JP6949181B2 - Square secondary battery - Google Patents

Description

The present invention relates to a square secondary battery.

Square secondary batteries such as alkaline secondary batteries and non-aqueous electrolyte secondary batteries are used in driving power sources of electric vehicles (EV) and hybrid electric vehicles (HEV, PHEV).

In these square secondary batteries, a battery case is composed of a bottomed cylindrical square outer body having an opening and a sealing plate for sealing the opening. An electrode body composed of a positive electrode plate, a negative electrode plate, and a separator is housed in the battery case together with the electrolytic solution. A positive electrode terminal and a negative electrode terminal are attached to the sealing plate. The positive electrode terminal is electrically connected to the positive electrode plate via the positive electrode current collector, and the negative electrode terminal is electrically connected to the negative electrode plate via the negative electrode current collector.

The positive electrode plate includes a metal positive electrode core body and a positive electrode active material mixture layer formed on the surface of the positive electrode core body. An exposed portion of the positive electrode core body from which the positive electrode active material mixture layer is not formed is formed on a part of the positive electrode core body. Then, the positive electrode current collector is connected to the exposed portion of the positive electrode core. Further, the negative electrode plate includes a metal negative electrode core body and a negative electrode active material mixture layer formed on the surface of the negative electrode core body. An exposed portion of the negative electrode core body is formed in a part of the negative electrode core body so that the negative electrode active material mixture layer is not formed. Then, the negative electrode current collector is connected to the exposed portion of the negative electrode core.

The battery case of a square secondary battery is a gas discharge valve that breaks when an abnormality occurs in the square secondary battery and the pressure inside the battery case exceeds a predetermined value, and the gas inside the battery case is discharged to the outside of the battery case. Is provided. Then, for example, in Patent Document 1, by arranging a blocking structure between the safety valve provided in the battery case and the electrode body, it is possible to prevent a high-temperature object from being blown out together with the flammable gas to the outside of the battery case. It is disclosed that it can be done.

Japanese Unexamined Patent Publication No. 2004-30946

Further improvement is required for the shielding structure disclosed in Patent Document 1 described above.

An object of the present invention is to provide a square secondary battery having a high volumetric energy density and high reliability.

The homogeneous square secondary battery of the present invention is
An electrode body including a positive electrode plate and a negative electrode plate,
An exterior body having an opening and accommodating the electrode body,
A square secondary battery including a sealing plate for sealing the opening.
The sealing plate is provided with a gas discharge valve.
A metal shielding member is arranged between the sealing plate and the electrode body at a position facing the gas discharge valve.
A resin member is arranged between the shielding member and the electrode body.
A square secondary battery in which the resin member is arranged so as to cover 50% or more of the surface of the shielding member and is fixed to the sealing plate.

With such a configuration, since the metal shielding member is fixed to the resin member, it is possible to prevent an unintended short circuit between the positive and negative electrodes via the metal shielding member. Further, since it is possible to suppress an unintended short circuit between the positive and negative electrodes via the metal shielding member, the distance between the members can be reduced, and the square secondary battery has a higher volume energy density. The resin member is preferably made of a resin having an electrical resistivity higher than the electrical resistivity of the metal constituting the shielding member. Further, the resin member is more preferably electrically insulating. Further, the gas discharge valve and the shielding member do not have to face each other directly, and another member such as a resin member may be arranged between the gas discharge valve and the shielding member.

According to the present invention, it is possible to provide a square secondary battery having a higher volumetric energy density and higher reliability.

It is a perspective view of the square secondary battery which concerns on embodiment. It is sectional drawing of the line II-II of FIG. It is a top view of the positive electrode plate which concerns on embodiment. It is a top view of the negative electrode plate which concerns on embodiment. It is a top view of the electrode body element which concerns on embodiment. It is a bottom view of the sealing plate after each component is attached. FIG. 6 is a cross-sectional view taken along the line VII-VII in FIG. FIG. 7 is an enlarged view of the vicinity of the first positive electrode current collector, the second positive electrode current collector, and the current cutoff mechanism in FIG. 7. FIG. 7 is an enlarged view of the vicinity of the first negative electrode current collector and the second negative electrode current collector in FIG. 7. It is a figure which shows the process of connecting a tab to a 2nd current collector. It is a perspective view of the 1st insulating member and the 2nd insulating member. It is sectional drawing along the lateral direction of the sealing plate near the connection part of the 1st insulating member and the 2nd insulating member. It is a top view of the 2nd insulating member. It is sectional drawing along the short side of the sealing plate near the connection part of the negative electrode tab and the 2nd negative electrode current collector. FIG. 5 is a cross-sectional view taken along the lateral direction of the sealing body, the shielding member, and the sealing plate of the second insulating member of the square secondary battery according to the first modification. FIG. 5 is a cross-sectional view taken along the lateral direction of the sealing body of the square secondary battery, the shielding member, and the sealing plate of the second insulating member according to the second modification. FIG. 5 is a cross-sectional view taken along the lateral direction of the sealing body of the square secondary battery, the shielding member, and the sealing plate of the second insulating member according to the third modification. FIG. 5 is a cross-sectional view taken along the lateral direction of the sealing body, the shielding member, and the sealing plate of the second insulating member of the square secondary battery according to the modified example 4. It is a perspective view of the shielding member of the square secondary battery which concerns on modification 5. FIG. It is a bottom view and the cross-sectional view of the shielding member and the second insulating member of the square secondary battery which concerns on modification 6.

The configuration of the square secondary battery 20 according to the embodiment will be described below. The present invention is not limited to the following embodiments.

FIG. 1 is a perspective view of the square secondary battery 20. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. As shown in FIGS. 1 and 2, the square secondary battery 20 includes a battery case 100 including a bottomed square cylindrical outer body 1 having an opening and a sealing plate 2 for sealing the opening of the square outer body 1. .. The square exterior body 1 and the sealing plate 2 are preferably made of metal, and are preferably made of, for example, aluminum or an aluminum alloy. In the square exterior body 1, a laminated electrode body 3 in which a plurality of positive electrode plates and a plurality of negative electrode plates are laminated via a separator is housed together with an electrolytic solution. A resin insulating sheet 14 is arranged between the electrode body 3 and the square exterior body 1.

A positive electrode tab 40 and a negative electrode tab 50 are provided at the end of the electrode body 3 on the sealing plate 2 side. The positive electrode tab 40 is electrically connected to the positive electrode external terminal 7 via the second positive electrode current collector 6b and the first positive electrode current collector 6a. The negative electrode tab 50 is electrically connected to the negative electrode external terminal 9 via the second negative electrode current collector 8b and the first negative electrode current collector 8a. Here, the first positive electrode current collector 6a and the second positive electrode current collector 6b constitute the positive electrode current collector 6. Further, the first negative electrode current collector 8a and the second negative electrode current collector 8b constitute the negative electrode current collector 8. The positive electrode current collector 6 can also be a single component. Further, the negative electrode current collecting member 8 can be made into one component.

The positive electrode external terminal 7 is fixed to the sealing plate 2 via a resin external insulating member 11. The negative electrode external terminal 9 is fixed to the sealing plate 2 via a resin external insulating member 13. The positive electrode external terminal 7 is preferably made of metal, more preferably aluminum or an aluminum alloy. The negative electrode external terminal 9 is preferably made of metal, more preferably copper or a copper alloy. Further, it is more preferable that the negative electrode external terminal 9 has a portion made of copper or a copper alloy on the inner side of the battery case 100 and a portion made of aluminum or an aluminum alloy on the outer side of the battery case 100. It is preferable that the surface of the negative electrode external terminal 9 is nickel-plated or the like.

The conductive path between the positive electrode plate and the positive electrode external terminal 7 operates when the pressure in the battery case 100 exceeds a predetermined value, and cuts off the conductive path between the positive electrode plate and the positive electrode external terminal 7. It is preferable that the mechanism 60 is provided. A current cutoff mechanism may be provided in the conductive path between the negative electrode plate and the negative electrode external terminal 9.

The sealing plate 2 is provided with a gas discharge valve 17 that breaks when the pressure inside the battery case 100 exceeds a predetermined value and discharges the gas inside the battery case 100 to the outside of the battery case 100. The gas discharge valve 17 is formed to be thinner than other parts of the sealing plate 2. The gas discharge valve 17 can be formed by pressing the sealing plate 2. Further, the sealing plate 2 may be provided with a through hole for a gas discharge valve, and the through hole may be closed with a thin-walled valve to form a gas discharge valve 17. The operating pressure of the gas discharge valve 17 is set to a value larger than the operating pressure of the current cutoff mechanism 60.

The sealing plate 2 is provided with an electrolytic solution injection hole 15. After the electrolytic solution is injected into the battery case 100 from the electrolytic solution injection hole 15, the electrolytic solution injection hole 15 is sealed by the sealing plug 16.

Next, a method of manufacturing the square secondary battery 20 will be described.
[Preparation of positive electrode plate]
Prepare a positive electrode slurry containing lithium nickel cobalt manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, a carbon material as a conductive agent, and N-methylpyrrolidone (NMP) as a dispersion medium. do. This positive electrode slurry is applied to both sides of a rectangular aluminum foil having a thickness of 15 μm as a positive electrode core. Then, by drying this, N-methylpyrrolidone in the positive electrode slurry is removed, and a positive electrode active material mixture layer is formed on the positive electrode core body. Then, the positive electrode active material mixture layer is compressed so as to have a predetermined thickness. The positive electrode plate thus obtained is cut into a predetermined shape.

FIG. 3 is a plan view of the positive electrode plate 4 produced by the above method. As shown in FIG. 3, the positive electrode plate 4 has a main body portion in which positive electrode active material mixture layers 4b are formed on both sides of a rectangular positive electrode core body 4a.
The positive electrode core body 4a protrudes from the end side of the main body portion, and the protruding positive electrode core body 4a constitutes the positive electrode tab 40. The positive electrode tab 40 may be a part of the positive electrode core body 4a as shown in FIG. 3, or another member may be connected to the positive electrode core body 4a to form the positive electrode tab 40. Further, it is preferable that the positive electrode protective layer 4d having an electric resistance larger than the electric resistance of the positive electrode active material mixture layer 4b is provided in the portion of the positive electrode tab 40 adjacent to the positive electrode active material mixture layer 4b. The positive electrode protective layer 4d preferably contains ceramic particles such as alumina, silica, and zirconia, and a binder. Further, it is more preferable that the positive electrode protective layer 4d contains conductive particles such as a carbon material.

[Manufacturing of negative electrode plate]
A negative electrode slurry containing graphite as a negative electrode active material, styrene-butadiene rubber (SBR) as a binder, carboxymethyl cellulose (CMC) as a thickener, and water is prepared. This negative electrode slurry is applied to both sides of a rectangular copper foil having a thickness of 8 μm as a negative electrode core. Then, by drying this, water in the negative electrode slurry is removed, and a negative electrode active material mixture layer is formed on the negative electrode body. Then, the negative electrode active material mixture layer is compressed so as to have a predetermined thickness. The negative electrode plate thus obtained is cut into a predetermined shape.

FIG. 4 is a plan view of the negative electrode plate 5 produced by the above method. As shown in FIG. 4, the negative electrode plate 5 has a main body portion in which the negative electrode active material mixture layer 5b is formed on both sides of the rectangular negative electrode core body 5a. The negative electrode core body 5a protrudes from the end side of the main body portion, and the protruding negative electrode core body 5a constitutes the negative electrode tab 50. The negative electrode tab 50 may be a part of the negative electrode core body 5a as shown in FIG. 4, or another member may be connected to the negative electrode core body 5a to form the negative electrode tab 50.

[Preparation of electrode body element]
Fifty positive electrode plates 4 and 51 negative electrode plates 5 are manufactured by the above method, and these are laminated via a rectangular separator made of polyolefin to prepare a laminated electrode body element (3a, 3b). As shown in FIG. 5, in the laminated electrode body elements (3a, 3b), the positive electrode tabs 40 of each positive electrode plate 4 are laminated and the negative electrode tabs 50 of each negative electrode plate 5 are laminated at one end. Is made. Separator is arranged on both outer surfaces of the electrode body elements (3a, 3b), and each electrode plate and the separator can be fixed in a laminated state by tape or the like. Alternatively, an adhesive layer may be provided on the separator so that the separator and the positive electrode plate 4 and the separator and the negative electrode plate 5 are adhered to each other.

It is preferable that the size of the separator in a plan view is the same as that of the negative electrode plate 5 or larger than that of the negative electrode plate 5. The positive electrode plate 4 may be arranged between the two separators so that the peripheral edge of the separator is heat-welded, and then the positive electrode plate 4 and the negative electrode plate 5 may be laminated. In producing the electrode body elements (3a, 3b), a long separator may be used, and the positive electrode plate 4 and the negative electrode plate 5 may be laminated while folding the long separator into a zigzag shape. Further, using a long separator, the positive electrode plate 4 and the negative electrode plate 5 can be laminated while winding the long separator.

[Attachment of each part to the sealing plate]
A method of attaching the positive electrode external terminal 7 and the first positive electrode current collector 6a to the sealing plate 2 and a configuration of the current cutoff mechanism 60 will be described with reference to FIGS. 2 and 6 to 8.
The external insulating member 11 is arranged on the outer surface side of the positive electrode terminal mounting hole 2a provided in the sealing plate 2, and the internal insulating member 10 and the conductive member 61 having a cup shape are arranged on the inner surface side of the positive electrode terminal mounting hole 2a. .. Next, the positive electrode external terminal 7 is inserted into each of the through hole of the external insulating member 11, the positive electrode terminal mounting hole 2a of the sealing plate 2, the through hole of the internal insulating member 10, and the through hole of the conductive member 61. Then, the tip of the positive electrode external terminal 7 is crimped onto the conductive member 61. As a result, the positive electrode external terminal 7, the external insulating member 11, the sealing plate 2, the internal insulating member 10 and the conductive member 61 are fixed. The crimped portion of the positive electrode external terminal 7 and the conductive member 61 are preferably welded by laser welding or the like. Further, it is preferable that the inner side insulating member 10 and the outer side insulating member 11 are each made of resin.

The conductive member 61 has an opening on the electrode body 3 side. The disk-shaped deformed plate 62 is arranged so as to close the opening of the conductive member 61, and the peripheral edge of the deformed plate 62 is welded and connected to the conductive member 61. As a result, the opening of the conductive member 61 is sealed by the deformed plate 62. The conductive member 61 and the deformed plate 62 are preferably made of metal, and more preferably aluminum or an aluminum alloy.

Next, a resin-made third insulating member 63 is arranged on the electrode body 3 side of the deformed plate 62. The third insulating member 63 has a connecting portion, and it is preferable that this connecting portion is connected to the internal insulating member 10. Further, the third insulating member 63 is provided with a claw-shaped hook fixing portion, the conductive member 61 is provided with a flange portion, a concave portion or a convex portion, the hook fixing portion of the third insulating member 63 is provided, and the conductive member 61 is provided with a flange portion and a concave portion. Alternatively, it is preferable to fix it on the convex portion.

A fixing protrusion is formed on the surface of the third insulating member 63 on the electrode body 3 side. Further, the third insulating member 63 includes an insulating member first region 63x arranged below the deformable plate 62 and an insulating member second region 63y extending from an end portion of the insulating member first region 63x toward the sealing plate 2. It is preferable to have the insulating member third region 63z extending from the end of the insulating member second region 63y along the sealing plate 2. In the third region 63z of the insulating member, an insulating member opening 63b is provided at a position facing the electrolytic solution injection hole 15 of the sealing plate 2. Further, an insulating member protrusion 63c protruding toward the electrode body 3 is provided at the edge of the insulating member opening 63b.

Next, the first positive electrode current collector 6a is arranged on the electrode body 3 side of the third insulating member 63. The first positive electrode current collector 6a has a through hole for fixing. Then, the fixing protrusion of the third insulating member 63 is inserted into the fixing through hole of the first positive electrode current collector 6a, the tip of the fixing protrusion is enlarged in diameter, and the third insulating member 63 and the first positive electrode current collector Fix 6a. As a result, the fixing portion 70 is formed. As shown in FIG. 6, the fixing portions 70 are preferably provided at four locations so as to surround the connecting portion between the deformed plate 62 and the first positive electrode current collector 6a.

After that, the deformed plate 62 and the first positive electrode current collector 6a are welded and connected through the through holes provided in the third insulating member 63. The first positive electrode current collector 6a preferably has a thin-walled portion 6c, and the thin-walled portion 6c is welded and connected to the deformed plate 62. An opening is provided in the center of the thin-walled portion 6c, and it is preferable that the edge portion of the opening is welded and connected to the deformed plate 62. Further, it is more preferable that the thin-walled portion 6c is provided with an annular notch portion so as to surround the connection portion between the first positive electrode current collector 6a and the deformed plate 62.

When the pressure inside the battery case 100 becomes equal to or higher than a predetermined value, the deformable plate 62 is deformed so that the central portion of the deformable plate 62 moves upward (toward the positive electrode external terminal 7). With the deformation of the deformed plate 62, the thin portion 6c of the first positive electrode current collector 6a is broken. As a result, the conductive path between the positive electrode plate 4 and the positive electrode external terminal 7 is cut.

A terminal through hole 7b is provided in the positive electrode external terminal 7, and gas can be flowed into the current cutoff mechanism 60 through the terminal through hole 7b to check for leakage at the connection portion between the conductive member 61 and the deformed plate 62. .. Further, the deformed plate 62 and the first positive electrode current collector 6a can be welded and connected in a state where the deformed plate 62 is pressed against the first positive electrode current collector 6a by gas. Finally, the terminal through hole 7b is sealed by the terminal sealing member 7a. The terminal sealing member 7a preferably has a metal member 7x and a rubber member 7y.

The first positive electrode current collector 6a has a current collector protrusion 6x on the surface on the electrode body 3 side.

A method of attaching the negative electrode external terminal 9 and the first negative electrode current collector 8a to the sealing plate 2 will be described with reference to FIGS. 2, 6, 7, and 9.
The external insulating member 13 is arranged on the outer surface side of the negative electrode terminal mounting hole 2b provided in the sealing plate 2, and the internal insulating member 12 and the first negative electrode current collector 8a are arranged on the inner surface side of the negative electrode terminal mounting hole 2b. .. Next, the negative electrode external terminal 9 is provided in each of the through hole of the external insulating member 13, the negative electrode terminal mounting hole 2b of the sealing plate 2, the through hole of the internal insulating member 12, and the through hole of the first negative electrode current collector 8a. insert. Then, the tip of the negative electrode external terminal 9 is crimped onto the first negative electrode current collector 8a. As a result, the outer insulating member 13, the sealing plate 2, the inner insulating member 12, and the first negative electrode current collector 8a are fixed. It is preferable that the crimped portion of the negative electrode external terminal 9 and the first negative electrode current collector 8a are welded by laser welding or the like. Further, it is preferable that the inner side insulating member 12 and the outer side insulating member 13 are each made of resin.

[Connection between the second current collector and the tab]
FIG. 10 is a diagram showing a method of connecting the positive electrode tab 40 to the second positive electrode current collector 6b and a method of connecting the negative electrode tab 50 to the second negative electrode current collector 8b. Two electrode body elements are produced by the above method, and are designated as a first electrode body element 3a and a second electrode body element 3b, respectively. The first electrode body element 3a and the second electrode body element 3b may have exactly the same configuration or may have different configurations. Here, a plurality of positive electrode tabs 40 of the first electrode body element 3a form the first positive electrode tab group 40a. A plurality of negative electrode tabs 50 of the first electrode body element 3a constitute the first negative electrode tab group 50a. A plurality of positive electrode tabs 40 of the second electrode body element 3b form a second positive electrode tab group 40b. A plurality of negative electrode tabs 50 of the second electrode body element 3b form a second negative electrode tab group 50b.

A second positive electrode current collector 6b and a second negative electrode current collector 8b are arranged between the first electrode body element 3a and the second electrode body element 3b. Then, a first positive electrode tab group 40a composed of a plurality of laminated positive electrode tabs 40 protruding from the first electrode body element 3a is arranged on the second positive electrode current collector 6b, and from the first electrode body element 3a. The first negative electrode tab group 50a composed of a plurality of laminated negative electrode tabs 50 protruding is arranged on the second negative electrode current collector 8b. Further, a second positive electrode tab group 40b composed of a plurality of laminated positive electrode tabs 40 protruding from the second electrode body element 3b is arranged on the second positive electrode current collector 6b, and is arranged from the second electrode body element 3b. A second negative electrode tab group 50b composed of a plurality of protruding negative electrode tabs 50 is arranged on the second negative electrode current collector 8b. The first positive electrode tab group 40a and the second positive electrode tab group 40b are respectively welded to the second positive electrode current collector 6b to form a welded connection portion 90. The first negative electrode tab group 50a and the second negative electrode tab group 50b are respectively welded to the second negative electrode current collector 8b to form a welded connection portion 90. Welding connections can be made as follows.

Tabs (first positive electrode tab group 40a, second positive electrode tab group 40b, first negative electrode tab group 50a, second negative electrode tab group 50b) and current collector (second positive electrode current collector) laminated from above and below by welding jigs. 6b, the second negative electrode current collector 8b) is sandwiched and welded. Here, the welding method is preferably ultrasonic welding or resistance welding. As a result, the laminated tabs and the current collector are more reliably welded and connected. When the number of laminated tabs is large, for example, when the number of laminated tabs is 20 or more, ultrasonic welding or resistance welding is more reliable because welding can be performed while sandwiched by a pair of welding jigs compared to laser welding. It is possible to form a highly resistant welded connection. The pair of welding jigs is a pair of electrodes for resistance welding in the case of resistance welding, and a horn and anvil in the case of ultrasonic welding. The tabs (first positive electrode tab group 40a, second positive electrode tab group 40b, first negative electrode tab group 50a, second negative electrode tab group 50b) and current collector (second positive electrode current collector 6b, second negative electrode current collector). The connection of the body 8b) can also be made by laser welding.

The first positive electrode tab group 40a of the first electrode body element 3a is connected to one side of the second positive electrode current collector 6b with respect to the central portion in the width direction of the second positive electrode current collector 6b. The second positive electrode tab group 40b of the second electrode body element 3b is connected to the second positive electrode current collector 6b on the opposite side of the central portion in the width direction of the second positive electrode current collector 6b.
The first negative electrode tab group 50a of the second electrode body element 3b is connected to one side of the second negative electrode current collector 8b with respect to the central portion in the width direction of the second negative electrode current collector 8b. The second negative electrode tab group 50b of the second electrode body element 3b is connected to the second positive electrode current collector 6b on the opposite side of the central portion in the width direction of the second positive electrode current collector 6b.

As shown in FIG. 10, the second positive electrode current collector 6b is provided with an opening 6z. After connecting the second positive electrode current collector 6b to the first positive electrode current collector 6a, the opening 6z is arranged at a position corresponding to the electrolytic solution injection hole 15 provided in the sealing plate 2. The first positive electrode tab group 40a of the first electrode body element 3a is connected to one side of the opening 6z in the width direction of the second positive electrode current collector 6b. Further, the second positive electrode tab group 40b of the second electrode body element 3b is connected to the other side of the opening 6z in the width direction of the second positive electrode current collector 6b. When the second positive electrode current collector 6b, the first positive electrode tab group 40a and the second positive electrode tab group 40b are viewed from the direction perpendicular to the sealing plate 2, the first positive electrode tab group 40a and the second positive electrode tab group 40b It is preferable that the portion arranged substantially parallel to the second positive electrode current collector 6b does not overlap with the opening 6z. This makes it possible to prevent the second positive electrode current collector 6b to the first positive electrode tab group 40a and the second positive electrode tab group 40b from interfering with the injection of the electrolytic solution.

The step of fixing the first positive electrode current collector 6a and the first negative electrode current collector 8a to the sealing plate 2 and the positive electrode tab 40 and the negative electrode tab 40 to the second positive electrode current collector 6b and the second negative electrode current collector 8b, respectively. Either of the steps of connecting the 50s may be performed first.

[Connection between the 1st positive electrode current collector and the 2nd positive electrode current collector]
As shown in FIGS. 6 and 7, the first positive electrode current collector 6a is provided with a current collector protrusion 6x. Then, as shown in FIG. 10, the second positive electrode current collector 6b is provided with a current collector opening 6y. As shown in FIGS. 7 and 8, the second positive current collector 6x of the first positive current collector 6a is located within the current collector opening 6y of the second positive current collector 6b. The body 6b is arranged on the third insulating member 63. Then, the edge of the current collector projection 6x of the first positive electrode current collector 6a and the current collector opening 6y of the second positive electrode current collector 6b are welded by irradiation with an energy ray such as a laser. As a result, the first positive electrode current collector 6a and the second positive electrode current collector 6b are connected. A current collector first recess 6f is provided around the current collector opening 6y of the second positive electrode current collector 6b. That is, a current collector opening 6y is formed in the center of the current collector first recess 6f. In the current collector first recess 6f, the first positive electrode current collector 6a and the second positive electrode current collector 6b are welded and connected.

As shown in FIG. 8, the second positive electrode current collector 6b has a current collector first region 6b1, a current collector second region 6b2, and a current collector third region 6b3. A positive electrode tab 40 is connected to the first region 6b1 of the current collector. The first positive electrode current collector 6a is connected to the third region 6b3 of the current collector. The current collector second region 6b2 connects the current collector first region 6b1 and the current collector third region 6b3. Then, in the direction perpendicular to the sealing plate 2, the distance between the sealing plate 2 and the current collector first region 6b1 is smaller than the distance between the sealing plate 2 and the current collector third region 6b3. With such a configuration, the space occupied by the current collector can be made smaller, and a square secondary battery having a higher volumetric energy density can be obtained.

As shown in FIG. 10, in the second positive electrode current collector 6b, target holes 6e are provided on both sides of the current collector opening 6y. When the first positive electrode current collector 6a and the second positive electrode current collector 6b are welded by irradiation with an energy ray such as a laser, it is preferable to use the target hole 6e as a target for image correction. It is preferable that the target hole 6e is image-detected, the position is corrected, and the energy ray is irradiated along the shape of the current collector opening 6y. The target hole 6e may be a recess instead of a through hole. The area of the target hole 6e in a plan view is preferably smaller than the area of the current collector opening 6y in a plan view. In addition, the second positive electrode current collector 6
It is preferable to arrange the current collector opening 6y and the target hole 6e so as to line up in a straight line in the width direction of b.

As shown in FIG. 8, a surface of the first positive electrode current collector 6a facing the third insulating member 63, and a current collector second recess 6w is formed on the back side of the current collector projection 6x. This is preferable because a larger welded connection portion can be easily formed between the first positive electrode current collector 6a and the second positive electrode current collector 6b. Further, since the second recess 6w of the current collector is formed, when the first positive electrode current collector 6a and the second positive electrode current collector 6b are welded and connected, the third insulating member 63 is generated by the heat at the time of welding. It can be prevented from being damaged.

As shown in FIG. 8, the tip of the third insulating member 63 below the insulating member protrusion 63c (on the electrode body 3 side) is below the lower surface around the opening 6z in the second positive electrode current collector 6b (electrode). It is preferable that it protrudes to the body 3 side). As a result, it is possible to reliably prevent the sealing plug 16 from coming into contact with the second positive electrode current collector 6b. The insulating member protrusion 63c is preferably annular. However, the insulating member protrusion 63c does not necessarily have to be annular, and may have a partially cutout shape.

[Connection between the 1st negative electrode current collector and the 2nd negative electrode current collector]
As shown in FIGS. 6 and 7, the first negative electrode current collector 8a is provided with a current collector protrusion 8x. Then, as shown in FIGS. 9 and 10, the second negative electrode current collector 8b is provided with a current collector opening 8y. As shown in FIG. 9, the current collector protrusion 8x of the first negative electrode current collector 8a is located within the current collector opening 8y of the second negative electrode current collector 8b, so that the second negative electrode current collector 8b Is arranged on the internal insulating member 12. Then, the edge of the current collector protrusion 8x of the first negative electrode current collector 8a and the current collector opening 8y of the second negative electrode current collector 8b are welded by irradiation with an energy ray such as a laser. As a result, the first negative electrode current collector 8a and the second negative electrode current collector 8b are connected. As shown in FIG. 10, a current collector first recess 8f is provided around the current collector opening 8y of the second negative electrode current collector 8b. That is, a current collector opening 8y is formed in the center of the current collector first recess 8f. In the current collector first recess 8f, the first negative electrode current collector 8a and the second negative electrode current collector 8b are welded and connected. Further, the second negative electrode current collector 8b is provided with a target hole 8e in the same manner as the second positive electrode current collector 6b.

As shown in FIG. 9, a surface facing the internal insulating member 12 of the first negative electrode current collector 8a, and a current collector second recess 8w is formed on the back side of the current collector projection 8x. This is preferable because a larger welded connection portion can be easily formed between the first negative electrode current collector 8a and the second negative electrode current collector 8b. Further, since the second negative electrode current collector 8w of the current collector is formed, when the first negative electrode current collector 8a and the second negative electrode current collector 8b are welded and connected, the internal insulating member 12 is affected by the heat during welding. It can be prevented from being damaged.

As shown in FIG. 9, the second negative electrode current collector 8b has a current collector first region 8b1, a current collector second region 8b2, and a current collector third region 8b3. A negative electrode tab 50 is connected to the first region 8b1 of the current collector. The first negative electrode current collector 8a is connected to the third region 8b3 of the current collector. The current collector second region 8b2 connects the current collector first region 8b1 and the current collector third region 8b3. Then, in the direction perpendicular to the sealing plate 2, the distance between the sealing plate 2 and the current collector first region 8b1 is smaller than the distance between the sealing plate 2 and the current collector third region 8b3. With such a configuration, the space occupied by the current collector can be made smaller, and a square secondary battery having a higher volumetric energy density can be obtained.

The current collector protrusions 6x and the current collector protrusions 8x are preferably non-round, preferably square, elliptical, or track-shaped.

<Connection between the first insulating member and the second insulating member>
As described above, the positive electrode tab 40 and the positive electrode external terminal 7 are electrically connected, the negative electrode tab 50 and the negative electrode external terminal 9 are electrically connected, and then the first insulating member and the second insulating member are connected. Is preferable.

FIG. 11 is a perspective view of the internal insulating member 12 and the second insulating member 80 as the first insulating member. The internal insulating member 12 has a first insulating member main body 12a facing the inner surface of the sealing plate 2. The first insulating member main body 12a is preferably plate-shaped. The first insulating member main body 12a has a through hole 12d, and the negative electrode external terminal 9 is inserted into the through hole 12d. A pair of first side walls 12b protruding toward the electrode body 3 are provided at both ends of the first insulating member main body 12a of the internal insulating member 12 in the lateral direction. Connection recesses 12e are provided on the outer surfaces of each of the pair of first side walls 12b. Further, a pair of second side walls 12c protruding toward the electrode body 3 are provided at both ends of the first insulating member main body 12a of the internal insulating member 12 in the longitudinal direction.

The second insulating member 80 has a second insulating member main body 80a arranged so as to face the sealing plate 2. The second insulating member main body 80a is arranged between the sealing plate 2 and the electrode body 3. The second insulating member main body 80a has a wide portion 80a1 in the center in the longitudinal direction of the sealing plate 2, and narrow portions 80a2 having a width smaller than the width of the wide portion 80a1 on both sides of the wide portion 80a1. In the lateral direction of the sealing plate 2, a pair of side walls 80b extending from the second insulating member main body 80a toward the sealing plate 2 are provided at both ends of the wide portion 80a1 of the second insulating member main body 80a. Further, in the lateral direction of the sealing plate 2, a pair of connecting portions 80c extending from the second insulating member main body 80a toward the sealing plate 2 are provided at both ends of the wide portion 80a1 of the second insulating member main body 80a. ing. The side wall 80b and the connecting portion 80c are preferably provided at intervals in the longitudinal direction of the sealing plate 2. As a result, the pair of connecting portions 80c can be easily deformed, so that when the connecting portion 80c is connected to the internal insulating member 12 as the first insulating member, the second insulating member 80 is damaged or damaged. It can be reliably prevented.

It is preferable that the upper end of the side wall 80b is in contact with the inner surface of the sealing plate 2. The height of the side wall 80b (the length from the second insulating member main body 80a to the upper end of the side wall 80b) is the height of the connecting portion 80c (the length from the second insulating member main body 80a to the upper end of the connecting portion 80c). Can be larger.

FIG. 12 is a cross-sectional view taken along the lateral direction of the sealing plate in the vicinity of the connection portion between the internal insulating member 12 as the first insulating member and the second insulating member 80. The connecting portion 80c of the second insulating member 80 serves as a vertical wall 80c1 extending from the second insulating member main body 80a of the second insulating member 80 toward the sealing plate 2 and as a first insulating member from the inner surface of the vertical wall 80c1. It has a protruding portion 80c2 that protrudes toward the internal insulating member 12. Then, the protruding portion 80c2 is fitted into the connecting recess 12e of the internal insulating member 12 as the first insulating member. As a result, the internal insulating member 12 as the first insulating member and the second insulating member 80 are connected. A connecting recess is provided at the end of the first side wall 12b of the internal insulating member 12 as the first insulating member on the sealing plate 2 side, and between the internal insulating member 12 as the first insulating member and the sealing plate 2. The protrusion 80c2 may be arranged on the surface.

In the second insulating member 80, it is preferable that a metal plate 81 as a shielding member is arranged at a position facing the gas discharge valve 17 provided on the sealing plate 2.

FIG. 13 is a top view of the second insulating member 80. The broken line in FIG. 13 indicates the outer peripheral edge of the metal plate 81. In the second insulating member 80, the metal plate 81 is molded in the second insulating member 80 made of resin.

The metal plate 81 is preferably made of an iron alloy such as iron or stainless steel, copper, a copper alloy, aluminum, an aluminum alloy, or the like. The melting point of the metal plate 81 is preferably higher than the melting point of the sealing plate 2. For example, it is preferable that the sealing plate 2 is made of aluminum or an aluminum alloy, and the metal plate 81 is made of stainless steel.

<Preparation of electrode body>
The first positive electrode tab group 40a, the second positive electrode tab group 40b, and the first positive electrode body element 3b in FIG. 10 so that the upper surface of the first electrode body element 3a and the upper surface of the second electrode body element 3b are in direct contact with each other via other members. The 1 negative electrode tab group 50a and the 2nd negative electrode tab group 50b are curved. As a result, the first electrode body element 3a and the second electrode body element 3b are combined into one electrode body 3. It is preferable that the first electrode body element 3a and the second electrode body element 3b are put together by tape or the like. Alternatively, it is preferable that the first electrode body element 3a and the second electrode body element 3b are arranged in a box-shaped or bag-shaped insulating sheet 14 and put together.

<Assembly of square secondary battery>
The electrode body 3 attached to the sealing plate 2 is covered with the insulating sheet 14 and inserted into the square exterior body 1. The insulating sheet 14 is preferably formed by bending a flat plate into a box shape or a bag shape. Then, the sealing plate 2 and the square exterior body 1 are joined by laser welding or the like to seal the opening of the square exterior body 1. Then, a non-aqueous electrolyte solution containing an electrolyte solvent and an electrolyte salt is injected through the electrolyte solution injection hole 15 provided in the sealing plate 2. Then, the electrolytic solution injection hole 15 is sealed with the sealing plug 16.

<About the square secondary battery 20>
In the square secondary battery 20, the second insulating member 80 is connected to the internal insulating member 12 as the first insulating member fixed to the sealing plate 2. Therefore, when vibration or impact is applied to the square secondary battery 20, it is possible to prevent the second insulating member 80 from moving significantly in the battery case 100. Therefore, an unexpected short circuit that may occur due to the misalignment of the second insulating member 80 can be reliably prevented. Alternatively, it is possible to prevent the second insulating member 80 from moving inside the battery case 100 and causing the second insulating member 80 to damage the positive electrode tab 40 or the negative electrode tab 50.

One narrow portion 80a2 of the second insulating member 80 is arranged between the first positive electrode tab group 40a and the second positive electrode tab group 40b, and between the first negative electrode tab group 50a and the second negative electrode tab group 50b. It is preferable that the other narrow portion 80a2 of the second insulating member 80 is arranged. Further, in the longitudinal direction of the sealing plate 2, the wide portion 80a1 of the second insulating member 80 is between the first positive electrode tab group 40a and the second positive electrode tab group 40b and the first negative electrode tab group 50a and the second negative electrode tab group 50b. Is preferably arranged. With such a configuration, it is possible to more reliably prevent the second insulating member 80 from damaging the tab. The second insulating member 80 does not necessarily have a wide portion and a narrow portion.

A pair of side walls 80b extending from the second insulating member main body 80a toward the sealing plate 2 at both ends of the wide portion 80a1 of the second insulating member main body 80a of the second insulating member 80 in the lateral direction of the sealing plate 2. Is provided. With such a configuration, a gas flow path can be reliably secured between the second insulating member main body 80a of the second insulating member 80 and the sealing plate 2. That is, it is possible to more reliably prevent the second insulating member main body 80a from blocking the gas discharge valve 17. Therefore, it is possible to prevent the second insulating member 80 from obstructing the gas discharge from the gas discharge valve 17. Further, it is possible to prevent the second insulating member 80 from coming into contact with the gas valve.

In the longitudinal direction of the sealing plate 2, the length of the side wall 80b is preferably shorter than the length of the second insulating member main body 80a. As a result, when the gas discharge valve 17 is activated, the gas generated in the electrode body 3 can be smoothly discharged to the outside of the battery case 100.

In the second insulating member 80, it is preferable that the metal plate 81 is arranged at a position facing the gas discharge valve 17 provided on the sealing plate 2. As a result, when an abnormality occurs in the square secondary battery 20, it is possible to prevent the high-temperature gas ejected from the electrode body 3 from being directly blown to the gas discharge valve 17. As a result, when the gas discharge valve 17 is broken, it is possible to prevent high-temperature gas or sparks from being ejected from the gas discharge valve 17. The metal plate 81 is particularly preferably made of stainless steel.

The method of attaching the metal plate 81 to the second insulating member 80 is not particularly limited. It can be attached to the upper surface (the surface on the sealing plate 2 side) or the lower surface (the surface on the electrode body 3 side) of the second insulating member 80 by adhesion or fitting. Further, as shown in FIGS. 2 and 12, the metal plate 81 may be arranged inside the second insulating member 80 made of resin. With such a configuration, it is possible to more reliably prevent an unexpected short circuit between the positive and negative electrodes via the metal plate 81. Molding is preferable as a method of arranging the metal plate 81 inside the second insulating member 80 made of resin.

In the square secondary battery 20, the second insulating member 80 that holds the metal plate 81 is connected to the internal insulating member 12 as the first insulating member fixed to the sealing plate 2. Therefore, the position of the metal plate 81 can be reliably arranged at a predetermined position, and the misalignment of the metal plate 81 can be suppressed. Therefore, it is possible to more reliably suppress the sealing of high-temperature gas, sparks, etc. from the gas discharge valve 17. Further, since the side wall 80b is provided on the second insulating member, it is possible to more reliably prevent an unexpected short circuit between the positive electrode and the negative electrode via the metal plate 81.

It is not necessary to provide the side wall 80b and the connecting portion 80c separately. For example, in the second insulating member 80, a protruding portion may be provided on the side wall 80b to form a connecting portion connected to the internal insulating member 12 as the first insulating member.

The internal insulating member 12 and the second insulating member as the first insulating member are preferably made of resin. For example, those made of polypropylene, polyethylene, perfluoroalkoxy alkane (PFA), polytetrafluoroethylene (PTFE), ethylene / ethylene tetrafluoroethylene copolymer (ETFE) and the like can be used.

A through hole can be provided in the second insulating member main body 80a of the second insulating member 80. The position where the through hole is provided is preferably such that the electrolytic solution injection hole 15 provided in the sealing plate 2 is provided from the center (on the gas discharge valve 17 side) in the longitudinal direction of the sealing plate 2.

FIG. 14 is a cross-sectional view of the sealing plate 2 in the vicinity of the connection portion between the first negative electrode tab group 50a and the second negative electrode tab group 50b and the second negative electrode current collector 8b along the lateral direction. As shown in FIG. 14, the first negative electrode tab group 50a of the first electrode body element 3a and the second negative electrode tab group 50b of the second electrode body element 3b are welded to the second negative electrode current collector 8b, respectively. It is connected. The narrow portion 80a2 of the second insulating member 80 is arranged between the first negative electrode tab group 50a and the second negative electrode tab group 50b.

According to such a configuration, there is a space between the second negative electrode current collector 8b and the base portion of the first negative electrode tab group 50a, and between the second negative electrode current collector 8b and the base portion of the second negative electrode tab group 50b. S can be secured. The space S serves as a flow path for the gas generated in the electrode body 3 to the gas discharge valve 17. Therefore, according to the above configuration, when an abnormality occurs in the square secondary battery, the gas can be smoothly discharged to the outside of the battery case, so that the square secondary battery has higher reliability.

In the narrow portion 80a2 of the second insulating member 80, the corner portion C facing the first negative electrode tab group 50a to the second negative electrode tab group 50b is preferably chamfered. As a result, it is possible to reliably prevent the first negative electrode tab group 50a to the second negative electrode tab group 50b from being damaged by the narrow portion 80a2 of the second insulating member 80.

As with the negative electrode side, on the positive electrode side as well, a second insulation is provided between the first positive electrode tab group 40a of the first electrode body element 3a and the second positive electrode tab group 40b of the second electrode body element 3b. The narrow portion 80a2 of the member 80 is arranged. As a result, a space can be secured between the second positive electrode current collector 6b and the base portion of the first positive electrode tab group 40a, and between the second positive electrode current collector 6b and the base portion of the second positive electrode tab group 40b.

<< Modification 1 >>
FIG. 15 shows a cross section of the sealing plate 2 of the secondary battery according to the first modification, the stainless metal plate 181 as a shielding member, and the sealing plate 2 of the resin second insulating member 180 along the lateral direction. It is a figure.
As shown in FIG. 15, the metal plate 181 is arranged between the sealing plate 2 and the electrode body 3 at a position facing the gas discharge valve 17. The metal plate 181 has a shielding member main body portion 181a arranged so as to face the sealing plate 2, and a pair of shielding member side wall portions 181b extending from both ends of the shielding member main body portion 181a toward the sealing plate 2. The shielding member main body 181a is arranged substantially parallel to the sealing plate 2. For example, the inclination of the shielding member main body 181a with respect to the sealing plate 2 can be set to about −10 ° to 10 °. The shielding member side wall portion 181b is provided at the end portion of the shielding member main body portion 181a of the sealing plate 2 in the lateral direction. In the shielding member main body portion 181a, side wall portions are not formed on both end portions in the longitudinal direction of the sealing plate 2.

Further, the second insulating member 180 includes a second insulating member main body 180a arranged so as to face the sealing plate 2 and a pair of insulating members extending from both ends of the second insulating member main body 180a toward the sealing plate 2. It has a member side wall portion 180b. The second insulating member main body 180a is arranged substantially parallel to the sealing plate 2. For example, the inclination of the second insulating member main body 180a with respect to the sealing plate 2 can be set to about −10 ° to 10 °.
The insulating member side wall portion 180b is provided at the end portion of the second insulating member main body portion 180a of the sealing plate 2 in the lateral direction. The shielding member main body 181a is arranged inside the second insulating member main body 180a, and the shielding member side wall 181b is arranged inside the insulating member side wall 180b. As shown in FIG. 15, the side wall portion 180b of the insulating member is in contact with the sealing plate 2 at a position different from that of the gas discharge valve 17.

The metal plate 181 has a pair of shielding member side wall portions 181b. Therefore, when the high-temperature gas is ejected from the electrode body 3, the second insulating member 180 melts, and even if the metal plate 181 moves to the sealing plate 2, the shielding member main body 181a comes into contact with the sealing plate 2. However, it is possible to reliably prevent the shielding member main body 181a from blocking the gas discharge valve 17 and hindering the discharge of gas.

<< Modification 2 >>
FIG. 16 shows the sealing plate 2 of the square secondary battery according to the second modification, the stainless metal plate 281 as a shielding member, and the sealing plate 2 of the resin second insulating member 280 along the lateral direction. It is a cross-sectional view. As shown in FIG. 16, the metal plate 281 is attached to the surface of the second insulating member 280 on the sealing plate 2 side.
The metal plate 281 has a shielding member main body portion 281a arranged so as to face the sealing plate 2, and a pair of shielding member side wall portions 281b extending from both ends of the shielding member main body portion 281a toward the sealing plate 2. The shielding member main body 281a is arranged substantially parallel to the sealing plate 2. The shielding member side wall portion 281b is provided at the end portion of the shielding member main body portion 281a in the lateral direction of the sealing plate 2.
Further, the second insulating member 280 is a pair of insulation extending from both ends of the second insulating member main body 280a arranged so as to face the sealing plate 2 and the second insulating member main body 280a toward the sealing plate 2. It has a member side wall portion 280b. The second insulating member main body portion 280a is arranged substantially parallel to the sealing plate 2.
The insulating member side wall portion 280b is provided at the end portion of the second insulating member main body portion 280a of the sealing plate 2 in the lateral direction.
The method of attaching the metal plate 281 to the second insulating member 280 is not particularly limited. The metal plate 281 may be attached to the second insulating member 280 with an adhesive or the like. Further, the metal plate 281 may be fitted and connected to the second insulating member 280.

<< Modification 3 >>
FIG. 17 shows the sealing plate 2 of the square secondary battery according to the modified example 3, the stainless metal plate 381 as the shielding member, and the sealing plate 2 of the resin second insulating member 380 along the lateral direction. It is a cross-sectional view.
As shown in FIG. 17, the metal plate 381 is attached to the surface of the second insulating member 380 on the electrode body 3 side. The metal plate 381 has a shielding member main body portion 381a arranged so as to face the sealing plate 2.
Further, the second insulating member 380 is a pair of insulation extending from both ends of the second insulating member main body 380a arranged so as to face the sealing plate 2 and the second insulating member main body 380a toward the sealing plate 2. It has a member side wall portion 380b. The insulating member side wall portion 380b is provided at the end portion of the second insulating member main body portion 380a of the sealing plate 2 in the lateral direction.
The method of attaching the metal plate 381 to the second insulating member 380 is not particularly limited. The metal plate 381 may be attached to the second insulating member 380 with an adhesive or the like. Further, the metal plate 381 may be fitted and connected to the second insulating member 380.

≪Modification example 4≫
FIG. 18 shows the sealing plate 2 of the square secondary battery according to the modified example 4, the stainless metal plate 481 as the shielding member, and the sealing plate 2 of the resin second insulating member 480 along the lateral direction. It is a cross-sectional view.
As shown in FIG. 18, the metal plate 481 is arranged in the second insulating member 480. It is preferable that the metal plate 481 is molded in the second insulating member 480 made of resin. An opening 482 is formed on the surface of the second insulating member 480 on the electrode body 3 side, and the metal plate 481 is exposed at the portion where the opening 482 is provided.

<< Modification 5 >>
FIG. 19 is a perspective view of a metal plate 581 as a shielding member in the square secondary battery according to the modified example 5. The metal plate 581 includes a shielding member main body portion 581a, a first shielding member side wall portion 581b1 extending from the shielding member main body portion 581a toward the sealing plate 2, a second shielding member side wall portion 581b2, a third shielding member side wall portion 581b3, and a first. 4 It has a shielding member side wall portion 581b4. The first shielding member side wall portion 581b1, the second shielding member side wall portion 581b2, the third shielding member side wall portion 581b3, and the fourth shielding member side wall portion 581b4 are formed at distant positions. By using such a metal plate 581, a gas flow path can be secured more reliably.

The metal plate 581 can be arranged inside the second insulating member. For example, using a second insulating member having a shape like the second insulating member 180 shown in FIG. 15, the shielding member main body 581a is arranged in the second insulating member main body 180a, and the shielding member main body 581a is arranged in one insulating member side wall 180b. The first shielding member side wall portion 581b1 and the second shielding member side wall portion 581b2 can be arranged, and the third shielding member side wall portion 581b3 and the fourth shielding member side wall portion 581b4 can be arranged in the other insulating member side wall portion 180b.

In this case, an opening may be provided in the side wall portion 180b of the insulating member where the metal plate 581 is not arranged to serve as a gas flow path. For example, in the insulating member side wall portion 180b, a portion located between the first shielding member side wall portion 581b1 and the second shielding member side wall portion 581b2, or between the third shielding member side wall portion 581b3 and the fourth shielding member side wall portion 581b4. An opening can be provided in the located portion.

<< Modification 6 >>
FIG. 20 is a view showing the lower surface (the surface on the electrode body 3 side) of the second insulating member 680 in which the metal plate 681 as a shielding member is arranged inside in the square secondary battery according to the modified example 6, and the longitudinal direction. It is a cross-sectional view along. The portion shown by the broken line in FIG. 20 is the position of the outer peripheral edge of the metal plate 681. The second insulating member 680 has a second insulating member main body portion 680a arranged so as to face the sealing plate 2. The second insulating member main body portion 680a has a wide portion 680a1 and narrow portions 680a2 provided on both sides of the wide portion 680a1.

The second insulating member 680 has an opening 680x at a position where the metal plate 681 is arranged. At this opening 680x, the metal plate 681 is exposed. The exposed portion 682 of the metal plate 681 is preferably provided at a position facing the gas discharge valve 17. A plurality of slit-shaped through holes 683 are formed in the exposed portion 682. With such a shape, it is possible to prevent a high-temperature object from being blown out together with the flammable gas to the outside of the battery case while smoothly discharging the gas to the outside of the battery case. The through hole 683 may be circular or the like.

In the above-described embodiment, the second insulating member 80 is made of resin and corresponds to the resin member. Further, the second insulating member main body 80a corresponds to the resin member main body, and the side wall 80b corresponds to the resin member side wall. Further, in the above-described modified examples 1 to 6, the second insulating member 180, the second insulating member 280, the second insulating member 380, the second insulating member 480, and the second insulating member 680 are made of resin, and each of them is a resin member. Corresponds to.

<Others>
Of the surface of the metal shielding member, 50% or more is preferably covered with the resin member, and 70% or more is preferably covered with the resin member.

A gap can be provided between the end portion of the separator constituting the electrode body 3 on the sealing plate 2 side and the second insulating member 80. That is, the end portion of the separator constituting the electrode body 3 on the sealing plate 2 side can be prevented from coming into contact with the second insulating member 80.

When the electrode body 3 is a laminated electrode body having a plurality of positive electrode plates and a plurality of negative electrode plates, or when the electrode body 3 is a wound electrode body and its winding axis is in a direction perpendicular to the sealing plate. In the electrode body 3, the tip of the positive electrode plate, the tip of the negative electrode plate, and the tip of the separator are located on the sealing plate 2 side. With such a configuration, when the sealing plate 2 is provided with the electrolytic solution injection hole 15, the liquid injection property of the electrolytic solution into the electrode body 3 is improved.
In such a case, it is preferable that the end portion of the separator on the sealing plate 2 side protrudes toward the sealing plate 2 side rather than the end portion of the negative electrode active material mixture layer on the sealing plate 2 side. Further, in the electrode body 3, it is preferable that the end portion of the separator on the sealing plate 2 side protrudes toward the sealing plate 2 side rather than the end portion of the positive electrode active material mixture layer on the sealing plate 2 side. Further, it is preferable that the positive electrode plate and the separator are adhered by the adhesive layer, and the negative electrode plate and the separator are adhered by the adhesive layer. With such a configuration, it is possible to reliably prevent the positive electrode active material mixture layer and the negative electrode active material mixture layer from coming into contact with the second insulating member and damaging the positive electrode active material layer or the negative electrode active material layer.

A current cutoff mechanism can be provided only in one of the conductive path between the positive electrode plate and the positive electrode external terminal 7 and the conductive path between the negative electrode plate and the negative electrode external terminal 9. In this case, the second insulating member can be connected only to the first insulating member on the side where the current cutoff mechanism is not provided. As a result, the load on the fragile portion of the current cutoff mechanism can be reduced.
As shown in the above-described embodiment, it is preferable that a current cutoff mechanism is formed in the conductive path between the positive electrode plate and the positive electrode external terminal 7. In such a case, the second insulating member can be connected only to the first insulating member on the negative electrode side.

As shown in the above-described embodiment, it is preferable that a current cutoff mechanism is formed in the conductive path between the positive electrode plate and the positive electrode external terminal 7. In such a case, the entire second insulating member 80 can be located closer to the sealing plate 2 than the end portion of the positive electrode current collecting member 6 on the electrode body 3 side. With such a configuration, a square secondary battery having a higher volumetric energy density can be obtained.

In the above-described embodiment, the example in which the current cutoff mechanism 60 is provided in the square secondary battery is shown, but the current cutoff mechanism may not be provided. Further, the internal insulating member 10 and the internal insulating member 12 can be combined into one component.

In the above-described embodiment, the internal insulating member 12 arranged between the first negative electrode current collector 8a and the second negative electrode current collector 8b constituting the sealing plate 2 and the negative electrode current collector 8 is the first insulating member. An example of connecting the second insulating member 80 to the first insulating member is shown. It is also possible to connect the second insulating member 80 to the third insulating member 63 or the internal insulating member 10 arranged between the sealing plate 2 and the positive electrode current collecting member 6.

In the above-described embodiment, an example in which the electrode body 3 is composed of two electrode body elements 3a and 3b is shown, but the present invention is not limited thereto. The electrode body 3 may be one laminated electrode body. Further, the electrode body 3 may be a single winding type electrode body in which a long positive electrode plate and a long negative electrode plate are wound via a separator. Further, the two electrode body elements 3a and 3b are not limited to the laminated electrode bodies, respectively, but are wound type electrode bodies in which a long positive electrode plate and a long negative electrode plate are wound via a separator. You may.

In the above-described embodiment, the positive electrode current collector is composed of the first positive electrode current collector and the second positive electrode current collector, and the negative electrode current collector is composed of the first negative electrode current collector and the second negative electrode current collector. As shown, the positive electrode current collecting member may be composed of one component, or the negative electrode current collecting member may be composed of one component.

In the above-described embodiment, an example in which the laminated electrode body is used is shown, but a wound electrode body may be used. Further, the orientation of the wound electrode body arranged inside the square exterior is not particularly limited.

In the above-described embodiment, an example of connecting the first insulating member and the second insulating member is shown, but the first insulating member and the second insulating member may not be connected.

20 ... Square secondary battery

1 ... Square exterior
2 ... Seal plate 2a ... Positive electrode terminal mounting hole
2b ・ ・ ・ Negative electrode terminal mounting hole 100 ・ ・ ・ Battery case

3 ... Electrode body 3a ... First electrode body element 3b ... Second electrode body element

4 ... Positive electrode plate 4a ... Positive electrode core 4b ... Positive electrode active material mixture layer 4d ... Positive electrode protective layer 40 ... Positive electrode tab 40a ... First positive electrode tab group 40b ... First 2 Positive electrode tab group

5 ... Negative electrode plate 5a ... Negative electrode core 5b ... Negative electrode active material mixture layer 50 ... Negative electrode tab 50a ... First negative electrode tab group 50b ... Second negative electrode tab group

6 ... Positive electrode current collector 6a ... First positive electrode current collector 6c ... Thin-walled part 6x ... Current collector protrusion 6w ... Current collector second recess

6b ... 2nd positive electrode current collector 6b1 ... Current collector 1st region 6b2 ... Current collector 2nd region 6b3 ... Current collector 3rd region 6e ... Target hole 6f ... Current collector first recess 6y ・ ・ ・ Current collector opening 6z ・ ・ ・ Opening

7 ... Positive electrode external terminal 7a ... Terminal sealing member 7x ... Metal member 7y ... Rubber member 7b ... Terminal through hole

8 ... Negative electrode current collector 8a ... First negative electrode current collector 8x ... Current collector protrusion 8w ... Current collector second recess

8b ... 2nd negative electrode current collector 8b1 ... Current collector 1st region 8b2 ... Current collector 2nd region 8b3 ... Current collector 3rd region 8e ... Target hole 8f ... Current collector 1st recess 8y ・ ・ ・ Current collector opening

9 ... Negative electrode external terminal 10 ... Internal side insulating member 11 ... External side insulating member 12 ... Internal side insulating member
12a ... 1st insulating member main body 12b ... 1st side wall 12c ... 2nd side wall
12d ・ ・ ・ Through hole 12e ・ ・ ・ Recess for connection

13: External insulation member 14: Insulation sheet 15: Electrolyte injection hole 16: Sealing plug 17: Gas discharge valve

60 ... Current cutoff mechanism 61 ... Conductive member 62 ... Deformation plate 63 ... Third insulating member 63b ... Insulating member opening 63c ... Insulating member protrusion 63x ... Insulating member first region 63y ・ ・ ・ Insulation member second region 63z ・ ・ ・ Insulation member third region

70 ... Fixed part

80 ... Second insulating member
80a ・ ・ ・ Second insulating member main body 80a1 ・ ・ ・ Wide part 80a2 ・ ・ ・ Narrow part 80b ・ ・ ・ Side wall 80c ・ ・ ・ Connection part 80c1 ・ ・ ・ Vertical wall 80c2 ・ ・ ・ Protruding part 81 ・ ・ ・Metal plate

90 ... Welded connection

180 ... Second insulating member
180a ... Second insulating member main body 180b ... Insulating member side wall 181 ... Metal plate
181a ・ ・ ・ Shielding member main body 181b ・ ・ ・ Shielding member side wall

280 ... Second insulating member
280a ... Second insulating member main body 280b ... Insulating member side wall 281 ... Metal plate
281a ・ ・ ・ Shielding member main body 281b ・ ・ ・ Shielding member side wall

380 ... Second insulating member
380a ... Second insulating member main body 380b ... Insulating member side wall 381 ... Metal plate
381a ・ ・ ・ Shielding member body

480 ... Second insulating member
481 ... Metal plate
482 ... Aperture

581 ... Metal plate
581a ... Shielding member main body 581b1 ... First shielding member side wall 581b2 ... Second shielding member side wall 581b3 ... Third shielding member side wall 581b4 ... Fourth shielding member side wall

680 ... Second insulating member
680a ・ ・ ・ Second insulating member main body 680a1 ・ ・ ・ Wide part 680a2 ・ ・ ・ Narrow part 680x ・ ・ ・ Opening 681 ・ ・ ・ Metal plate
682 ・ ・ ・ Exposed part 683 ・ ・ ・ Through hole

Claims (8)

An electrode body including a positive electrode plate and a negative electrode plate,
An exterior body having an opening and accommodating the electrode body,
A square secondary battery including a sealing plate for sealing the opening.
The sealing plate is provided with a gas discharge valve.
A metal shielding member is arranged between the sealing plate and the electrode body at a position facing the gas discharge valve.
A resin member is arranged between the shielding member and the electrode body.
A square secondary battery in which the resin member is arranged so as to cover 50% or more of the surface of the shielding member and is fixed to the sealing plate. The positive electrode tab provided on the positive electrode plate and
The negative electrode tab provided on the negative electrode plate and
With the positive electrode external terminal electrically connected to the positive electrode tab and attached to the sealing plate,
With the negative electrode external terminal electrically connected to the negative electrode tab and attached to the sealing plate,
A positive electrode current collector member that electrically connects the positive electrode tab and the positive electrode external terminal,
A negative electrode current collecting member for electrically connecting the negative electrode tab and the negative electrode external terminal is provided.
The positive electrode tab and the negative electrode tab are arranged at the end portion of the electrode body on the sealing plate side.
A plurality of the positive electrode tabs are connected to the positive electrode current collector member in a laminated state, and the positive electrode tabs are connected to the positive electrode current collector member.
The square secondary battery according to claim 1, wherein a plurality of the negative electrode tabs are stacked and connected to the negative electrode current collecting member. The square secondary battery according to claim 1 or 2, wherein the shielding member is arranged inside the resin member. The square secondary battery according to any one of claims 1 to 3, wherein the shielding member is covered with the resin member in a state where a part of the shielding member is exposed. The square secondary battery according to any one of claims 1 to 4, wherein the melting point of the material constituting the shielding member is higher than the melting point of the material constituting the sealing plate. Claims 1 to 5 include a shielding member main body portion arranged so as to face the sealing plate, and a pair of shielding member side wall portions extending from both ends of the shielding member main body toward the sealing plate. The square secondary battery described in any of the above. The square secondary battery according to any one of claims 1 to 6, wherein the shielding member is arranged inside the exterior body in a state where the shielding member is not in direct contact with the sealing plate. The resin member has a resin member main body portion arranged so as to face the sealing plate, and a pair of resin member side wall portions extending from both ends of the resin member main body portion toward the sealing plate.
The square secondary battery according to any one of claims 1 to 7, wherein the shielding member is fixed to the resin member main body.

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