Secondary battery

Abstract

A secondary battery includes an electrode assembly, an electrolyte solution, a case, and an exhaust valve. The case accommodates the electrode assembly and the electrolyte solution. The case includes a bottom plate. The bottom plate is located below the electrode assembly. The bottom plate includes a first portion and a second portion. The exhaust valve is provided to the first portion. The second portion is away from the exhaust valve and spaced apart from the exhaust valve. The first portion includes a first inner surface facing an accommodation space of the case. The second portion includes a second inner surface facing the accommodation space of the case. The second inner surface is located below the first inner surface.

Description

Technical Field

[0001] This disclosure relates to a secondary battery. Background Technology

[0002] Japanese Unexamined Patent Application Publication No. 2022-543185 (JP 2022-543185A) discloses a battery. The battery includes multiple battery cells and a bus assembly. The bus assembly is used for electrical connection between the battery cells. Each battery cell includes a release mechanism and a housing. The release mechanism is operable to release internal pressure when the internal pressure or temperature of the battery cell reaches a threshold. The release mechanism is also known as an explosion-proof valve, air valve, pressure reducing valve, safety valve, etc. For example, when the battery is used in a battery-powered electric vehicle, due to wiring and other factors, the high-voltage side of the bus assembly is positioned adjacent to the driver's cab. When the release mechanism is located on a different side, substances from the battery cells can be released away from the bus assembly during operation of the release mechanism. The housing is formed by multiple walls. The release mechanism is located on at least one wall. Summary of the Invention

[0003] When the vent valve is located on the bottom plate of the battery cell casing and is opened, a large amount of excess electrolyte solution that has accumulated inside the casing is also discharged to the outside.

[0004] This disclosure was made in view of the above-mentioned problems, and this disclosure provides a secondary battery that can suppress the discharge of excess electrolyte solution to the outside when the vent valve is opened.

[0005] A secondary battery according to one aspect of this disclosure includes an electrode assembly, an electrolyte solution, a housing, and a vent valve. The housing houses the electrode assembly and the electrolyte solution. The housing includes a base plate. The base plate is located below the electrode assembly. The base plate includes a first portion and a second portion. The vent valve is disposed to the first portion. The second portion is located away from and spaced apart from the vent valve. The first portion includes a first inner surface facing the housing's receiving space. The second portion includes a second inner surface facing the housing's receiving space. The second inner surface is located below the first inner surface.

[0006] When the vent valve is open, it can prevent excess electrolyte solution from being discharged to the outside. Attached Figure Description

[0007] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like symbols denote like elements, and wherein: Figure 1 This is a schematic side view of an example vehicle equipped with an energy storage device, which includes a secondary battery according to one embodiment. Figure 2This is a cross-sectional view showing a secondary battery according to an embodiment; Figure 3 This is a partial cross-sectional view showing a secondary battery according to an embodiment; and Figure 4 This is a partial bottom view of the secondary battery according to the implementation plan, viewed from below. Detailed Implementation

[0008] In the following description, a secondary battery according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or equivalent parts, and descriptions of these parts will not be repeated.

[0009] Figure 1 This is a schematic side view of an example vehicle equipped with an energy storage device, which includes a secondary battery according to an embodiment. Figure 1 The symbol "H" in the diagram represents the vertical direction of vehicle 1. The symbol "W" represents the width direction of vehicle 1. The symbol "D" represents the front-rear direction of vehicle 1.

[0010] like Figure 1 As shown, vehicle 1 includes a body 2 and an energy storage device 3. Examples of vehicle 1 include plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs). The energy storage device 3 is mounted on the lower part of the body 2. The energy storage device 3 includes a housing 4 and a battery stack 5. The battery stack 5 is housed within the housing space of the housing 4. The battery stack 5 may be formed from a plurality of secondary batteries 10 (secondary battery cells) according to embodiments of the present disclosure.

[0011] Figure 2 This is a cross-sectional view showing a secondary battery according to an embodiment. Figure 2 In the accompanying drawings, the symbol "D1" indicates the first direction of the secondary battery. The first direction is orthogonal to the vertical direction. The symbol "D2" indicates the second direction of the secondary battery. The second direction is orthogonal to both the first direction and the vertical direction. In this embodiment, the first direction is the width direction of vehicle 1, but it can also be the front-rear direction of vehicle 1.

[0012] Figure 2 The secondary battery 10 shown is a so-called prismatic battery. The secondary battery 10 is rechargeable and dischargeable, and can be, for example, a lithium-ion battery or a nickel-metal hydride battery.

[0013] The secondary battery 10 according to the embodiments of this disclosure includes an electrode assembly 100, an electrolyte solution 150, a housing 200, an exhaust valve 300, an insulating member 400, a first external terminal 500 A, a second external terminal 500 B, a first connecting member 600 A, and a second connecting member 600 B.

[0014] The electrode assembly 100 includes an electrode assembly body 110, a first connector 120A, and a second connector 120B.

[0015] The electrode assembly body 110 can be, for example, a wound electrode assembly formed by winding a cathode sheet, a separator, and an anode sheet stacked on top of each other around a virtual central axis extending in the vertical direction. The cathode sheet includes a cathode metal foil and a cathode composite layer disposed on the cathode metal foil. The anode sheet includes an anode metal foil and an anode composite layer formed on the metal foil. The electrode assembly body 110 can also be a laminated electrode assembly formed by laminating multiple cathode sheets, multiple separators, and multiple anode sheets in a second direction.

[0016] A first terminal block 120A and a second terminal block 120B extend upward from the electrode assembly body 110. The first terminal block 120A may be, for example, a cathode terminal block. The cathode terminal block may be formed from a portion of a cathode metal foil on which a cathode composite layer is not provided, or may be connected to the cathode metal foil. The second terminal block 120B extends upward from the electrode assembly body 110. The second terminal block 120B may be, for example, an anode terminal block. The anode terminal block may be formed from a portion of an anode metal foil on which an anode composite layer is not provided, or may be connected to the anode composite layer.

[0017] The electrolyte solution 150 can be a non-aqueous electrolyte solution. The electrolyte solution 150 may contain, for example, lithium salts and organic solvents. The electrolyte solution 150 is immersed in the electrode assembly body 110 of the electrode assembly 100. In the secondary battery 10, excess electrolyte solution 150 may be located below the electrode assembly body 110 of the electrode assembly 100. Figure 2 And described later Figure 3 As shown in the image.

[0018] Figure 3 This is a cross-sectional view showing a secondary battery according to an embodiment. Figure 4 This is a partial bottom view of the secondary battery according to the implementation plan, viewed from below.

[0019] like Figures 2 to 4 As shown, the housing 200 houses the electrode assembly 100 and the electrolyte solution 150.

[0020] The housing 200 includes a base plate 210, an outer peripheral wall 220, and a cover 230. The base plate 210 is located below the electrode assembly 100. The base plate 210 includes a first portion 211, a second portion 212, a third portion 213, a fourth portion 214, an outer protective film 215, and an inner protective film 216. The first portion 211, the second portion 212, the third portion 213, and the fourth portion 214 are conductive and are made of a metal such as aluminum.

[0021] The first part 211 is provided with an exhaust valve 300. The first part 211 includes a first inner surface 211a, a first outer surface 211b and a first through hole 211c.

[0022] The first inner surface 211a faces the receiving space of the housing 200. The first outer surface 211b faces the outside of the housing 200. The first through hole 211c passes through the first portion 211 in the vertical direction. The exhaust valve 300 closes the first through hole 211c.

[0023] The second part 212 is spaced apart from the exhaust valve 300. When viewed vertically, the second part 212 is positioned to surround the first part 211 (see below). Figure 4 ).

[0024] The second part 212 includes a second inner surface 212a, a second outer surface 212b, and a plurality of grooves 212c. The second inner surface 212a faces the receiving space of the housing 200. The second inner surface 212a is located below the first inner surface 211a. The second inner surface 212a extends in a horizontal direction. The second outer surface 212b faces the exterior of the housing 200. The second outer surface 212b is located below the first outer surface 211b. The second outer surface 212b extends in a horizontal direction. The grooves 212c extend downward from the second inner surface 212a. The width of each groove 212c can be any size that allows excess electrolyte solution 150 to enter through capillary action. The width of each groove 212c can, for example, be greater than 1 nm and less than 100 nm. The grooves 212c may be omitted.

[0025] Part 3, 213, extends in a circular shape (see...). Figure 4 The third part 213 includes a third inner surface 213a and a third outer surface 213b. The third inner surface 213a faces the receiving space of the housing 200. The third inner surface 213a connects the first inner surface 211a and the second inner surface 212a. The third inner surface 213a slopes downward from the first inner surface 211a toward the second inner surface 212a. The third outer surface 213b connects the first outer surface 211b and the second outer surface 212b. The third outer surface 213b slopes downward from the first outer surface 211b toward the second outer surface 212b.

[0026] The fourth part 214 extends from the first part 211. The fourth part 214 is located above the exhaust valve 300. The fourth part 214 has a second through hole 214H passing through the fourth part 214 in the vertical direction. The second through hole 214H is located above the exhaust valve 300.

[0027] An outer protective film 215 covers the exhaust valve 300 from the outside. The outer protective film 215 is disposed on the first outer surface 211b. The outer protective film 215 is made of electrically insulating resin.

[0028] An inner protective film 216 covers the exhaust valve 300 from the inside. The inner protective film 216 is disposed on the first inner surface 211a. The inner protective film 216 is made of electrically insulating resin.

[0029] The outer peripheral wall 220 rises upward from the outer peripheral edge of the second portion 212 of the base plate 210. An opening is formed at the upper end of the outer peripheral wall 220. When viewed in the opening direction of this opening, the outer peripheral wall 220 has a generally rectangular external shape. The opening and the base plate 210 are arranged vertically. The outer peripheral wall 220 is made of a metal such as aluminum.

[0030] The cover 230 is joined to the outer peripheral wall 220 by welding or the like to close the opening in the outer peripheral wall 220. The cover 230 has a first connecting hole 231 A and a second connecting hole 231 B.

[0031] The exhaust valve 300 is made of a metal such as aluminum. The thickness of the exhaust valve 300 is less than the thickness of any one of the first portion 211, the second portion 212, and the third portion 213. In this case, the thickness of the second portion 212 may be the thickness of the portion of the second portion 212 without the groove 212c.

[0032] The exhaust valve 300 includes a valve body 310 and a welded portion 320. When viewed in the vertical direction, the welded portion 320 is located radially outward of the valve body 310 and extends in an annular shape. The welded portion 320 is connected to the first portion 211. The welded portion 320 is formed by fusing a portion of the material of the valve body 310 to the first portion 211 by means of laser welding or the like.

[0033] The insulating member 400 is electrically insulating. The insulating member 400 is disposed between the electrode assembly 100 and the housing 200. The insulating member 400 electrically insulates the electrode assembly 100 and the housing 200 from each other. The insulating member 400 includes an insulating support 410, a peripheral insulating portion 420, a bottom insulating portion 430, and an insulating tape 440.

[0034] An insulating bracket 410 is disposed between the electrode assembly 100 and the cover 230. The insulating bracket 410 has relatively high rigidity and contacts both the electrode assembly 100 and the cover 230. Therefore, the electrode assembly 100 is fixed to the housing 200 in the vertical direction.

[0035] A peripheral insulating portion 420 is disposed between the electrode assembly 100 and the outer peripheral wall 220. The peripheral insulating portion 420 is a membrane-like component.

[0036] A bottom insulating portion 430 is disposed between the electrode assembly 100 and the base plate 210. The bottom insulating portion 430 is a membrane-like component.

[0037] The insulating tape 440 is attached to both the peripheral insulating portion 420 and the bottom insulating portion 430. The insulating tape 440 secures the peripheral insulating portion 420 and the bottom insulating portion 430 to each other.

[0038] The first external terminal 500 A and the second external terminal 500 B are disposed in the secondary battery 10 so as to be exposed to the outside. The first connecting member 600 A and the second connecting member 600 B are conductive. At least a portion of the first connecting member 600 A and at least a portion of the second connecting member 600 B are disposed inside the housing 200.

[0039] The first external terminal 500 A or the first connecting member 600 A is inserted through the first connecting hole 231 A. The first external terminal 500 A is electrically connected to the first connecting member 600 A. Specifically, the first external terminal 500 A and the first connecting member 600 A engage with each other. The first connecting member 600 A engages with the first terminal block 120 A. Therefore, the first external terminal 500 A is electrically connected to the first terminal block 120 A.

[0040] The second external terminal 500 B or the second connecting member 600 B is inserted through the second connecting hole 231 B. The second external terminal 500 B is electrically connected to the second connecting member 600 B. Specifically, the second external terminal 500 B and the second connecting member 600 B engage with each other. The second connecting member 600 B engages with the second terminal block 120 B. Therefore, the second external terminal 500 B is electrically connected to the second terminal block 120 B.

[0041] In this embodiment, the first external terminal 500 A is a cathode terminal, and the second external terminal 500 B is an anode terminal. The first external terminal 500 A and the second external terminal 500 B are arranged in a first direction.

[0042] As described above, the secondary battery 10 according to an embodiment of the present disclosure includes an electrode assembly 100, an electrolyte solution 150, a housing 200, and an vent valve 300. The housing 200 houses the electrode assembly 100 and the electrolyte solution 150. The housing 200 includes a base plate 210 located below the electrode assembly 100. The base plate 210 includes a first portion 211 and a second portion 212. The vent valve 300 is disposed to the first portion 211. The second portion 212 is spaced apart from the vent valve 300. The first portion 211 includes a first inner surface 211a facing the housing 200's receiving space. The second portion 212 includes a second inner surface 212a facing the housing 200's receiving space. The second inner surface 212a is located below the first inner surface 211a.

[0043] With the above-described structure, excess electrolyte solution 150 may accumulate on the second inner surface 212a located below the first inner surface 211a. Therefore, the liquid surface of excess electrolyte solution 150 can easily be located below the first inner surface 211a. Thus, when the vent valve 300 provided to the first portion 211 is opened, the discharge of excess electrolyte solution 150 to the outside can be suppressed.

[0044] In this embodiment, the second inner surface 212a extends in a horizontal direction. With this configuration, excess electrolyte solution 150 is more likely to remain on the second inner surface 212a. Furthermore, excess electrolyte solution 150 on the second inner surface 212a is less likely to flow to the first inner surface 211a. Therefore, when the vent valve 300 provided to the first portion 211 is opened, the discharge of excess electrolyte solution 150 to the outside can be further suppressed.

[0045] In this embodiment, the base plate 210 further includes a third portion 213. The third portion 213 includes a third inner surface 213a facing the receiving space of the housing 200. The third inner surface 213a connects the first inner surface 211a and the second inner surface 212a. The third inner surface 213a slopes downward from the first inner surface 211a toward the second inner surface 212a.

[0046] With the above-described structure, excess electrolyte solution 150 on the first inner surface 211a is more likely to flow onto the second inner surface 212a. Therefore, when the vent valve 300 provided to the first portion 211 is opened, the discharge of excess electrolyte solution 150 to the outside can be further suppressed.

[0047] In this embodiment, the first portion 211 further includes a first outer surface 211b facing the exterior of the housing 200. The second portion 212 further includes a second outer surface 212b facing the exterior of the housing 200. The second outer surface 212b is located below the first outer surface 211b.

[0048] With the above-described structure, when the housing 200 is installed (e.g., inside the housing 4), the obstruction of the installation of the housing 200 by the exhaust valve 300 provided to the first part 211 can be suppressed.

[0049] In this embodiment, the second part 212 further includes a groove 212c. The groove 212c extends downward from the second inner surface 212a.

[0050] Using the above-described structure, excess electrolyte solution 150 contained in housing 200 enters groove 212c through capillary action. Therefore, when the vent valve 300 provided to the first part 211 is opened, the discharge of excess electrolyte solution 150 to the outside can be further suppressed.

[0051] In the above description of the implementation plan, the various configurations that can be combined can be combined with each other.

[0052] The embodiments disclosed herein should be considered exemplary in all respects, not restrictive. The scope of this disclosure is defined by the claims, not by the foregoing description, and is intended to include all variations within the meaning and scope equivalent to that of the claims.

Claims

1. A secondary battery, comprising: Electrode assembly; Electrolyte solution; case; as well as Exhaust valve, among which The housing contains the electrode assembly and the electrolyte solution. The housing includes a base plate. The base plate is located below the electrode assembly. The base plate comprises a first part and a second part. The exhaust valve is located in the first part. The second part is separated from and spaced apart from the exhaust valve. The first portion includes a first inner surface facing the receiving space of the housing. The second portion includes a second inner surface facing the receiving space of the housing, and The second inner surface is located below the first inner surface.

2. The secondary battery according to claim 1, wherein, The second inner surface extends in the horizontal direction.

3. The secondary battery according to claim 2, wherein: The base plate also includes a third part; The third portion includes a third inner surface facing the receiving space of the housing; The third inner surface connects the first inner surface and the second inner surface; and The third inner surface slopes downward from the first inner surface toward the second inner surface.

4. The secondary battery according to claim 3, wherein: The first portion also includes a first outer surface facing the exterior of the housing; The second portion also includes a second outer surface facing the exterior of the housing; and The second outer surface is located below the first outer surface.

5. The secondary battery according to any one of claims 1 to 4, wherein: The second part also includes multiple trenches; and The groove extends downward from the second inner surface.

Images