Square secondary batteries, battery packs using square secondary batteries, and vehicles

Abstract

This invention provides a square secondary battery, a battery pack using the same, and a vehicle that prevents short circuits between the terminals and the sealing plate. The square secondary battery (50) comprises: an electrode body including a positive electrode plate and a negative electrode plate; a square outer casing (1) for housing the electrode body; a sealing plate (2) for sealing the opening of the square outer casing (1); and a negative terminal (8) electrically connected to the negative electrode plate. The square secondary battery is configured such that the sealing plate (2) extends in the vertical direction, the positive electrode plate is electrically connected to the sealing plate (2), the sealing plate (2) has a recess (20) on its outer side and a terminal mounting hole (21) formed in the recess (20), the negative terminal (8) is inserted into the terminal mounting hole (21), an external insulating member (10) is disposed between the negative terminal (8) and the sealing plate (2), and the sealing plate (2) has a first groove (22) configured to connect to the end of the recess (20) in the long side direction of the sealing plate (2).

Description

[0001] This application is a divisional application of the invention patent application filed on May 30, 2018, with application number 201810544647.9 and invention title "Square Secondary Battery, Battery Pack Using Square Secondary Battery and Vehicle". Technical Field

[0002] This invention relates to square secondary batteries, battery packs using square secondary batteries, and vehicles. Background Technology

[0003] In the power supply for driving electric vehicles (EVs), hybrid electric vehicles (HEVs, PHEVs), etc., square secondary batteries such as non-aqueous electrolyte secondary batteries are used.

[0004] In these square secondary batteries, the battery casing is formed by a square, bottomed, cylindrical outer body with an opening and a sealing plate that seals the opening of the square outer body. Inside the battery casing, electrode bodies, including a positive electrode plate, a negative electrode plate, and a separator, are housed together with the electrolyte. The positive and negative terminals are mounted on the sealing plate, separated by insulating components. The positive terminal is electrically connected to the positive electrode plate via a positive current collector, and the negative terminal is electrically connected to the negative electrode plate via a negative current collector.

[0005] Furthermore, as described in Patent Document 1 below, a square secondary battery with a structure in which the positive current collector is connected to the inner surface of the battery sealing plate, and the battery casing also serves as the positive terminal, has advantages such as reducing the number of components.

[0006] Prior art literature

[0007] Patent documents

[0008] Patent Document 1: JP 2011-18645

[0009] In a square secondary battery where the battery casing is electrically connected to one electrode plate, it is necessary to prevent short circuits caused by water or other factors such as condensation between the sealing plate electrically connected to one electrode plate and the terminal electrically connected to the other electrode plate. Summary of the Invention

[0010] One object of the present invention is to provide a square secondary battery in which short circuits between the battery casing and terminals are prevented, a battery pack using the square secondary battery, and a vehicle.

[0011] The first invention relates to a square secondary battery comprising: an electrode body including a first electrode plate and a second electrode plate having a polarity different from that of the first electrode plate; a square outer casing having an opening for receiving the electrode body; a sealing plate for sealing the opening; and a terminal electrically connected to the first electrode plate. The square secondary battery is used in an orientation in which 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, and a terminal mounting hole is provided in the recess. The terminal is inserted into the terminal mounting hole. An external insulating member is disposed between the terminal and the sealing plate. The sealing plate has a groove that is configured to connect to the end of the recess in the long side direction of the sealing plate.

[0012] The second invention relates to a square secondary battery comprising: an electrode body including a first electrode plate and a second electrode plate having a polarity different from that of the first electrode plate; a square outer casing having an opening for receiving the electrode body; a sealing plate for sealing the opening; and a terminal electrically connected to the first electrode plate. The square secondary battery is used in an orientation in which 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, and a terminal mounting hole is provided in the recess. The terminal is inserted into the terminal mounting hole. An external insulating member is disposed between the terminal and the sealing plate. In the long side direction of the sealing plate, the distance between the end of the recess and the external insulating member is 1.5 mm or more.

[0013] The third invention relates to a square secondary battery comprising: an electrode body including a first electrode plate and a second electrode plate having a polarity different from that of the first electrode plate; a square outer casing having an opening for receiving the electrode body; a sealing plate for sealing the opening; and a terminal electrically connected to the first electrode plate. The square secondary battery is configured to be used with the sealing plate extending 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, and a terminal mounting hole is provided in the recess. The terminal is inserted into the terminal mounting hole. An external insulating member is disposed between the terminal and the sealing plate. An inclined portion is provided at the end of the recess in the long side direction of the sealing plate.

[0014] The inventors discovered that in a square secondary battery where the sealing plate is positioned vertically and electrically connected to an electrode plate, short circuits between the sealing plate and terminals are easily caused by condensation and other factors. The following uses... Figure 10A as well as Figure 10B Let us explain the reasons behind it.

[0015] Figure 10AThis is an enlarged view of the vicinity of the negative terminal 108 of a square secondary battery positioned in the vertical direction of the sealing plate 102. (See image below.) Figure 10A As shown, the negative terminal 108 is mounted on the sealing plate 102 via the external insulating member 110. A recess 120 is provided in the sealing plate 102. The external insulating member 110 is disposed within the recess 120. Gaps 121a and 121b are provided between the sidewall of the recess 120 in the sealing plate 102 and the external insulating member 110. Furthermore, Figure 10A The up and down directions in the text correspond to the up and down directions of a square secondary battery in actual use.

[0016] Square secondary batteries may be used in a configuration where the sealing plate 102, on which the negative terminal 108 is mounted, is arranged in a vertically extending orientation. For example, multiple square secondary batteries may be connected in series or even in parallel to create a battery pack. Furthermore, sometimes the sealing plates 102 on the sides of the battery pack, with the negative terminals 108 of each square secondary battery mounted side by side, are used in electric vehicles and hybrid vehicles.

[0017] When using a square secondary battery in this condition, water droplets may form on the surface of the sealing plate 102 and the surface of the negative terminal 108 due to condensation. Figure 10B This diagram illustrates the state in which water droplets are generated on the surfaces of the sealing plate 102 and the negative terminal 108. When water droplets are generated on the surfaces of the sealing plate 102 and the negative terminal 108, since the sealing plate 102 is configured to extend vertically, the water droplets move downwards due to gravity. The water droplets generated on the surface of the sealing plate 102 accumulate in the gaps 121a and 121b between the recess 120 surrounding the mounting hole of the negative terminal 108 of the sealing plate 102 and the outer insulating member 110. Furthermore, the water accumulated in the upper gap 121b moves further downwards to the lower gap 121a. Thus, more water accumulates in the lower gap 121a. Simultaneously, the water droplets generated on the surface of the negative terminal 108 also move downwards due to gravity. Furthermore, the water droplet 130a moving towards the lower end of the negative terminal 108 comes into contact with the water droplet 130b accumulated in the gap 121a on the lower side. As a result, the sealing plate 102 short-circuits with the negative terminal 108 via this water. In addition, this problem is particularly prone to occur in vehicle applications used in environments with large temperature variations.

[0018] In the square secondary battery according to the first invention described above, the sealing plate has a groove that is configured to connect with the recess. Therefore, it is possible to suppress the flow of water entering the recess into the groove and to prevent the water level in the recess from rising. Thus, it is possible to effectively prevent short circuits between the sealing plate and the negative terminal caused by condensation or other water-related issues.

[0019] In the square secondary battery according to the second invention described above, the distance between the end of the recess and the external insulating member in the long side direction of the sealing plate is 1.5 mm or more. Therefore, sufficient space can be ensured between the end of the recess and the external insulating member. Thus, even if water droplets are immersed in the recess, it is difficult for water droplets on the terminal to come into contact with water droplets inside the recess. Therefore, short circuits between the sealing plate and the negative terminal caused by water or other condensation can be effectively prevented.

[0020] In the square secondary battery according to the third invention described above, an inclined portion is provided at the end of the recess in the long side direction of the sealing plate. Therefore, even if water or the like, generated by condensation, seeps into the recess, the water can easily flow out of the recess through the inclined portion. Thus, it is possible to effectively prevent a short circuit between the sealing plate and the terminals due to water in the recess.

[0021] A battery pack can be formed using multiple square secondary batteries as described in the first, second, or third invention. Furthermore, a vehicle equipped with such a battery pack can be formed.

[0022] According to the present invention, a square secondary battery that prevents short circuits between the sealing plate and the terminals caused by water or the like due to condensation, a battery pack using the square secondary battery, and a vehicle can be provided. Attached Figure Description

[0023] Figure 1 This is a perspective view of the square secondary battery involved in the implementation method.

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

[0025] Figure 3 This is a front view of the electrode body involved in the embodiment.

[0026] Figure 4 This is a diagram showing the inside of the battery side of the sealing plate after all components have been installed.

[0027] Figure 5A This is a magnified view of a portion of the protrusion on the inside of the battery in the sealing plate. Figure 5B This is a magnified view of the base of the positive current collector.

[0028] Figure 6 It is an enlarged cross-sectional view of the sealing plate and the base of the positive current collector along the short side of the sealing plate.

[0029] Figure 7A This is an enlarged view of the area near the terminal mounting holes on the outer side of the battery of the sealing plate. Figure 7BThis is a diagram showing the external insulating components and negative terminal on the sealing plate. Figure 7C It is along Figure 7B Sectional view of VIIC-VIIC.

[0030] Figure 8 This is a diagram showing the battery pack involved in the implementation method.

[0031] Figure 9 This is a diagram showing a vehicle equipped with a power supply unit that includes a battery pack.

[0032] Figure 10A This is a diagram showing the area near the negative terminal of a square secondary battery. Figure 10B It is a diagram showing what a short circuit is caused by water produced by condensation.

[0033] Figure 11A This is an enlarged view of the area near the terminal mounting hole on the outer side of the sealing plate of the square secondary battery according to the second embodiment. Figure 11B This is a diagram showing the external insulating components and negative terminal on the sealing plate. Figure 11C It is along Figure 11B Cross-sectional view of XIC-XIC in the diagram.

[0034] Figure 12A This is an enlarged view of the area near the terminal mounting hole on the outer side of the sealing plate of the square secondary battery according to the third embodiment. Figure 12B This is a diagram showing the external insulating components and negative terminal on the sealing plate. Figure 12C It is along Figure 12B The sectional view of XIIC-XIIC in the diagram.

[0035] Figure 13 yes Figure 12C A magnified view of the area near the sloping part.

[0036] -Symbol Explanation-

[0037] 50 square secondary batteries

[0038] 1··· Square outer casing

[0039] 2··· Sealing board

[0040] 2a···protrusion

[0041] 2b···Front end concave part

[0042] 2c···Concave part on outer surface

[0043] 20···Concave part

[0044] 21···Terminal mounting holes

[0045] 22···First Groove Section

[0046] 22a··· Inclined section

[0047] 23···Second Groove Section

[0048] 23a··· Inclined section

[0049] 3···Electrode

[0050] 4. Exposed portion of the positive electrode core

[0051] 5. Exposed part of the negative electrode core

[0052] 6··· Positive current collector

[0053] 6a···base

[0054] 6b··· Conductor section

[0055] 6c··· Connection opening

[0056] 6d··· Annular thin-walled portion

[0057] 6e··· Ring-shaped protrusions

[0058] 7··· Negative current collector

[0059] 7a···base

[0060] 7b··· Conductor Section

[0061] 8··· Negative extremes

[0062] 8a···First Metal Section

[0063] 8b···Second Metal Section

[0064] 8c···Flange

[0065] 9. Internal insulation components

[0066] 10. External insulation components

[0067] 14··· Insulating sheet

[0068] 15···Electrolyte injection hole

[0069] 16···Sealing plug

[0070] 17. Gas discharge valve

[0071] 30··· Welded joint

[0072] 102··· Sealing board

[0073] 108··· Negative extremes

[0074] 110··· External insulation components

[0075] 120···Concave part

[0076] 121a···gap

[0077] 121b··· Gap

[0078] 200 sets of batteries

[0079] 201···Endplate

[0080] 202···Connecting rod

[0081] 203···Bus

[0082] 204···Isolation Material

[0083] 205··· battery base

[0084] 300 vehicles

[0085] 301 engine

[0086] 302··· Motor

[0087] 303 Power Supply Unit

[0088] 304 Generator

[0089] 305···DC / AC Inverter 402···Sealing Plate

[0090] 420···Concave

[0091] 421···Terminal mounting hole

[0092] 502 sealing board

[0093] 520···Concave

[0094] 521···Terminal mounting hole

[0095] 522···First Inclined Section

[0096] 523···Second Inclined Section Detailed Implementation

[0097] The structure of the square secondary battery 50 according to the embodiments will be described below. However, the present invention is not limited to the following embodiments.

[0098] Figure 1 It 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] Next, the manufacturing method of the square secondary battery 50 will be described. Furthermore, 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.

[0104] [Making the positive electrode plate]

[0105] A positive electrode slurry comprising a lithium nickel cobalt manganese composite oxide as the positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, a carbon material as a conductive agent, and N-methyl-2-pyrrolidone (NMP) is prepared. This positive electrode slurry is applied to both sides of a 15 μm thick strip of aluminum foil, which serves as the positive electrode core. The NMP in the slurry is removed by drying, forming a positive electrode active material layer on the positive electrode core. The layer is then compressed to a specified thickness and cut into a specified shape. The resulting positive electrode plate has an exposed portion 4 at the end of the strip-shaped positive electrode core in the width direction, where no positive electrode active material slurry layer is formed on either side along the long side of the positive electrode core.

[0106] [Making the negative electrode plate]

[0107] A negative electrode slurry comprising graphite as the negative electrode active material, styrene-butadiene rubber (SBR) as a binder, carboxymethyl cellulose (CMC) as a tackifier, and water is prepared. This negative electrode slurry is applied to both sides of an 8 μm thick strip of copper foil, which serves as the negative electrode core. The negative electrode slurry is then dried to remove water, forming a negative electrode active material layer on the negative core. After compression to achieve a specified thickness, the negative electrode active material layer is cut into a specified shape. The resulting negative electrode plate has an exposed portion 5 at the end of the strip-shaped negative electrode core in the width direction, where no negative electrode active material slurry layer is formed on either side along the long side of the negative electrode core.

[0108] [Electrode fabrication]

[0109] A wound electrode body 3 is fabricated by winding a positive electrode plate and a negative electrode plate, both prepared using the method described above, together with a separator in between. Furthermore, the electrode body 3 is shaped to be relatively flat. Figure 3 As shown, the electrode body 3 has a wound positive electrode core exposed portion 4 at one end in the winding axis direction and a wound negative electrode core exposed portion 5 at the other end. Furthermore, it is preferable that the outermost periphery of the electrode body 3 is covered by a partition.

[0110] [Installation of the negative current collector and the negative terminal towards the sealing plate]

[0111] 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).

[0112] [Installation of the positive current collector to the sealing plate]

[0113] 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.

[0114] 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.

[0115] [Bending of the positive and negative current collectors]

[0116] 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.

[0117] [Connection of the positive and negative current collectors to the electrode body]

[0118] The conductive portion 6b of the positive current collector 6 is welded to the outermost surface of the exposed positive core portion 4 of the electrode body 3. The conductive portion 7b of the negative current collector 7 is welded to the outermost surface of the exposed negative core portion 5 of the electrode body 3. Furthermore, resistance welding, ultrasonic welding, laser welding, etc., can be used as connection methods.

[0119] [Assembly of a square secondary battery]

[0120] The electrode body 3, which is mounted on the sealing plate 2 via the positive current collector 6 and the negative current collector 7, is covered by an insulating sheet 14. Next, the electrode body 3 covered by the insulating sheet 14 is inserted into the square outer casing 1. Then, the opening of the square outer casing 1 is sealed by the sealing plate 2 through laser welding of the square outer casing 1 and the sealing plate 2. Then, a non-aqueous electrolyte containing a non-aqueous solvent and electrolyte salt is injected through the electrolyte injection hole 15 provided on the sealing plate 2, and the electrolyte injection hole 15 is sealed by a sealing plug 16. A blind rivet is preferably used as the sealing plug 16. Alternatively, a metal sealing plug 16 can be welded to the sealing plate 2.

[0121] [50g Square Rechargeable Battery]

[0122] Figure 7A This is an enlarged view of the area near the terminal mounting hole 21 on the outer side of the battery of the sealing plate 2. (See image below.) Figure 7A As shown, a terminal mounting hole 21 is provided in the recess 20 of the sealing plate 2. Furthermore, a first groove 22 is provided at one end of the recess 20 along the long side of the sealing plate 2. Additionally, a second groove 23 is provided at the other end of the recess 20 along the long side of the sealing plate 2. Here, the first groove 22 is positioned along the long side of the sealing plate 2, closer to the end of the sealing plate 2 than the recess 20. The second groove 23 is positioned along the long side of the sealing plate 2, closer to the center of the sealing plate 2 than the recess 20. It is not necessary to provide both the first groove 22 and the second groove 23; providing at least one is sufficient. However, if only one is provided, it is preferable to provide the first groove 22 positioned along the long side of the sealing plate 2, closer to the end of the sealing plate 2 than the recess 20.

[0123] Figure 7B This diagram shows the outer insulating member 10 disposed on the recess 20 and the negative terminal 8 disposed on the outer insulating member 10. Furthermore, Figure 7C yes Figure 7B Sectional view of VIIC-VIIC.

[0124] In the square secondary battery 50, a first groove 22 and a second groove 23 are provided at the end of the recess 20. Therefore, even if water or the like, generated by condensation, seeps between the recess 20 and the external insulating member 10, the water flows to the first groove 22 or the second groove 23, thus effectively preventing a short circuit between the sealing plate 2 and the negative terminal 8 caused by the water in the recess 20.

[0125] Preferably, the lengths of the first groove 22 and the second groove 23 along the long side of the sealing plate 2 are 1mm to 20mm, more preferably 2mm to 10mm, and even more preferably 3mm to 10mm. Additionally, the end of the sealing plate 2 along the long side of the sealing plate 2 is preferably... Figure 7A The lower end of the sealing plate 2) and the end of the first groove 22 in the long side direction of the sealing plate 2 ( Figure 7A The distance between the lower end of the first groove 22 in the sealing plate 2 is 1.5 mm or more, more preferably 1.8 mm or more. If the distance between the end of the sealing plate 2 in the long side direction and the end of the first groove 22 in the long side direction of the sealing plate 2 is too close, the heat escape near the first groove 22 and the area outside it will be different when the sealing plate 2 is welded to the square outer body 1, so the welded part may not be formed stably. By setting the distance between the end of the sealing plate 2 in the long side direction and the end of the first groove 22 in the long side direction of the sealing plate 2 to 1.5 mm or more, the welded part between the sealing plate 2 and the square outer body 1 is formed more stably.

[0126] Preferably, a gap is formed between the recess 20 and the outer insulating member 10 along the long side of the sealing plate 2. Preferably, the length of the gap along the long side of the sealing plate 2 is 0.1 mm to 10 mm, more preferably 0.1 mm to 5 mm, and even more preferably 0.1 mm to 3 mm.

[0127] Furthermore, a gap is formed between the recess 20 and the outer insulating member 10 in the short side direction of the sealing plate 2. Preferably, the length of the gap in the short side direction of the sealing plate 2 is 0.1 mm to 5 mm, more preferably 0.1 mm to 3 mm, and even more preferably 0.1 mm to 1 mm. Alternatively, the gap may not be formed.

[0128] The height of the bottom of the first groove 22 and even the second groove 23 can be set to be the same as the bottom of the recess 20. Alternatively, the height of the bottom of the first groove 22 and even the second groove 23 can be different from the bottom of the recess 20.

[0129] Preferably, an inclined portion 22a is formed at the end of the first groove 22 opposite to the end of the recess 20. With this inclined portion 22a, when the sealing plate 2 is configured to extend vertically and a square secondary battery 50 is used, even if water or the like, generated by condensation, enters the recess 20 and the first groove 22, it can easily flow from inside the first groove 22 to outside. Furthermore, it is preferable that the inclined portion 22a is inclined at 30 to 80 degrees relative to the bottom of the first groove 22. Alternatively, the entire bottom of the first groove 22 may be inclined relative to the bottom of the recess 20.

[0130] Preferably, in the second groove 23, an inclined portion 23a is also formed at the end opposite to the end of the recess 20.

[0131] In addition, in the sealing plate 2, the portion where the recess 20 is formed is a thin-walled portion that is thinner than its surroundings.

[0132] Preferably, the outer insulating member 10 has an insulating member base 10a disposed between the sealing plate 2 and the flange portion 8c of the negative terminal 8, and a wall portion 10b formed on the outer periphery of the insulating member base 10a. The wall portion 10b faces the side of the flange portion 8c of the negative terminal 8. By forming the wall portion 10b, short circuits between the sealing plate 2 and the negative terminal 8 can be prevented more reliably.

[0133] Furthermore, considering the connectivity between the busbar connecting adjacent square secondary batteries in the battery pack and the flange 8c of the negative terminal 8, it is preferable that the height of the wall portion 10b is smaller than the thickness of the flange portion 8c. That is, it is preferable that, in the direction perpendicular to the sealing plate 2, the flange portion 8c protrudes further away from the sealing plate 2 than the wall portion 10b.

[0134] Furthermore, when the length of the sealing plate 2 in the long side direction is set to L, it is preferable to start from one end in the long side direction of the sealing plate 2. Figure 2 The distance from the left end of the sealing plate 2 to the terminal mounting hole 21 is less than 1 / 3L. Preferably, it is from one end of the sealing plate 2 along its long side. Figure 2 The distance from the left end of the sealing plate 2 to the gas discharge valve 17 is 1 / 3L to 2 / 3L. Preferably, it is from one end of the sealing plate 2 along the long side. Figure 2 The distance from the left end of the middle section to the portion connected to the positive current collector 6 in the sealing plate 2 is greater than 2 / 3L. With this structure, it is easy to manufacture a battery pack with alternating orientations of the square secondary batteries.

[0135] When the length of the sealing plate 2 in the short side direction is 10 mm or more, and the length of the sealing plate 2 in the long side direction is 5 times or more than the length of the sealing plate 2 in the short side direction, the present invention is particularly effective because the amount of water generated due to condensation increases.

[0136] Preferably, the recess 20 is formed in the long side direction of the sealing plate 2 between one end of the sealing plate 2 and one-third of the length of the sealing plate from one end of the sealing plate 2.

[0137] Preferably, the length of the first groove 22 in the short side direction of the sealing plate 2 is less than the length of the recess 20 in the short side direction of the sealing plate 2. Furthermore, preferably, the length of the second groove 23 in the short side direction of the sealing plate 2 is less than the length of the recess 20 in the short side direction of the sealing plate 2. With this structure, it is possible to prevent significant displacement of the insulating member 10 on the inner and outer sides of the recess 20.

[0138] Furthermore, it is preferable that the first groove 22 and the second groove 23 are connected to the central portion of the recess 20 in the short side direction of the sealing plate 2. With this structure, it is possible to more effectively prevent the sealing plate 2 from short-circuiting with the negative terminal 8 due to water.

[0139] Preferably, the distance between the end of the recess 20 in the long side direction of the sealing plate 2 and the outer insulating member 10 is greater than the distance between the end of the recess 20 in the short side direction of the sealing plate 2 and the outer insulating member 10. This structure prevents significant displacement of the outer insulating member 10 within and outside the recess 20. Furthermore, preferably, the length of the first groove 22 in the short side direction of the sealing plate 2 is less than half the length of the recess 20 in the short side direction of the sealing plate 2. Preferably, the length of the second groove 23 in the short side direction of the sealing plate 2 is less than half the length of the recess 20 in the short side direction of the sealing plate 2. Preferably, the lengths of the first groove 22 and the second groove 23 in the short side direction of the sealing plate 2 are both 0.5 mm or more, more preferably 1 mm or more.

[0140] It is also possible to vary the length of the first groove 22 and the second groove 23 in the short side direction of the sealing plate 2 at various positions in the long side direction of the sealing plate 2. For example, the length of the first groove 22 in the short side direction of the sealing plate 2 can gradually decrease as it approaches the end in the long side direction of the sealing plate 2.

[0141] Furthermore, it is preferable that the first groove 22 and the second groove 23 are connected to the central portion of the recess 20 in the short side direction of the sealing plate 2. With this structure, it is possible to more effectively prevent the sealing plate 2 from short-circuiting with the negative terminal 8 due to water. In addition, it is preferable that at least a portion of the first groove 22 or the second groove 23 is connected to the center of the end of the recess 20 in the long side direction of the sealing plate 2, that is, the end of the recess 20 in the short side direction of the sealing plate 2.

[0142] [Battery Set]

[0143] Figure 8 This diagram illustrates a battery pack 200 using multiple square secondary batteries 50. The multiple square secondary batteries 50 are stacked between a pair of end plates 201, separated by a resin separator 204. The pair of end plates 201 are connected by a connecting rod 202. The stacked square secondary batteries 50 are disposed on a battery pack base 205. Furthermore, the pair of end plates 201 are respectively connected to the battery pack base 205. Preferably, the end plates 201 are made of metal or resin. Furthermore, preferably, the connecting rod 202 is made of metal.

[0144] The negative terminal 8 of a square secondary battery 50 is electrically connected to the sealing plate 2 of another adjacent square secondary battery 50 via a metal busbar 203. Preferably, the busbar 203 is made of aluminum or aluminum alloy.

[0145] As described above, when the sealing plate 2 extends vertically to accommodate the square secondary battery 50, short circuits between the sealing plate 2 and the negative terminal 8 are easily caused by condensation and the resulting water. Therefore, by providing the first groove 22 and even the second groove 23 when the sealing plate 2 extends vertically to accommodate the square secondary battery 50, short circuits between the sealing plate 2 and the negative terminal 8 can be effectively prevented.

[0146] Figure 9 This is a diagram of a vehicle 300 equipped with a battery pack 200.

[0147] Vehicle 300 can be configured as a hybrid electric vehicle that is driven by both an engine and an electric motor. In this case, vehicle 300 is equipped with an engine 301, an electric motor 302 for driving, a power supply unit 303 with a battery pack that supplies power to the electric motor 302, and a generator 304. The power supply unit 303 is connected to the electric motor 302 and the generator 304 via a DC / AC inverter 305.

[0148] <Method 2>

[0149] The square secondary battery involved in the second method has the same structure as the square secondary battery 50 mentioned above, except that the shape of the sealing plate is different.

[0150] Figures 11A to 11C It refers to the square secondary battery involved in method 2. Figures 7A to 7C The corresponding diagram. Figure 11A This is an enlarged view of the area near the terminal mounting hole 421 on the outer side of the battery of the sealing plate 402. (See attached image.) Figure 11A As shown, a terminal mounting hole 421 is provided in the recess 420 of the sealing plate 402.

[0151] Figure 11B The figure shows an outer-side insulating member 10 disposed on the recess 420, and a negative terminal 8 disposed on the outer-side insulating member 10. Furthermore, Figure 11C yes Figure 11B The cross-sectional view of XIC-XIC in the diagram.

[0152] Along the long side of the sealing plate 402, at one end of the recess 420 ( Figure 11B The end on the lower side of the middle section and the end on one side of the outer insulating member 10 ( Figure 11B The distance between the lower end and the middle end is 1.5 mm or more. With this structure, even if water or other substances caused by condensation seep into the recess 420, the water moves downwards within the recess 420. Therefore, it is possible to prevent water from accumulating near the outer insulating member 10 within the recess 420. Thus, it is possible to effectively prevent water droplets on the negative terminal 8 from contacting water droplets within the recess 420.

[0153] Additionally, along the long side of the sealing plate 402, the other end of the recess 420 ( Figure 11B The upper end of the middle) and the other end of the outer insulating member 10 ( Figure 11B The distance between the upper end of the middle part and the upper end of the middle part is more than 1.5 mm.

[0154] Furthermore, the structure of the battery pack using the square secondary battery according to the second embodiment can be set to the same structure as the battery pack 200 described above. Additionally, the structure of the vehicle equipped with the square secondary battery according to the second embodiment can be set to the same structure as the vehicle 300 described above.

[0155] Preferably, in the long side direction of the sealing plate 402, at one end of the recess 420 ( Figure 11B The end on the lower side of the middle section and the end on one side of the outer insulating member 10 ( Figure 11B The distance between the lower end (the middle part) and the end portion 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 portion on one side of the recess 420 ( Figure 11B The end on the lower side of the middle section and the end on one side of the outer insulating member 10 ( Figure 11BThe distance between the ends (the lower side) is 30 mm or less, more preferably 20 mm or less.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] <Third Method>

[0160] 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.

[0161] Figures 12A-12C It refers to the square secondary battery involved in method 3. Figures 7A to 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, in the sealing plate 502, a terminal mounting hole 521 is provided in the recess 520.

[0162] In the sealing plate 502, a terminal mounting hole 521 is provided in the recess 520. Furthermore, at one end of the recess 520 in the long side direction of the sealing plate 502... Figure 12B A first inclined portion 522 is provided at the lower end of the sealing plate 502. Furthermore, at the other end of the recess 520 in the long side direction of the sealing plate 502... Figure 12B A second inclined portion 523 is provided at the upper end of the sealing plate 502. It is not necessary to provide both the first inclined portion 522 and the second inclined portion 523; at least one is sufficient. In addition, when only one is provided, it is preferable to provide the first inclined portion 522 in the long side direction of the sealing plate 502, which is disposed on the end side of the sealing plate 502 that is closer to the end of the sealing plate 502 than the recess 520.

[0163] Figure 12B The diagram shows an outer insulating member 10 disposed on the recess 520, and a negative terminal 8 disposed on the outer insulating member 10. Furthermore, Figure 12C yes Figure 12B The sectional view of XIIC-XIIC in the diagram.

[0164] In the square secondary battery 50, a first inclined portion 522 and even a second inclined portion 523 are provided at the end of the recess 520. Therefore, even if water or the like, generated by condensation, seeps between the recess 520 and the outer insulating member 10, the water can easily flow out of the recess 520 through the first inclined portion 522 and even the second inclined portion 523. Thus, it is possible to effectively prevent a short circuit between the sealing plate 502 and the negative terminal 8 due to water in the recess 520.

[0165] In addition, the first inclined portion 522 and the second inclined portion 523 are preferably inclined at 15 degrees to 80 degrees relative to the bottom surface of the recess 520, and more preferably at 30 degrees to 60 degrees.

[0166] like Figure 13 As shown, it is preferable to form a gap between the first inclined portion 522 and the outer insulating member 10 in the long side direction of the sealing plate 502. With this structure, short circuits between the sealing plate 502 and the negative terminal 8 caused by water or other contaminants due to condensation can be prevented more effectively. In addition, it is preferable that the distance W between the first inclined portion 522 and the outer insulating member 10 in the long side direction of the sealing plate 502 is 0.5 mm or more, more preferably 1 mm or more, and even more preferably 1.5 mm or more.

[0167] Furthermore, the structure of the battery pack using the square secondary battery according to the third embodiment can be set to the same structure as the battery pack 200 described above. Additionally, the structure of the vehicle equipped with the square secondary battery according to the third embodiment can be set to the same structure as the vehicle 300 described above.

[0168] "other"

[0169] In the above embodiment, an example of connecting the sealing plate to the positive current collector is shown. However, the sealing plate can be connected to the negative current collector using the same method. In this case, the sealing plate is insulated from the positive current collector.

[0170] The shape of the electrode body is not particularly limited; it can be a wound electrode body or a stacked electrode body. In addition, the structures of the positive electrode plate, negative electrode plate, separator, electrolyte, etc., can be set to known structures.

[0171] Furthermore, the vehicle equipped with a square secondary battery is not limited to a hybrid electric vehicle; it can also be an electric vehicle.

[0172] Preferably, an outer peripheral groove is provided on the outer side of the battery of the sealing plate, near the outer periphery of the sealing plate. By providing an outer peripheral groove on the sealing plate, the weld between the sealing plate and the square outer casing can be formed more stably. Therefore, a square secondary battery with higher reliability is obtained. In addition, it is preferable that the outer peripheral groove is a groove along the outer periphery of the sealing plate. The outer peripheral groove can be an annular groove or a shape in which a portion of the annulus has been 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. 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. An inclined portion is provided at the end of the recess along the long side of the sealing plate. A gap is formed between the inclined portion and the outer side insulating component along the long side direction 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.

Images