Square secondary battery, battery using the same, and vehicle

Abstract

Provided is a square secondary battery, a battery pack using the same, and a vehicle, which prevent short circuit of a terminal and a sealing plate. A square secondary battery (50) includes an electrode body including a positive electrode plate and a negative electrode plate; a square exterior body (1) that houses the electrode body; a sealing plate (2) that seals an opening of the square exterior body (1); and a negative electrode terminal (8) that is electrically connected to the negative electrode plate, the square secondary battery being configured such that the sealing plate (2) extends in a direction in which a positive electrode plate is electrically connected to the sealing plate (2), a surface of the sealing plate (2) on an outer side has a recessed portion (20), and the sealing plate (2) has a terminal mounting hole (21) formed in the recessed portion (20), the negative electrode terminal (8) is inserted into the terminal mounting hole (21), an external side insulating member (10) is disposed between the negative electrode terminal (8) and the sealing plate (2), and the sealing plate (2) has a first groove portion (22) that is provided so as to be continuous with an end portion of the recessed portion (20) in a longitudinal direction of the sealing plate (2).

Description

[0001] This application is a divisional application of the patent application with the application date of May 30, 2018, the application number of 201810544647.9, and the invention name of "Square secondary battery, battery pack using the square secondary battery, and vehicle". TECHNICAL FIELD

[0002] The present application relates to a square secondary battery, a battery pack using the square secondary battery, and a vehicle. BACKGROUND

[0003] In a driving power source for an electric vehicle (EV), a hybrid electric vehicle (HEV, PHEV), etc., a square secondary battery such as a non-aqueous electrolyte secondary battery is used.

[0004] In these square secondary batteries, a battery case is constituted by a bottomed square cylindrical square exterior body having an opening and a sealing plate that seals the opening of the square exterior body. Inside the battery case, an electrode body including a positive electrode plate, a negative electrode plate, and a separator is housed together with an electrolyte. A positive electrode terminal and a negative electrode terminal are installed on the sealing plate respectively through an insulating member. The positive electrode terminal is electrically connected to the positive electrode plate via a positive electrode current collector, and the negative electrode terminal is electrically connected to the negative electrode plate via a negative electrode current collector.

[0005] Further, as in the following Patent Document 1, a square secondary battery is proposed in which a positive electrode current collector is connected to the inner surface of the sealing plate of a battery case, and the battery case functions as a positive electrode terminal. If this structure is adopted, there are advantages such as being able to reduce the number of parts.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT DOCUMENTS

[0008] Patent Document 1: JP-A No. 2011-18645

[0009] In a square secondary battery in which a battery case is electrically connected to one electrode plate, it is necessary to prevent the sealing plate electrically connected to the one electrode plate from being short-circuited with a terminal electrically connected to the other electrode plate due to water or the like generated by condensation. SUMMARY

[0010] An object of the present application is to provide a square secondary battery in which short-circuiting of a battery case and a terminal is prevented, a battery pack using the square secondary battery, and a vehicle.

[0011] The first invention relates to a square secondary battery including: an electrode body including a first electrode plate and a second electrode plate having a polarity different from the first electrode plate; a square exterior body having an opening that houses the electrode body; a sealing plate that seals the opening; and a terminal that is electrically connected to the first electrode plate, the square secondary battery being configured to be used in an orientation in which the sealing plate extends in a vertical direction, the second electrode plate is electrically connected to the sealing plate, a recess is provided on an outer surface of the sealing plate, a terminal mounting hole is provided in the recess, the terminal is inserted into the terminal mounting hole, an external-side insulating member is disposed between the terminal and the sealing plate, and the sealing plate has a groove portion that is provided to be continuous with an end portion of the recess in a long-side direction of the sealing plate.

[0012] The second invention relates to a square secondary battery including: an electrode body including a first electrode plate and a second electrode plate having a polarity different from the first electrode plate; a square exterior body having an opening that houses the electrode body; a sealing plate that seals the opening; and a terminal that is electrically connected to the first electrode plate, the square secondary battery being configured to be used in an orientation in which the sealing plate extends in a vertical direction, the second electrode plate is electrically connected to the sealing plate, a recess is provided on an outer surface of the sealing plate, a terminal mounting hole is provided in the recess, the terminal is inserted into the terminal mounting hole, an external-side insulating member is disposed between the terminal and the sealing plate, and a distance between an end portion of the recess and the external-side insulating member in a long-side direction of the sealing plate is 1.5 mm or more.

[0013] The third invention relates to a square secondary battery including: an electrode body including a first electrode plate and a second electrode plate having a polarity different from the first electrode plate; a square exterior body having an opening that houses the electrode body; a sealing plate that seals the opening; and a terminal that is electrically connected to the first electrode plate, the square secondary battery being configured to be used in an orientation in which the sealing plate extends in a vertical direction, the second electrode plate is electrically connected to the sealing plate, a recess is provided on an outer surface of the sealing plate, a terminal mounting hole is provided in the recess, the terminal is inserted into the terminal mounting hole, an external-side insulating member is disposed between the terminal and the sealing plate, and an inclined portion is provided at an end portion of the recess in a long-side direction of the sealing plate.

[0014] The inventor has found that, in the case of a square secondary battery in which a sealing plate is disposed in an orientation in which the sealing plate extends in a vertical direction and an electrode plate is electrically connected to the sealing plate, short-circuiting of the sealing plate and a terminal due to water or the like resulting from condensation is likely to occur. The reasons for this are explained below using Figure 10A and Figure 10B .

[0015] Figure 10Ais an enlarged view of the vicinity of the negative terminal 108 of the square secondary battery which is arranged in the direction in which the gasket plate 102 extends in the vertical direction. As shown in Figure 10A the negative terminal 108 is attached to the gasket plate 102 with the external side insulating member 110 interposed therebetween. The recess 120 is provided in the gasket plate 102. The external side insulating member 110 is arranged in the recess 120. The gap 121a, the gap 121b are provided between the side wall portion of the recess 120 provided in the gasket plate 102 and the external side insulating member 110. In addition, Figure 10A the upward and downward directions in the above-described first embodiment correspond to the upward and downward directions of the square secondary battery in the state in which it is actually used.

[0016] The square secondary battery can be used in a state in which the gasket plate 102 to which the negative terminal 108 is attached is arranged in the direction in which it extends in the vertical direction. For example, a plurality of square secondary batteries are connected in series or in parallel to make a group battery. Also, at times, the gasket plates 102 to which the negative terminals 108 of the respective square secondary batteries are attached are arranged side by side in the group battery, and are used mounted on an electric automobile, a hybrid automobile.

[0017] In the case in which the square secondary battery is used in such a state, water droplets can be generated on the surface of the gasket plate 102 and the surface of the negative terminal 108 due to condensation or the like. Figure 10B is a view showing a state in which water droplets are generated on the surface of the gasket plate 102 and the surface of the negative terminal 108. In the case in which water droplets are generated on the surface of the gasket plate 102 and the surface of the negative terminal 108, since the gasket plate 102 is arranged so as to extend in the vertical direction, the water droplets move downward due to gravity. The water droplets generated on the surface of the gasket plate 102 accumulate in the gap 121a, the gap 121b between the recess 120 provided in the gasket plate 102 around the mounting hole of the negative terminal 108 and the external side insulating member 110. In addition, the water accumulated in the gap 121b on the upward side further moves to the gap 121a on the downward side. Also, a state in which more water is accumulated in the gap 121a on the downward side is brought about. In addition, at the same time, the water droplets generated on the surface of the negative terminal 108 also move downward due to gravity. Also, the water droplets 130a which move to the lower end of the negative terminal 108 come into contact with the water droplets 130b accumulated in the gap 121a on the downward side. As a result, the gasket plate 102 and the negative terminal 108 are short-circuited via the water. In addition, such a problem is particularly likely to occur in the case of a vehicle-mounted use in an environment in which the temperature changes greatly.

[0018] In the square secondary battery according to the above-described first embodiment, the gasket plate has the groove portion which is provided so as to be connected to the recess. Therefore, it is possible to suppress the water which enters the recess from flowing to the groove portion and the water level of the water in the recess from becoming high. Therefore, it is possible to effectively prevent the short-circuit of the gasket plate and the negative terminal due to the water or the like generated due to condensation.

[0019] In the square secondary battery according to the above-described second application, the distance between the end portion of the recess and the external-side insulating member in the long side direction of the sealing plate is 1.5 mm or more. Therefore, a sufficient space can be ensured between the end portion of the recess and the external-side insulating member. Therefore, even in the case where a water droplet is immersed in the recess, the water droplet on the terminal is less likely to come into contact with the water droplet in the recess. Thus, short circuit of the sealing plate and the negative electrode terminal due to water or the like resulting from condensation can be effectively prevented.

[0020] In the square secondary battery according to the above-described third application, the end portion of the recess in the long side direction of the sealing plate is provided with a slanted portion. Therefore, even in the case where water or the like resulting from condensation is immersed in the recess, the water is likely to flow out of the recess through the slanted portion. Thus, short circuit of the sealing plate and the terminal due to water in the recess can be effectively prevented.

[0021] A plurality of square secondary batteries according to the first application, the second application, or the third application can be used to form a battery pack. Furthermore, a vehicle equipped with such a battery pack can be formed.

[0022] According to the present application, a square secondary battery in which short circuit of a sealing plate and a terminal due to water or the like resulting from condensation is prevented, a battery pack using the square secondary battery, and a vehicle can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a perspective view of a square secondary battery according to an embodiment.

[0024] Figure 2 is a sectional view of the square secondary battery along the line II-II of Figure 1 .

[0025] Figure 3 is a front view of an electrode body according to an embodiment.

[0026] Figure 4 is a view showing the face of the sealing plate on the battery inner side after installation of each component.

[0027] Figure 5A is a partial enlarged view of the vicinity of the protrusion on the battery inner side of the sealing plate. Figure 5B is a partial enlarged view of the base portion of the positive electrode current collector.

[0028] Figure 6 is an enlarged sectional view of the sealing plate and the base portion of the positive electrode current collector in the short side direction of the sealing plate.

[0029] Figure 7A is an enlarged view of the vicinity of the terminal mounting hole at the face on the battery outer side of the sealing plate. Figure 7BFig. 2 is a view showing a state in which an external side insulating member and a negative electrode terminal are arranged on the closure plate. Figure 7C Fig. 3 is a sectional view along the line Figure 7B VIIC-VIIC in Fig. 2.

[0030] Figure 8 Fig. 4 is a view showing a group battery according to the embodiment.

[0031] Figure 9 Fig. 5 is a view showing a vehicle in which a power supply device including the group battery is mounted.

[0032] Figure 10A Fig. 6 is a view showing a vicinity of a negative electrode terminal of a square secondary battery, Figure 10B Fig. 7 is a view showing a pattern of short circuit due to water generated by condensation.

[0033] Figure 11A Fig. 8 is an enlarged view of a vicinity of a terminal mounting hole at a face of the battery external side of the closure plate of the square secondary battery according to the second embodiment. Figure 11B Fig. 9 is a view showing a state in which an external side insulating member and a negative electrode terminal are arranged on the closure plate. Figure 11C Fig. 10 is a sectional view along the line Figure 11B XIIC-XIIC in Fig. 9.

[0034] Figure 12A Fig. 11 is an enlarged view of a vicinity of a terminal mounting hole at a face of the battery external side of the closure plate of the square secondary battery according to the third embodiment. Figure 12B Fig. 12 is a view showing a state in which an external side insulating member and a negative electrode terminal are arranged on the closure plate. Figure 12C Fig. 13 is a sectional view along the line Figure 12B XIIC-XIIC in Fig. 12.

[0035] Figure 13 Fig. 14 is an enlarged view of a vicinity of an inclined portion in Fig. Figure 12C

[0036] -Explanation of Symbols-

[0037] 50 · · square secondary battery

[0038] 1 · · square outer body

[0039] 2 · · closure plate

[0040] 2a · · protrusion

[0041] 2b · · front end recess

[0042] 2c · · outer surface recess

[0043] 20 · · recess

[0044] 21 · · terminal mounting hole ​

[0045] 22 first groove portion

[0046] 22a inclined portion

[0047] 23 second groove portion

[0048] 23a inclined portion

[0049] 3 electrode body

[0050] 4 positive electrode core exposure portion

[0051] 5 negative electrode core exposure portion

[0052] 6 positive current collector

[0053] 6a base portion

[0054] 6b wire portion

[0055] 6c connection opening

[0056] 6d annular thin-walled portion

[0057] 6e annular protrusion

[0058] 7 negative current collector

[0059] 7a base portion

[0060] 7b wire portion

[0061] 8 negative terminal

[0062] 8a first metal portion

[0063] 8b second metal portion

[0064] 8c flange portion

[0065] 9 inner side insulating member

[0066] 10 outer side insulating member

[0067] 14 insulating sheet

[0068] 15 electrolyte injection hole

[0069] 16 sealing plug

[0070] 17 gas discharge valve

[0071] 30 welded connection portion

[0072] 102 sealing plate

[0073] 108 ••• negative terminal

[0074] 110 ••• outer side insulating member

[0075] 120 ••• recess

[0076] 121a ••• slit

[0077] 121b ••• slit

[0078] 200 ••• group battery

[0079] 201 ••• end plate

[0080] 202 ••• connecting rod

[0081] 203 ••• bus bar

[0082] 204 ••• separator

[0083] 205 ••• group battery base

[0084] 300 ••• vehicle

[0085] 301 ••• engine

[0086] 302 ••• motor

[0087] 303 ••• power supply device

[0088] 304 ••• generator

[0089] 305 ••• DC / AC inverter

[0090] 402 ••• closing plate

[0091] 420 ••• recess

[0092] 421 ••• terminal mounting hole

[0093] 502 ••• closing plate

[0094] 520 ••• recess

[0095] 521 ••• terminal mounting hole

[0096] 522 ••• 1st inclined portion

[0097] 523 ••• 2nd inclined portion DETAILED DESCRIPTION

[0098] Hereinafter, the structure of the square-shaped secondary battery 50 according to the embodiment will be described. Note that the present application is not limited to the following embodiment.

[0099] Figure 1It is a 3D diagram of a square secondary battery 50. Figure 2 It is along Figure 1 A cross-sectional view of the square secondary battery 50 along line II-II. (See image.) Figure 1 as well as Figure 2 As shown, the square secondary battery 50 includes a battery casing comprising a bottomed, cylindrical, square outer body 1 with an opening, and a sealing plate 2 that seals the opening of the square outer body 1. Preferably, both the square outer body 1 and the sealing plate 2 are made of metal, such as aluminum or an aluminum alloy. Inside the square outer body 1, electrode bodies 3, which are stacked or even wound together with a separator between the positive and negative electrode bodies, are housed together with the electrolyte. A resin insulating sheet 14 is disposed between the electrode bodies 3 and the square outer body 1.

[0100] A positive current collector 6 is connected to the positive electrode plate constituting the electrode body 3. The positive current collector 6 is connected to the inner side of the sealing plate 2. Thus, the positive electrode plate is electrically connected to the sealing plate 2 via the positive current collector 6. Preferably, the positive current collector 6 is made of metal, preferably aluminum or an aluminum alloy.

[0101] A negative current collector 7 is connected to the negative electrode plate constituting the electrode body 3. The negative current collector 7 is electrically connected to the negative terminal 8. An internal insulating member 9 is disposed between the negative current collector 7 and the sealing plate 2. An external insulating member 10 is disposed between the negative terminal 8 and the sealing plate 2. Thus, the negative current collector 7 and the negative terminal 8 are insulated from the sealing plate 2. Preferably, the negative current collector 7 is made of metal, preferably copper or a copper alloy. Preferably, the internal insulating member 9 and the external insulating member 10 are made of resin. Preferably, the negative terminal 8 is made of metal, preferably copper or a copper alloy. Furthermore, as... Figure 2 As shown, the preferred negative terminal 8 includes a first metal portion 8a disposed on the inner side of the battery and a second metal portion 8b disposed on the outer side of the battery. Preferably, the first metal portion 8a is made of copper or a copper alloy. Preferably, the second metal portion 8b is made of aluminum or an aluminum alloy. With this structure, when using multiple square secondary batteries to manufacture a battery pack, a busbar made of aluminum or an aluminum alloy can be appropriately used as the busbar connecting the positive terminal of one square secondary battery to the negative terminal of another square secondary battery. Furthermore, it is preferable to form a nickel layer on the surface of the first metal portion 8a.

[0102] A recess 20 is provided on the outer side of the battery of the sealing plate 2. A terminal mounting hole 21 is provided in the recess 20. The negative terminal 8 is inserted into the terminal mounting hole 21.

[0103] The sealing plate 2 is equipped with a gas venting valve 17 that breaks when the pressure inside the battery casing exceeds a specified value, venting the gas inside the battery casing to the outside. The sealing plate 2 is also equipped with an electrolyte injection hole 15, which is sealed by a sealing plug 16 after electrolyte is injected into the battery casing.

[0104] Next, the manufacturing method of the square secondary battery 50 will be described. In the square secondary battery 50 according to the embodiment, the negative electrode plate is the first electrode plate, and the positive electrode plate is the second electrode plate.

[0105] [Manufacture of Positive Electrode Plate]

[0106] A positive electrode mixture slurry containing a lithium nickel cobalt manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binding agent, a carbon material as a conductive agent, and N-methyl-2-pyrrolidone (NMP) was prepared. The positive electrode mixture slurry was applied to both surfaces of an aluminum foil having a thickness of 15 μm in a long strip shape as a positive electrode core. Further, by drying, the NMP in the positive electrode mixture slurry was removed, and a positive electrode active material layer was formed on the positive electrode core. Then, after compression processing was performed so that the positive electrode active material layer had a prescribed thickness, it was cut into a prescribed shape. The positive electrode plate thus obtained had, at the end portion in the width direction of the long strip-shaped positive electrode core, a positive electrode core exposed portion 4 in which the positive electrode active material layer was not formed on both surfaces along the long side direction of the positive electrode core.

[0107] [Manufacture of Negative Electrode Plate]

[0108] A negative electrode mixture slurry containing graphite as a negative electrode active material, styrene butadiene rubber (SBR) as a binding agent, carboxymethyl cellulose (CMC) as a tackifier, and water was prepared. The negative electrode mixture slurry was applied to both surfaces of a copper foil having a thickness of 8 μm in a long strip shape as a negative electrode core. Further, by drying, the water in the negative electrode mixture slurry was removed, and a negative electrode active material layer was formed on the negative core. Then, after compression processing was performed so that the negative electrode active material layer had a prescribed thickness, it was cut into a prescribed shape. The negative electrode plate thus obtained had, at the end portion in the width direction of the long strip-shaped negative electrode core, a negative electrode core exposed portion 5 in which the negative electrode active material layer was not formed on both surfaces along the long side direction of the negative electrode core.

[0109] [Manufacture of Electrode Body]

[0110] An electrode body 3 in a wound type was manufactured by winding the positive electrode plate and the negative electrode plate manufactured by the above-described method with a separator therebetween. In addition, the electrode body 3 was shaped in a flat shape. As shown in FIG. 1, the electrode body 3 had, at one end portion in the winding axis direction, a wound positive electrode core exposed portion 4, and, at the other end portion, a wound negative electrode core exposed portion 5. In addition, it is preferable that the outermost periphery of the electrode body 3 be covered with the separator. Figure 3

[0111] [Installation of Negative Electrode Current Collector and Negative Electrode Terminal to Seal Plate]

[0112] ​Around the terminal mounting holes 21 provided in the sealing plate 2, an inner-side insulating member 9 and the base 7a of the negative current collector 7 are disposed on the inner surface of the battery of the sealing plate 2, and an outer-side insulating member 10 is disposed on the outer surface of the battery of the sealing plate 2. Next, the negative terminal 8 is inserted into the through holes respectively provided in the outer-side insulating member 10, the sealing plate 2, the inner-side insulating member 9, and the base 7a of the negative current collector 7, and the front end of the negative terminal 8 is riveted to the base 7a of the negative current collector 7. Thus, as Figure 2 , Figure 4 As shown, the negative terminal 8, the outer insulating component 10, the inner insulating component 9, and the negative current collector 7 are fixed to the sealing plate 2. Furthermore, it is preferable to further weld the portion riveted to the negative terminal 8 and the base 7a of the negative current collector 7 by means of laser welding or the like to form a welded connection (not shown).

[0113] [Installation of the positive current collector to the sealing plate]

[0114] like Figure 5A As shown, a protrusion 2a is provided on the inner side of the sealing plate 2, on the battery side. Preferably, the protrusion 2a is offset to one side (upward in Figure 5) from the center of the sealing plate 2 in the short side direction. Preferably, a front end recess 2b is provided at the front end of the protrusion 2a. Preferably, the shape of the protrusion 2a in top view is an elongated oval shape. On the outer side of the sealing plate 2, a surface recess 2c is provided at a position corresponding to the protrusion 2a. Figure 5B As shown, a connection opening 6c is provided at the base 6a of the positive current collector 6. Preferably, an annular thin-walled portion 6d is provided on the outer periphery of the connection opening 6c. Preferably, an annular protrusion 6e is provided at the edge of the connection opening 6c.

[0115] like Figure 6 As shown, the base 6a of the positive current collector 6 is disposed on the inner surface of the sealing plate 2, such that the protrusion 2a of the sealing plate 2 is disposed within the connection opening 6c of the positive current collector 6. Furthermore, the protrusion 2a of the sealing plate 2 and the base 6a of the positive current collector 6 are welded together by laser welding or the like, thereby forming a welded connection portion 30. The welded connection portion 30 can be annular or multiple portions spaced apart.

[0116] [Bending of the positive and negative current collectors]

[0117] The positive current collector 6, which is mounted on the sealing plate 2, is bent at the boundary between its base 6a and the lead wire 6b. Similarly, the negative current collector 7, which is mounted on the sealing plate 2, is bent at the boundary between its base 7a and the lead wire 7b. Therefore, the pre-bent positive current collector 6 and negative current collector 7 can be mounted on the sealing plate 2.

[0118] [Positive electrode current collector and negative electrode current collector and connection with electrode body]

[0119] The lead portion 6b of the positive electrode current collector 6 is welded to the outermost surface of the wound positive electrode core exposed portion 4 of the electrode body 3. The lead portion 7b of the negative electrode current collector 7 is welded to the outermost surface of the wound negative electrode core exposed portion 5 of the electrode body 3. As the connection method, resistance welding, ultrasonic welding, laser welding, or the like can be used.

[0120] [Assembly of square secondary battery]

[0121] The electrode body 3 mounted to the gasket plate 2 via the positive electrode current collector 6 and the negative electrode current collector 7 is covered by the insulating sheet 14. Next, the electrode body 3 covered by the insulating sheet 14 is inserted into the square outer case 1. Then, the opening of the square outer case 1 is sealed by the gasket plate 2 by laser welding of the square outer case 1 and the gasket plate 2. Then, a nonaqueous electrolyte solution containing a nonaqueous solvent and an electrolyte salt is injected from the electrolyte injection hole 15 provided in the gasket plate 2, and the electrolyte injection hole 15 is sealed by the sealing plug 16. As the sealing plug 16, a blind rivet is preferably used. Alternatively, the metal sealing plug 16 can be welded to the gasket plate 2.

[0122] [Square secondary battery 50]

[0123] Figure 7A is an enlarged view of the vicinity of the terminal mounting hole 21 at the face of the battery exterior side of the gasket plate 2. As shown in Figure 7A , the gasket plate 2 is provided with the terminal mounting hole 21 at the recess 20. Further, the gasket plate 2 is provided with the first groove portion 22 at one end portion of the recess 20 in the longitudinal direction of the gasket plate 2. Further, the gasket plate 2 is provided with the second groove portion 23 at the other end portion of the recess 20 in the longitudinal direction of the gasket plate 2. Here, the first groove portion 22 is disposed at a position closer to the end portion side of the gasket plate 2 than the recess 20 in the longitudinal direction of the gasket plate 2. The second groove portion 23 is disposed at a position closer to the center side of the gasket plate 2 than the recess 20 in the longitudinal direction of the gasket plate 2. It is also possible to provide at least one of the first groove portion 22 and the second groove portion 23. Further, in the case of providing only one, it is preferable to provide the first groove portion 22 disposed at a position closer to the end portion side of the gasket plate 2 than the recess 20 in the longitudinal direction of the gasket plate 2.

[0124] Figure 7B is a view in which the exterior side insulating member 10 is disposed on the recess 20, and the negative electrode terminal 8 is disposed on the exterior side insulating member 10. Further, Figure 7C is Figure 7B is a cross-sectional view of VIIC-VIIC in

[0125] In the prismatic secondary battery 50, the first groove portion 22 to the second groove portion 23 are provided at the end portion of the recess portion 20. Therefore, even if water or the like due to condensation is infiltrated between the recess portion 20 and the external side insulating member 10, since the water flows to the first groove portion 22 or the second groove portion 23, it is possible to effectively prevent short-circuiting of the gasket 2 and the negative electrode terminal 8 due to water in the recess portion 20.

[0126] It is preferable that the length of the first groove portion 22 and the length of the second groove portion 23 in the long side direction of the gasket 2 be 1 mm to 20 mm, more preferably 2 mm to 10 mm, and further preferably 3 mm to 10 mm. In addition, it is preferable that the distance between the end portion of the gasket 2 (lower end portion of the gasket 2 in the case of the gasket 2 of Figure 7A Figure 7A the first groove portion 22 in the long side direction of the gasket 2) and the end portion of the first groove portion 22 (lower end portion of the first groove portion 22 in the case of the first groove portion 22 of

[0127] It is preferable that a gap be formed between the recess portion 20 and the external side insulating member 10 in the long side direction of the gasket 2. It is preferable that the length of the gap in the long side direction of the gasket 2 be 0.1 mm to 10 mm, more preferably 0.1 mm to 5 mm, and further preferably 0.1 mm to 3 mm.

[0128] In addition, a gap is formed between the recess portion 20 and the external side insulating member 10 in the short side direction of the gasket 2. It is preferable that the length of the gap in the short side direction of the gasket 2 be 0.1 mm to 5 mm, more preferably 0.1 mm to 3 mm, and further preferably 0.1 mm to 1 mm. In addition, the gap can not be formed.

[0129] The height of the bottom portion of the first groove portion 22 to the second groove portion 23 can be set to the same height as the bottom portion of the recess portion 20. In this case, the height of the bottom portion of the first groove portion 22 to the second groove portion 23 can be different from the height of the bottom portion of the recess portion 20.

[0130] ​It is preferable that the inclined portion 22a be formed at the end portion on the side opposite to the end portion of the recessed portion 20 in the first groove portion 22. If such an inclined portion 22a is formed, even if water or the like that has been generated due to condensation enters the recessed portion 20 and the first groove portion 22 in the case where the sealing plate 2 is arranged so as to extend in the vertical direction and a square secondary battery 50 is used, it is easy for the water or the like to flow out of the first groove portion 22 from the first groove portion 22. In addition, it is preferable that the inclined portion 22a be inclined at an angle of 30 degrees to 80 degrees with respect to the bottom of the first groove portion 22. Furthermore, the entire bottom of the first groove portion 22 can be inclined with respect to the bottom of the recessed portion 20.

[0131] It is preferable that the inclined portion 23a be formed at the end portion on the side opposite to the end portion of the recessed portion 20 in the second groove portion 23.

[0132] In addition, in the sealing plate 2, the portion in which the recessed portion 20 is formed is a thin-walled portion that is thinner in thickness than the surrounding portions.

[0133] It is preferable that the external side insulating member 10 have an insulating member base portion 10a arranged between the sealing plate 2 and the flange portion 8c of the negative electrode terminal 8, and a wall portion 10b formed on the outer periphery of the insulating member base portion 10a. The wall portion 10b opposes the side surface of the flange portion 8c of the negative electrode terminal 8. By forming the wall portion 10b, it is possible to more reliably prevent short-circuiting between the sealing plate 2 and the negative electrode terminal 8.

[0134] In addition, in consideration of the connectivity of the bus bars that connect adjacent square secondary batteries to each other in a group battery and the flange portion 8c of the negative electrode terminal 8, it is preferable that the height of the wall portion 10b be smaller than the thickness of the flange portion 8c. That is, it is preferable that, in a direction perpendicular with respect to the sealing plate 2, the flange portion 8c protrude more in a direction away from the sealing plate 2 than the wall portion 10b.

[0135] In addition, in the case where the length of the sealing plate 2 in the longitudinal direction thereof is set to L, it is preferable that the distance from one end portion (the left end portion in FIG. 6) in the longitudinal direction of the sealing plate 2 to the terminal mounting hole 21 be less than 1 / 3L. It is preferable that the distance from one end portion (the left end portion in FIG. 6) in the longitudinal direction of the sealing plate 2 to the gas discharge valve 17 be 1 / 3L to 2 / 3L. It is preferable that the distance from one end portion (the left end portion in FIG. 6) in the longitudinal direction of the sealing plate 2 to the portion in the sealing plate 2 to which the positive electrode current collector 6 is connected be more than 2 / 3L. If such a structure is employed, it is easy to manufacture a group battery in which the orientations of the square secondary batteries are alternated. Figure 2 Figure 2 Figure 2

[0136] ​​​The length of the sealing plate 2 in the short side direction thereof is 10 mm or more, and the length of the sealing plate 2 in the long side direction thereof is 5 times or more the length of the sealing plate 2 in the short side direction thereof. In this case, the amount of water generated due to condensation is large, and thus the present application is particularly effective.

[0137] The recess 20 is preferably formed in the long side direction of the sealing plate 2 between one end portion of the sealing plate 2 and a position that is 1 / 3 of the length of the sealing plate 2 from the one end portion of the sealing plate 2.

[0138] The length of the first groove portion 22 in the short side direction of the sealing plate 2 is preferably smaller than the length of the recess 20 in the short side direction of the sealing plate 2. Also, the length of the second groove portion 23 in the short side direction of the sealing plate 2 is preferably smaller than the length of the recess 20 in the short side direction of the sealing plate 2. With this structure, the position of the external side insulating member 10 in the recess 20 can be prevented from greatly shifting.

[0139] Also, the first groove portion 22 and the second groove portion 23 are preferably connected to the central portion of the recess 20 in the short side direction of the sealing plate 2. With this structure, the sealing plate 2 and the negative electrode terminal 8 can be more effectively prevented from short-circuiting due to water.

[0140] The distance between the end portion of the recess 20 in the long side direction of the sealing plate 2 and the external side insulating member 10 is preferably larger than the distance between the end portion of the recess 20 in the short side direction of the sealing plate 2 and the external side insulating member 10. With this structure, the position of the external side insulating member 10 in the recess 20 can be prevented from greatly shifting. Also, the length of the first groove portion 22 in the short side direction of the sealing plate 2 is preferably half or less the length of the recess 20 in the short side direction of the sealing plate 2. Also, the length of the second groove portion 23 in the short side direction of the sealing plate 2 is preferably half or less the length of the recess 20 in the short side direction of the sealing plate 2. The length of the first groove portion 22 and the length of the second groove portion 23 in the short side direction of the sealing plate 2 are each preferably 0.5 mm or more, and more preferably 1 mm or more.

[0141] The length of the first groove portion 22 and the length of the second groove portion 23 in the short side direction of the sealing plate 2 can also vary at each position in the long side direction of the sealing plate 2. For example, the length of the first groove portion 22 in the short side direction of the sealing plate 2 can gradually decrease toward the end portion in the long side direction of the sealing plate 2.

[0142] Further, it is preferable that the first groove portion 22 and the second groove portion 23 be connected to the central portion of the recessed portion 20 in the short side direction of the sealing plate 2. If this structure is adopted, short circuiting of the sealing plate 2 and the negative electrode terminal 8 due to water can be more effectively prevented. Further, it is preferable that at least a portion of the first groove portion 22 or the second groove portion 23 be connected to the central portion of the end portion of the recessed portion 20 in the long side direction of the sealing plate 2, i.e., the end portion of the recessed portion 20 in the short side direction of the sealing plate 2.

[0143] [Group battery]

[0144] Figure 8 is a view showing a group battery 200 using a plurality of square secondary batteries 50. Between a pair of end plates 201, the plurality of square secondary batteries 50 are stacked with separators 204 made of resin interposed therebetween. The pair of end plates 201 are connected by a connecting rod 202. The stacked square secondary batteries 50 are disposed on a group battery base 205. Further, the pair of end plates 201 are connected to the group battery base 205, respectively. Further, it is preferable that the end plates 201 be made of metal or resin. Furthermore, it is preferable that the connecting rod 202 be made of metal.

[0145] The negative electrode terminal 8 of one square secondary battery 50 and the sealing plate 2 of another square secondary battery 50 adjacent thereto are electrically connected by a metal-made bus bar 203. It is preferable that the bus bar 203 be made of aluminum or an aluminum alloy.

[0146] As described above, in the case where the sealing plate 2 is disposed so as to extend in the vertical direction using the square secondary battery 50, short circuiting of the sealing plate 2 and the negative electrode terminal 8 due to water or the like resulting from condensation is likely to occur. Therefore, in the case where the sealing plate 2 is disposed so as to extend in the vertical direction using the square secondary battery 50, by providing the first groove portion 22 or the second groove portion 23, short circuiting of the sealing plate 2 and the negative electrode terminal 8 can be effectively prevented.

[0147] Figure 9 is a view showing a vehicle 300 equipped with the group battery 200.

[0148] The vehicle 300 can be configured as a hybrid electric vehicle that travels by both an engine and a motor, for example. In this case, the vehicle 300 is equipped with an engine 301 and a motor 302 for traveling, a power supply device 303 provided with a group battery that supplies electric power to the motor 302, and a generator 304. The power supply device 303 is connected to the motor 302 and the generator 304 via a DC / AC inverter 305.

[0149] [Second mode]

[0150] The square secondary battery according to the second mode has the same structure as the square secondary battery 50 described above except for the shape of the sealing plate.

[0151] Figures 11A-11C is a square secondary battery of the second embodiment Figures 7A-7C corresponding view. Figure 11A is an enlarged view of the vicinity of a terminal mounting hole 421 at a face of the battery external side of the seal plate 402. As shown in Figure 11A , in the seal plate 402, the terminal mounting hole 421 is provided in the recessed portion 420.

[0152] Figure 11B is a view in which the external side insulating member 10 is disposed on the recessed portion 420 and the negative electrode terminal 8 is disposed on the external side insulating member 10. Further, Figure 11C is a cross-sectional view of XIC-XIC in Figure 11B

[0153] In the long direction of the seal plate 402, the distance between the end portion (lower side end portion in Figure 11B ) of one side of the recessed portion 420 and the end portion (lower side end portion in Figure 11B ) of one side of the external side insulating member 10 is 1.5 mm or more. With this structure, even in the case where water or the like due to condensation is immersed into the recessed portion 420, the water moves downward within the recessed portion 420. Therefore, it is possible to prevent water from accumulating in the vicinity of the external side insulating member 10 within the recessed portion 420. Therefore, it is possible to effectively prevent the water droplets on the negative electrode terminal 8 from contacting the water droplets within the recessed portion 420.

[0154] Further, in the long direction of the seal plate 402, the distance between the end portion (upper side end portion in Figure 11B ) of the other side of the recessed portion 420 and the end portion (upper side end portion in Figure 11B ) of the other side of the external side insulating member 10 is 1.5 mm or more.

[0155] Further, the structure of the battery pack using the square secondary battery of the second embodiment can be configured to be the same structure as the above-described battery pack 200. Further, the structure of the vehicle equipped with the square secondary battery of the second embodiment can be configured to be the same structure as the above-described vehicle 300.

[0156] Preferably, in the long direction of the seal plate 402, the distance between the end portion (lower side end portion in Figure 11B ) of one side of the recessed portion 420 and the end portion (lower side end portion in Figure 11B ) of one side of the external side insulating member 10 is 1.5 mm or more, more preferably 5 mm or more, and further preferably 10 mm or more. Preferably, in the long direction of the seal plate 402, the distance between the end portion (lower side end portion in Figure 11B ) of one side of the recessed portion 420 and the end portion (lower side end portion in Figure 11B ​The distance between the ends (the lower side) is 30 mm or less, more preferably 20 mm or less.

[0157] Preferably, in the long side direction of the sealing plate 402, at the end of the recess 420 on the other side ( Figure 11B The end on the upper side of the middle section and the end on the other side of the outer insulating member 10 ( Figure 11B The distance between the ends of the upper side (in the middle) is 1.5 mm or more, more preferably 5 mm or more, and even more preferably 10 mm or more. Preferably, in the long side direction of the sealing plate 402, the end of the other side of the recess 420 ( Figure 11B The end on the upper side of the middle section and the end on the other side of the outer insulating member 10 ( Figure 11B The distance between the ends (the upper side) is 30 mm or less, more preferably 20 mm or less.

[0158] Furthermore, it is preferable to provide an inclined portion at the end of the recess 420 in the long side direction of the sealing plate 402. Preferably, the inclined portion is inclined at 30 degrees to 80 degrees relative to the bottom surface of the recess 420.

[0159] The end of the sealing plate 402 along the long side direction is preferred. Figure 11A The lower end of the sealing plate 402 and the end of the recess 420 in the long side direction of the sealing plate 402 ( Figure 11A The distance between the lower end of the recess 420 in the sealing plate 402 and the end of the recess 420 in the long side direction of the sealing plate 402 is 1.5 mm or more, more preferably 1.8 mm or more. If the distance between the end of the sealing plate 402 in the long side direction and the end of the recess 420 in the long side direction of the sealing plate 402 is too close, when welding the sealing plate 402 to the square outer body 1, the heat escape is different in the vicinity of the recess 420 and in other areas, so the weld may not be formed stably. By making the distance between the end of the sealing plate 402 in the long side direction of the sealing plate 402 and the end of the recess 420 in the long side direction of the sealing plate 402 1.5 mm or more, the weld between the sealing plate 402 and the square outer body 1 can be formed more stably.

[0160] <Third Method>

[0161] The square secondary battery involved in the third method has the same structure as the square secondary battery 50 mentioned above, except that the shape of the sealing plate is different.

[0162] Figures 12A-12C It refers to the square secondary battery involved in method 3. Figures 7A-7C The corresponding diagram. Figure 12A This is an enlarged view of the area near the terminal mounting hole 521 on the outer side of the battery of the sealing plate 502. (See attached image.) Figure 12AAs shown, the terminal mounting hole 521 is provided in the recess 520 in the sealing plate 502.

[0163] The terminal mounting hole 521 is provided in the recess 520 in the sealing plate 502. Further, the first inclined portion 522 is provided in one end portion of the recess 520 in the longitudinal direction of the sealing plate 502 (in the lower side in the drawing). Further, the second inclined portion 523 is provided in the other end portion of the recess 520 in the longitudinal direction of the sealing plate 502 (in the upper side in the drawing). It is not necessary to provide both the first inclined portion 522 and the second inclined portion 523, and at least one of them can be provided. In the case where only one of them is provided, it is preferable that the first inclined portion 522 be provided on the side of the end portion of the sealing plate 502 than the recess 520 in the longitudinal direction of the sealing plate 502. Figure 12B Figure 12B

[0164] Figure 12B is a view in which the external side insulating member 10 is provided on the recess 520 and the negative electrode terminal 8 is provided on the external side insulating member 10. Further, Figure 12C is Figure 12B is a sectional view of XIIC-XIIC in

[0165] In the prismatic secondary battery 50, the first inclined portion 522 or the second inclined portion 523 is provided in the end portion of the recess 520. Therefore, even if water or the like produced due to condensation is introduced between the recess 520 and the external side insulating member 10, the water is easily drained outside the recess 520 through the first inclined portion 522 or the second inclined portion 523. Therefore, it is possible to effectively prevent the short circuit between the sealing plate 502 and the negative electrode terminal 8 due to the water in the recess 520.

[0166] Further, it is preferable that the first inclined portion 522 and the second inclined portion 523 be inclined at an angle of 15 degrees to 80 degrees with respect to the bottom surface of the recess 520, and more preferably at an angle of 30 degrees to 60 degrees.

[0167] As shown, it is preferable that a gap be formed between the first inclined portion 522 and the external side insulating member 10 in the longitudinal direction of the sealing plate 502. If this structure is employed, it is possible to more effectively prevent the short circuit between the sealing plate 502 and the negative electrode terminal 8 due to water or the like produced due to condensation. Further, it is preferable that the distance W between the first inclined portion 522 and the external side insulating member 10 in the longitudinal direction of the sealing plate 502 be 0.5 mm or more, more preferably 1 mm or more, and further more preferably 1.5 mm or more. Figure 13

[0168] ​​​Further, the structure of the battery pack using the square secondary battery according to the third embodiment can be the same as the structure of the battery pack 200 described above. Further, the structure of the vehicle equipped with the square secondary battery according to the third embodiment can be the same as the structure of the vehicle 300 described above.

[0169]

[0170] In the above-described embodiment, an example in which the sealing plate is connected to the positive electrode current collector is described. However, the sealing plate can be connected to the negative electrode current collector by the same method. In this case, the sealing plate is insulated from the positive electrode current collector.

[0171] The shape of the electrode body is not particularly limited, and can be a jelly-roll electrode body or a stacked electrode body. Further, the structure of the positive electrode plate, the negative electrode plate, the separator, the electrolyte, and the like can be a publicly known structure.

[0172] Further, the vehicle equipped with the square secondary battery is not limited to a hybrid electric vehicle, and can be an electric vehicle.

[0173] It is preferable that a peripheral groove be provided in the vicinity of the outer peripheral portion of the sealing plate on the side of the outside of the battery of the sealing plate. By providing the peripheral groove in the sealing plate, the welding portion of the sealing plate and the square outer case can be more stably formed. Thus, a square secondary battery with higher reliability is obtained. Further, it is preferable that the peripheral groove be a groove along the outer periphery of the sealing plate. The peripheral groove can be a ring-shaped groove, or can be a shape in which a portion of the ring shape is removed.​

Claims

1. A square secondary battery, comprising: An electrode body includes a first electrode plate and a second electrode plate with a polarity different from that of the first electrode plate; A square outer casing with an opening to accommodate the electrode body; A sealing plate is used to seal the opening. and The terminal is electrically connected to the first electrode plate. The square secondary battery is used in a configuration where the sealing plate extends in the vertical direction. The second electrode plate is electrically connected to the sealing plate. A recess is provided on the outer surface of the sealing plate, along the long side direction of the sealing plate, between one end of the sealing plate and a position one-third of the length of the sealing plate extending from that one end. A terminal mounting hole is provided in the recess. The terminal is inserted into the terminal mounting hole. An external insulating component is disposed between the terminal and the sealing plate. Along the long side of the sealing plate, the distance between the end of the recess and the outer insulating component is 1.5 mm or more. An inclined portion is provided at the end of the recess along the long side of the sealing plate.

2. The square secondary battery according to claim 1, wherein, A gas discharge valve is provided on the sealing plate. A current collector, electrically connected to the second electrode plate, is connected to the inner surface of the sealing plate. Let L be the length of the sealing plate along its long side. The distance from one end of the sealing plate along its long side to the terminal mounting hole is less than 1 / 3L. The distance from one end of the sealing plate along its long side to the gas discharge valve is 1 / 3L to 2 / 3L. The distance from one end of the sealing plate along its long side to the portion of the sealing plate to which the current collector is connected is greater than 2 / 3L.

3. The square secondary battery according to claim 1 or 2, wherein, The length of the sealing plate in the short side direction is 10mm or more. The length of the sealing plate along its long side is more than five times the length of the sealing plate along its short side.

4. A battery pack comprising a plurality of square secondary batteries as described in any one of claims 1 to 3, configured such that the sealing plate extends in the vertical direction.

5. A vehicle equipped with the battery pack of claim 4.

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