Battery pack

Abstract

To enable gas generated from a battery to be discharged to the outside with a simple configuration.SOLUTION: A battery pack 10 includes an exterior body 12, a storage battery 14 housed in the exterior body 12, a battery fixing base material 16 (holding member) that holds the storage battery 14, a bottom member 18 that is provided on the opposite side of the battery fixing base material 16 from the storage battery 14 and that can house a circuit board 30, and an exhaust port 20 that is provided in the exterior body 12 and leads from the inside of the exterior body 12 in which the storage battery 14 is housed to the outside of the exterior body 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] BACKGROUND ART An electricity storage device has been disclosed in which an electricity storage element such as a lithium ion secondary battery and a circuit board are housed in an exterior body (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-16886 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the widespread use of electric vehicles (xEVs), such as hybrid vehicles and electric vehicles, and the increasing number of automobiles equipped with various functions, such as automatic door opening and closing and automatic activation of car navigation systems, have led to an increase in the amount of power supplied to devices while parked, raising the importance of dedicated auxiliary storage batteries, separate from the engine-starting storage battery that supplies the above power. Against this background, there is a growing demand for battery packs using lithium-ion battery packs as dedicated auxiliary storage batteries for vehicles. Lithium-ion batteries (hereinafter sometimes referred to as lithium-ion batteries) use an organic solvent as their electrolyte. If the electrolyte evaporates inside the exterior housing and generates gas, this could potentially affect the circuit boards of BMSs (Battery Management Systems), and measures to address this issue are therefore required.

[0005] An object of the present disclosure is to enable gas generated from a battery to be discharged to the outside using a simple configuration. [Means for solving the problem]

[0006] The battery pack of the first aspect includes an exterior body, a storage battery housed in the exterior body, a holding member that holds the storage battery, a bottom member that is provided on the opposite side of the holding member from the storage battery and that can house a circuit board, and an exhaust port that is provided in the exterior body and leads from the inside of the exterior body in which the storage battery is housed to the outside of the exterior body.

[0007] In this battery pack, a holding member holds the storage batteries and houses them inside an exterior body. The exterior body is also provided with an exhaust port that leads from the inside of the exterior body housing the storage batteries to the outside of the exterior body. Therefore, even if the electrolyte in the storage batteries evaporates and gas is generated, the gas is discharged to the outside of the exterior body through the exhaust port. This eliminates the need for a complex gas discharge path, simplifying the structure.

[0008] In a second aspect, in the battery pack according to the first aspect, the cross-sectional area of ​​the exhaust port is 2 to 15 mm 2 Item 2. The battery pack according to item 1, wherein the battery has a maximum value of 1 / Ah.

[0009] In this battery pack, the cross-sectional area of ​​the exhaust port is appropriately set, so that gas generated from the storage battery can be efficiently exhausted to the outside of the exterior housing.

[0010] A third aspect is the battery pack according to the first or second aspect, wherein the circuit board is isolated from the storage battery.

[0011] In this battery pack, the circuit board is isolated from the storage battery, which prevents gas generated from the storage battery from coming into contact with the circuit board, thereby preventing corrosion of the circuit board due to gas.

[0012] In a fourth aspect, in the battery pack according to the third aspect, a sealant is provided in a portion where the exterior body and the holding member are overlapped.

[0013] In this battery pack, the overlapping portion of the exterior body and the holding member is sealed with a sealant, which prevents gas from flowing from the storage battery housing in the exterior body through the gap between the exterior body and the holding member toward the circuit board, thereby preventing gas generated from the storage battery from coming into contact with the circuit board. [Effects of the Invention]

[0014] According to the present disclosure, gas generated from a battery can be discharged to the outside with a simple configuration. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a battery pack according to an embodiment of the present invention; [Figure 2] 1 is an exploded perspective view showing a battery pack according to an embodiment of the present invention; [Figure 3] 2 is a perspective view of the battery pack according to the embodiment, seen from the bottom side, with the bottom member removed. FIG. [Figure 4] FIG. 10 is a perspective view showing a step portion of the bottom member into which the battery fixing base material fits. [Figure 5] FIG. 2 is a bottom view showing the exterior body and the sealing material. [Figure 6] 4 is a partially enlarged cross-sectional view showing the assembled state of the exterior body, the battery fixing base material, and the bottom member. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. Components indicated by the same reference numerals in each drawing are the same or similar components. Note that duplicated explanations and reference numerals may be omitted in the embodiments described below. Furthermore, all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of each element shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships, ratios, etc. of each element between multiple drawings do not necessarily match.

[0017] In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples.

[0018] 1 and 2, a battery pack 10 according to this embodiment is, for example, a storage battery dedicated to vehicle auxiliaries, and includes an outer casing 12, a storage battery 14, a battery fixing substrate 16 as an example of a holding member, a bottom member 18, and an exhaust port 20.

[0019] The exterior body 12 has, for example, a substantially rectangular parallelepiped shape with a rectangular ceiling portion 12A and sidewall portions 12B extending downward from the four sides of the ceiling portion, and is open at the bottom as shown in FIGS. 1 and 2. A sealant 24 is provided where the exterior body 12 and the battery fixing substrate 16 overlap. As shown in FIG. 6, a step 12D is formed at the lower end 12C of the sidewall portion 12B, where the inside of the exterior body is recessed from the outside of the exterior body. This step 12D is where the sealant 24 (FIGS. 2, 5, and 6) fits into the peripheral portion 16A of the battery fixing substrate 16. This step 12D is formed continuously at the same depth along the four sidewall portions 12B. The depth of the step 12D is set corresponding to the thickness of the peripheral portion 16A of the battery fixing substrate 16 and the thickness of the sealant 24, which will be described later. Considering the elasticity of the sealing material 24, the depth of the step 12D may be slightly shallower than the sum of the thickness of the peripheral edge 16A of the battery fixing base material 16 and the thickness of the sealing material 24 before attachment. The sealing material 24 may be compressed by tightening the screws 22 so that the lower end 12C of the side wall portion 12B and the peripheral edge 16A of the battery fixing base material 16 are flush with each other.

[0020] Holes 12E into which screws 22 are respectively threaded are formed at, for example, eight locations on the step portion 12D (FIGS. 2, 4, and 6). The thickness of the side wall portion 12B around the holes 12E may be set to be partially larger than the thickness of the general portion other than the holes 12E. This is to ensure the strength of the periphery of the holes 12E against the tightening of the screws 22.

[0021] The sealing material 24 is a gasket or packing made of an elastic material such as rubber. The sealing material 24 is formed in, for example, a rectangular ring shape so as to fit into the step portion 12D of the exterior body 12 (FIGS. 2 and 5). The sealing material 24 has eight holes 24A for passing the screws 22. The positions of the holes 24A correspond to the positions of the holes 12E. The width of the sealing material 24 around the holes 24A may be set to be partially larger than the width of the general portion other than the holes 24A. This is to ensure the strength of the area around the holes 24A against the tightening of the screws 22. Note that other materials may also be used for the sealing material 24.

[0022] As shown in FIG. 5, reinforcing ribs 12F may be provided on the rear surface of the ceiling portion of exterior body 12, for example, in a lattice pattern.

[0023] The storage batteries 14 are, for example, a lithium-ion battery pack housed in the exterior body 12. In the illustrated example, four, for example, cylindrical storage batteries 14 are housed in parallel in the exterior body 12. Specifically, the storage batteries 14 are housed inside the exterior body 12, held by, for example, a battery fixing base material 16 and a battery fixing cover 26. The battery fixing base material 16 has a recessed battery housing portion 16B into which the four storage batteries 14 fit by approximately the lower half of its diameter. The periphery of the battery housing portion 16B is formed as a flange-like protruding peripheral portion 16A. Eight holes 16C for passing screws 22 are formed in the peripheral portion 16A.

[0024] The lithium-ion battery pack is a storage battery that uses, for example, a lithium transition metal composite oxide for the positive electrode, a carbon material or lithium titanate for the negative electrode, and an electrolyte solution composed of a lithium salt (electrolyte) and an organic solvent that dissolves it, and that charges and discharges by the movement of lithium ions between the positive electrode and the negative electrode via the electrolyte. As long as charging and discharging are performed by the movement of lithium ions between the positive electrode and the negative electrode via the electrolyte, the materials for the positive electrode, negative electrode, and electrolyte solution (organic solvent) are not limited to those described above. Positive electrode materials can include single or composite metal oxides of cobalt, nickel, and manganese, or iron phosphate-based materials. Negative electrode materials can include carbon-based or alloy-based materials. Organic solvents that can be used include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and the like.

[0025] A lithium ion battery pack (single cell) manufactured using the above materials has a voltage of 2V to 4V, and the voltage of the assembled battery 10 can be adjusted by the number of lithium ion battery packs and the connection method (series connection or parallel connection).

[0026] The battery accommodating section 16B is provided with bus bars 27, 28 that are electrically connected to the electrodes of the storage battery 14. As shown in Fig. 3, the bus bars 27, 28 penetrate the battery fixing base material 16, protrude toward the bottom member 18, and are electrically connected to the circuit board 30.

[0027] The battery fixing cover 26 is a member that covers the battery accommodating portion 16B and holds the storage battery 14 between it and the battery fixing base material 16. The battery fixing cover 26 has, for example, a rectangular frame portion 26A that is open at the top. A hole 26B that allows gas generated from the storage battery 14 to pass through is formed in the frame portion 26A at a portion that faces the edge of the storage battery 14. A concave battery pressing portion 26C that fits approximately the upper half of the diameter of the storage battery 14 is formed in the frame portion 26A at a portion that faces the outer periphery of the storage battery 14.

[0028] As shown in FIGS. 2 and 3 , a circuit board 30, such as a BMS, is provided on the bottom surface of the battery fixing substrate 16. As described above, the space between the exterior body 12 and the battery fixing substrate 16 is sealed by the sealant 24, and the circuit board 30 is isolated from the storage battery 14. The circuit board 30 is electrically connected to the bus bars 27 and 28 directly or via a flexible substrate 32. An electrode plate 42, which is electrically connected to, for example, a cylindrical cathode terminal 41, is connected to the circuit board 30. The electrode plate 42 is attached to the battery fixing substrate 16 and terminates outside the peripheral edge 16A of the battery fixing substrate 16, with the cathode terminal 41 standing on its end. An electrode plate 52, which is electrically connected to, for example, a cylindrical anode terminal 51, is connected to the circuit board 30. The electrode plate 52 is attached to the battery fixing substrate 16 and terminates outside the peripheral edge 16A of the battery fixing substrate 16, with the anode terminal 51 standing on its end. The cathode terminal 41 and the anode terminal 51 may be arranged in reverse.

[0029] A relay 34 and a fuse 36 are provided between the circuit board 30 and the electrode plate 52. A communication connector 38 is also connected to the circuit board 30. The relay 34, fuse 36, and connector 38 are attached to the battery fixing base material 16. The arrangement of the various components on the bottom surface of the battery fixing base material 16 is not limited to that shown in the figure, and can be changed as appropriate.

[0030] 2, the bottom member 18 is provided on the opposite side of the battery fixing substrate 16 from the storage battery 14, and is capable of accommodating a circuit board 30 in the space between the bottom member 18 and the battery fixing substrate 16. The bottom member 18 has a bottom plate portion 18A and a side wall portion 18B that is provided in an annular shape around the bottom plate portion 18A. The height of the side wall portion 18B is set smaller than the height of the exterior body 12. The height of the exterior body 12 is greater than the diameter of the storage battery 14, and the storage battery 14 is accommodated inside the exterior body 12. In other words, the storage battery 14 is not accommodated on the bottom member 18 side, and the above-mentioned circuit board 30 and the like are accommodated on the bottom member 18 side.

[0031] The side wall portion 18B is formed with eight holes 18C for passing through the screws 22. The thickness of the side wall portion 18B around the holes 18C may be set to be partially larger than the thickness of the general portion other than the holes 18C. This is to ensure the strength of the areas around the holes 18C against the tightening of the screws 22.

[0032] The front side wall portion 18B1 of the bottom member 18 is formed with a recess 44 in which the electrode plate 42 of the cathode terminal 41 is disposed, a recess 54 in which the electrode plate 52 of the anode terminal 51 is disposed, and a recess 40 in which the connector 38 is disposed.

[0033] The battery pack of this embodiment has a height (the sum of the short sides of side wall portion 12B and side wall portion 18B in FIG. 1) of 40 to 70 mm, or may be 50 to 60 mm. The length (the long sides of side wall portion 12B in FIG. 1) is 150 to 250 mm, or may be 180 to 220 mm. The width (the long sides of side wall portion 18B1 in FIG. 2) is 140 to 240 mm, or may be 170 to 210 mm.

[0034] The exhaust port 20 is provided in the exterior body 12 and communicates from the inside of the exterior body 12, which houses the storage battery 14, to the outside of the exterior body 12. Specifically, the exhaust port 20 is provided in, for example, the front side wall portion 12B1 of the exterior body 12, and protrudes in the shape of a pipe from the side wall portion 12B1. The amount of protrusion of the exhaust port 20 is set, for example, so as not to exceed the side wall portion 18B1 of the bottom member 18. The position and shape of the exhaust port 20 can be changed as desired.

[0035] The cross-sectional area of ​​the exhaust port 20 per rated capacity is, for example, 2 to 15 mm 2 / Ah. This range is 3 to 13 mm 2 / Ah, and 4 to 10 mm 2 / Ah is also acceptable, and 5 to 8 mm 2 / Ah may also be used.

[0036] When the cross-sectional area per rated capacity of the exhaust port 20 is equal to or greater than the lower limit, it is possible to suppress a pressure increase inside the battery pack even if gas is generated. Furthermore, when the cross-sectional area per rated capacity of the exhaust port 20 is equal to or less than the upper limit, it is possible to reduce the size of piping such as tubes connected to the exhaust port 20, thereby improving the ease of handling after installation in a vehicle.

[0037] The voltage of the battery pack according to this embodiment is 8V to 20V, may be 10V to 16V, or may be 11V to 15V.

[0038] The rated capacity of the battery pack according to this embodiment is 5 Ah to 100 Ah, may be 8 Ah to 50 Ah, or may be 10 Ah to 40 Ah.

[0039] (action) This embodiment is configured as described above, and its operation will be described below. In FIG. 1 , in a battery pack 10 according to this embodiment, a battery fixing substrate 16 holds a storage battery 14 and houses it inside an exterior body 12. The exterior body 12 is provided with an exhaust port 20 that connects the inside of the exterior body 12 housing the storage battery 14 to the outside of the exterior body 12. Therefore, even if the electrolyte in the storage battery 14 evaporates and gas is generated, the gas is discharged from the exhaust port 20 to the outside of the exterior body 12. This eliminates the need for a complex gas discharge path, simplifying the structure. Furthermore, by appropriately setting the cross-sectional area of ​​the exhaust port 20, gas generated from the storage battery 14 can be efficiently discharged to the outside of the exterior body 12.

[0040] When the space between the exterior body 12 and the battery fixing base material 16 is sealed and the circuit board 30 is isolated from the storage battery 14, the gas generated from the storage battery 14 does not come into contact with the circuit board 30. In particular, when the overlapping portion of the exterior body 12 and the battery fixing base material 16 is sealed with the sealant 24, the storage battery 14 accommodation portion in the exterior body 12 is prevented from flowing toward the circuit board 30 through the gap between the exterior body 12 and the battery fixing base material 16. This prevents the gas generated from the storage battery 14 from coming into contact with the circuit board 30. Therefore, corrosion of the circuit board 30 by the gas can be prevented.

[0041] As described above, according to this embodiment, the gas generated from the battery can be discharged to the outside with a simple configuration.

[0042] [Other embodiments] The above describes one example of an embodiment of the present disclosure, but the embodiment of the present disclosure is not limited to the above, and it goes without saying that various modifications can be made without departing from the spirit of the present disclosure. [Explanation of symbols]

[0043] 10 battery packs 12 Exterior body 14 Storage battery 16 Battery fixing substrate (holding member) 18 Bottom member 20 exhaust port

Claims

1. An exterior body; a storage battery housed in the exterior housing; a holding member for holding the storage battery; a bottom member provided on the opposite side of the holding member from the storage battery and capable of accommodating a circuit board; an exhaust port provided in the exterior body, the exhaust port leading from the inside of the exterior body accommodating the storage battery to the outside of the exterior body; A battery pack having:

2. The cross-sectional area of ​​the exhaust port is 2 to 15 mm ２ 2. The battery pack according to claim 1, wherein the capacity is 1 / Ah.

3. 3. The battery pack according to claim 1, wherein the circuit board is isolated from the storage battery.

4. The battery pack according to claim 3 , wherein a sealing material is provided at a portion where the exterior body and the holding member are overlapped.

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