power storage module

Abstract

The battery pack (1) includes: a housing (10); a plurality of batteries (30) housed within the housing (10); a coolant (50) filled within the housing (10); a first retainer (61) disposed within the housing (10) and housing the upper portion of the batteries (30); and a heat insulation member (90) located around the plurality of batteries (30) and disposed on the lower surface of the first retainer (61), wherein the plurality of batteries (30) are immersed in the coolant (50) within the housing (10).

Description

Technical Field

[0001] This disclosure relates to an energy storage module that houses multiple energy storage devices. Background Technology

[0002] Traditionally, energy storage modules have achieved specified capacity and voltage by housing multiple energy storage devices and connecting them in parallel or series. Other energy storage devices include secondary batteries such as lithium-ion batteries and capacitors.

[0003] In conventional energy storage modules, the energy storage device generates heat during charging and discharging, thus requiring cooling. For example, in battery packs that use batteries as energy storage devices and have energy storage modules that house multiple batteries, liquid immersion cooling using an insulating coolant is known as a cooling method.

[0004] Patent document 1 discloses the following technology: a cooling method using coolant is adopted, in which gas is generated due to battery abnormality, the gas is not directly discharged to the outside, but is discharged to the outside through other spaces in the battery pack, thereby suppressing the flow of coolant to the outside.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-276997 Summary of the Invention

[0008] One embodiment of the present disclosure provides an energy storage module comprising: a housing; a plurality of energy storage devices housed within the housing; a coolant filling the housing; a retainer disposed within the housing and housing the upper portion of the energy storage devices; and a heat insulation member located around the plurality of energy storage devices and disposed on the lower surface of the retainer, wherein the plurality of energy storage devices are immersed in the coolant within the housing.

[0009] According to this disclosure, it is possible to prevent the coolant, which becomes hot when one energy storage device overheats, from reaching the upper part of other batteries, thereby suppressing abnormalities in other batteries. Attached Figure Description

[0010] Figure 1 This is a perspective view of a battery pack, which is an example of an energy storage module involved in the implementation method.

[0011] Figure 2 It is along Figure 1 A planar cross-sectional view viewed from the AA direction.

[0012] Figure 3 This is a top view showing the structure of the first retainer.

[0013] Figure 4 This is a top view showing the structure of the thermal insulation component.

[0014] Figure 5 This is a cross-sectional view showing an example of the structure of a battery.

[0015] Figure 6 It shows along Figure 1 Figures of other examples of planar cross-sections viewed from the AA direction. Detailed Implementation

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, the following embodiments do not limit the present disclosure, and structures selectively combined from multiple examples are also included in the present disclosure.

[0017] The energy storage device disclosed herein can be either a secondary battery using an aqueous electrolyte or a secondary battery using a non-aqueous electrolyte. The energy storage device disclosed herein can be a cylindrical battery with a cylindrical (e.g., a bottomed cylindrical) outer can, a square battery with a square outer can, or a pouch-type battery with an outer body composed of laminated sheets. In these batteries, the cylindrical outer can, the square outer can, and the laminated sheets constitute the outer body. Alternatively, the energy storage device disclosed herein can also be a capacitor capable of repeated charging and discharging.

[0018] In addition, in this disclosure, a battery pack containing multiple batteries within a casing is used as an energy storage module.

[0019] "Structure of the battery pack"

[0020] Figure 1 This is a perspective view of a battery pack 1, which is an example of an energy storage module according to an embodiment. The battery pack 1 houses multiple batteries within a housing 10. Furthermore, an insulating coolant is stored inside the housing 10, and at least a portion of the batteries is immersed in the coolant. Additionally, the battery 30 is sometimes referred to as an "energy storage device." Furthermore, the battery pack 1 is sometimes referred to as an "energy storage module."

[0021] The housing 10 is made of a metal such as aluminum and has a generally rectangular shape. However, the housing 10 is not limited to being made of metal and may also be made of resin. Furthermore, the shape of the housing 10 is not limited to a generally rectangular shape. The housing 10 serves to protect the battery 30 housed inside from dust and water.

[0022] Battery pack 1 can be used as a power source for motor-driven electric devices such as electric cars, power tools, electric-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric vehicles. However, the application of battery pack 1 is not specific, and it can also be used as a power source for electrical devices other than electric devices, such as cleaners, cordless phones, lighting fixtures, digital cameras, and camcorders used indoors and outdoors.

[0023] Figure 2 yes Figure 1 AA cross-section diagram (schematically showing the cross-section when cut by the XZ plane through the center in the width direction of battery pack 1).

[0024] The battery pack 1 includes a battery block 20 that houses multiple batteries 30 inside the housing 10. In this example, cylindrical lithium-ion batteries are used as the batteries 30. A cover 45 is disposed on the top of the battery 30.

[0025] Coolant 50 is stored inside the casing 10, and at least a portion of the battery 30 is immersed in the coolant 50. In this example, the entire battery 30 is immersed in the coolant 50.

[0026] The coolant 50 is insulating. This prevents leakage of current from multiple batteries 30 via the coolant 50. Examples of coolant 50 include insulating oil, trans oil, silicone oil, hydrofluoroether, and other fluorine-based inert liquids.

[0027] The battery block 20 includes a plurality of batteries 30 and a retainer 60 for holding the batteries 30. The retainer 60 includes a first retainer 61 for holding the upper end of the battery 30 and a second retainer 62 for holding the lower end. The two ends of the plurality of batteries 30 in the Z direction are respectively inserted into and held in the first retainer 61 and the second retainer 62.

[0028] An exhaust chamber 12 is formed in the upper part of the housing 10 for gas discharged from the safety valve of the battery 30 to flow in. The exhaust chamber 12 is formed between the top plate of the housing 10 and the first retainer 61. The exhaust chamber 12 is formed on the surface of the coolant inside the housing 10, and an exhaust port 14 is provided on a part of the side wall of the housing 10 to discharge the gas in the exhaust chamber 12 to the outside of the housing 10. Therefore, if the pressure inside the battery 30 rises when the battery 30 overheats abnormally, the gas generated inside the battery 30 is discharged to the outside of the housing 10 through the safety valve, the exhaust chamber 12, and the exhaust port 14.

[0029] "Structure of the retaining component"

[0030] As described above, the retainer 60 of the battery block 20 includes a plurality of batteries 30, a first retainer 61 that retains the upper end of the battery 30, and a second retainer 62 that retains the lower end of the battery 30.

[0031] Figure 3 This is a view of the first retainer 61 from above. As shown, the first retainer 61 includes a cylindrical recess 63 on the upper shoulder of the battery 30 and an opening 64 that exposes the upper surface of the cover 45 of the battery 30. The recess 63 is formed on the lower surface of the first retainer 61, and is circular when viewed from below in the Z direction, with concave cross-sections in the X and Y directions.

[0032] The opening 64 is formed as a circular hole with a diameter smaller than that of the circular shape of the recess 63 when viewed from below in the Z direction. In addition, when viewed from below in the Z direction, the center of the recess 63 and the center of the opening 64 are formed to be the same.

[0033] Preferably, a positive electrode wire is provided on the surface of the first retainer 61, from which a positive electrode lead extends into the opening 64 and connects to the positive external terminal of the battery 30. Alternatively, the cover 45 can be provided as the positive external terminal. Furthermore, depending on the battery 30, a negative external terminal may sometimes be removed from the top. In this case, a negative electrode wire can also be provided on the first retainer 61 and connected to the negative external terminal of the battery 30 via a negative electrode lead.

[0034] The second retainer 62 holds the lower shoulder of the battery 30, but the first retainer 61 can be reversed to have the same structure.

[0035] The retaining element 60 (61, 62) may be made of, for example, highly thermally conductive PPS (polyphenylene sulfide) resin, resin containing heat-dissipating filler, or thermosetting resin capable of injection molding. More specifically, the retaining element 60 may also be made of phenolic resin, unsaturated polyester, or unsaturated polyester mixed with a heat-absorbing agent. Furthermore, the retaining element 60 may also be made of inorganic minerals such as mica, or a material in which inorganic minerals such as mica are mixed into a resin material.

[0036] Furthermore, when the battery 30 overheats abnormally, the gas discharged from the safety valve of the battery 30 can flow into the exhaust chamber 12 through the opening 64.

[0037] "Structure of thermal insulation components"

[0038] In this embodiment, a heat insulation member 90 is provided to cover the lower side of the first retainer 61.

[0039] Figure 4 This is a view of the heat insulation member 90 from below with the battery 30 removed. As shown, the heat insulation member 90 has an opening 91 corresponding to the size of the battery 30. When the heat insulation member 90 is viewed from below with the battery 30 removed, the recess 63 of the first retainer 61 can be seen through the opening 91.

[0040] The heat insulation member 90 can be pre-formed on the lower surface of the first retainer 61 before the battery 30 is inserted into the opening 91, or the heat insulation member 90 can be inserted after the battery 30 is housed in the recess 63 of the first retainer 61. In addition, the lower surface of the first retainer 61 and the upper surface of the heat insulation member 90 can also be bonded together with an adhesive or the like.

[0041] The thermal conductivity of the insulation element 90 is lower than that of the first retaining element 61, and it can be formed from foamed resin with independent air bubbles, ceramics, mica board, glass epoxy resin, etc.

[0042] In this embodiment, a heat insulation member 90 is disposed on the lower side of the first retainer 61 at the upper end of the battery 30. That is, the heat insulation member 90 is located between the first retainer 61 and the coolant.

[0043] In the event that the coolant below the heat insulation member 90 located around the battery 30 becomes hot due to an abnormal thermal runaway, the hot coolant concentrates above, i.e., below the heat insulation member 90. Therefore, the heat propagation of the hot coolant is blocked by the heat insulation member 90, preventing heat transfer in the first retaining member 61 and thus preventing the resin components of the battery 30 from melting and softening.

[0044] Therefore, in the event of thermal runaway of a battery 30, it is possible to prevent the normal surrounding batteries 30 from short-circuiting and thus preventing the battery pack 1 from becoming dangerous.

[0045] "Battery Structure"

[0046] Figure 5 This is a cross-sectional view showing a structural example of a battery 30 as an energy storage device. Battery 30 is a cylindrical battery and is a lithium-ion battery. However, battery 30 is not limited to a cylindrical battery; it can also be a prismatic battery, a laminated battery, etc. Furthermore, battery 30 can be either an aqueous battery or a non-aqueous battery. As an example of a non-aqueous battery, a lithium-ion battery is preferred.

[0047] The battery 30 has an electrode body 34, an electrolyte (not shown), and an outer casing 35 that houses the electrode body 34 and the electrolyte. The electrode body 34 has a positive electrode 31, a negative electrode 32, and a separator 33, and has a spiral winding structure in which the positive electrode 31 and the negative electrode 32 are wound together with the separator 33 in between.

[0048] The outer casing 35 is a bottomed cylindrical shape with an opening on the upper side, and the opening of the outer casing 35 is blocked by the sealing body 36.

[0049] The battery 30 has insulating plates 37 and 38 respectively disposed above and below the electrode body 34. Figure 3In the example shown, the positive lead 39, installed on the positive electrode 31, extends towards the sealing body 36 through the through hole in the insulating plate 37, and the negative lead 40, installed on the negative electrode 32, extends towards the bottom of the outer casing 35 through the outer side of the insulating plate 38. The positive lead 39 is connected to the lower surface of the bottom plate of the sealing body 36, i.e., the inner terminal plate 41, by welding or the like, and the top plate of the sealing body 36, i.e., the cover 45, which is electrically connected to the inner terminal plate 41, becomes the positive external terminal. The negative lead 40 is connected to the inner bottom surface of the outer casing 35 by welding or the like, and the bottom of the outer casing 35 becomes the negative external terminal.

[0050] 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 sequentially from the electrode body 34 side. The components constituting the sealing body 36 are, for example, disc-shaped or annular, and all components except the insulating member 43 are electrically connected to each other. The lower valve body 42 and the upper valve body 44 are connected to each other through their respective central portions, and the insulating member 43 is located between the peripheral portions.

[0051] Furthermore, the periphery of the sealing body 36, which is composed of an internal terminal plate 41, a lower valve body 42, an insulating member 43, an upper valve body 44, and a cover 45, is covered by a resin gasket 46 and an outer casing 35 located on its outer side. That is, by riveting the outer casing 35 in a manner that encloses the periphery of the sealing body 36, the periphery of the sealing body 36 is sealed using the gasket 46.

[0052] Furthermore, the lower valve body 42, the upper valve body 44, and the cover 45 constitute a safety valve for the sealing body 36. If the internal pressure rises when the battery 30 overheats abnormally, the lower valve body 42 deforms and breaks by pushing the upper valve body 44 upward toward the cover 45, thus cutting off the current path between the lower valve body 42 and the upper valve body 44. When the internal pressure rises further, the upper valve body 44 breaks, and gas is discharged from the vent hole 45A formed on the side surface of the protrusion of the cover 45.

[0053] Other structural examples

[0054] Figure 6 This figure shows another structural example of the heat insulation member 90. In this example, the heat insulation member 90 is not only disposed on the lower surface of the first retainer 61, but also disposed on the upper side surface and the peripheral portion of the upper surface in a manner that covers the upper shoulder of the battery 30. With this structure, it is also possible to prevent high-temperature coolant from reaching the periphery of the sealing body.

[0055] Explanation of reference numerals in the attached figures

[0056] 1: Battery pack (energy storage module);

[0057] 10: Shell;

[0058] 12: Exhaust chamber;

[0059] 20: Battery pack;

[0060] 30: Battery (energy storage device);

[0061] 31: Positive electrode;

[0062] 32: Negative electrode;

[0063] 33: Separator;

[0064] 34: Electrode body;

[0065] 35: Exterior body;

[0066] 36: Sealing body;

[0067] 37: Insulating board;

[0068] 38: Insulating board;

[0069] 39: Positive lead;

[0070] 40: Negative lead;

[0071] 41: Internal terminal block;

[0072] 42: Lower valve body;

[0073] 43: Insulating components;

[0074] 44: Upper valve body;

[0075] 45: Cover;

[0076] 45A: Exhaust port;

[0077] 46: Washer;

[0078] 50: Coolant;

[0079] 60: Retaining element;

[0080] 61: First retainer;

[0081] 62: Second retainer;

[0082] 63: concave part;

[0083] 64: Opening;

[0084] 90: Thermal insulation components;

[0085] 91: Opening.

Claims

1. An electricity storage module comprising: a case; a plurality of electricity storage devices housed in the case; a coolant filled in the case; a holder disposed in the case to house upper portions of the electricity storage devices; and a heat insulating member disposed on a lower surface of the holder at a periphery of the plurality of electricity storage devices, wherein the plurality of electricity storage devices are immersed in the coolant in the case.

2. The electricity storage module according to claim 1, wherein the heat insulating member is in contact with side surfaces of the plurality of electricity storage devices to prevent the coolant located below the heat insulating member from reaching top portions of the plurality of electricity storage devices. ​ ​ ​ ​ ​ ​ ​ ​

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