Battery case, battery, method for manufacturing a battery, and automobile

Abstract

The present invention provides a battery case, a battery, a method for manufacturing a battery, and an automobile, in which a safety valve port is opened when the internal pressure of the battery increases, while the safety valve port is tightly sealed when the battery is functioning normally. [Solution] The device comprises a metal housing with a through-hole and a metal safety valve that seals the through-hole. The safety valve has a small diameter portion inserted into the through-hole, a first large diameter portion located on the outside of the housing, and a second large diameter portion located on the inside of the housing. The first and second large diameter portions are larger than the through-hole, and they clamp and tighten around the periphery of the through-hole in the housing. The melting point of the safety valve is lower than the melting point of the housing.

Description

Technical Field

[0001] The present invention relates to a battery case, a battery, a method for manufacturing a battery, and an automobile.

Background Art

[0002] A battery case, which is an exterior material of a battery, has through-holes used as a liquid injection port, a safety valve port, and the like.

[0003] The liquid injection port is used to supply an electrolyte into the battery case. After the electrolyte is injected into the battery case, the liquid injection port is sealed with a liquid injection plug.

[0004] The safety valve port is a part that releases the internal pressure of the battery case when the internal pressure of the battery case rises. The safety valve port is sealed with a safety valve for the battery.

[0005] A safety valve for a battery is a valve that releases gas when the internal pressure of the battery increases in order to prevent the outside air from being inhaled into the battery and at the same time prevent the battery from being destroyed by the internal pressure caused by gas generated during charging or the like. When the gas is released, a general safety valve for a battery is deformed or destroyed. The safety valve may be referred to as a cleavage valve or a gas discharge valve.

[0006] Regarding the configuration of the safety valve provided in the battery case, various techniques have been proposed. For example, Patent Documents 1 to 3 disclose battery cases having a safety valve.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0008] Typical battery safety valves have a thin-walled section. One example of a thin-walled section is a groove formed in a metal plate by press molding. In other cases, a metal foil with a groove is placed over a hole in the battery housing and welded. In this case, the thin metal foil functions as a safety valve. The thin-walled section ruptures when the internal pressure of the battery increases, releasing the contents of the battery to the outside.

[0009] An example of a thin-walled portion is disclosed in Patent Document 1. The container of the energy storage element in Patent Document 1 has a thin-walled portion, and when the pressure inside the container reaches a predetermined opening pressure, the thin-walled portion ruptures and opens, thereby releasing the pressure inside the container.

[0010] However, the thin-walled sections may rupture even when the internal pressure of the battery is not high. In other words, the thin-walled sections may rupture under circumstances not anticipated during the battery's design, such as when the battery casing is subjected to a strong impact.

[0011] It is preferable that a safety valve for a battery ruptures only when the internal pressure of the battery increases, and firmly seals the safety valve opening in all other situations. While the technologies described in Patent Documents 1 to 3 can prevent the battery from rupturing when the internal pressure of the battery increases, they do not provide a method for ensuring the strength of the safety valve in all other situations.

[0012] In view of the above circumstances, the object of this disclosure is to provide a battery case in which the safety valve port is opened when the internal pressure of the battery increases, while the safety valve port is firmly sealed when the battery is functioning normally, a battery, a method for manufacturing a battery, and an automobile. [Means for solving the problem]

[0013] The gist of this disclosure is as follows:

[0014] (1) A battery case according to one aspect of the present disclosure comprises a metal housing having a through hole and a metal safety valve sealing the through hole, wherein the safety valve has a small diameter portion inserted into the through hole, a first large diameter portion disposed on the outside of the housing and a second large diameter portion disposed on the inside of the housing, the first large diameter portion and the second large diameter portion being larger than the through hole, the first large diameter portion and the second large diameter portion sandwiching and tightening the peripheral portion of the through hole in the housing, and the melting point of the safety valve being lower than the melting point of the housing. (2) Preferably, in the battery case described in (1) above, the housing has a body with an opening and a lid that closes the opening, and the through hole is provided in the lid. (3) Preferably, in the battery case described in (1) or (2) above, the safety valve is a rivet. (4) Preferably, in the battery case described in (3) above, the rivet is a hot-crimped rivet. (5) Preferably, in the battery case described in (3) above, the rivet is a blind rivet, and the melting point of the safety valve is the melting point of the body of the blind rivet. (6) Preferably, in the battery case described in any one of the above items (1) to (5), the through hole is the liquid filling port. (7) Preferably, in the battery case described in any one of the above items (1) to (6), the melting point of the safety valve at a unit temperature is 50% or less of the melting point of the housing at a unit temperature. (8) Preferably, in the battery case described in any one of the above items (1) to (7), the material of the safety valve is an aluminum alloy, zinc alloy, indium alloy, tin alloy, or bismuth alloy. (9) Preferably, in the battery case described in any one of the above items (1) to (8), the material of the housing is a Ni-plated steel sheet, a stainless steel sheet, or an aluminum alloy sheet. (10) Preferably, in the battery case described in any one of the above items (1) to (9), the housing has a body having an opening and a lid that seals the opening, the thickness of the body being 0.1 to 1.0 mm and the thickness of the lid being 0.3 to 2.5 mm. (11) Preferably, the battery case described in any one of the above items (1) to (10) further comprises a resin layer that covers one or both of the first large diameter portion and the second large diameter portion.

[0015] (12) A battery according to another aspect of the present disclosure comprises a battery case as described in any one of paragraphs (1) to (11) above.

[0016] (13) A method for manufacturing a battery according to another aspect of the present disclosure comprises the steps of: making a plurality of through holes in a body or lid; sealing some of the through holes with a safety valve; storing battery components inside the body through an opening in the body; joining the lid to the opening in the body to form a housing; injecting electrolyte into the housing through the unsealed through holes; and sealing the unsealed through holes with an electrolyte plug. The housing and the safety valve are made of metal, and the safety valve that seals the through hole has a small diameter portion inserted into the through hole, a first large diameter portion located on the outside of the housing, and a second large diameter portion located on the inside of the housing, the first large diameter portion and the second large diameter portion being larger than the through hole, the first large diameter portion and the second large diameter portion sandwiching and tightening the peripheral portion of the through hole in the housing, and the melting point of the safety valve is lower than the melting point of the housing.

[0017] (14) A method for manufacturing a battery according to another aspect of the present disclosure comprises the steps of: making a through hole in a body or lid; storing battery components inside the body through an opening in the body; joining the lid to the opening in the body to form a housing; injecting an electrolyte into the housing through the through hole; and sealing the through hole with a safety valve, wherein the safety valve sealing the through hole has a small diameter portion inserted into the through hole, a first large diameter portion disposed on the outside of the housing, and a second large diameter portion disposed on the inside of the housing, the first large diameter portion and the second large diameter portion being larger than the through hole, the first large diameter portion and the second large diameter portion sandwiching and tightening the peripheral portion of the through hole in the housing, the safety valve being a blind rivet, and the melting point of the body of the blind rivet being lower than the melting point of the housing.

[0018] (15) An automobile according to another aspect of the present disclosure includes the battery described in (12) above.

Advantages of the Invention

[0019] According to the present disclosure, there are provided a battery case, a battery, a method for manufacturing the battery, and an automobile in which a safety valve opening is opened when the internal pressure of the battery increases, while the safety valve opening is firmly sealed when the battery is normal.

Brief Description of the Drawings

[0020] [Figure 1] It is a perspective view of an example of a battery including a battery case. [Figure 2] It is a schematic cross-sectional view of an example of a safety valve and its peripheral portion. [Figure 3] It is a schematic view of a blind rivet before caulking. [Figure 4] It is a schematic view of a blind rivet after caulking. [Figure 5] It is a schematic cross-sectional view of an example of a safety valve provided with a resin layer and its peripheral portion. [Figure 6] It is a flowchart of an example of a method for manufacturing a battery. [Figure 7] It is a flowchart of another example of a method for manufacturing a battery.

Modes for Carrying Out the Invention

[0021] (1. Battery Case) A battery case 1 according to one aspect of the present disclosure includes a metal housing 11 provided with a through hole and a metal safety valve 12 for sealing the through hole. The safety valve 12 has a small-diameter portion 123 inserted into the through hole, a first large-diameter portion 12 on the outside of the housing 11, and a second large-diameter portion 122 arranged inside the housing 11. The first large-diameter portion 121 and the second large-diameter portion 122 are larger than the through hole, and the first large-diameter portion 121 and the second large-diameter portion 122 sandwich and clamp the peripheral portion of the through hole in the housing 11, and the melting point of the safety valve 12 is lower than the melting point of the housing 11.

[0022] (Battery case 1) The battery case 1 according to this embodiment is an exterior material for a battery 2. The type of battery 2 is not particularly limited. For example, it is preferable to use the battery case 1 according to this disclosure as an exterior material for a lithium-ion battery. The shape of the battery case 1 is also not particularly limited. It is preferable to make the battery case 1 cylindrical, rectangular, or pouch-shaped. When using the battery case 1 according to this disclosure as an exterior material for a battery 2 in an electric vehicle, the shape of the battery case 1 can be, for example, cylindrical or rectangular.

[0023] Figure 1 shows an example of a battery 2 equipped with a rectangular battery case 1. The housing 11 of the battery case 1 illustrated in Figure 1 comprises a lid 111 and a body 112. The body 112 comprises a side plate 112A and a bottom plate 112B. The housing 11 is provided with through holes, which will be described later. In the battery case 1 illustrated in Figure 1, one or more through holes are provided in the lid 111. The purpose of the through holes is, for example, a liquid injection port 11B and / or a safety valve port 11A. The battery case 1 illustrated in Figure 1 has two through holes, namely a liquid injection port 11B and a safety valve port 11A.

[0024] When injecting the electrolyte 22 into the battery case 1, it is preferable to hold the battery case 1 so that the area with the through-hole is facing upwards. When injecting the electrolyte 22 into the battery case 1 as illustrated in Figure 1, it is preferable to hold the battery case 1 so that the lid 111 is facing upwards. On the other hand, when using the battery 2, the battery case 1 may be held in any orientation. For example, as shown in Figure 1, the battery case 1 and battery 2 may be installed so that the lid 111 is facing horizontally.

[0025] The lid 111, side plates 112A, and bottom plate 112B may be joined by means of welding, crimping, or other means. Alternatively, these components may be integrally molded. For example, by deep drawing the raw material for the fuselage 112, the side plates 112A and bottom plate 112B can be integrally molded to obtain a fuselage 112 without any joints.

[0026] The housing 11 is made of metal. Preferably, the lid 111, side plate 112A, and bottom plate 112B included in the housing 11 are made of the same type of metal.

[0027] In the battery case 1 illustrated in Figure 1, a pair of electrodes 21 are separately arranged on the lid 111 and the bottom plate 112B. When the battery 2 is installed in the electric vehicle, the electrodes 21 are oriented toward the side of the electric vehicle. A battery case 1 having such a configuration is called a side-terminal can. Alternatively, both electrodes 21 may be arranged on the lid 111, or both electrodes 21 may be arranged on the bottom plate 112B, or the electrodes 21 may be arranged on the body 112. Furthermore, the battery case 1 may be configured so that when the battery 2 is installed in the electric vehicle, the electrodes 21 are oriented toward the upward or downward direction of the electric vehicle.

[0028] Furthermore, a current collector and electrolyte 22, etc., are arranged inside the housing 11 in Figure 1. The electrode 21 is inserted into the battery case 1 through an electrode insertion opening (not shown) provided in the lid 111 and is electrically connected to the current collector. If the battery case 1 is a neutral case, an insulating material is inserted between the edge of the electrode insertion opening and the electrode 21. A neutral case is a battery case 1 that is electrically insulated from the positive and negative electrodes of the battery 2. The insulating material is, for example, a resin component such as a gasket and packing.

[0029] (Through-hole) The housing 11 of the battery case 1 according to this embodiment has through holes. Examples of through holes are a safety valve port 11A and an electrolyte port 11B. The safety valve port 11A is used to discharge the contents of the battery 2 when the internal pressure of the battery 2 increases. The electrolyte port 11B is used to inject electrolyte 22 into the housing 11. The battery case 1 in Figure 1 is provided with both an electrolyte port 11B and a safety valve port 11A. Alternatively, the electrolyte port 11B may be used as the safety valve port 11A. In this case, the housing 11 only needs to have at least one through hole in addition to the electrode insertion port.

[0030] (Safety valve 12) The through-hole used as the safety valve opening 11A is sealed by a metal safety valve 12. When the battery 2 is functioning normally, the safety valve 12 prevents outside air from entering the battery case 1 and also prevents the contents of the battery case 1, such as the electrolyte 22, from leaking out of the battery case 1. However, if the internal pressure of the battery case 1 rises due to some abnormal situation, the safety valve 12 deforms or ruptures. Then, the contents of the battery case 1 leak out of the battery case 1 through the safety valve opening 11A, and the internal pressure of the battery case 1 is released. This ensures the safety of the battery case 1 in the event of an abnormal situation.

[0031] The through-hole used as the liquid injection port 11B is sealed by the liquid injection plug 13. The liquid injection plug 13 also prevents outside air from entering the battery case 1 and prevents the contents of the battery case 1, such as the electrolyte 22, from leaking out of the battery case 1.

[0032] If a single through-hole serves both as a safety valve port 11A and a liquid injection port 11B, the safety valve 12 also serves as a liquid injection plug 13. On the other hand, as illustrated in Figure 1, if the safety valve port 11A and the liquid injection port 11B are provided independently in the housing 11, the liquid injection plug 13 does not need to have the function of deforming or rupturing in an abnormal situation.

[0033] (Shape of safety valve 12) Figure 2 shows a schematic cross-sectional view of an example of a safety valve 12 and its surrounding area. The safety valve 12 has a small diameter portion 123 and a pair of large diameter portions provided at both ends of the small diameter portion 123. The small diameter portion 123 is inserted into a through hole in the housing 11, i.e., the safety valve opening 11A. One of the large diameter portions is located on the outside of the housing 11, and the other large diameter portion is located on the inside of the housing 11. For convenience, in this disclosure, the large diameter portion located on the outside of the housing 11 is referred to as the first large diameter portion 121, and the large diameter portion located on the inside of the housing 11 is referred to as the second large diameter portion 122.

[0034] The first diameter portion 121 and the second diameter portion 122 are larger than the through-hole in which the safety valve 12 is provided, i.e., the safety valve opening 11A. For example, if the first diameter portion 121, the second diameter portion 122, and the through-hole are circular, the diameters of the first diameter portion 121 and the second diameter portion 122 are larger than the diameter of the through-hole. For example, if one or more of the first diameter portion 121, the second diameter portion 122, and the through-hole are not circular, the diameters of the circumscribed circle of the first diameter portion 121 and the circumscribed circle of the second diameter portion 122 are larger than the diameter of the circumscribed circle of the through-hole. Examples of the shapes of the first diameter portion 121, the second diameter portion 122, and the through-hole are circles, as well as polygons such as equilateral triangles, squares, regular pentagons, and regular hexagons.

[0035] Since the first large diameter portion 121 and the second large diameter portion 122 are larger than the safety valve opening 11A, they cannot pass through the safety valve opening 11A. The first large diameter portion 121 and the second large diameter portion 122 prevent the safety valve 12 from falling out of the safety valve opening 11A.

[0036] The first large diameter portion 121 and the second large diameter portion 122 clamp and tighten around the periphery of the through hole in the housing 11. As a result, the first large diameter portion 121 and the second large diameter portion 122 of the safety valve 12 seal the through hole.

[0037] An example of the safety valve 12 is a rivet. The rivet may also be a blind rivet 3 as illustrated in Figure 4. Details of the rivet and blind rivet 3 will be described later. When the safety valve 12 is a rivet, the safety valve 12 crimps the periphery of the through hole. Alternatively, the safety valve 12 may be a bolt and nut. In this case, the head of the bolt and the nut are a pair of large diameter parts, and the shaft of the bolt is a small diameter part 123. When the safety valve 12 is a bolt and nut, the safety valve 12 fastens the periphery of the through hole.

[0038] (Melting point of safety valve 12 and housing 11) The melting point of the safety valve 12 is lower than that of the housing 11. Therefore, when the battery case 1 is at a high temperature, the strength of the safety valve 12 is significantly lower than that of the housing 11.

[0039] "Melting point" refers to the so-called liquidus temperature. The liquidus temperature is the temperature at which an object in a solid state stops melting when heated, or the temperature at which an object in a liquid state begins to solidify when cooled. "Melting point of housing 11" refers to the melting points of all components included in housing 11. For example, if the melting points of the lid 111, side plate 112A, and bottom plate 112B of housing 11 are different, the melting point of the safety valve 12 will be lower than the melting points of the lid 111, side plate 112A, and bottom plate 112B, respectively. Also, if the safety valve 12 is a blind rivet 3 described later, and its hidden head 325 includes the head 331 of the mandrel 33, then "Melting point of safety valve 12" refers to the melting point of the body 32 of the blind rivet.

[0040] (Effects and Benefits) The battery case 1 according to this embodiment has a metal safety valve 12. The safety valve 12 has a first large diameter portion 121 and a second large diameter portion 122. The first large diameter portion 121 and the second large diameter portion 122 sandwich and tighten around the through hole in the housing 11, i.e., the periphery of the safety valve opening 11A. As a result, when the battery 2 is in a normal state, the safety valve 12 firmly seals the safety valve opening 11A of the battery case 1.

[0041] On the other hand, the melting point of the safety valve 12 is lower than that of the housing 11. Normally, when the internal pressure of the battery case 1 increases and the safety valve port 11A should open, the battery case 1 is at a high temperature. Therefore, when the internal pressure of the battery case 1 is high, the strength of the safety valve 12 is less than that of the housing 11. In other words, the safety valve 12 becomes the most vulnerable part of the battery case 1. Consequently, when the internal pressure of the battery 2 increases, the safety valve 12 quickly deforms or breaks, opening the safety valve port 11A and reducing the internal pressure of the battery 2.

[0042] The most basic embodiment of the battery case 1 according to this embodiment has been described above. A more preferred embodiment will be described below.

[0043] (Position of the through-hole where the safety valve 12 is located) As described above, the housing 11 may have a body 112 and a lid 111. The body 112 is a container with an opening. Battery components such as a current collector and electrolyte 22 are housed in the body 112 through the opening. The lid 111 closes the opening of the body 112. The lid 111 prevents the contents of the battery case 1 from coming out of the body 112.

[0044] The location of the through-hole, i.e., the safety valve opening 11A, which is sealed by the safety valve 12, is not particularly limited. Depending on the shape of the battery case 1 and the application of the battery 2, the through-hole can be provided at any location in the housing 11.

[0045] For example, if the battery case 1 is a horizontal terminal can, it is preferable that the through hole be provided in the lid 111 of the housing 11 and / or in the bottom plate 112B of the body 112 of the housing 11. In a horizontal terminal type battery 2, the side plate 112A of the body 112 is arranged so that it is in contact with other batteries 2 or a cooling medium. The first large diameter portion 121 of the safety valve 12 located on the side plate 112A interferes with other components located in contact with the side plate 112A of the battery 2, reducing the degree of freedom in the arrangement of the battery 2. Therefore, it is preferable to provide the through hole and the safety valve 12 in the lid 111 or bottom plate 112B of the housing 11 of the battery 2.

[0046] Furthermore, other components such as electrodes 21 are often placed on the lid 111 of the housing 11 of the battery case 1. By providing a through hole and a safety valve 12 in the lid 111, it becomes possible to eliminate the need for components on the bottom plate 112B and to easily allow other mechanical components to come into contact with the bottom plate 112B. Therefore, it is most preferable to provide a through hole in the lid 111.

[0047] (rivet) A preferred example of the safety valve 12 is a rivet, as illustrated in Figure 1. A rivet is a fastening member having a shaft and a head, with the shaft being threadless. The through-hole is sealed by inserting the shaft of the rivet into the through-hole and then crimping the tip of the shaft. The crimped tip of the shaft of the rivet is referred to in this disclosure as the deformed portion. The head and deformed portion of the rivet are a pair of large-diameter portions of the safety valve 12, and the shaft of the rivet is the small-diameter portion 123.

[0048] (Hot-sealed rivets) Preferably, the rivet used as the safety valve 12 is either a hot-crimped rivet or a cold-crimped rivet. A hot-crimped rivet is obtained by heating the rivet to soften it and then crimping the tip of the rivet shaft. A cold-crimped rivet is obtained by crimping the tip of the rivet shaft while the rivet is at room temperature. By exposing and observing the metal structure of the cross-section of the rivet, it can be determined whether the rivet is a hot-crimped rivet or a cold-crimped rivet.

[0049] Hot-crimped rivets have higher strength at room temperature than cold-crimped rivets. From the viewpoint of further enhancing the safety of battery 2, it is preferable to use a hot-crimped rivet for the safety valve 12.

[0050] (Blind rivet 3) Preferably, the rivet used as the safety valve 12 is a blind rivet. A blind rivet is a rivet that has a structure that allows crimping from the insertion side. Specific examples of the configuration of blind rivets are disclosed in JIS B 0147:2004 "Blind rivets - Terms and definitions". Figures 3 and 4 show schematic cross-sectional views of an example of a blind rivet 3.

[0051] First, an example of the configuration of a blind rivet 3 before crimping will be described with reference to Figure 3. The blind rivet 3 has a body 32 and a mandrel 33. The body 32 of the blind rivet is cylindrical. The hole provided in the body 32 of the blind rivet is called the core 324. The body 32 of the blind rivet 3 has a casing 323 and ends 321 and a head 322 located at both ends of the casing 323. In the blind rivet 3 before crimping, the diameters of the casing 323 and the ends 321 of the body 32 are approximately the same, but the diameter of the head 322 of the body 32 is larger than the diameters of the casing 323 and the ends 321. The diameters of the casing 323 and the ends 321 of the body 32 are smaller than the diameter of the through hole to be crimped, but the diameter of the head 322 of the body 32 is larger than the diameter of the through hole. The body portion 323 and end portion 321 of the main body 32 can pass through the through hole, but the head portion 322 of the main body 32 cannot pass through the through hole.

[0052] The mandrel 33 is a rod-shaped component inserted into the core 324 of the body 32 of the blind rivet 3. The mandrel 33 has a shaft portion 332, a head portion 331 located at one end of the shaft portion 332, and a fracture region 333 located near the head portion 331. The head portion 331 of the mandrel 33 is located on the side of the end portion 321 of the body 32.

[0053] The diameter of the shaft portion 332 of the mandrel 33 is smaller than the diameter of the core portion 324 of the main body 32. The diameter of the head portion 331 of the mandrel 33 is larger than the diameter of the core portion 324 of the main body 32. The mandrel 33 is movable along the axial direction of the main body 32. However, the head portion 331 of the mandrel 33 illustrated in Figure 3 cannot pass through the core portion 324 of the main body 32. Also, the diameter of the head portion 331 of the mandrel 33 is smaller than the through hole to be crimped. The head portion 331 of the mandrel 33 can pass through the through hole.

[0054] In the process of crimping a blind rivet 3 into a through hole, first, the end 321 of the body 32 of the blind rivet 3 is inserted into the through hole. Next, the mandrel 33 is pulled out from the head 322 of the body 32. At this time, the head 331 of the mandrel 33 deforms the end 321 of the body 32. Specifically, the head 331 of the mandrel 33 compresses the end 321 of the body 32 in the axial direction and expands it in the circumferential direction. The head 331 of the mandrel 33 deforms the end 321 of the body 32, forming a deformed portion with a diameter larger than the through hole. The deformed portion formed by the mandrel 33 is called a hidden head 325.

[0055] After the hidden head 325 is formed, the fracture region 333 of the mandrel 33 breaks. The shaft portion 332 of the mandrel 33 is then removed from the blind rivet 3. Meanwhile, the head 331 of the mandrel 33 remains inside the end portion 321 of the body 32.

[0056] Next, an example of the configuration of the blind rivet 3 after crimping will be described with reference to Figure 4. The body 32 of the blind rivet 3 is a so-called hollow rivet. The head 322 and the concealed head 325 of the body 32 of the blind rivet 3 form a pair of large-diameter sections. The body 323 of the body 32 forms a small-diameter section 123. The head 322 and the concealed head 325 of the body 32 have a diameter larger than the through hole in the housing 11, i.e., the safety valve opening 11A. The head 322 and the concealed head 325 of the body 32 clamp and tighten around the periphery of the safety valve opening 11A. In this way, the blind rivet 3 seals the safety valve opening 11A.

[0057] In the crimped blind rivet 3 illustrated in Figure 4, the head 331 of the mandrel 33 remains in the concealed head 325. Such a mandrel 33 is referred to as a tensile fracture mandrel in JIS B 0147:2004. However, it is not essential to leave the head 331 of the mandrel 33 in the concealed head 325. In the battery case 1 according to this embodiment, the blind rivet 3 that crimps the safety valve opening 11A may or may not have the head 331 of the mandrel 33.

[0058] For example, the mandrel 33 of the blind rivet 3 can be an extruded mandrel as exemplified in JIS B 0147:2004. The extruded mandrel does not have a fracture region 333. The head 331 of the extruded mandrel has a tapered shape in which the diameter decreases from the end 321 side of the body 32 to the head 322 side of the body 32. The head 331 of the extruded mandrel can pass through the core 324 of the body 32 while deforming the end 321 of the body 32. The extruded mandrel can crimp the body 32 of the blind rivet 3 to the safety valve opening 11A without leaving the head 331 of the mandrel 33 in the hidden head 325.

[0059] When a blind rivet 3 is used as the safety valve 12, the melting point of the safety valve 12 refers to the melting point of the body 32 of the blind rivet 3. The melting point of the body 32 is lower than the melting point of the housing 11. If the head 331 of the mandrel 33 remains in the hidden head 325, the melting point of the mandrel 33 is not particularly limited. At least the body 32 of the blind rivet 3 softens when the internal pressure of the battery 2 increases, so that the blind rivet 3 can fully perform its function as a safety valve 12. On the other hand, in order to further enhance the safety of the battery 2, the melting point of the mandrel 33, in addition to the body 32, can also be made lower than the melting point of the housing 11.

[0060] (A through-hole that serves as both an injection port 11B and a safety valve port 11A) Preferably, the through-hole sealed by the safety valve 12 is the liquid injection port 11B. That is, the through-hole may serve as the liquid injection port 11B during the manufacturing of the battery 2, and as the safety valve port 11A in the battery 2. In this case, the safety valve 12 serves as the liquid injection plug 13. When the through-hole is used as the liquid injection port 11B, the number of parts in the battery 2 can be reduced.

[0061] When the through-hole is used as the liquid injection port 11B, the lid 111 and the body 112 are joined to form the housing 11, the electrolyte 22 is injected into the housing 11 through the through-hole, and then the safety valve 12 is installed in the through-hole. Therefore, in this case, it is preferable to use a blind rivet 3 for the safety valve 12. This makes the installation of the safety valve 12 extremely easy. In this case, the hidden head 325 of the blind rivet 3 becomes the second large diameter portion 122 located inside the battery case 1. Also, the head 322 of the body 32 of the blind rivet 3 becomes the first large diameter portion 121 located outside the battery case 1.

[0062] (Preferred melting point of safety valve 12) Preferably, the melting point of the safety valve 12 at a unit temperature is 50% or less of the melting point of the housing 11 at a unit temperature. This further reduces the strength of the safety valve 12 when the battery case 1 is in a high-temperature state, thereby further enhancing the safety of the battery 2. More preferably, the melting point of the safety valve 12 at a unit temperature is 45% or less, 40% or less, or 35% or less of the melting point of the housing 11 at a unit temperature. For example, if the housing 11 is made of steel, the melting point of the housing 11 is approximately 1500°C. Therefore, if the housing 11 is made of steel, preferably the melting point of the safety valve is 750°C or less, 600°C or less, or 400°C or less.

[0063] The lower limit of the melting point of the safety valve 12 is not particularly limited. For example, the melting point of the safety valve 12 at a unit temperature may be 5% or more, 10% or more, or 20% or more of the melting point of the housing 11 at a unit temperature. If the housing 11 is made of steel, the melting point of the safety valve is preferably 80°C or higher, 150°C or higher, or 300°C or higher.

[0064] (Material of safety valve 12) Suitable materials for the safety valve 12 include aluminum alloy, zinc alloy, indium alloy, tin alloy, and bismuth alloy. A safety valve 12 made from these metals can firmly seal the safety valve port 11A when the battery 2 is in a normal state, and can quickly open the safety valve port 11A when the internal pressure of the battery 2 increases. Specific examples of these metals include Wood's alloy, Rose alloy, ChipQuik, In52, Bi58, KappAloy9, SAC405, SAC305, SAC105, and 96S.

[0065] (Material of the housing 11) Suitable materials for the housing 11 include nickel-plated steel sheets, stainless steel sheets, and aluminum alloy sheets. Housings 11 manufactured from these metal sheets have high strength and high corrosion resistance.

[0066] A specific example of a Ni-plated steel sheet is described below. A Ni-plated steel sheet has a base steel sheet and a Ni-plated layer provided on the surface of the base steel sheet. The Ni-plated layer is a plating layer whose main component is Ni, and which optionally contains alloying elements such as Co, Fe, and W.

[0067] The base steel sheet for the Ni-plated steel sheet is preferably low-carbon aluminum-killed steel or IF steel (Interstitial Free Steel / ultra-low carbon steel). Specific examples of the chemical composition of the base steel sheet are as follows. The units for the elemental content shown below are in mass percent. (Example 1) Low carbon aluminum-killed steel C: 0.057, Si: 0.004, Mn: 0.29, P: 0.014, S: 0.007, Al: 0.050, Cu: 0.034, Ni: 0.021, remainder: iron and impurities. (Example 2) IF steel C: 0.004, Si: 0.01, Mn: 0.16, P: 0.013, S: 0.006, Al: 0.029, Cu: 0.027, Ni: 0.022, Ti: 0.013, remainder: iron and impurities. (Example 3) IF steel C: 0.0012, Si: <0.01, Mn: 0.16, P: 0.013, S: 0.006, Al: 0.029, Cu: 0.027, Ni: 0.022, Ti: 0.020, remainder: iron and impurities

[0068] The Ni-based plating layer of a Ni-plated steel sheet may be an alloyed plating layer that is alloyed with the underlying steel sheet. In this case, the Ni-based plating layer may be a fully diffused plating layer in which the Fe from the underlying steel sheet is diffused to its surface, or it may be a partially diffused plating layer in which the Fe from the underlying steel sheet is not diffused to its surface. On the other hand, the Ni-based plating layer may not be alloyed with the underlying steel sheet.

[0069] The Ni-based plating layer is a plating layer mainly composed of Ni, optionally containing alloying elements such as Co, Fe, and W. The thickness of the Ni-based plating layer can be, for example, within the range of 0.3 μm to 3.0 μm. Furthermore, the amount of Ni deposited in the Ni-based plating layer can be, for example, 2.6 to 35.6 g / m². 2 It can be within the range of

[0070] Preferred stainless steel sheets include ferritic stainless steel sheets and austenitic stainless steel sheets. Preferred ferritic stainless steels include SUS405, SUS430, SUS436L, SUS430LX, NSSC FW® series (e.g., FW0, FW1, FW2), NSSC 439, and NSSC PDX. Preferred austenitic stainless steels include SUS304 and SUS316. Stainless steels with a carbon content of 0.030% by mass or less, such as SUS430LX and SUS304L, can also be used as the material for the housing 11.

[0071] Preferred aluminum alloy sheets include the A1000 series, A3000 series (e.g., A3003), and A8000 series (e.g., A8079).

[0072] (Thickness of the casing 11) The thickness of the housing 11 is not particularly limited, but preferred examples are shown below. Preferably, the thickness of the body 112 of the housing 11 is 0.1 to 1.0 mm. Particularly preferably, the thickness of the body 112 of the housing 11 is 0.2 mm or more, 0.3 mm or more, or 0.5 mm or more. Particularly preferably, the thickness of the body 112 of the housing 11 is 0.9 mm or less, 0.8 mm or less, or 0.6 mm or less. Also preferably, the thickness of the lid 111 of the housing 11 is 0.3 to 2.5 mm. Particularly preferably, the thickness of the lid 111 of the housing 11 is 0.5 mm or more, 0.8 mm or more, or 1.0 mm or more. Particularly preferably, the thickness of the lid 111 of the housing 11 is 2.2 mm or less, 2.0 mm or less, or 1.5 mm or less.

[0073] (Resin layer 14) Preferably, the battery case 1 further comprises a resin layer 14 that covers one or both of the first diameter portion 121 and the second diameter portion 122. Figure 5 shows an example of a battery case 1 comprising the resin layer 14.

[0074] The material of the safety valve 12 is different from the material of the housing 11. Therefore, galvanic corrosion is likely to occur at the contact point between the safety valve 12 and the housing 11. The resin layer 14 covering the first large diameter portion 121 of the safety valve 12 prevents the first large diameter portion 121 from being exposed to the outside air and corroding. The resin layer 14 covering the second large diameter portion 122 of the safety valve 12 prevents the second large diameter portion 122 from being exposed to the electrolyte 22 and corroding.

[0075] The resin layer 14 preferably covers at least the contact area between the large diameter portion and the housing 11, and more preferably covers the entire large diameter portion. The material of the resin layer 14 is preferably, for example, PPS (polyphenylene sulfide), PAS (polyarylene sulfide), polyester, polyamide, epoxy, acrylic, fluororesin, polyurethane, silicon resin, phenol, polyetherimide, polyimide, or polycarbonate. Mixtures or copolymers of these resins can also be used as the material for the resin layer 14.

[0076] (2.Battery) A battery 2 according to another aspect of the present disclosure comprises a battery case 1 according to this embodiment. A more specific example of the battery 2 according to this embodiment comprises a battery case 1 according to this embodiment, an electrode body and an electrolyte 22 housed in the battery case 1, and a pair of electrodes 21 electrically connected to the electrode body. In the battery 2 according to this embodiment, the safety valve port 11A is opened when its internal pressure increases, while the safety valve port 11A is firmly sealed by the safety valve 12 when it is functioning normally.

[0077] The battery 2 according to this embodiment may be a battery cell. A battery cell is the smallest unit of battery 2 in a battery module. A battery module is constructed by electrically connecting multiple battery cells. Multiple battery modules can be further electrically connected to form a battery 2 pack. A battery 2 pack can also be constructed by electrically connecting a large number of battery cells without constructing a battery module. A battery module or a battery 2 pack can be used, for example, as a power source for an electric vehicle. However, it is not essential to use a battery module or a battery 2 pack in an electric vehicle. It is also possible to mount a large number of battery cells in an electric vehicle without constructing a module or pack.

[0078] (3. Method for manufacturing a battery 2 in which a safety valve port 11A and a liquid filling port 11B are provided separately) A first method for manufacturing the battery 2 according to another aspect of the present disclosure, as shown in the flowchart of Figure 6, includes the steps of: making a plurality of through holes in the body 112 or lid 111; sealing some of the through holes with a safety valve 12; storing battery components inside the body 112 through the opening of the body 112; joining the lid 111 to the opening of the body 112 to form a housing 11; injecting electrolyte 22 into the housing 11 through an unsealed through hole; and sealing the unsealed through hole with an electrolyte plug 13 The device includes a sealing step, and the housing 11 and safety valve 12 are made of metal. The safety valve 12 that seals the through hole has a small diameter portion 123 inserted into the through hole, a first large diameter portion 121 located on the outside of the housing 11, and a second large diameter portion 122 located on the inside of the housing 11. The first large diameter portion 121 and the second large diameter portion 122 are larger than the through hole, and the first large diameter portion 121 and the second large diameter portion 122 sandwich and tighten around the periphery of the through hole in the housing 11, and the melting point of the safety valve 12 is lower than the melting point of the housing 11.

[0079] (S11 perforation) First, multiple through-holes are made in either the body 112 or the lid 111, which are the materials of the housing 11. At least one of the multiple through-holes is used as a safety valve port 11A. Also, at least one of the multiple through-holes is used as a liquid injection port 11B. Further through-holes with uses other than the safety valve port 11A and liquid injection port 11B, such as electrode insertion ports, may be provided in the material of the housing 11.

[0080] (Sealing of safety valve port 11A in S12) Next, some of the multiple through-holes, which will be used as safety valve ports 11A, are sealed with the safety valve 12. The remaining through-holes will be used later as liquid injection ports 11B, so they are not sealed at this point.

[0081] The safety valve 12, which is installed in the through-hole and seals the through-hole, has a small diameter portion 123 inserted into the through-hole, a first large diameter portion 121 arranged on the outside of the housing 11, and a second large diameter portion 122 arranged on the inside of the housing 11. The first large diameter portion 121 and the second large diameter portion 122 are larger than the through-hole, and the first large diameter portion 121 and the second large diameter portion 122 clamp and tighten around the periphery of the through-hole in the housing 11. The safety valve 12 is manufactured from a material with a lower melting point than the housing 11. Alternatively, a safety valve 12 manufactured from a material with a lower melting point than the housing 11 is selected. The specific embodiment of the safety valve 12 is similar to the safety valve 12 of the battery case 1 according to this embodiment described above.

[0082] If the safety valve 12 is a bolt and nut, the process of sealing the through hole with the safety valve 12 is to insert the shaft of the bolt through the through hole, and then fasten the bolt and nut. If the safety valve 12 is a rivet, the process of sealing the through hole with the safety valve 12 is a riveting process. In the riveting process, the shaft of the rivet is inserted through the through hole, and then the tip of the shaft is crimped to form a deformed portion. The riveting may be cold riveting or hot riveting. Hot riveting is preferably energized riveting. In energized riveting, first an electric current is passed through the rivet to generate resistive heating, and then the tip of the shaft is crimped while the rivet is thermally softened. For example, energized riveting can be performed using a resistance spot welding device.

[0083] (S13 Storage of battery components) Next, the battery components are stored inside the body 112 through the opening in the body 112. The battery components include, for example, electrodes and current collectors. If the safety valve 12 is provided on the lid 111, the battery components may be stored in the body 112 before attaching the safety valve 12 to the lid 111. On the other hand, if the safety valve 12 is provided on the body 112, it is preferable to store the battery components in the body 112 after attaching the safety valve 12 to the lid 111.

[0084] (S14 Joining of lid 111 and body 112) Next, the lid 111 is joined to the opening of the fuselage 112 to form the housing 11. The method of joining the fuselage 112 and the lid 111 is not limited. Preferred examples of joining the fuselage 112 and the lid 111 are welding and crimping. Preferred examples of welding are laser welding, plasma welding and arc welding.

[0085] (S15 Injection of electrolyte 22) (Sealing of the liquid injection port 11B in S16) Next, the electrolyte 22 is injected into the housing 11 through an unsealed through-hole, the liquid injection port 11B. Then, the liquid injection port 11B is sealed with the liquid injection plug 13. The method of sealing the liquid injection port 11B with the liquid injection plug 13 is not particularly limited. A preferred method of sealing the liquid injection port 11B with the liquid injection plug 13 is welding. Preferred welding methods include laser welding, plasma welding, and arc welding. Alternatively, the liquid injection plug 13 may be a blind rivet 3. The liquid injection port 11B is sealed by crimping the body 32 of the blind rivet onto the liquid injection port 11B.

[0086] The first method for manufacturing the battery 2 may further include a step of covering the first diameter portion 121 and / or the second diameter portion 122 of the safety valve 12 with a resin layer 14. The step of covering the first diameter portion 121 with a resin layer 14 can be performed at any point after the safety valve 12 has been installed in the through hole. The step of covering the second diameter portion 122 with a resin layer 14 can be performed at any point after the safety valve 12 has been installed in the through hole and before the lid 111 has been joined to the body 112.

[0087] According to the first manufacturing method of the battery 2 according to this embodiment, a battery 2 according to this embodiment, in which the safety valve port 11A and the liquid injection port 11B are separately provided, can be suitably manufactured. Naturally, preferred embodiments of the battery case 1 or battery 2 according to this embodiment can be applied to the first manufacturing method of the battery 2 according to this embodiment. However, the first manufacturing method of the battery 2 according to this embodiment does not limit the technical scope of the battery 2 according to this embodiment.

[0088] (4. Manufacturing method of battery 2 in which the safety valve port 11A and the liquid filling port 11B are the same) A second method for manufacturing the battery 2 according to another aspect of the present disclosure, as shown in the flowchart of Figure 7, comprises the steps of: making through holes in the body 112 or lid 111; storing battery components inside the body 112 through the opening in the body 112; joining the lid 111 to the opening in the body 112 to form a housing 11; injecting electrolyte 22 into the housing 11 through the through holes; and sealing the through holes with a safety valve 12. The valve 12 has a narrow diameter portion 123 inserted into a through hole, a first large diameter portion 121 positioned on the outside of the housing 11, and a second large diameter portion 122 positioned on the inside of the housing 11. The first large diameter portion 121 and the second large diameter portion 122 are larger than the through hole, and the first large diameter portion 121 and the second large diameter portion 122 sandwich and tighten around the periphery of the through hole in the housing 11. The safety valve 12 is a blind rivet 3, and the melting point of the body 32 of the blind rivet 3 is lower than the melting point of the housing 11.

[0089] (S21 perforation) First, a through-hole is made in either the body 112 or the lid 111, which are the materials of the housing 11. This through-hole is used as the electrolyte injection port 11B during the manufacturing stage of the battery 2, and as the safety valve port 11A in the battery 2. Further through-holes with uses other than the safety valve port 11A and the electrolyte injection port 11B, such as electrode insertion ports, may be provided in the material of the housing 11.

[0090] (S22 Storage of battery components) Next, the battery components are stored inside the body 112 through the opening in the body 112. The battery components include, for example, electrodes and current collectors. If the safety valve 12 is provided on the lid 111, the battery components may be stored in the body 112 before the safety valve 12 is installed. On the other hand, if the safety valve 12 is provided on the body 112, it is preferable to store the battery components in the body 112 after the safety valve 12 has been installed.

[0091] (S23 Joining of lid 111 and body 112) Next, the lid 111 is joined to the opening of the fuselage 112 to form the housing 11. The method of joining the fuselage 112 and the lid 111 is not limited. Preferred examples of joining the fuselage 112 and the lid 111 are welding and crimping. Preferred examples of welding are laser welding, plasma welding and arc welding.

[0092] (S24 Injection of electrolyte 22) (S25 Sealing of through-holes) Next, electrolyte 22 is injected into the housing 11 through the through-hole. Then, the through-hole is sealed with a blind rivet 3. Specifically, first, the end portion 321 and the body portion 323 of the body 32 of the blind rivet are inserted through the through-hole. Then, the mandrel 33 of the blind rivet 3 is pulled out from the head portion 322 of the body 32 of the blind rivet.

[0093] In battery 2, the blind rivet 3 functions as a safety valve 12. The body portion 323 of the body 32 of the blind rivet 3 becomes the narrow diameter portion 123 of the safety valve 12, the head portion 322 of the body 32 of the blind rivet 3 becomes the first large diameter portion 121 of the safety valve 12, and the hidden head portion 325 of the body 32 of the blind rivet 3 becomes the second large diameter portion 122 of the safety valve 12.

[0094] The safety valve 12, which is installed in the through-hole and seals the through-hole, has a small diameter portion 123 inserted into the through-hole, a first large diameter portion 121 arranged on the outside of the housing 11, and a second large diameter portion 122 arranged on the inside of the housing 11. The first large diameter portion 121 and the second large diameter portion 122 are larger than the through-hole, and the first large diameter portion 121 and the second large diameter portion 122 clamp and tighten the periphery of the through-hole in the housing 11. At least the body 32 of the blind rivet 3 is manufactured from a material with a melting point lower than that of the housing 11. Alternatively, a blind rivet 3 is selected in which the body 32 is manufactured from a material with a melting point lower than that of the housing 11. The specific embodiment of the safety valve 12 is similar to the safety valve 12 of the battery case 1 according to this embodiment described above.

[0095] The second method for manufacturing the battery 2 may further include a step of covering the first large diameter portion 121 of the safety valve 12 with a resin layer 14. The step of covering the first large diameter portion 121 with a resin layer 14 can be performed at any point after the safety valve 12 has been installed in the through hole.

[0096] According to the manufacturing method of the battery 2 of this embodiment, a battery 2 of this embodiment can be suitably manufactured in which the safety valve port 11A and the liquid injection port 11B are identical. Naturally, preferred embodiments of the battery case 1 or battery 2 of this embodiment can be applied to a second manufacturing method of the battery 2 of this embodiment. However, the second manufacturing method of the battery 2 of this embodiment does not limit the technical scope of the battery 2 of this embodiment.

[0097] (5. Automobiles) Another aspect of the present disclosure is an electric vehicle equipped with the battery according to the present embodiment described above. Preferably, the battery is located at the bottom of the vehicle. For example, it is preferable to arrange horizontal terminal batteries having a rectangular parallelepiped shape at the bottom of the vehicle to constitute a battery module. [Explanation of symbols]

[0098] 1 Battery case 11 cabinets 111 Lid 112 Torso 112A side plate 112B Bottom plate 11A Safety valve port 11B Liquid injection port 12 Safety valve 121 First large diameter section 122 Second large diameter section 123 Thin section 13. Injection plug 14 resin layer 2 batteries 21 electrodes 22 Electrolyte 3 Blind rivets 32 Blind rivet body 321 End of the main body 322 Main body head 323 Main body 324 Core of the main body 325 Hidden Head 33 Mandrels 331 Mandrel head 332 Mandrel shaft 333 Fracture region

Claims

1. A metal casing with through-holes, A metal safety valve that seals the aforementioned through hole, Equipped with, The safety valve has a small diameter portion inserted into the through hole, a first large diameter portion located on the outside of the housing, and a second large diameter portion located on the inside of the housing. The first large diameter portion and the second large diameter portion are larger than the through hole. The first and second large diameter portions sandwich and tighten around the periphery of the through-hole in the housing. The melting point of the safety valve is lower than the melting point of the housing. Battery case.

2. The housing comprises a body with an opening and a lid that closes the opening. The aforementioned through hole is provided in the lid. The battery case according to feature 1.

3. The battery case according to claim 1, characterized in that the safety valve is a rivet.

4. The battery case according to claim 3, characterized in that the rivet is a hot-crimped rivet.

5. The aforementioned rivet is a blind rivet, The melting point of the safety valve is the melting point of the body of the blind rivet. The battery case according to feature 3.

6. The battery case according to claim 1, characterized in that the aforementioned through hole is a liquid injection port.

7. The battery case according to claim 1, characterized in that the melting point of the safety valve at a unit temperature is 50% or less of the melting point of the housing at a unit temperature.

8. The battery case according to claim 1, characterized in that the material of the safety valve is an aluminum alloy, zinc alloy, indium alloy, tin alloy, or bismuth alloy.

9. The battery case according to claim 1, characterized in that the material of the housing is a Ni-plated steel sheet, a stainless steel sheet, or an aluminum alloy sheet.

10. The housing comprises a body having an opening and a lid that seals the opening. The thickness of the aforementioned body is 0.1 to 1.0 mm. The thickness of the lid is 0.3 to 2.5 mm. The battery case according to feature 1.

11. The battery case according to claim 1, further comprising a resin layer covering one or both of the first large diameter portion and the second large diameter portion.

12. A battery comprising the battery case described in any one of claims 1 to 11.

13. The process involves making multiple through-holes in the body or lid, A step of sealing some of the aforementioned through holes with a safety valve, The process of storing battery components inside the body through an opening in the body, The process of joining the lid to the opening of the body to form a housing, The process involves injecting the electrolyte into the interior of the housing through the unsealed through-hole, The process involves sealing the unsealed through-hole with a liquid injection plug, Equipped with, The housing and the safety valve are made of metal. The safety valve that seals the through hole has a small diameter portion inserted into the through hole, a first large diameter portion located on the outside of the housing, and a second large diameter portion located on the inside of the housing. The first large diameter portion and the second large diameter portion are larger than the through hole. The first and second large diameter portions sandwich and tighten around the periphery of the through-hole in the housing. The melting point of the safety valve is lower than the melting point of the housing. Battery manufacturing method.

14. The process involves making through holes in the body or lid, The process of storing battery components inside the body through an opening in the body, The process of joining the lid to the opening of the body to form a housing, The process involves injecting an electrolyte solution into the interior of the housing through the through-hole, The process involves sealing the aforementioned through-hole with a safety valve, Equipped with, The safety valve that seals the through hole has a small diameter portion inserted into the through hole, a first large diameter portion located on the outside of the housing, and a second large diameter portion located on the inside of the housing. The first large diameter portion and the second large diameter portion are larger than the through hole. The first and second large diameter portions sandwich and tighten around the periphery of the through-hole in the housing. The aforementioned safety valve is a blind rivet, The melting point of the body of the blind rivet is lower than the melting point of the housing. Battery manufacturing method.

15. An automobile equipped with the battery described in claim 12.

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