JP6632952B2 - Insulator, secondary battery and method of manufacturing insulator - Google Patents

Description

  The present invention relates to an insulator that secures electrical insulation between a battery case and a connection bolt, a secondary battery including the insulator, and a method for manufacturing the insulator.

  2. Description of the Related Art Conventionally, there is known an assembled battery in which a plurality of batteries are connected by a bus bar in order to increase the capacity and output of a secondary battery. The bus bar is electrically and mechanically fixed to the external terminal by fastening a nut to a connection bolt protruding from the external terminal of the battery, but when an external force in the vertical and horizontal directions is applied to the external terminal via the bus bar, While the external terminal is supported by the secondary battery, a large load may be applied to the current collecting terminal that is an electrode and extracts electricity from inside the battery. Thus, an example of a technique for reducing the load applied to the current collecting terminal is described in Patent Document 1.

  The secondary battery described in Patent Literature 1 is provided outside a lid of a bottomed cylindrical battery case that houses a power generating element, and has a connection bolt (terminal electrode) used for connection with another battery. ing. In addition, the secondary battery has a current collecting terminal that penetrates the lid to take out the power of the power generating element to the outside of the battery case, and an external device that is attached to the current collecting terminal and supports a bolt-shaped connection bolt (terminal electrode). Terminal (connection electrode). The external terminal (connection electrode) is provided outside the battery case, and has a first flat plate portion to which a connection bolt (terminal electrode) is connected and a second flat plate portion to which a current collecting terminal is connected. are doing. The first and second flat plate portions have overlapping regions when viewed in a direction perpendicular to the thickness direction of the external terminal (connection electrode).

International Publication No. WO2013 / 030869

  According to the technology described in Patent Literature 1, stress applied to the current collecting terminal through the external terminal (connection electrode) is caused by the external terminal (connection electrode) interposed between the connection bolt (terminal electrode) and the current collection terminal. Will be reduced.

  By the way, since it is necessary to ensure insulation between the connection bolt, the current collecting terminal, and the external terminal with respect to the battery case and the like, it is necessary to provide an insulator between the connection bolt and the battery case. Also, when the bus bar is fastened to the threaded portion protruding from the battery, the connecting bolt applies a rotating force to the head in accordance with the tightening of the nut, and this force is applied to the concave portion of the insulator that houses the head. It is received on the inner peripheral surface. This prevents the connection bolt from being rotated together with the tightening of the nut, and the nut is tightened to the connection bolt. However, since the insulator is made of resin, its strength is limited, and if the nut is excessively tightened, it may crack or break.

  The present invention has been made in view of such circumstances, and an object of the present invention is to increase the resistance to a rotational force applied from the connection bolt head as an insulator for housing the connection bolt head. An object of the present invention is to provide an insulator that can be used, a secondary battery including the insulator, and a method for manufacturing the insulator.

  An insulator that solves the above-mentioned problem is disposed along an outer surface of a battery case that houses a power generation element, and is a length that ensures electrical insulation between the battery case and a connection bolt to which external wiring is connected. A scale-shaped resin insulator, the insulator having a back surface facing the outer surface of the battery case, and a surface opposite to the back surface, wherein the front surface has a longitudinal direction. Has a current collecting terminal insertion portion through which a current collecting terminal for taking out the power of the power generating element to the outside of the battery case is inserted, and the other side in the longitudinal direction houses the head of the connection bolt. A recess having a peripheral wall that also serves as a detent for the connection bolt, and a groove extending in the longitudinal direction at the center of the bottom of the receiving hole in the short direction. On the longitudinal line of the groove Wherein the supply port and becomes a gate port of the resin during the formation at a location beyond the accommodation hole as viewed from the groove is provided.

  A secondary battery that solves the above problem is a secondary battery that has a connection bolt to which an external wiring is connected outside a battery case that houses a power generation element, and is arranged along an outer surface of the battery case. The above-mentioned description is provided as the insulator, wherein a long-sized resin insulator having a receiving hole for accommodating a head of the connection bolt is provided while ensuring electrical insulation between a battery case and the connection bolt. Characterized by having an insulator of (1).

  A method of manufacturing an insulator that solves the above-described problem is arranged along an outer surface of a battery case that houses a power generation element, and provides electrical insulation between the battery case and a connection bolt to which external wiring is connected. A method for manufacturing a long-sized resin insulator to be secured, the insulator having a back surface facing an outer surface of the battery case, and a front surface opposite to the back surface. The surface has a current collecting terminal insertion portion through which a current collecting terminal for taking out the power of the power generating element to the outside of the battery case is inserted on one side in the longitudinal direction, and the connection is formed on the other side in the longitudinal direction. A recess for accommodating the head of the bolt, having a receiving hole provided with a peripheral wall that also serves as a detent for the connection bolt, and having a groove extending in the longitudinal direction at the center of the bottom of the receiving hole in the short direction. At the time of forming the insulator Along the line in the longitudinal direction of the groove on the back surface, a gate which is a resin supply port is provided at a position past the accommodation hole when viewed from the groove, and a resin forming the insulator is formed from the provided gate. It is characterized by injection.

  Although the orientation of the solidified resin occurs along the flow of the resin at the time of formation, cracks are likely to occur in the same direction as the orientation, and there is a risk of breakage therefrom. In this regard, according to this configuration, the gate serving as the resin supply port during formation is on the line in the longitudinal direction of the groove on the back surface facing the outer surface of the battery case, and viewed from the groove. And was placed in a position past the accommodation hole. Therefore, the resin supplied from the gate is divided at the groove portion where the flow is resistant to the flow and changes in the direction of the peripheral wall portion, and the peripheral wall portion that abuts against the changed direction is at least a part thereof. The resin is oriented in the vertical direction, which is the direction from the back surface to the front surface of the insulator. By inclining the orientation of the resin in the vertical direction of the insulator, the resistance of the peripheral wall portion against the pressure received from the head of the connection bolt as a detent is improved, and the occurrence of cracks and the accompanying damage is suppressed. For example, when the bolt is turned, a lateral force (rotational direction of the bolt) is applied to the housing hole so as to shear the peripheral wall. At this time, in the insulator, when the orientation of the resin constituting the peripheral wall portion of the accommodation hole is in the vertical direction, the inventors have found that cracks are less likely to occur than in the case where the orientation of the resin is in the lateral direction. I found it.

  Also, for example, when the insulator is long, the width of the insulator in the short direction is often limited, and the peripheral wall portion along the longitudinal direction of the insulator has a thickness whose width is limited. Due to the regulation, the wall thickness of the peripheral wall portion along the short direction of the insulator is often thinner than the wall thickness. In such a case, the orientation of the resin is inclined in the vertical direction of the insulator with respect to the peripheral wall portion having a small wall thickness, so that the strength can be maintained even for the peripheral wall portion having a small wall thickness, and the usefulness is high. .

As a preferred configuration, a concave groove along the longitudinal direction of the groove is provided on the back surface of the insulator on both sides of the groove.
According to such a configuration, the flow of the resin is more strongly directed in the direction away from the groove due to the concave groove, so that the degree of orientation of the resin in the peripheral wall portion in the longitudinal direction from the back surface to the surface direction is increased.

  As a preferred configuration, the thickness of the wall of the peripheral wall portion along the longitudinal direction is smaller than the thickness from the back surface of the insulator to the bottom of the accommodation hole, and the bottom of the concave groove on the back surface is formed from the bottom. It is thinner than the thickness up to the bottom of the receiving hole on the surface.

  According to such a configuration, the resistance acting on the flow of the resin in the longitudinal direction of the peripheral wall along the longitudinal direction increases, so that the resin flows from the back surface of the insulator (the bottom of the receiving hole) toward the peripheral wall. Therefore, the orientation of the resin of the peripheral wall portion along the longitudinal direction is along the direction from the back surface to the front surface of the insulator, or is inclined in the same direction.

  As a preferred configuration, the height of the peripheral wall along the longitudinal direction is shorter than the length of the peripheral wall in the longitudinal direction, and the height of the accommodation hole in the front surface from the bottom of the concave groove on the back surface of the insulator. The thickness up to the bottom is greater than the thickness from the back surface of the insulator to the bottom surface of the groove.

  According to such a configuration, since the height of the peripheral wall portion is shorter than the length in the longitudinal direction, the resin easily flows in the height direction where the length is shorter at the peripheral wall portion. Further, the resin easily flows on the upper side of the concave groove which is thicker than the lower side of the groove at the bottom. This further increases the tendency of the resin to be oriented such that the orientation of the resin in the peripheral wall portion along the longitudinal direction extends from the back surface of the insulator to the surface or inclines in the same direction.

  According to the insulator, the secondary battery including the insulator, and the method for manufacturing the insulator, the insulator accommodating the head of the connection bolt is resistant to the rotational force applied from the head of the connection bolt. To be higher.

FIG. 1 is a perspective view showing a schematic perspective structure of an embodiment embodying a secondary battery. FIG. 3 is a perspective view showing a perspective structure of an insulator, connection bolts, and external terminals in the same embodiment. FIG. 3 is a surface view showing the surface structure of the insulator in the same embodiment. FIG. 4 is an exemplary sectional view showing a cross-sectional structure of the insulator according to the embodiment, taken along line 4-4 in FIG. 3; It is a figure which shows the outline of the orientation of the resin of the insulator in the embodiment typically, (a) is a figure which shows the orientation when seen from the back surface, (b) shows the orientation when seen from the front surface. FIG. FIG. 9 is a schematic view schematically showing the outline of the orientation of a resin in an insulator of a conventional secondary battery. FIG. 7 is an exemplary cross-sectional view schematically showing the orientation of the resin in the cross-sectional structure taken along line 7-7 of FIG. 3 of the insulator according to the embodiment. It is a figure which shows typically the flow of resin when the bolt mounting part of the insulator in the same embodiment is resin-molded, (a) is a figure which shows the flow of the position near a gate, (b) is an accommodation hole The figure which shows the flow at the time of flowing into (a), (c) is a figure which shows the flow in the front of an accommodation hole.

  With reference to FIG. 1, an embodiment of the rechargeable battery 1 will be described. A plurality of secondary batteries 1 of the present embodiment are connected to each other by a bus bar to form an assembled battery. The assembled battery is mounted on an electric vehicle or a hybrid vehicle and supplies electric power to an electric motor or the like. The secondary battery 1 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, and is a sealed battery having a rectangular parallelepiped outer shape.

  The secondary battery 1 includes a battery case 2. The battery case 2 has a rectangular parallelepiped shape that accommodates the power generation element 10 and the electrolyte. In the battery case 2, a lid 3 for sealing the opening of the container is welded to a container having an opening at the top.

  The secondary battery 1 includes a current collecting terminal 4 for extracting the power of the power generating element 10 through the cover 3 of the battery case 2 to the outside, and an external terminal 7 connected to the current collecting terminal 4 and arranged at an upper portion of the cover. And a connection bolt 8 connected to the external terminal 7 and connected to an external wiring such as a bus bar on the outer surface of the battery case 2. There are two connection bolts 8, one of which is a connection bolt 8 P on the positive electrode side and the other is a connection bolt 8 N on the negative electrode side, each of which protrudes in a direction away from the lid 3.

  The power generation element 10 includes a positive electrode body, a negative electrode body, and a separator disposed between the positive electrode body and the negative electrode body. A current collecting terminal 4P on the positive electrode side is electrically and mechanically connected to one end of the power generating element 10 on the positive electrode side, and a current collecting terminal 4N on the negative electrode side is connected to one end of the power generating element 10 on the negative electrode side. Are electrically and mechanically connected. In the following, when it is not necessary to distinguish between the positive electrode side and the negative electrode side, they are simply referred to as the current collecting terminal 4 and the connection bolt 8.

  The lid 3 is a rectangular plate-shaped member, and is welded to the opening of the container by laser welding or the like. The lid 3 is provided between the two connection bolts 8, a gas release valve 3 a which is broken when the internal pressure of the battery case 2 reaches the operating pressure, and an electrolyte inlet 3 b for injecting the electrolyte into the battery case 2. And

  In the lid 3, an insulator (insulator) 6 is disposed between a connection bolt 8 and a surface that is a surface that is separated from the battery case 2. The insulator 6 is a long resin molded product, and is provided between the lid 3, the external terminals 7, and the connection bolts 8 so that the longitudinal direction thereof is along the longitudinal direction of the lid 3. ing.

  The current collecting terminal 4 is mechanically and electrically connected to the connection bolt 8 via the external terminal 7. Therefore, the electric power of the power generating element 10 is extracted from the connection bolt 8 via the current collecting terminal 4 and the external terminal 7. In the secondary battery 1, hermeticity and electrical insulation are secured between the current collecting terminal 4 and the lid 3.

  The structure in which the connection bolt 8 is connected to the power generation element 10 will be described in detail with reference to FIGS. In this embodiment, for convenience of explanation, the direction away from the power generating element 10 in the cover 3 (upward in FIGS. 1 and 2) is referred to as “up”, and the direction toward the power generating element 10 in the cover 3 (FIG. 1 and the lower side in FIG. 2) are referred to as “lower”. FIG. 2 is a diagram showing a perspective structure of each component after assembly, with each component virtually separated.

  As shown in FIG. 2, the connection bolt 8 includes a rectangular plate-shaped head 81 having a rounded corner, a flange portion 84 enlarging an upper surface of the head portion 81, and a flange portion 84 side of the head portion 81. And a columnar portion 83 protruding vertically from the surface. The columnar portion 83 has a columnar shape extending in the vertical direction, and a thread groove (not shown) is formed on a part of the outer peripheral surface. Therefore, the head 81 of the connection bolt 8 has a portion on the rectangular outer periphery that has a distance difference from the center axis of the columnar portion 83 of the connection bolt 8. More specifically, the head 81 has a square shape with rounded corners, and distributes the pressure applied due to the rotational force of the connection bolt 8 to members that come into contact with the four sides. The columnar portion 83 has a constricted concave portion 82 at an outer peripheral portion connected to the flange portion 84 of the head portion 81. The concave portion 82 allows a displacement between the connection bolt 8 and the external terminal 7 that occurs in the surface direction of the surface of the flange portion 84.

  The external terminal 7 is a plate-like member formed by bending a conductive metal plate such as aluminum or the like, and extends above the lid 3. The external terminal 7 includes a terminal fastening portion 73 to which the connection bolt 8 is connected, and a stepped portion different from the terminal fastening portion 73, and an enlarged portion 44 at an upper end of an extension portion which is a part of the current collecting terminal 4. Are connected, and a step portion 72 that forms a step between the terminal fastening portion 73 and the terminal fixing portion 71 is provided. The terminal fastening part 73 has a terminal insertion hole 75 penetrating the center in the plane thereof. The terminal fixing portion 71 has a caulking hole 74 penetrating the center in the plane. The stepped portion 72 extends in a direction intersecting the plane direction of the terminal fastening portion 73, for example, in a vertical direction. The current collecting terminal 4 is connected and fixed to the terminal fixing portion 71 by the expanded portion 44 through which the caulking hole 74 penetrates being crushed and wider than the caulking hole 74.

  The columnar portion 83 of the connection bolt 8 is inserted into the terminal insertion hole 75 of the terminal fastening portion 73. The columnar portion 83 having the terminal insertion hole 75 inserted therein is inserted with a through hole of a bus bar (not shown), and a fastening nut (not shown) is fastened from above the bus bar. As a result, one end of the bus bar is electrically and mechanically connected to the connection bolt 8, and the other end of the bus bar is electrically and mechanically connected to the connection bolt of another adjacent battery (not shown). Since the height of the concave portion 82 of the connection bolt 8 in the vertical direction is higher than the thickness of the terminal fastening portion 73, play in the surface direction of the head portion 81 of the connection bolt 8 in the terminal insertion hole 75 is ensured. Transmission of the force applied from the bus bar is reduced.

  As shown in FIG. 3, the insulator 6 includes a bolt mounting portion 61 having a recess for accommodating the head 81 of the connection bolt 8, and a current collecting terminal insertion portion 62 for supporting the terminal fixing portion 71. The insulator 6 is arranged in the bolt mounting portion 61 and the current collecting terminal insertion portion 62 so as to be aligned in the longitudinal direction which is the left-right direction in FIG. 3, and a step portion 65 is provided therebetween. For example, the current collecting terminal insertion portion 62 is disposed on one side in the longitudinal direction of the insulator 6 (the right side in FIG. 3), and the bolt mounting portion 61 is disposed on the other side in the same longitudinal direction (the left side in FIG. 3). . The insulator 6 has electrical insulation properties, and is interposed between the lid 3 and the external terminals 7 and the connection bolts 8, so that the lid 3 can be electrically connected to the external terminals 7 and the connection bolts 8. Ensure the electrical insulation of the The insulator 6 is formed by injection molding using a resin made of an insulating material. The resin may be, for example, a nylon (PA) resin or a polyphenylene sulfide (PPS) resin.

  The bolt mounting portion 61 includes a housing hole 50 that is a recess for housing the head 81 of the connection bolt 8. The accommodation hole 50 has a shape corresponding to the head 81 of the connection bolt 8, and has a longitudinal length of "length D50". The accommodation hole 50 is a square bottomed hole having an inner periphery with a rounded corner, and around the hole is provided a peripheral wall composed of four peripheral wall portions 68, 66, 67. The accommodation hole 50 enhances the resistance by dispersing the pressure applied from the head 81 of the connection bolt 8 due to the rotational force of the connection bolt 8 to the peripheral wall portions 68, 66, 67. The peripheral wall 68 has a thickness “D68” in the widthwise direction (the vertical direction in FIG. 3) of the insulator 6, and the peripheral wall 67 has a thickness “D67W” in the longitudinal direction of the insulator 6. The portion 68 is configured to be thicker than the thickness “thickness D68”. The housing hole 50 surrounds the outer periphery of the head 81 of the connection bolt 8 housed therein by the peripheral wall portions 68, 66, 67 serving as peripheral walls, so that the head 81 of the connection bolt 8 is positioned in the horizontal direction. The displacement is suppressed, and the rotation against the rotation of the shaft transmitted from the columnar portion 83 when the nut is fastened to the connection bolt 8 is suppressed. Since the connection bolt 8 is held in the housing hole 50 of the insulator 6, it is prevented that the connection bolt 8 comes off the housing hole 50 and contacts the lid 3 to short-circuit to the battery case 2.

  The current collecting terminal insertion portion 62 has a thickness of “thickness D62”, and its outer periphery is surrounded by an outer wall portion 64 having a protruding surface, and a portion surrounded by the outer wall portion 64 has an external terminal 7 (see FIG. 2) is mounted. The current collecting terminal insertion hole 63 is disposed at a position overlapping with the swaging hole 74 (see FIG. 2) of the terminal fixing portion 71 placed on the current collecting terminal inserting portion 62, and has the same diameter as the circular shape of the swaging hole 74. Has a circular opening. The current collecting terminal insertion portion 62 suppresses the horizontal movement of the terminal fixing portion 71 by surrounding the terminal fixing portion 71 placed thereon with the outer wall portion 64. Therefore, it is possible to prevent the secondary battery 1 from being short-circuited when the external terminal 7 comes off the insulator 6 and comes into contact with the lid 3.

  As shown in FIG. 4, the insulator 6 includes a pair of first and second protrusions 69 and 69B on a back surface 6R facing the lid 3. The first protrusion 69 is provided below the accommodation hole 50, and the second protrusion 69B is provided below the current collector terminal insertion portion 62 and at a position away from the first protrusion 69. ing.

  As shown in FIGS. 3 and 4, the bolt mounting portion 61 has a “thickness D61” in a vertical direction (a vertical direction in FIG. 4) that is a direction from the rear surface 6R to the front surface 6F. The accommodation hole 50 is a hole provided at the center of the bolt attachment portion 61. The accommodation hole 50 has a bottom portion 51 at a position where the depth is “depth D67” from the upper end of each of the peripheral wall portions 68, 66, and 67, which are peripheral walls of the hole. In addition, the thickness of the bottom portion 51 from the back surface 6R of the insulator 6 is “thickness D51”. Here, the insulator 6 satisfies the first condition and the second condition. The first condition is that “thickness D51” is greater than “thickness D68” (see FIG. 7) which is the thickness of the peripheral wall portion 68 along the longitudinal direction, that is, “thickness D51> thickness D68”. It is. The second condition is that the “thin thickness D69A” (see FIG. 7), which is a thin thickness at the bottom portion 51, is greater than the “thickness D68” (see FIG. 7), that is, “thin thickness D69A> thickness”. D68 ". According to the first condition, since the “thickness D68” is smaller than the “thickness D51”, the resistance of the resin flowing from the direction of the peripheral wall 66 to the peripheral wall 66 during molding is smaller than that of the bottom 51. Becomes longer, the resin flows from the “thickness D51” of the bottom portion 51 to the peripheral wall portion 68, and flows vertically through the peripheral wall portion 68. According to the second condition, since the “thickness D68” is smaller than the “thin thickness D69A”, the resistance to the flow of the resin flowing from the direction of the peripheral wall 66 during molding is smaller than that of the bottom 51 in the peripheral wall. Since the longitudinal direction of 68 becomes higher, the resin flows from the “thin thickness D69A” of the bottom portion 51 to the peripheral wall portion 68 and flows vertically through the peripheral wall portion 68. In this way, at the time of molding, since the resin flows from the back surface of the insulator (the bottom of the receiving hole) toward the peripheral wall, the orientation of the resin of the peripheral wall along the longitudinal direction is changed from the back surface of the insulator to the front surface. Along the direction or lean in the same direction.

  Between the bottom part 51 and each of the peripheral wall parts 68, 66, 67, there are provided circumferential peripheral grooves 52, 53, 54 surrounding the bottom part 51. The bottom portion 51 has a groove 55 extending in the longitudinal direction of the insulator 6 at the center of the insulator 6 in the lateral direction. The groove portion 55 has a length in the longitudinal direction that fits in the longitudinal direction of the bottom portion 51, and has a bottom at a position recessed by “thickness D51” from the surface of the bottom portion 51. In addition, the bolt mounting portion 61 includes, on the back surface 6 </ b> R of the insulator 6, a first protrusion 69 having a thickness “D69” and projecting downward in a range wider than the opening of the groove 55. . In the present embodiment, the vertical “thickness D61” of a portion other than the first protrusion 69 of the bolt mounting portion 61 is the same as the “depth D67 + thickness D51” which is the depth to the bottom of the groove 55. However, since the groove 55 is formed in the portion of the first protrusion 69, the groove 55 is provided as a bottomed groove having a bottom having a thickness of “thickness D69”. Note that the “thickness D61” of the bolt mounting portion 61 does not have to be the same as the “depth D67 + thickness D51” which is the depth to the bottom of the groove 55, and in this case, the first protrusion 69 The groove 55 is formed in the portion of the groove 55, so that the groove 55 has a required bottom thickness.

  As shown in FIG. 5, on both sides of the back surface 6 </ b> R of the insulator 6 in the short direction of the first protrusion 69, a groove 69 </ b> A recessed from the back surface 6 </ b> R along the first protrusion 69 is provided. Accordingly, the bottom portion 51 has a “thickness D51” from the back surface 6R, but a “thickness D69A” (see FIG. 7) in which the concave groove 69A is formed, which is a thin thickness up to the bottom of the concave groove 69A. Has become. Here, the insulator 6 satisfies the third condition and the fourth condition. The third condition is that the “depth D67”, which is the height of the wall of the peripheral wall 68, is shorter than the length “length D55” of the peripheral wall 68 along the longitudinal direction (see FIG. 3), that is, the “depth”. D67 <length D55 ”. The fourth condition is that the “thickness D69A” obtained by subtracting the recess of the concave groove 69A from the “thickness D51” of the bottom 51 of the accommodation hole 50 is larger than the “thickness D69” of the bottom of the groove 55, that is, “thickness D69”. Thickness D69A> thickness D69 ". According to the third condition, at the time of molding, the resin flows more easily in the shorter distance, so that the resin flows more easily in the longitudinal direction of the bottom portion 51 than in the peripheral wall portion 68, and flows from the bottom portion 51 toward the peripheral wall portion 68. In the part 68, the direction is up and down. According to the fourth condition, at the time of molding, the resistance of “thickness D69” with respect to the flow of the resin becomes higher than the “thickness D69A”. Since the groove 55 becomes a resistance, the resin can be reliably dispersed on both sides of the groove 55. The resin is dispersed by the groove 55 and flows through the groove 69A, and flows from the groove 69A toward the peripheral wall 68. The resin flows vertically in the peripheral wall 68. Further, since the “thickness D69A” of the concave groove 69A is smaller than the “thickness D51”, it becomes a resistance to the flow of the resin, and the flow of the resin flows from the “thickness D69A” portion to the “thickness D51” portion. In other words, it is strengthened in the direction toward the peripheral wall 68.

The orientation of the resin forming the insulator 6 will be described with reference to FIGS. The orientation of the resin occurs along the flow of the resin at the time of injection molding.
As shown in FIGS. 5A and 5B, the insulator 6 is injection-molded with a resin supplied from a gate G1 which is a resin supply port of a mold for molding the insulator 6. In the present embodiment, the gate G <b> 1 is provided on the back surface 6 </ b> R and in the bolt mounting portion 61 at a position on the side of the current collecting terminal insertion portion 62. The gate G1 is a range including the position of the gate G1 described above, and is within a range of “length D66” (see FIG. 4) in the longitudinal direction of the bolt mounting portion 61 in the longitudinal direction of the insulator 6. Thus, it may be provided at a position past the accommodation hole 50 when viewed from the groove 55. In the insulator 6, the position of the gate G1 remains as a gate port.

  The resin supplied from the gate G1 is filled in the mold by moving from the vicinity of the gate G1 to the distance, and then cooled and solidified to form the insulator 6. Although the resin supplied from the gate G <b> 1 bypasses the current collecting terminal insertion hole 63 in the current collecting terminal insertion portion 62, the resin is supplied to the end of the current collection terminal insertion portion 62 substantially along the longitudinal direction of the insulator 6. Flows. That is, the resin is oriented in the current collecting terminal insertion portion 62 along the longitudinal direction. In the bolt mounting portion 61, the resin supplied from the gate G1 flows to the peripheral wall portion 67 farthest from the gate G1 through the first protrusion 69 and the concave groove 69A. At this time, the resin flows from the longitudinal direction to the lateral direction according to the above-described first to fourth conditions. Then, the flow of the resin is a flow from the bottom to the top with respect to the peripheral wall portion 68 at the end in the short direction. Therefore, the peripheral wall portion 68 is filled in such a manner that the resin flows upward from below, and the resin is oriented along this flow. The resin that has moved along the first protrusion 69 and the concave groove 69A is filled in the peripheral wall 67 farthest from the gate G1.

  On the other hand, conventionally, as shown in FIG. 6, a gate G2 may be provided at one longitudinal end of the insulator 6A of the bolt mounting portion 61A. In this case, the resin supplied to the gate G2 flows around the accommodation hole 50A. That is, the resin passes from the peripheral wall 67A extending at the one end in the longitudinal direction and extending in the lateral direction of the insulator 6A, through the peripheral wall 68A extending in the longitudinal direction, passes through the stepped portion 65A, and passes through the step portion 65A. It flows along substantially the same longitudinal direction to the other end in the longitudinal direction. Therefore, the orientation of the resin in the peripheral wall portion 68A was the longitudinal direction along the direction in which the resin flowed.

  As described above, the orientation of the solidified resin occurs along the direction in which the resin flows. In the insulator 6 of the present embodiment, the resin-molded peripheral wall portion 68 along the longitudinal direction is also improved in resistance to pressing received from the head 81 of the connection bolt 8 as a detent because the orientation of the resin is inclined in the vertical direction. In addition, cracks and the like hardly occur, and the strength against the pressing force is high. For example, when the inventors turn the connection bolt 8, a lateral (rotational direction of the bolt) force is applied to the housing hole 50 so as to shear the peripheral wall 68. At this time, in the insulator 6, when the orientation of the resin forming the peripheral wall portion 68 of the housing hole 50 is in the vertical direction, cracks are less likely to occur than in the case where the orientation of the resin is in the horizontal direction. They found. In other words, the inventors have previously recognized that lateral cracks are likely to occur in the peripheral wall 68 of the insulator 6. The decrease in strength due to the orientation of the resin can be compensated for by increasing the thickness of the resin.

With reference to FIGS. 7 and 8, an operation of flowing the resin when the insulator 6 is molded with the resin will be described.
As shown by an arrow FD in FIG. 8A, the resin supplied to the gate G1 flows in a direction in which the bolt mounting portion 61 is configured to spread from the gate G1. Then, the supply resin flows in the direction in which the bottom portion 51 of the housing hole 50 is formed after passing through the peripheral wall portion 66 closest to the gate G1.

  As shown by an arrow FD in FIG. 8B, a groove portion 55 and a concave groove 69 </ b> A are provided in the bottom portion 51 of the accommodation hole 50, and the flow resistance near the peripheral wall portion 68 is reduced. Therefore, the supply resin changes its flow direction so as to move in the direction of lower flow resistance, and moves toward the lower side of the peripheral wall 68 extending in the longitudinal direction from the bottom 51 of the housing hole 50. In other words, the groove 55 and the like of the bolt mounting portion 61 change the flow of the resin. The resin supplied from the gate G1 is divided into right and left by a groove 55 provided at the bottom 51 of the accommodation hole 50. Also at this time, the component of the resin flowing toward the left and right peripheral wall portions 68 is generated. Further, since the flow resistance is lower at the bottom portion 51 than at the peripheral wall portion 68, the resin flows to the bottom portion 51 and then to the left and right peripheral walls rather than flows from the peripheral wall portion 66 to the left and right peripheral wall portions 68. It also goes to the part 68.

  As shown by an arrow FD in FIG. 8C, the supplied resin proceeds along the bottom 51 of the accommodation hole 50, but changes the flow direction from the groove 55 having a high flow resistance to the peripheral wall 68. , Toward the lower side of the peripheral wall 68 extending in the longitudinal direction from the bottom 51 of the accommodation hole 50.

  In other words, according to the second condition “the thickness D68 of the wall of the peripheral wall portion 68” <“the thin thickness D69A of the bottom portion 51”, the resin first flows to the bottom portion 51 of the accommodation hole 50, and from there the resin becomes thin. It flows to the peripheral wall portion 68. That is, the flow of the resin to the peripheral wall portion 68 flows more bypassing the bolt mounting portion 61 than the resin flows in the longitudinal direction along a short distance wall from the gate G1. As a result, the peripheral wall 68 is filled with the resin from the bottom 51 of the housing hole 50, and the orientation of the peripheral wall 68 is inclined in the vertical direction. Further, the third condition and the fourth condition further increase the change in the flow of the resin at the time of molding so that the orientation of the peripheral wall portion 68 is inclined in the vertical direction.

  With reference to FIG. 7, a description will be given of the flow of the resin from the bottom 51 of the storage hole 50 toward the lower side of the peripheral wall 68 extending in the longitudinal direction. First, the resin supplied from the gate G1 travels along the bottom 51 of the housing hole 50 toward the peripheral wall 67 at the longitudinal end. At this time, since the “thickness D69A” above the concave groove 69A is thicker than the “thickness D69” at the bottom of the groove 55, the flow of the resin flows from the bottom of the groove 55 toward the upper side of the concave groove 69A. Changes to Further, since the “thickness D51” of the bottom portion 51 of the storage hole 50 is thicker than the “thickness D69A” above the concave groove 69A, the flow of the resin flows from the groove 69A at the bottom portion 51 of the storage hole 50. It changes in the direction of the peripheral wall 68. That is, the supplied resin changes the direction in which it flows toward the peripheral wall 68. In this manner, the resin whose flow has changed in the horizontal direction or in the direction including the horizontal component is, as shown by the arrow FD, between the groove 55 and the first protrusion 69 and between the bottom 51 and the groove 69A. And passes between the back surface 6R and the peripheral groove 52 to reach a lower side of the peripheral wall portion 68 along the longitudinal direction. The resin that has reached the lower side of the peripheral wall portion 68 moves upward from the lower side of the peripheral wall portion 68 and fills the peripheral wall portion 68. That is, in the peripheral wall portion 68, the filled resin flows from the lower side to the upper side, and cools and solidifies, so that the orientation of the resin is from the lower side to the upper side, that is, the so-called vertical direction.

  By the way, since the bottom 51 is connected to the peripheral wall 68 via the peripheral groove 52, the flow path from the bottom 51 to the peripheral wall 68 is curved by the peripheral groove 52, so that the peripheral wall 68 extends vertically from the bottom 51. The flow resistance is reduced as compared with the case of standing up. Thereby, the flow of the resin in the peripheral wall portion 68 is more preferably from the lower side to the upper side.

As described above, according to the insulator, the secondary battery, and the method for manufacturing the insulator of the present embodiment, the following effects can be obtained.
(1) The gate G1 which is a resin supply port at the time of formation is on a line in the longitudinal direction of the groove portion 55 on the back surface 6R which is a surface facing the outer surface of the battery case 2, and the receiving hole is viewed from the groove portion 55. It was arranged at a position past 50, for example, at a position on the side of the current collecting terminal insertion portion 62. Therefore, the resin supplied from the gate G1 is divided by the groove 55 whose flow is resistant to the flow and changes in the direction of the peripheral wall 68, and at least the peripheral wall 68 that abuts in the changed direction is At a part thereof, the orientation of the resin is in the vertical direction which is the direction from the back surface 6R to the front surface 6F of the insulator 6. By inclining the orientation of the resin in the vertical direction of the insulator 6, the peripheral wall portion 68 also serves as a detent to improve the resistance to the pressure received from the head 81 of the connection bolt 8, thereby suppressing the occurrence of cracks and associated damage. You. For example, when the connection bolt 8 is turned, a lateral force (rotational direction of the connection bolt 8) is applied to the housing hole 50 so as to shear the peripheral wall 68.

  For example, when the insulator 6 is long, the width of the insulator 6 in the short direction is restricted by the size of the lid 3. That is, the thickness of the peripheral wall portion 68 along the longitudinal direction of the insulator 6 is regulated by the width of the lid 3, and the wall thickness is greater than the wall thickness of the peripheral wall portion 68 along the lateral direction of the insulator 6. thin. In such a case, since the orientation of the resin is inclined in the vertical direction of the insulator 6 with respect to the peripheral wall portion 68 having a small wall thickness, the strength of the peripheral wall portion 68 having a small wall thickness can be maintained.

  (2) Since the flow of the resin is more strongly directed away from the groove 55 by the concave groove 69A, the degree of the orientation of the resin of the peripheral wall portion 68 in the longitudinal direction along the direction from the rear surface 6R to the front surface 6F increases.

  (3) Under the first condition and the second condition, the resistance of the peripheral wall portion 68 along the longitudinal direction acting on the resin flowing in the longitudinal direction is increased, so that the resin is exposed to the back surface 6R of the insulator 6 (the bottom portion of the housing hole 50). From 51), it flows in the direction of the peripheral wall portion 68. As a result, the resin is oriented such that the resin of the peripheral wall portion 68 along the longitudinal direction extends along the direction from the rear surface 6R to the front surface 6F of the insulator 6 or is inclined in the same direction.

  (4) According to the third condition and the fourth condition, the height “depth D67” of the peripheral wall portion 68 is shorter than the length “length D55” in the longitudinal direction. It becomes easy to flow in the direction (height direction). In addition, the resin easily flows on the upper side of the concave groove 69A that is thicker than the lower side of the groove 55 at the bottom 51. This further increases the tendency of the resin to be oriented along the longitudinal direction of the peripheral wall portion 68 along the direction from the rear surface 6R to the front surface 6F of the insulator 6 or to be inclined in the same direction.

(Other embodiments)
The above embodiment can be implemented in the following modes.
-In above-mentioned embodiment, although the case where the accommodation hole 50 was the square shape where the inner periphery was rounded at the corner was illustrated, it is not restricted to this, If it functions as a detent of a connection bolt, the accommodation hole 50 The inner circumference may be a shape other than a circle, for example, an ellipse, a triangle, or a polygonal shape with five or more angles. Further, when the axis of the columnar portion of the connection bolt is deviated from the center of the circle, the inner periphery of the accommodation hole may be a circle because it can function as a detent. This increases the degree of freedom in forming the insulator.

  -In above-mentioned embodiment, the case where the gate opening was provided in the back surface 6R of the insulator 6 from the groove part 55 to the collector terminal insertion part 62 side was illustrated. At this time, the gate port may be an externally identifiable port as long as it can be specified as a resin injection port into the insulator, or may be specified by analyzing or cutting the insulator. It may be a possible mouth.

  In the above embodiment, the case where the insulator 6 is disposed on the lid 3 of the battery case 2 is illustrated. However, the present invention is not limited thereto. May be located anywhere on the outer surface of the.

  -In above-mentioned embodiment, the case where the bolt attachment part 61 of the insulator 6 satisfies the 1st condition and the 2nd condition, and the 3rd condition and the 4th condition was illustrated. However, the present invention is not limited to this, and only one of the first condition and the second condition or the third condition and the fourth condition may be satisfied. Thereby, the degree of freedom related to the formation of the insulator can be increased.

  -In the said embodiment, the case where the 3rd condition and the 4th condition were satisfied was illustrated. However, the present invention is not limited to this, and if the orientation of the resin on the peripheral wall is inclined in the up-down direction, at least one or more of these conditions may not be satisfied. Thereby, the degree of freedom in designing the insulator is increased.

  -In the said embodiment, the case where the 1st condition and the 2nd condition are materialized was illustrated. However, the present invention is not limited to this, and if the orientation of the resin on the peripheral wall portion is inclined in the up-down direction, at least one of these conditions may be satisfied. Thereby, the degree of freedom in designing the insulator is increased.

  In the above-described embodiment, the case where the concave groove 69A is provided along the groove 55 is illustrated. However, if the orientation of the resin of the peripheral wall portion along the longitudinal direction is in the vertical direction, the concave groove is formed along the groove. May not be provided, and the length may be longer or shorter. This increases the degree of freedom in adjusting the flow of the resin.

  -In the above-mentioned embodiment, the case where peripheral grooves 52, 53, and 54 were provided around bottom 51 of accommodation hole 50 was illustrated. However, the present invention is not limited to this. If the orientation of the resin of the peripheral wall portion along the longitudinal direction is in the vertical direction, the peripheral groove may not be provided around the bottom of the accommodation hole, and a part of the periphery of the bottom may be provided. Only the groove may be provided. For example, the peripheral groove 52 may be eliminated at a connection portion between the longitudinal peripheral wall portion and the bottom of the accommodation hole. This increases the degree of freedom in adjusting the flow of the resin.

  In the above embodiment, the case where the secondary battery 1 is formed of a lithium ion secondary battery is described as an example. However, the present invention is not limited to this, and another secondary battery, for example, a nickel hydride secondary battery or the like may be used. .

  In the above embodiment, the case where the plurality of secondary batteries 1 are mounted on an electric vehicle or a hybrid vehicle as an assembled battery is exemplified. However, the present invention is not limited to this, and the secondary battery may be an electric vehicle such as a gasoline vehicle or a diesel vehicle. Or a vehicle other than a hybrid vehicle. Further, the secondary battery may be used as a power source for a mobile object other than an automobile or a fixed power source. For example, power supplies other than automobiles include power supplies for moving objects such as railroads, ships, aircraft and robots, and power supplies for electrical products such as information processing devices.

  DESCRIPTION OF SYMBOLS 1 ... Secondary battery, 2 ... Battery case, 3 ... Lid, 3a ... Gas release valve, 3b ... Electrolyte inlet, 4, 4N, 4P ... Current collecting terminal, 6, 6A ... Insulator, 6F ... Surface, 6R: Back surface, 7: External terminal, 8, 8N, 8P: Connection bolt, 10: Power generation element, 44: Expanding part, 50, 50A: Housing hole, 51: Bottom part, 52, 53, 54: Peripheral groove, 55 ... Groove, 61, 61A ... bolt mounting part, 62, 62A ... collector terminal insertion part, 63 ... collector terminal insertion hole, 64 ... outer wall part, 66, 67, 67A ... peripheral wall part, 68, 68A ... peripheral wall part, 69: first projection, 69A: concave groove, 69B: second projection, 71: terminal fixing part, 72: step, 73: terminal fastening part, 74: caulking hole, 75: terminal insertion hole, 81 .., Head, 82, recess, 83, column, 84, flange, G1, G2, gate.

Claims (6)

A long resin insulator that is arranged along the outer surface of the battery case that houses the power generating element and that secures electrical insulation between the battery case and connection bolts to which external wiring is connected. So,
The insulator has a back surface facing the outer surface of the battery case, and a surface that is a surface opposite to the back surface, and the front surface is configured to receive power of the power generating element on one side in a longitudinal direction. It has a current collecting terminal insertion portion through which a current collecting terminal to be taken out of the battery case is inserted, and a concave portion in which the head of the connection bolt is accommodated on the other side in the longitudinal direction, and which serves to prevent rotation of the connection bolt. It has an accommodation hole provided with a peripheral wall that also serves as a groove, and has a groove extending in the longitudinal direction at the center of the bottom of the accommodation hole in the short direction,
On the back surface, a gate port serving as a resin supply port at the time of formation is provided at a position on a line in the longitudinal direction of the groove portion and beyond the accommodation hole when viewed from the groove portion. Insulator. The insulator according to claim 1, wherein a concave groove is provided on the back surface of the insulator on both sides of the groove, the groove extending in a longitudinal direction of the groove. The thickness of the wall of the peripheral wall portion along the longitudinal direction is thinner than the thickness from the back surface of the insulator to the bottom of the accommodation hole, and the thickness from the bottom of the concave groove on the back surface to the surface. The insulator according to claim 2, wherein the insulator is thinner than a thickness up to a bottom of the accommodation hole. The height of the peripheral wall along the longitudinal direction is shorter than the longitudinal length of the peripheral wall,
The thickness from the bottom of the concave groove on the back surface of the insulator to the bottom of the accommodation hole on the front surface is greater than the thickness from the back surface of the insulator to the bottom surface of the groove. 2. The insulator according to claim 1. A secondary battery having a connection bolt to which an external wiring is connected outside a battery case containing a power generation element,
A long resin material is disposed along the outer surface of the battery case to ensure electrical insulation between the battery case and the connection bolt, and has a receiving hole for receiving a head of the connection bolt. With an insulator of
A secondary battery comprising the insulator according to any one of claims 1 to 4 as the insulator. A long resin insulator that is arranged along the outer surface of the battery case that houses the power generating element and that secures electrical insulation between the battery case and a connection bolt to which external wiring is connected. A method of manufacturing,
The insulator has a back surface facing the outer surface of the battery case, and a surface that is a surface opposite to the back surface, and the front surface is configured to receive power of the power generating element on one side in a longitudinal direction. It has a current collecting terminal insertion portion through which a current collecting terminal to be taken out of the battery case is inserted, and a concave portion in which the head of the connection bolt is accommodated on the other side in the longitudinal direction, and which serves to prevent rotation of the connection bolt. It has an accommodation hole provided with a peripheral wall part also serving as a peripheral part, and has a groove extending in the longitudinal direction at the center in the short direction of the bottom of the accommodation hole,
At the time of forming the insulator, a gate which is a resin supply port is provided on the back surface on a line in a longitudinal direction of the groove portion and at a position past the accommodation hole when viewed from the groove portion, and from the provided gate. A method for manufacturing an insulator, comprising injecting a resin for forming the insulator.