JP6318871B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device having an insulating member that insulates electrode terminals.

  2. Description of the Related Art Conventionally, a secondary battery as a power storage device that stores power supplied to a traveling motor is mounted on a vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) (for example, Patent Document 1). . The power storage module includes a plurality of the secondary batteries described above.

Japanese Patent Laid-Open No. 9-120836

  As shown in FIG. 6, when configuring the power storage module, the electrode terminals 54 of the adjacent secondary batteries 51 are connected by bus bars 52 using bolts 53. However, since a part of the electrode terminal 54 is exposed at the lid portion 55 of the secondary battery 51, there is a possibility that the electrode terminal 54 contacts the outside and short-circuits when the secondary battery 51 is handled.

  The present invention has been made paying attention to the problems existing in the above-described prior art, and an object thereof is to provide a power storage device capable of suppressing the occurrence of a short circuit.

  A power storage device for solving the above problems is a power storage device including a metal case, an electrode assembly housed in the case, and an electrode terminal that exchanges electricity with the electrode assembly. The insulating member surrounding the exposed portion of the electrode terminal exposed on the outer surface of the case is provided, and the upper end surface of the insulating member is higher than the upper end surface of the exposed portion.

  According to this, since the upper end surface of the insulating member is at a position higher than the upper end surface of the exposed portion of the electrode terminal, the exposed portion is positioned in an inner region surrounded by the insulating member. As a result, when the power storage device falls, the insulating member comes into contact with the outside, so that the occurrence of a short circuit can be suppressed.

  In the power storage device, the insulating member has a high insulating wall and a low insulating wall, and the upper end surface of the high insulating wall is fixed to the upper end surface of the exposed portion using a bus bar fixing member. While being in a position higher than the upper end surface of the bus bar and in a state where the bus bar is fixed to the upper end surface of the exposed portion using the bus bar fixing member, the bus bar is positioned higher than the upper end surface of the bus bar fixing member, The upper end surface of the low insulating wall is at a position lower than the upper end surface of the bus bar in a state where the bus bar is fixed to the upper end surface of the exposed portion using the bus bar fixing member, and the bus bar fixing member is used to It is preferable that the bus bar is positioned lower than the upper end surface of the bus bar fixing member in a state where the bus bar is fixed to the upper end surface of the exposed portion.

  According to this, even when the bus bar is fixed to the upper end surface of the exposed portion using the bus bar fixing member, the exposed portion, the bus bar, and the bus bar fixing member are located in the inner region surrounded by the insulating member. become. As a result, when the power storage device falls, the insulating member comes into contact with the outside, so that the occurrence of a short circuit can be suppressed. Furthermore, the low insulating wall does not get in the way when attaching the bus bar to the exposed part.

  In the power storage device, the insulating member has a cylindrical shape, and the insulating member includes a receiving portion provided in the case and an engaging portion having an engaging surface that engages in the circumferential direction of the insulating member. It is preferable.

  According to this, when the engaging surface of the engaging portion and the receiving portion of the case are engaged, it is possible to suppress the rotation of the insulating member in the circumferential direction, and the insulating member does not rotate. The assembly of the bus bar is improved.

  The power storage device is a secondary battery.

  According to the present invention, occurrence of a short circuit can be suppressed.

The disassembled perspective view which shows a secondary battery. The top view which shows an electrical storage module. The fragmentary sectional view which shows the electrode terminal to which the terminal cover was fixed. The disassembled perspective view which shows another example of a terminal cover. The disassembled perspective view which shows another example of a terminal cover. Sectional drawing which shows the vicinity of the conventional electrode terminal.

Hereinafter, an embodiment in which a power storage device is embodied as a secondary battery will be described with reference to the drawings.
As shown in FIG. 1, a secondary battery 10 as a power storage device includes a case 11 made of metal (for example, made of stainless steel or aluminum). The case 11 includes a rectangular box-like container 12 and a rectangular flat lid 13 that closes the opening of the container 12. The lid 13 is provided with a pair of insertion holes 13b having a circular shape in plan view. Further, a pair of grooves 13c having a circular arc shape in plan view as a receiving portion is provided between the pair of insertion holes 13b in the lid 13.

  The case 11 houses an electrode assembly 14. A positive electrode terminal 15 and a negative electrode terminal 16 are electrically connected to the electrode assembly 14 and exchange electricity with the electrode assembly 14 respectively. A ring-shaped insulating ring 17 for insulating from the case 11 is attached to the positive electrode terminal 15 and the negative electrode terminal 16, respectively.

  The electrode assembly 14 includes a positive electrode, a negative electrode, and a separator that insulates the positive electrode and the negative electrode. The positive electrode includes a positive electrode active material layer on both surfaces of a positive electrode metal foil (aluminum foil). The negative electrode includes a negative electrode active material layer on both sides of a negative electrode metal foil (copper foil). The electrode assembly 14 has a laminated structure in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated, and a separator is interposed between the two electrodes.

  The positive electrode terminal 15 and the negative electrode terminal 16 pass through the insertion hole 13 b of the lid 13 and are partially exposed (projected) outside the case 11. Hereinafter, the exposed portion of the positive electrode terminal 15 and the negative electrode terminal 16 located outside the lid 13 is referred to as an exposed portion 18. The exposed part 18 is cylindrical. The outer periphery of the exposed portion 18 has a male screw portion, while the inner periphery of the exposed portion 18 has a female screw portion.

  A nut 26 is screwed onto the outer periphery of the exposed portion 18. The outer surface 13 a of the lid 13 and the nut 26 are insulated by the insulating ring 17. The positive electrode terminal 15 and the negative electrode terminal 16 are attached to the case 11 by screwing the nut 26 into the exposed portion 18.

  A terminal cover 20 as an insulating member for insulating from the case 11 is positioned on the outer surface 13 a of the lid 13 so as to surround the exposed portion 18. The terminal cover 20 is made of resin. The terminal cover 20 has a cylindrical shape.

  As shown in FIG. 3, the terminal cover 20 has a high insulating wall 22 whose wall height is a height N1, and a low insulating wall 23 whose wall height is a height N2. The upper end surface 22a of the high insulating wall 22 and the upper end surface 23a of the low insulating wall 23 are connected in steps. Due to the connection between the high insulating wall 22 and the low insulating wall 23, the terminal cover 20 has a recess 24 in which a part thereof is recessed. The bottom surface of the recess 24 is also the upper end surface 23 a of the low insulating wall 23. In addition, the recess 24 has a pair of side wall surfaces 24 a that connect the upper end surface 22 a of the high insulating wall 22 and the upper end surface 23 a of the low insulating wall 23 at the inner periphery thereof and that descend vertically from the upper end surface of the high insulating wall 22. .

  Returning to the description of FIG. 1, an attachment piece 25 as an engagement portion having a circular arc shape in plan view extending in the axial direction is extended on the lower end side in the axial direction of the terminal cover 20. The length of the mounting piece 25 in the axial direction is shorter than the thickness of the lid 13. The planar shape of the attachment piece 25 is substantially the same as the planar shape of the groove 13c of the lid 13, and the attachment piece 25 can be fitted into the groove 13c. Further, in the attachment piece 25, the pair of side walls located in the circumferential direction of the terminal cover 20 has an engagement surface 25a that abuts against the inner wall of the groove 13c.

Next, the power storage module 40 will be described.
In FIG. 2, the description of overlapping symbols is omitted.
As shown in FIGS. 1 and 2, the power storage module 40 includes a plurality of secondary batteries 10. The plurality of secondary batteries 10 constituting the power storage module 40 are arranged in parallel with the negative electrode terminal 16 of the other secondary battery 10 adjacent to the positive electrode terminal 15 of the other secondary battery 10 arranged in parallel. The negative electrode terminal 16 of the secondary battery 10 is connected to the positive electrode terminal 15 of the other adjacent secondary battery 10 via the bus bar 30. The bus bar 30 has a rectangular flat plate shape and has a pair of insertion holes 30a. The bus bar 30 is made of aluminum.

  A bolt 31 as a bus bar fixing member is screwed into the exposed portion 18, and the bus bar 30 is connected to the exposed portion 18 by the bolt 31. The bolt 31 has a bolt screw portion 31a that is screwed into the inner periphery of the exposed portion 18, and a head portion 31b at one end in the axial direction of the bolt screw portion 31a. The bus bar 30 is pressed toward the exposed portion 18 by the head 31b of the bolt 31, and the bus bar 30 and the upper end surface 18a of the exposed portion 18 come into surface contact with each other, so that the bus bar 30 and the positive electrode terminal 15 or the negative electrode terminal 16 are in contact. Is conducting.

  Further, as shown in FIG. 2, each terminal cover 20 fixed to the positive electrode terminal 15 of one secondary battery 10 to be connected and the negative electrode terminal 16 of the other secondary battery 10 to be connected is In order to receive the bus bar 30 in the recess 24, the low insulating walls 23 face each other.

Next, the height of the electrode terminal to which the terminal cover 20 and the bus bar 30 are fixed will be described.
As shown in FIG. 3, the height N1 of the high insulating wall 22 is higher than the height N4 of the exposed portion 18. Further, the height N 1 of the high insulating wall 22 is higher than the height N 3 from the upper end surface 31 c of the bolt 31 fixed to the upper end surface 18 a of the exposed portion 18 to the outer surface 13 a of the lid 13. On the other hand, the height N2 of the low insulating wall 23 is substantially the same as the height N4 of the exposed portion 18, and the outer surface 13a of the lid 13 extends from the upper end surface 30b of the bus bar 30 fixed to the upper end surface 18a of the exposed portion 18. It is lower than the height N5. Similarly, the height N2 of the low insulating wall 23 is lower than the height N3 from the upper end surface 31c of the bolt 31 fixed to the upper end surface 18a of the exposed portion 18 to the outer surface 13a of the lid 13. The opening width N6 in the radial direction of the recess 24 is substantially the same as the width N7 of the bus bar 30. Therefore, the pair of side wall surfaces 24 a that connect the upper end surface 22 a of the high insulating wall 22 and the upper end surface 23 a of the low insulating wall 23 function as a bus bar abutting portion that abuts on the bus bar 30.

Next, the operation of the secondary battery 10 will be described.
The height N1 of the high insulating wall 22 is higher than the height N4 of the exposed portion 18 and the height N3 from the upper end surface 31c of the bolt 31 fixed to the upper end surface 18a of the exposed portion 18 to the outer surface 13a of the lid 13. . Therefore, the exposed portion 18 is located in the inner region surrounded by the terminal cover 20, and the exposed portion 18 is not exposed to the outside.

According to the above embodiment, the following effects can be obtained.
(1) When the terminal cover 20 in the present embodiment is employed in the secondary battery 10, the exposed portion 18 is located in an inner region surrounded by the terminal cover 20, and the exposed portion 18 is not exposed to the outside. Thereby, it can suppress that a short circuit generate | occur | produces.

  (2) Further, even if the case 11 and the terminal cover 20 are not integrally molded, the short circuit between the positive electrode terminal 15 and the negative electrode terminal 16 is suppressed only by retrofitting the insulating terminal cover 20 to the metal case 11. be able to. For this reason, it is rich in versatility compared with the case where the case 11 and the terminal cover 20 are integrally formed.

  (3) Even when the bus bar 30 is fixed to the upper end surface 18 a of the exposed portion 18 using the bolt 31, the exposed portion 18, the bus bar 30, and the bolt 31 are located in the inner region surrounded by the terminal cover 20. However, it is not exposed from the terminal cover 20. Thereby, when the secondary battery 10 falls, since the terminal cover 20 contacts outside, it can suppress that a short circuit generate | occur | produces. Further, when the bus bar 30 is attached to the exposed portion 18, the low insulating wall 23 does not interfere with the concave portion 24, and the assembling property of the bus bar 30 to the positive electrode terminal 15 and the negative electrode terminal 16 is improved. improves.

  (4) The engagement between the engagement surface 25a of the mounting piece 25 and the inner wall of the groove 13c of the lid 13 and the contact of the side wall surface 24a of the recess 24 with the bus bar 30 from the width direction causes the terminal cover 20 and the bus bar 30 to It is possible to suppress the rotation of both in the circumferential direction.

  (5) Since the terminal cover 20 can be attached so that the low insulating wall 23 is positioned at a position where the bus bar 30 can be received, the terminal cover 20 can be easily positioned and the assembly property of the bus bar 30 is improved.

  (6) When a terminal cover that collectively encloses a plurality of electrode terminals is employed, when a defect such as a chipping occurs, the entire terminal cover must be replaced. However, the terminal cover 20 is provided for each electrode terminal. If each is attached, it is only necessary to replace the defective terminal cover 20, and it is not time-consuming.

In addition, you may change the said embodiment as follows.
In the embodiment, the opening width N6 in the radial direction of the recess 24 may be slightly longer than the width N7 of the bus bar 30, and a clearance may be provided in the radial direction of the recess 24.

  ○ In the embodiment, the bus bar 30 is used regardless of the positional relationship between the positive electrode terminal 15 in one secondary battery 10 to be connected and the negative electrode terminal 16 in the other secondary battery to be connected. Two or more low insulating walls 23 may be formed in the terminal cover 20 so that they can be connected.

  O The formation positions of the attachment pieces 25 and the grooves 13c may be appropriately changed according to the arrangement of the secondary batteries 10 to which the bus bars 30 are attached. Moreover, when the secondary battery 10 is arranged in parallel as in the embodiment and the power storage module 40 is configured, the positive electrode terminal 15 of one secondary battery 10 to be connected and the other secondary battery to be connected. Each terminal cover 20 fixed to the negative electrode terminal 16 of the battery 10 has low insulating walls 23 facing each other. In this case, in the terminal cover 20 that surrounds the positive electrode terminal 15 and the negative electrode terminal 16 of the same secondary battery 10, the low insulating walls 23 face outward in the opposite directions by 180 °. That is, in the plurality of secondary batteries 10, since the terminal covers 20 attached to the electrode terminals having the same polarity are opened in the same direction, the electrode terminals having the same polarity cannot be connected by the bus bar 30. That is, the same polarity electrode terminal is not accidentally connected by the bus bar 30.

In the embodiment, the terminal cover 20 having only the high insulating wall 22 may be embodied.
In the embodiment, as long as the terminal cover 20 has a cylindrical shape, the planar view may have any shape such as a circular shape or a rectangular shape.

  In the embodiment, the entire circumference of the exposed portion 18 may not be surrounded by the terminal cover 20. For example, the terminal cover 20 may be U-shaped in plan view. However, the width of the portion that is not surrounded by the terminal cover 20 is preferably a width in which a metal substance (for example, a metal piece or tool) does not easily enter.

In the embodiment, the terminal cover 20 may be provided with a groove, while the lid 13 may be provided with an attachment piece.
○ By fastening the bolt 31, the terminal cover 20 is held by the bus bar 30 and the outer surface 13 a of the lid 13, so that the attachment piece 25 and the groove 13 c need not be formed.

  The terminal cover 45 shown in FIG. 4 has a bottomed cylindrical shape with a track shape in plan view. The track shape is a shape in which the ends of two parallel straight lines are connected by an arc. A protruding portion 46 that protrudes in the axial direction of the terminal cover 45 is formed outside the bottom plate 45 a of the terminal cover 45. The protrusion 46 also has a track shape. In the example shown in FIG. 4, an insertion hole 13 b having the same shape as the bottom plate 45 a of the protrusion 46 and having a size that allows the protrusion 46 to be inserted is formed in the outer surface 13 a of the lid 13. The terminal cover 45 is attached to the lid 13 by inserting the protruding portion 46 into the insertion hole 13b. In the example shown in FIG. 4, since the protrusion 46 and the insertion hole 13b have a track shape, the protrusion 46 and the inner wall of the insertion hole 13b are in surface contact with each other on two surfaces. As a result, the terminal cover 45 does not rotate along the circumferential direction.

In addition, the shape of the protruding portion 46 and the insertion hole 13b may be a triangular column shape or a rectangular column shape so that the inner wall of the insertion hole 13b and the protruding portion 46 are in surface contact with each other at two or more surfaces.
In the embodiment, the terminal cover 20 is attached to the outer surface of the lid 13 and used. However, the terminal cover 20 may be inserted into the insertion hole 13 b of the lid 13 and attached to the lid 13.

  As shown in FIG. 5, the method of attaching the terminal cover to the lid 13 is not limited to the method of the embodiment. In FIG. 5, a plurality of (four pieces in this example) blades 47 are provided at equal intervals in the direction orthogonal to the axial direction on the outer peripheral surface of the terminal cover 20 on the lower end side in the axial direction. On the other hand, the same number of protrusions 13 d as the blades 47 are provided on the outer surface 13 a of the lid 13 so as to face the blades 47. According to this configuration, the blades 47 abut against the protrusions 13d when the bolts 31 are fastened, so that the accompanying rotation along the circumferential direction of the terminal cover 20 can be suppressed.

  In the embodiment, if the height N1 of the high insulating wall 22 is higher than the height N4 of the exposed portion 18, the outer surface 13a of the lid 13 from the upper end surface 31c of the bolt 31 fixed to the upper end surface 18a of the exposed portion 18 It may be lower than the height N3. In this case, it is preferable to coat the surfaces of the nut 26 and the bus bar 30 with an insulating material.

The terminal cover 20 is not limited to resin and may be made of rubber.
○ The shape of the case 11 may be cylindrical or elliptical.
The power storage device is not limited to the secondary battery 10 and may be, for example, an electric double layer capacitor or a lithium ion capacitor.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) The upper end surface of the high insulating wall and the upper end surface of the low insulating wall are connected in a stepped shape, and the pair of side wall surfaces connecting the upper end surface of the high insulating wall and the upper end surface of the low insulating wall are A power storage device that is a bus bar contact portion that contacts the bus bar.

  N1 to N5: height, N6: opening width, N7: bus bar width, 10 ... secondary battery as power storage device, 11 ... case, 13 ... lid, 13a ... outer surface of lid, 13c ... groove as receiving portion, DESCRIPTION OF SYMBOLS 14 ... Electrode assembly, 15 ... Positive electrode terminal, 16 ... Negative electrode terminal, 18 ... Exposed part of electrode terminal, 20 ... Terminal cover as an insulating member, 22 ... High insulating wall, 22a ... Upper end surface of a high insulating wall, 23 ... Low insulating wall, 23a ... Upper end surface of the low insulating wall, 25 ... Mounting piece as an engaging portion, 25a ... Engaging surface of the mounting piece, 26 ... Nut, 30 ... Bus bar, 30b ... Upper end surface of the bus bar, 31 A bolt as a bus bar fixing member, 31c, an upper end surface of the bolt, 40, a power storage module.

Claims (3)

A metal case,
An electrode assembly housed in the case;
A power storage device comprising the electrode assembly and an electrode terminal for transferring electricity,
An insulating member surrounding the exposed portion of the electrode terminal exposed on the outer surface of the case;
The insulating member has a high insulating wall and a low insulating wall,
The upper end surface of the high insulating wall is positioned higher than the upper end surface of the bus bar in a state where the bus bar is fixed to the upper end surface of the exposed portion using a bus bar fixing member, and the exposure using the bus bar fixing member is performed. While in a state where the bus bar is fixed to the upper end surface of the part, it is at a position higher than the upper end surface of the bus bar fixing member,
The upper end surface of the low insulating wall is at a position lower than the upper end surface of the bus bar in a state where the bus bar is fixed to the upper end surface of the exposed portion using the bus bar fixing member, and the bus bar fixing member is used. In a state where the bus bar is fixed to the upper end surface of the exposed portion, the bus bar is positioned lower than the upper end surface of the bus bar fixing member.
It said insulating member is a power storage device which is characterized that you have been configured to be attached individually to the respective electrode terminals to be connected by the bus bar. The insulating member is cylindrical,
The power storage device according to claim 1, wherein the insulating member includes an engaging portion having an engaging surface that engages with a receiving portion provided in the case in a circumferential direction of the insulating member. The power storage device power storage device according to claim 1 or 2 is a secondary battery.