JP4999819B2 - Sealed prismatic battery - Google Patents

Description

  The present invention relates to a sealed prismatic storage battery in which an electrode plate group and an electrolytic solution are accommodated in a rectangular battery case and hermetically sealed, and electrode terminals are protruded from both ends in the longitudinal direction of the rectangular battery case.

  In recent years, alkaline storage batteries such as nickel metal hydride batteries, which are excellent in terms of energy density, have been used as power sources for electric vehicles, etc., and in a rectangular battery case so as to obtain a large output while being compact. For example, Japanese Patent Application Laid-Open No. 7-161377 proposes a sealed prismatic storage battery that encloses and seals an electrode plate group in which a positive electrode plate and a negative electrode plate parallel to the long side surface are stacked via a separator.

  In this type of sealed prismatic storage battery 41, as shown in FIG. 7, it is connected to a large number of positive and negative electrode plates of the electrode plate group via leads on a lid 43 that seals the upper surface opening of the battery case 42, respectively. Positive and negative electrode terminals 44 and 45 are projected. 46 is a safety valve which discharges | emits an internal gas, when the inside of the battery case 42 becomes a pressure more than fixed.

  In use, such a sealed prismatic storage battery (unit battery) 41 is arranged in parallel in one or a plurality of rows so that the long side faces are overlapped, and the positive and negative electrode terminals 44 and 45 of adjacent unit batteries 41 are arranged. Are connected in series to obtain a predetermined output voltage. However, when a large number of unit batteries 41 are connected on the upper surface in this way, there is a problem that the connection configuration becomes complicated and the cost is increased.

  Therefore, as shown in FIG. 8, a sealed rectangular storage battery 51 in which a plurality of single cells are built in a flat rectangular parallelepiped battery case 52 along the longitudinal direction and connected in series inside is formed. The thing which protruded the pole terminal 54 in the both-ends wall 53 is considered.

According to the sealed rectangular storage battery 51 having such a configuration, the number of connections of the electrode terminals 54 outside the sealed rectangular storage battery 51 can be significantly reduced to obtain the same output voltage. Can be configured.
Japanese Patent Laid-Open No. 7-161377

  However, in the configuration of the sealed prismatic storage battery 51 as shown in FIG. 8, when an electric vehicle on which the vehicle is mounted collides, an obstacle hits the sealed prismatic storage battery 51 from the side and a direct impact is applied to the pole terminal 54. There is a possibility that a situation of being loaded may occur, and in this case, there is a problem that the electrode terminal 54 moves greatly and causes a short circuit.

  Moreover, as shown in FIGS. 9A and 9B, the battery case 52 of such a sealed prismatic storage battery 51 has a single-point gate 55 at the center of the bottom surface or both sides of the center line in the longitudinal direction. In this case, as shown in FIG. 10, a terminal hole 57 provided for attaching the electrode terminal 54 to the both end walls 53 of the battery case 52 is produced. In this portion, the resin flows separately on the left and right sides, and then contacts on the center line at the top of the terminal hole 57. Therefore, a weld line 58 is generated at the top of the terminal hole 57 along the center line. .

  In this weld line 58, although the resin integrity is small and the portion is weak in strength, the center line position above the terminal hole 57 is the portion where the cross-sectional area is the smallest and the stress is concentrated. When the stress line overlaps the weld line 58 and the internal pressure of the battery case 52 becomes high, or when an external force or vibration is applied to the electrode terminal 54, cracks are likely to occur, and the mounting strength of the electrode terminal 54 is sufficiently secured. There was a problem that I could not.

  In addition, in a use state in which a plurality of sealed rectangular storage batteries 51 are arranged in parallel so that their long side surfaces overlap and are constrained between end plates arranged at both ends, the long side surfaces of each sealed rectangular storage battery 51 are constrained. Since both end walls 53 are not constrained, there is a problem that when the battery internal pressure rises, it expands and deforms and may adversely affect the connection portion of the electrode terminal 54.

  Further, in this type of sealed rectangular storage battery 51, when connecting a bus bar or external wiring connecting the sealed rectangular storage battery 51 to the pole terminal 54, these are clamped by nuts. A large rotational torque acts on the pole terminal 54 at the time of connection, and an appropriate detent means for the polar terminal 54 is required. However, as a conventional detent means, a detent portion is extended from the pole terminal 54 as long as possible, and the tip thereof In general, the part is engaged with a part of the battery case 52, but excessive stress is applied to receive rotational torque by the point engagement between the tip of the non-rotating part and the battery case. There is a problem that the tip of the non-rotating portion is easily broken, and that the anti-rotating portion is enlarged when an action load is reduced.

  In view of the above-described conventional problems, the present invention is suitable even when an impact is difficult to be applied to the pole terminal even when an obstacle hits from the side, and even when an external force acts on the pole terminal or the battery internal pressure increases. An object of the present invention is to provide a sealed prismatic storage battery that can secure a connected state and can prevent rotation of a pole terminal with a compact configuration and has high reliability against a load on the pole terminal portion.

The sealed prismatic storage battery of the present invention is a sealed prismatic storage battery in which terminal holes are formed at both ends in the longitudinal direction of the rectangular battery case, and pole terminals are attached to the terminal holes. 1 or a plurality of engaging grooves in the radial direction centered on the electrode terminal, and an engaging piece that fits into and engages with the engaging groove is formed on the joint surface with respect to the end wall of the electrode terminal, and acts on the electrode terminal. The rotating torque can be received over a large area by engaging the engagement groove and the engagement piece in the radial direction, and the area can be easily increased by increasing the number of engagement grooves and engagement pieces. The stress of the engagement surface that receives a load can be reduced with a compact configuration, and the fracture limit can be improved.

  In addition, the engagement groove of the end face wall is formed around a circular recess centered on the axis of the terminal hole, and the engagement piece of the pole terminal is formed on the outer periphery of a circular or annular projection that fits into the circular recess. Because the load due to rotational torque always acts perpendicularly to the engagement groove and the engagement surface of the engagement piece due to the fitting between the circular recess and the circular or annular protrusion, high support strength against the load is obtained. And the fracture limit can be further improved.

  In addition, if the engagement taper is provided in the engagement groove on the end face wall and the engagement piece that engages and engages with the engagement groove, the insertion property at the time of engagement is improved, and the fixing failure of the pole terminal is prevented. can do.

In addition, if a reverse taper is provided on the inner peripheral wall of the annular groove formed inside the annular protrusion, an O-ring is attached to the annular groove of the pole terminal to prevent the O-ring from falling off and rising up to the fixing process. it can be.

According to the sealed prismatic storage battery of the present invention, one or more engaging grooves in the radial direction centering on the axial center of the terminal hole are formed around the terminal hole of the end face wall, and the joint surface to the end face wall of the pole terminal is formed. Since the engaging piece that fits into and engages with the engaging groove protrudes, the rotational torque acting on the pole terminal can be received in a large area by the engagement of the engaging groove and the engaging piece in the radial direction, and a compact configuration The stress of the engagement surface that receives the load can be reduced, and the fracture limit can be improved.

  In addition, the engagement groove of the end face wall is formed around a circular recess centered on the axis of the terminal hole, and the engagement piece of the pole terminal is formed on the outer periphery of a circular or annular projection that fits into the circular recess. Because the load due to rotational torque always acts perpendicularly to the engagement groove and the engagement surface of the engagement piece due to the fitting between the circular recess and the circular or annular protrusion, high support strength against the load is obtained. And the fracture limit can be further improved.

  In addition, if the engagement taper is provided in the engagement groove on the end face wall and the engagement piece that engages and engages with the engagement groove, the insertion property at the time of engagement is improved, and the fixing failure of the pole terminal is prevented. can do.

  In addition, if a reverse taper is provided on the inner peripheral wall of the annular groove formed inside the annular protrusion, an O-ring is attached to the annular groove of the pole terminal to prevent the O-ring from falling off and rising up to the fixing process. Thus, highly reliable electrode terminal fixation is possible.

  Hereinafter, an embodiment of the sealed prismatic storage battery of the present invention will be described with reference to FIGS.

  The sealed rectangular storage battery 1 of the present embodiment is composed of a nickel-hydrogen secondary battery that can be suitably used as a drive power source for an electric vehicle. As shown in FIG. 1, a narrow short side surface and a wide long side surface are provided. And a plurality of (six in the illustrated example) battery case 3 having a rectangular parallelepiped shape having a top opening and a flat rectangular integrated battery case 2 integrally connected to each other while sharing its short side surface. The upper surface opening of each battery case 3 is integrally closed by an integral lid body 4.

  In each battery case 3, a group of electrode plates 5 formed by laminating a number of positive and negative electrode plates parallel to the long side surface of the battery case 3 in the direction of the short side surface through a separator, and a collection joined to both end faces thereof. The electric plate 6 is accommodated together with the electrolytic solution, and the unit cell 7 is configured.

  The electrode plate group 5 is configured such that a large number of positive electrode plates and a large number of negative electrode plates are alternately arranged, and each positive electrode plate is covered with a bag-like separator having an opening in the horizontal direction. In these positive electrode plate group and negative electrode plate group, opposite side edge portions protrude outward, the protruding side edge portions are configured as lead portions, and current collector plates 6 are welded to the side edge portions, respectively.

  Terminal holes 10 are formed at the upper end portions of the end face walls 8 at both ends of the integrated battery case 2, and connection holes 11 are formed at the upper end portions of the partition walls 9 between the battery cases 3 and 3. As will be described in detail later, positive or negative electrode terminals 12 are mounted in the terminal holes 10 of the end face walls 8 at both ends, and the unit cells 7, 7 on both sides are connected in series through the connection holes 11 of the partition wall 9. Yes.

  At the upper ends of the end face walls 8 at both ends of the integral battery case 2, as shown in FIG. 2, a thick portion 28 is formed on one side of the portion in the vicinity of the terminal hole 10 over an appropriate range in the vertical direction. The wall thicknesses are different from each other on both sides of the hole 10.

  Further, as shown in FIG. 3, the outer surface of the intermediate portion excluding the later-described projecting portions 26 at the upper end portion and the lower end portion of the end surface wall 8 is provided with a plurality of lateral ribs 8a and one or more plurality of ribs. The vertical ribs 8b are projected in a lattice shape.

  A projecting portion 26 projecting outward is provided at the lower end portion of the end wall 8. The protruding length l2 of the protruding portion 26 from the end surface wall 8 is preferably set to be about 1 to 10 mm larger than the protruding length l1 of the pole terminal 12 from the end surface wall 8. Further, the upper surface of the protruding portion 26 is constituted by an inclined surface 27 inclined obliquely downward toward the outer end, and the inclination angle θ with respect to the horizontal plane is 5 ° to 60 °, preferably 45 ± 10 °. Is set to about.

  On the upper surface of the lid 4, a through hole 13 is formed at the adjacent end portions of the battery cases 3 and 3 adjacent to each other, and a communication path 14 a that communicates between the through holes 13 and 13 is formed on the lid 4. The communication lid 14 is welded. 14b is a reinforcing protrusion projecting from the central portion of the inner surface of the communication lid 14, which is sized so as not to close the communication passage 14a and welded with its tip abutting against the upper surface of the lid body 4. Is secured.

  The integrated battery case 2, the lid body 4, and the communication lid 14 are made of a synthetic resin material such as PP / PPE alloy and have liquid repellency with respect to the electrolytic solution.

  The lid 4 is provided with a single safety valve 15 for releasing the pressure when the internal pressure of each battery case 3 exceeds a certain level, and a temperature detection sensor for detecting the temperature of the unit cell 7. The sensor mounting hole 16 for mounting is recessedly formed so as to be in contact with the upper end of the electrode plate group 5 of the appropriate unit cell 7.

  On the long side surface 17 of the integrated battery case 2 in which the long side surface of each battery case 3 forms a flat surface, ribs 18 extending in the vertical direction are projected at positions corresponding to both side ends of each battery case 3. A large number of relatively small circular protrusions 19 are provided between 18 and 18 in a matrix at an appropriate pitch interval. The ribs 18 and the protrusions 19 have the same height. Further, the upper end portion of the battery case 3 and the side surface of the lid body 4 have the same height as the rib 18 and the projecting portion 19 so as to extend between the side surfaces corresponding to the extended position of the rib 18 and the arrangement position of the projecting portion 19. The connecting ribs 20a and 20b are formed. The ribs 18, the protrusions 19, and the connecting ribs 20 a and 20 b form a refrigerant passage for efficiently and uniformly cooling each battery case 3 between them when the integrated battery case 2 is arranged in parallel.

  Moreover, it is located in the approximate center of each battery case 3 symmetrically with respect to the center line with respect to the longitudinal direction of the long side surface 17 of the integral battery case 2, and it mutually fits when the integral battery case 2 overlaps with the long side surface 17 mutually. Positioning projections 21 and recesses 22 are provided.

  A connecting projection 23 is formed to project outward from the upper end of the current collector plate 6, and the connecting projection 23 is inserted into the terminal hole 10 or the connecting hole 11 formed through the upper end of the end wall 8 and the partition wall 9. By doing so, the electrode plate group 5 is positioned with respect to the battery case 3. Moreover, the electrical connection of the adjacent unit cell 7 is carried out inside the battery by welding the tips of the connection projections 23 and 23 inserted into the connection hole 11 of the partition wall 9 between the adjacent battery cases 3 and 3. In addition, in the end face wall 8, a connection projection 24 that fits into the terminal hole 11 is projected from the electrode terminal 12, and the tips of the connection projections 23 and 24 of the current collector 6 and the electrode terminal 12 are welded together. Has been. In addition, an annular groove is formed around the connection protrusion 23 of the current collector plate 6 or the connection protrusion 24 of the electrode terminal 11, and an O-ring 25 is provided for sealing between the end face wall 8 and the partition wall 9. ing.

The details of the mounting portion of the electrode terminal 12 in this embodiment will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, the range of the predetermined radius around the terminal hole 10 of the end face wall 8 is thick. A circular recess 39 having the same axis as the axis of the terminal hole 10 is formed at the center thereof, and one or a plurality of engagement grooves 37 are formed radially around it. Further, as shown in FIG. 5, the electrode terminal 12 is provided with a projecting projection 24 that fits into the terminal hole 10 at the center of the joint surface with respect to the end wall 8 of the disc-shaped seat 12a, An annular protrusion 40 that fits into the circular recess 39 protrudes from the periphery, and engagement pieces 38 that engage with the engagement groove 37 protrude radially from the periphery. An O-ring for sealing is disposed in the annular groove 40 a between the annular protrusion 40 and the base of the connection protrusion 24.

  Further, a fitting taper α as shown in FIGS. 4C and 5C is provided in the engaging groove 37 of the end face wall 8 and the engaging piece 38 fitted and engaged in the engaging groove 37. And the insertion property at the time of fitting engagement improves, and the sticking defect of the pole terminal 12 can be prevented. The size of the fitting taper α is preferably 5 to 20 °.

  Further, when a reverse taper β is provided on the inner peripheral wall of the annular groove 40a of the electrode terminal 12 as shown in FIG. 5 (d), an O-ring is attached to the outer periphery of the connection projection 24 of the electrode terminal 12, and the end wall 8 It is possible to prevent the O-ring from dropping off or rising up to the step of fixing to the surface. The size of the reverse taper β is preferably 0 to 10 °.

  The above-described sealed prismatic battery 1 is arranged in parallel with a plurality of the long side surfaces 17 overlapped, end plates are arranged at both ends in the arrangement direction, and these end plates are connected by a restraining band to be packed. The battery pack is installed on the installation table 31 as shown in part in FIG. The battery pack is fixed by pressing the inclined surface 27 on the upper surface of the protruding portion 26 protruding from the lower end portion of the sealed prismatic storage battery 1 with the pressing piece 32 in the state where the battery pack is installed on the installation base 31, and the upper portion thereof. Is covered with a cover 33. The pressing piece 32 and the cover 33 are fastened and fastened together with the installation base 31 by fastening bolts 34. The installation base 31 is formed with a cooling air introduction space 35 for distributing cooling air over the entire lower surface of the battery pack, and a cooling air discharge space 36 is formed between the cover 33 and the upper outer surface of the battery pack. In addition, each single cell 7 is effectively cooled by passing cooling air between the sealed rectangular storage batteries 1 and 1 arranged in parallel.

  In the rectangular sealed battery 1 having the above configuration, since the protruding portion 26 protruding from the end wall 8 of the integrated battery case 2 is provided, an obstacle hits from the side with the sealed rectangular battery 1 installed. Even in this case, the obstacle hits the protruding portion 26 before hitting the pole terminal 12, and the impact energy is absorbed by the protruding portion 26. A short circuit can be prevented from occurring.

  Furthermore, since the protrusion part 26 which protrudes from the end surface wall 8 of the integrated battery case 2 is provided, since the protrusion part 26 is mounted and sealed on the installation base 31, as shown in FIG. The space 35 is formed up to the end of the integrated battery case 2, and each unit cell 7 can be effectively cooled.

  Further, the projecting portion 26 projects from the lower end portion of the end wall 8 and has an upper surface inclined at an angle of 5 ° to 60 °, preferably 45 ± 10 ° obliquely downward with respect to the horizontal plane. 27, and the inclined surface 27 is pressed and fixed by the pressing piece 32, so that it can be fixedly installed without exerting a load on the electrode terminal 12, and the rectangular sealed battery 1 can be installed in the vertical direction. Not only that, the length of the integrated battery case 2 can be restricted at the same time.

  Moreover, since the thick part 28 is formed in one side part of the end surface wall 8 of the integrated battery case 2 in the vicinity of the terminal hole 10 and the thicknesses are different from each other on both side parts of the terminal hole 10, the integrated battery case 2, when the resin is divided into the left and right sides in the terminal hole 10 at the time of injection molding, the resin flow is different on both sides. As a result, as shown in FIG. The weld line 29 formed in contact is formed obliquely upward at a position deviating from the center line position of the terminal hole 10, and the weld line 29 has the smallest cross-sectional area from the center line position of the terminal hole 10 where stress is concentrated. It will be located off. Therefore, the weld line 29 and the high-stress part do not overlap each other, and even when the internal pressure of each battery case 3 in the integrated battery case 2 is increased or when an external force or vibration is applied to the electrode terminal 12, cracks are hardly generated. The mounting strength of the electrode terminal 12 can be ensured.

  Further, the lateral ribs 8a and the vertical ribs 8b are protruded from the end face wall 8 to enhance the surface rigidity. Therefore, even if the battery internal pressure increases and a large load acts on the end face wall 8, the end face wall 8 is expanded and deformed. Can be effectively suppressed, and an appropriate connection state can be secured without adversely affecting the connection portion of the pole terminal 12.

  Further, since the engagement piece 38 is engaged with the radial engagement groove 37 in the mounting portion of the pole terminal 12, the rotational torque acting when connecting the bus bar and the external connection line to the pole terminal 12 is large. Further, by increasing the number of the engagement grooves 37 and the engagement pieces 38, the area can be further increased easily, and the stress of the engagement surface that receives the load can be reduced with a compact configuration. The breakage limit with respect to the rotational torque acting on the pole terminal 12 at the time of connection can be improved. Further, since the load due to the rotational torque always acts perpendicularly to the engagement surface of the engagement groove 37 and the engagement piece 38 by the fitting of the circular recess 39 and the annular protrusion 40, the support is high against the load. Strength can be obtained and the fracture limit can be further improved.

In addition , since the adjacent unit cells 7 are connected in series at the connection protrusions 23 that are formed by press forming of the current collector plate 6, internal connection can be made within the integrated battery case 2, and connection parts are required separately. Therefore, it is possible to easily connect at a low cost with a small number of parts, and since the connection protrusion 26 is integral with the current collector plate 6 and connected by welding at one place, the electrical resistance is extremely high. Fewer connections are possible.

  Further, in the adjacent end portions of the battery cases 3 and 3 adjacent to each other, a communication hole 14 is formed in the lid body 4, and a communication path 14 a is formed on the lid body 4 to communicate between the through holes 13 and 13. The lid 14 is welded, whereby the internal pressure between the battery cases 3 is made uniform, and the lifetime of the unit cells 7 is reduced due to the increase in the internal pressure of some of the battery cases 3, and accordingly the sealed rectangular shape is formed. It is possible to prevent the life of the storage battery 1 from being shortened, and it is only necessary to provide a single safety valve 15 on the lid 4, thereby reducing the cost.

Next, a reference example of the present invention will be described with reference to FIG. In addition, about the component same as the said embodiment, the same referential mark is attached | subjected and description is abbreviate | omitted and only a different point is demonstrated.

In the above embodiment, the electrode terminal 12 protrudes outward from the end face wall 8 of the integrated battery case 2, but in this reference example , terminal holes 30 are formed at both end portions of the upper wall of the lid body 4. And the electrode terminal 12 is mounted from the inside. The pole terminal 12 is mounted and fixed by sandwiching the upper wall of the lid body 4 between the seat portion 12a and the fixing nut 30a, and a sealing material 30b interposed between the fixing nut 30a and the upper surface of the upper wall of the lid body 4; Double sealing is performed by an O-ring 25 interposed between the seat 12 a of the electrode terminal 12 and the lower surface of the upper wall of the lid 4. Further, the current collector plate 6 disposed along the inner surface of the end face wall 8 of the unit cell 7 at both ends is formed with an extending portion 6 a extending upward, and the tip portion thereof is connected to the seat portion 12 a of the electrode terminal 12. Has been.

According to this reference example , even when an obstacle hits from the side with the sealed prismatic storage battery 1 installed, the pole terminal 12 is disposed on the lid body 4 so that a large impact is directly applied. In other words, it is possible to prevent a short circuit from occurring due to the movement of the electrode terminal 12, and when connecting a bus bar or an external connection line to the electrode terminal 12, it is possible to work from above, so that workability is improved.

  The present invention can be used for an assembled battery as a drive power source for an electric vehicle including a hybrid vehicle.

One Embodiment of the sealed prismatic storage battery of this invention is shown, (a) is a top view, (b) is a front view. It is a detailed perspective view of the principal part of the battery case of the embodiment. It is a perspective view of the edge part of the sealed square storage battery of the embodiment. The electrode terminal mounting part of the battery case in the embodiment is shown, (a) is a side view, (b) is a longitudinal front view, and (c) is an AA arrow enlarged cross-sectional view of (a). The pole terminal in the embodiment is shown, (a) is a partial cross-sectional front view, (b) is a right side view of (a), (c) is an enlarged cross-sectional view as viewed from arrow (b) BB, (d) is It is CC sectional view taken on the line of (b). The reference example of the sealed prismatic storage battery of this invention is shown, (a) is a top view of the principal part, (b) is the longitudinal cross-sectional front view. It is a perspective view of the sealed square storage battery of a prior art example. It is a fragmentary perspective view of the improved sealed prismatic storage battery of a prior art example. It is explanatory drawing of the gate arrangement position at the time of injection molding of the battery case of a sealed prismatic storage battery. It is a detailed perspective view of the principal part of the battery case in the improved sealed prismatic storage battery of a prior art example.

DESCRIPTION OF SYMBOLS 1 Sealed prismatic battery 2 Integrated battery case 6 Current collector plate 6a Extension part 8 End wall 8a Horizontal rib 8b Vertical rib 10 Terminal hole 12 Polar terminal 26 Protruding part 27 Inclined surface 28 Thick part 30 Terminal hole 37 Engaging groove 38 Engagement Joint piece 39 Circular recess 40 Annular protrusion 40a Annular groove

Claims (4)

In a sealed prismatic storage battery in which terminal holes are formed at both ends in the longitudinal direction of a rectangular battery case, and pole terminals are attached to the terminal holes, a radial direction centering on the axis of the terminal hole is provided around the terminal hole on the end wall. Alternatively, a sealed prismatic battery characterized in that a plurality of engagement grooves are formed, and an engagement piece that fits into and engages with the engagement groove is formed on the joint surface with respect to the end face wall of the electrode terminal. The engagement groove of the end face wall is formed around a circular recess centered on the axis of the terminal hole, and the engagement piece of the pole terminal is formed on the outer periphery of a circular or annular projection that fits into the circular recess. The sealed prismatic storage battery according to claim 1. 2. The sealed prismatic storage battery according to claim 1, wherein a fitting taper is provided in the engaging groove of the end face wall and the engaging piece fitted and engaged in the engaging groove. The sealed prismatic storage battery according to claim 2, wherein a reverse taper is provided on an inner peripheral wall of an annular groove formed inside the annular protrusion.

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