tank 35, and the internal gas is exhausted from the other side in the Z direction when the internal pressure rises, the first protrusion 53 may be provided on the second retaining frame 55.

[0051] <Current collector>

[0052] use Figure 4 The current collector plate 60 as an example of the embodiment will be described.

[0053] The collector plate 60 is provided on one side of the first holder 50 and is connected to the cover 45 which is the positive external terminal of the battery 30. More specifically, the collector plate 60 connects the covers 45 which are the positive terminals of the two batteries 30 held in the first holder 50 to each other. The collector plate 60 is made of a metal plate such as an aluminum plate or a copper plate. The collector plate 60 has a main body 61 which abuts against the first protrusion 53 described later of the first holder 50 and a collector lead 62 connected to the cover 45.

[0054] The main body 61 has a shape substantially the same as the oval shape of the first holder 50 as viewed from the Z direction, and is provided on the first holder 50 in contact with the first protrusion 53 of the first holder 50. An opening 63 is formed at a position of the main body 61 corresponding to the opening 52 of the first holder 50. In addition, other current collecting leads 65 and the like connected to the negative terminals of other battery modules 20 are connected to the main body 61.

[0055] The current collecting lead 62 extends from the edge of the opening 63, and is electrically connected to the cover 45 by being welded to the cover 45. As described above, the current collecting lead 62 blocks a part of the opening 52 of the first holder 50.

[0056] Summary

[0057] The battery pack 10 of the present embodiment comprises: a battery 30, which is provided with a top plate of a sealing body 36, i.e., a cover 45, which serves as a positive electrode external terminal on one side in the Z direction, and discharges internal gas from a vent 45A of the cover 45 when the internal pressure rises; a first retaining frame 50, which retains a plurality of batteries 30 arranged in an arranged manner on one side in the Z direction and has an opening 52 for exposing the cover 45; and a collector plate 60, which is provided on one side of the first retaining frame 50, blocks a portion of the opening 52 and is connected to the cover 45, a first protrusion 53 is formed on a surface on one side in the Z direction of the first retaining frame 50, and the collector plate 60 is provided on the first retaining frame 50 in contact with the first protrusion 53, thereby forming a gap between the surface on one side in the Z direction of the first retaining frame 50 and the collector plate 60.

[0058] By setting the above structure, when the battery 30 thermally runs away, the internal gas discharged from the battery 30 is not blocked by the collector lead 62, but is discharged to the outside of the first holder 50 through the gap formed between the surface of one side of the first holder 50 in the Z direction and the collector plate 60. As a result, it is possible to avoid a situation in which, when one battery 30 of the battery module 20 thermally runs away, the high-temperature internal gas flows into the inside of the first holder 50, the high-temperature internal gas contacts the battery 30 held inside the first holder 50, and the battery 30 held inside the first holder 50 thermally runs away, thereby causing a chain reaction of thermal runaway.

[0059] <Other embodiments>

[0060] use Figure 5 The first holder 70 and the current collector plate 80 as another example of the embodiment will be described.

[0061] The first holder 70 has a storage portion (not shown), an opening 72, a first protrusion 73 formed on a surface on one side in the Z direction, and a second protrusion 74 formed on a surface on one side in the Z direction of the first protrusion 73. The storage portion and the opening 72 are the same as the storage portion 51 and the opening 52 of the first holder 50 described above, and therefore description thereof is omitted.

[0062] The first protrusion 73 is formed on the surface on one side in the Z direction at the middle part in the X direction between the opening 72 on one side of the first holder 70 and the opening 72 on the other side. The first protrusion 73 is formed in a rectangular shape with rounded corners when viewed from the Z direction. The main body 81 of the collector plate 80 described later abuts against the surface on one side in the Z direction of the first protrusion 73. As a result, a gap is formed between the first holder 70 and the collector plate 80, and the portion of the opening 72 of the first holder 70 blocked by the collector lead 82 of the collector plate 80 can reliably discharge the internal gas discharged from the battery 30 to the outside of the first holder 70.

[0063] The second protrusion 74 is formed on one side of the surface in the Z direction at the middle portion between the X direction and the Y direction of the first protrusion 73. The second protrusion 74 is formed in a rectangular shape with rounded corners when viewed from the Z direction. The surface on one side of the Z direction of the second protrusion 74 is fitted into the positioning opening 83 of the collector plate 80 described later. Thus, the collector plate 80 is positioned relative to the first holder 70.

[0064] The collector plate 80 is provided on one side of the first holder 70 and is connected to the cover 45 which is the positive external terminal of the battery 30. More specifically, the collector plate 80 connects the covers 45 which are the positive terminals of the batteries 30 held by the first holder 70 to each other. The collector plate 80 is made of a metal plate such as an aluminum plate or a copper plate. The collector plate 80 includes a main body 81 which abuts against one side of the surface of the first protrusion 73 in the Z direction and a collector lead 82 connected to the cover 45.

[0065] The main body 81 is formed in a square shape with rounded corners when viewed from the Z direction, and abuts against the first protrusion 73 of the first holder 70. In addition, the collector lead 65 connected to the negative terminal of the other battery module 20 is connected to the main body 81. In addition, a positioning opening 83 is formed in the center of the main body 81 in the X direction and the Y direction. The above-mentioned second protrusion 74 is fitted into the positioning opening 83.

[0066] The current collecting lead 82 extends from the main body 81 and is electrically connected to the cover 45 by being welded to the cover 45. As described above, the current collecting lead 82 blocks a portion of the cover 45 exposed from the opening 72 of the first holder 70.

[0067] In addition, the shape and size of the main body 81 are not limited to the present embodiment, and the size of the positioning opening 83 may be enlarged together with the size of the main body 81 to include at least a portion of the opening 72 on one side of the first holder 70 and the opening 72 on the other side, and the overall shape of the collector plate 80 may be set to be in the shape of a Japanese katakana when viewed from the Z direction. In this case, the first protrusion 53 is formed on the surface of one side of the first holder 70 in the Z direction instead of the first protrusion 73 and the second protrusion 74, and the main body 81 is brought into contact with the first protrusion 53. Thus, a gap is formed between the first holder 70 and the collector plate 80, and the internal gas discharged from the battery 30 can be reliably discharged to the outside of the first holder 70.

[0068] In addition, the present invention is not limited to the above-described embodiment and its modified examples, and it goes without saying that various changes and improvements can be made within the scope of the matters described in the claims of the present application.

[0069] Description of Reference Numerals

[0070] 10. Battery pack; 11. External casing; 12. External terminal of battery pack; 13. Exhaust hole; 20. Battery module; 30. Battery; 31. Positive electrode; 32. Negative electrode; 33. Diaphragm; 34. Electrode body; 35. External can; 36. Sealing body; 37. Insulating plate; 38. Insulating plate; 39. Positive electrode lead; 40. Negative electrode lead; 41. Internal terminal plate; 42. Lower valve body; 43. Insulating member; 44. Upper valve body ; 45. Cover (positive external terminal); 45A. Exhaust hole; 50. First retaining frame; 51. Storage portion; 52. Opening; 53. First protrusion; 55. Second retaining frame; 60. Collector plate; 61. Main body; 62. Collector lead; 63. Opening; 65. Collector lead; 72. Opening; 73. First protrusion; 74. Second protrusion; 80. Collector plate; 81. Main body; 82. Collector lead; 83. Positioning opening.

Claims

1. A battery pack, wherein: The battery pack has: A battery having an external terminal on one side in the length direction, the battery discharging internal gas from the one side in the length direction when the internal pressure of the battery increases; A holder that holds one side of the length direction of the plurality of batteries arranged in an array and has an opening for exposing the external terminal; as well as a collector plate, which is disposed on one side of the holder, blocks a portion of the opening and is connected to the external terminal, A first protrusion is formed on one side surface of the retainer in the longitudinal direction. The current collector plate is provided on the holder so as to abut against the first protrusion, and a gap is formed between a surface on one side in the longitudinal direction of the holder and the current collector plate.

2. The battery pack according to claim 1, wherein: A second protrusion is formed on one side of the first protrusion in the longitudinal direction. The collector plate is formed with an opening into which the second protrusion is fitted, The opening is fitted with the second protrusion, so that the current collector plate is positioned relative to the holder.

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