JP5673384B2 - Assembled battery - Google Patents

Description

  The present invention relates to a battery case for a unit cell suitable for manufacturing a battery pack.

  As a technology for connecting a plurality of unit cells to form a module (assembled battery), a plurality of unit cells, a battery partition wall disposed between the stacked unit cells, and a pair of end plates for sandwiching them There is known a secondary battery module including a fastening member protruding from an end plate and a fastening rod inserted through the fastening member to fasten a pair of end plates (Patent Document 1).

JP 2006-156392 A

  In contrast to the conventional structure in which the assembled battery is held only by a pair of end plates and a fastening (connecting) rod, the present inventor has provided a connecting member provided with a through hole for inserting the connecting rod in the side surface of each unit cell. We are considering a new structure with

  However, the connecting hole and the end plate are both concentric, and the inner diameter of the through hole is larger than the inner diameter of the connecting rod by the clearance when the connecting rod is inserted. Therefore, backlash is likely to occur due to vibration and impact. . Furthermore, rattling increases under a long-term vibration environment, the through-holes wear and the load is easily applied to the connecting rod.

  The present invention has been made in view of the above, and a main technical problem is to suppress the occurrence of rattling due to vibration and impact even when the assembled battery is placed in a vibration environment for a long period of time.

In the battery case according to the present invention, the battery case has a rectangular parallelepiped shape having a pair of narrow short side surfaces and a pair of wide long side surfaces, and connecting members at both upper and lower ends of the pair of short side surfaces. With
The connecting member includes a through-hole penetrating in the width direction of the short side surface,
The shape of the through hole is a substantially oval shape that is flatter than a perfect circle.

  In addition, a unit cell can be configured by including the power generation element housed in the battery case and the output terminal of the power generation element above the battery case, and a plurality of the unit cells can be formed. An assembled battery can be comprised by arrange | positioning and connecting.

  The assembled battery configured by using the present invention can suppress the occurrence and increase of rattling due to vibration and impact even in a vibration environment for a long period of time.

The assembled battery of 1st Embodiment, (a) is a perspective view of an assembled battery, (b) is sectional drawing of an assembled battery 1A is a perspective view of a unit cell, and FIG. 1B is a front view of the unit cell. The modification of the assembled battery of 1st Embodiment, (a) is sectional drawing of an example of an assembled battery, (b) is sectional drawing of the other example of an assembled battery. Single battery of the assembled battery of the second embodiment An example of the assembled battery of 3rd Embodiment, (a) is a figure explaining a mode that a buffer member is attached, (b) is a figure which shows the assembled battery after attachment of a buffer member. The other example of the assembled battery of 4th Embodiment, (a) is a figure explaining a mode that a buffer member is attached, (b) is a figure which shows the assembled battery after attachment of a buffer member. A battery case that houses a single cell described in each embodiment

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, about the component which exhibits the same or the same kind of function, description may be abbreviate | omitted using the same code | symbol. Each embodiment is only an example and does not give a limited interpretation on the present invention. First, the whole assembled battery of 1st Embodiment is demonstrated.

(First embodiment)
FIG. 1 is a diagram illustrating the assembled battery according to the first embodiment. Fig.1 (a) is a perspective view of an assembled battery, FIG.1 (b) is sectional drawing seen in the direction of AA of Fig.1 (a). In addition, the arrow in FIG.1 (b) shows the direction pressed by a connection rod. As shown to Fig.1 (a), the assembled battery 20 was provided with the several cell 10, the pair of end plate 11, the metal connection rod 12, the nut 13, and the convex part in the both ends. And a spacer 14.

  FIG. 2 is a diagram showing a unit cell of the assembled battery of FIG. FIG. 2A is a perspective view of the unit cell, and FIG. 2B is a front view of the unit cell. As shown in FIG. 2A, the cell 10 includes a power generation element housed in the battery case 1, the positive electrode terminal 2 and the negative electrode terminal 3 are provided at both ends of the upper surface of the cell 10, and a safety valve 6 is provided at the center. Is provided.

  FIG. 7A is a perspective view of the battery case 1, and FIG. 7B is a front view of the battery case 1. As shown in this figure, the battery case 1 has a rectangular parallelepiped shape having a pair of narrow short side surfaces and a pair of wide long side surfaces. A positive electrode, a negative electrode, an electrolyte, and the like are placed inside the battery case 1. The power generation element provided can be accommodated. And the connection members 4 and 5 comprised by resin etc. are provided in each of this pair of short side surfaces. In addition, this battery case is used for the single cell demonstrated by each following embodiment.

  Each of the connecting members 4 and 5 and the pair of end plates 11 has a through hole for inserting the connecting rod 12 in the width direction of the short side surface. Here, the through-hole of the end plate 11 is a perfect circle, but the shape of the through-hole provided in the connecting members 4 and 5 is a substantially elliptical shape that is flatter than the perfect circle. In the present specification, the “substantially elliptical shape” does not necessarily indicate a mathematically exact elliptical shape, and a pressing force acts on the through hole of the connecting member eccentrically from the center of the through hole of the end plate. In addition, it may be an annular shape that is flatter than a perfect circle. For example, the substantially elliptical shape includes a rectangle with rounded ends. With such a configuration, the pressing force from the connecting rod can be received at a fixed position, that is, the restraint at the fixed position is improved. Therefore, even if the assembled battery continues to receive vibration for a long period of time and the through hole wears and the inner diameter is expanded, the vibration load increases compared to the case where the end plate and the through hole are both concentric. Vibration resistance is improved.

  The through holes 41, 42, 51, 52 are formed so that the direction of the substantially elliptical long axis is directed toward the center of the unit cell 10 (battery case 1). In this way, the pressing force from the four connecting rods 12 can be efficiently received by the flat and narrow portion of the through-hole, and the restraining force at the fixed position is improved and each unit cell 10 is firmly held. Vibration resistance can be improved. Moreover, since the stress received from the connecting rod continues to act toward the central portion of the battery case 1, that is, in the bonding direction of the connecting member, there is an advantage that the connecting member itself is difficult to peel off.

  As shown in FIG. 2, the battery case 1 exemplified in the present embodiment is composed of upper and lower connecting members attached to one short side surface as a single body, and window frame portions 44, 54 leading to the center portion thereof. Respectively. The window frame portions 44 and 54 play a role of promoting heat dissipation from the short side surface of the unit cell 10. Further, the connecting members 4 and 5 are provided with a spacer 14 for forming a gap between adjacent unit cells. Concave portions 43 and 53 for attaching the spacer 14 are provided on both sides of the window frame portion. When the connecting member is configured integrally with the upper and lower sides, there is an advantage that the manufacturing process can be simplified by reducing the number of injection ports when forming by injection molding, and there is also an advantage that the recesses 43 and 53 can be provided. However, the upper and lower connecting members may be configured separately. If it is configured as a separate body, the exposed portion of the battery case becomes larger, so that it has the effect of promoting heat dissipation more than when a window frame is provided.

  As shown in FIG. 2B, a gap 7 is formed by the connecting member 4 or the connecting member 5 and the curved surface portion of the short side surface. Even when the connecting members 4 and 5 are subjected to a pressing force in the peeling direction with respect to the battery case 1 by forming the gap 7, the connection member 4, 5 and the battery case 1 are less likely to be directly subjected to the load. Moreover, when providing the buffer member which consists of an elastic body between the connection members 4 and 5 so that it may mention later, it can utilize also as a gap | interval for installation.

  As shown in FIG. 2A, the widths of the connecting members 4 and 5 are configured to be larger than the width of the short side surface of the battery case in consideration of the width of the spacer 14. As illustrated in the embodiment, a buffer member that also functions as a spacer may be provided between adjacent connecting members with the same width as the short side surface of the battery case.

  The material of the battery case 1 is made of a metal such as aluminum or a synthetic resin, for example. The connecting members 4 and 5 are made of a material that is mechanically softer than a connecting rod such as a resin, and is manufactured by injection molding. The connecting members 4 and 5 may be attached to the battery case 1 with an adhesive, or may be formed integrally with the metal battery case 1 by injection molding.

  For example, a resin connecting member may be joined to an aluminum battery case using the following method. First, in an aqueous electrolyte solution containing a triazine thiol derivative, a battery case (aluminum) is used as an anode, a platinum plate, a titanium plate, or a carbon plate is used as a cathode, and a voltage is applied between the anode and the cathode. An anodized film is formed on the surface of the case (electrodeposition process). Thereafter, the battery case is washed with water at a temperature of 40 ° C. to 60 ° C. for 5 seconds to 120 seconds (cleaning step). Thereby, the aluminum member excellent in bondability with the resin material is formed in the battery case. And a resin connection member can be joined to a battery case made of aluminum by directly forming a connection member into the aluminum member by injection molding.

  The assembled method of the assembled battery 20 is as follows. First, the cells 10 are juxtaposed so that the connecting members 4 and the connecting members 5 are adjacent to each other. At this time, the spacers 14 are arranged between the single cells 10 by fitting the convex portions of the spacers 14 into the concave portions of the connecting members 4 and 5, respectively. Next, they are clamped by a pair of end plates 11, and the connecting rods 12 are inserted into the connecting members 4, 5 and the through holes of the end plate 11, respectively. Next, both ends of the connecting rod 12 are tightened with nuts 13 to connect the unit cells 10. Thereby, the assembled battery 20 can be obtained.

  FIG. 3 is a diagram illustrating a modification of the assembled battery according to the first embodiment. FIG. 3A is a cross-sectional view of an example of the assembled battery, and FIG. 3B is a cross-sectional view of another example of the assembled battery. 3 (a) and 3 (b) are cross-sectional views as seen from the contact surface between predetermined connecting members in the same manner as FIG. 1 (b). The arrow indicates the direction pressed by the connecting rod.

  As shown in FIG. 3A, the assembled battery 60 includes a plurality of unit cells 61, an end plate 68, and a metal connecting rod 12. The unit cell 61 is provided with connecting members 62 and 63 made of resin or the like on each of a pair of short side surfaces. The connecting members 62 and 63 are provided with substantially elliptical through holes 64, 65, 66, and 67, respectively. The end plate 68 has a through hole through which the connecting rod 12 is inserted. Other configurations of the assembled battery 60 are the same as those of the assembled battery 20.

  The through holes 64, 65, 66, 67 are formed so that the direction of the substantially elliptical long axis is directed toward the center of the upper surface or the bottom surface of the unit cell 10 (battery case 1). Even in such a configuration, the pressing force from the four connecting rods 12 can be efficiently received by the flat and narrow portion of the through-hole, and the restraining force at a fixed position is improved, and each unit cell 61 is fixed. The vibration resistance can be improved by holding firmly. Moreover, as in the case of FIG. 2B, since the stress received from the connecting rod continues to act in the bonding direction of the connecting member, there is an advantage that the connecting member itself is difficult to peel off.

  A modification as shown in FIG. 3B is also conceivable. That is, as shown in FIG. 3B, the assembled battery 70 includes a plurality of unit cells 71, an end plate 78, and a metal connecting rod 12. The unit cell 71 is provided with connecting members 72 and 73 made of resin or the like on each of a pair of short side surfaces. The connecting members 72 and 73 are provided with substantially elliptical through holes 74, 75, 76, and 77. The end plate 78 has a through hole through which the connecting rod 12 is inserted. Other configurations of the assembled battery 70 are the same as those of the assembled battery 20.

  The through holes 74, 75, 76, 77 are formed toward the four corners so that the direction of the major axis of the substantially elliptical shape is away from the central portion of the unit cell 10 (battery case 1). Even in such a configuration, the pressing force from the four connecting rods 12 can be efficiently received by the flat and narrow portion of the through-hole, and the restraining force at a fixed position is improved, and each unit cell 61 is fixed. The vibration resistance can be improved by holding firmly. However, unlike FIG. 2 (b) and FIG. 3 (a) described above, in this case, it acts in the peeling direction of the connecting member, but even in that case, as a whole, each unit cell 71 is firmly held. Vibration resistance can be improved.

(Second Embodiment)
FIG. 4 is a front view showing a unit cell of the assembled battery according to the second embodiment. The unit cell 81 is provided with connecting members 82 and 83 made of resin or the like on each of a pair of short side surfaces. The connecting member 82 has substantially elliptical through holes 84 and 85, and the connecting member 83 has substantially elliptical through holes 86 and 87, respectively. The shape of the through holes 84, 85, 86, 87 is formed in a tapered shape toward the center of the unit cell 81 (battery case 1) in the direction of the major axis of the substantially elliptical shape. Other configurations of the unit cell 81 are the same as those of the unit cell 10.

  When the assembled battery is configured using the unit cell 81 similarly to the assembled battery of the first embodiment, even when the assembled battery is subjected to a vibration load for a long period of time, the pressure from the connecting rod is reduced to each through hole 84, The taper portions 85, 86, and 87 can be efficiently received, and the restraining force at a fixed position can be improved, and each cell 81 can be more firmly held and vibration resistance can be further improved.

(Third embodiment)
In the assembled battery exemplified in the first and second embodiments, the width of each connecting member may be equal to the width of the short side surface of the battery case, and a buffer member may be provided between adjacent connecting members. FIG. 5 is a diagram illustrating an example of the assembled battery according to the third embodiment. Fig.5 (a) is a figure explaining a mode that a buffer member is attached, FIG.5 (b) is a figure which shows the assembled battery after the attachment of a buffer member. In FIG. 5, other cells, end plates, connecting rods and the like are omitted. An arrow shows the direction in which the fitting convex part of a buffer member is inserted. As shown in FIGS. 5A and 5B, the buffer member 16 is made of an elastic member such as rubber and has a fitting convex portion 17. The buffer member 16 is disposed so as to be sandwiched between the upper and lower ends of the connecting members 4 and 5. At this time, the fitting convex portion 17 is fitted into the gap 7 formed by the short side surface of the battery case 1 and the connecting member 4 or the connecting member 5 to prevent the buffer member 16 itself from rotating.

  Since the buffer member 16 is formed of an elastic member, when the assembled battery receives a mechanical shock, the shock applied to each unit cell is reduced. In particular, compared to the case where the connecting members are in direct contact with each other, even when the assembled battery receives stress due to external impact, the stress is not directly transmitted through the connecting member, so that the damage and peeling of the connecting member can be suppressed. .

  In the assembled battery of the third embodiment, the buffer member 16 can buffer vibrations and shocks between the unit cells 10 to suppress loosening between the unit cells 10. Moreover, the distance between each single battery 10 can be adjusted by using the buffer member 16 as a spacer. Moreover, it is possible to reduce the standard score of the component parts (ASSY) of the battery case of each expensive unit cell, which is advantageous in terms of cost.

(Fourth embodiment)
FIG. 6 is a diagram illustrating another example of the assembled battery according to the fourth embodiment. Fig.6 (a) is a figure explaining a mode that a buffer member is attached, FIG.6 (b) is a figure which shows the assembled battery after the attachment of a buffer member. In FIG. 6, other cells, end plates, connecting rods and the like are omitted. An arrow shows the direction in which the fitting convex part of a buffer member is inserted. As shown in FIGS. 6A and 6B, the unit cell 91 is provided with connecting members 92 and 93 made of resin or the like on each of a pair of short side surfaces. The configuration of the unit cell 91 other than the connecting members 92 and 93 is basically the same as that of the unit cell 10 of the first embodiment. The connecting member 92 has a configuration similar to that of the connecting member 4, and further has grooves 94 at both upper and lower ends. The connecting member 93 has the same configuration as that of the connecting member 5 and is further provided with grooves 94 at both upper and lower ends. The buffer member 95 is made of an elastic member such as rubber and has a fitting convex portion 96. The buffer member 95 is disposed so as to be sandwiched between the upper and lower ends of the connecting members 92 and 93. At this time, the fitting convex portions 96 are respectively fitted in the grooves 94 of the connecting member 92 or the connecting member 93 to prevent the buffer member 95 itself from rotating. The buffer member 95 reduces the impact on each unit cell when the assembled battery receives a mechanical impact.

  In the assembled battery of the fourth embodiment, the buffer member 95 can buffer vibrations and shocks between the unit cells 91 to suppress loosening between the unit cells 91. Moreover, the distance between each cell 91 can be adjusted by using the buffer member 95 as a spacer. Moreover, it is possible to reduce the standard score of the component parts (ASSY) of the battery case of each expensive unit cell, which is advantageous in terms of cost.

DESCRIPTION OF SYMBOLS 1 Battery case 2, 3 Output terminal 4, 5 Connection member 6 Safety valve 7 Space | gap 10 Cell 11 End plate 12 Connection rod 13 Nut 14 Spacer 16 Buffer member 20 Battery assembly 41, 42, 51, 52 Through-hole 43, 53 Spacer Mounting recess 60, 70 Battery pack 61, 71, 81, 91 Cell 62, 63, 72, 73 Connecting member 64, 65, 66, 67 Through hole 74, 75, 76, 77 Through hole 81, 82 Connecting member 84 , 85, 86, 87 Through holes 92, 93 Connecting member 95 Buffer member

Claims (5)

A battery pack including a battery case, a power generation element housed in the battery case, and a plurality of battery cells arranged in parallel, each having an output terminal of the power generation element , and a connecting rod,
The output terminal is provided above the battery case,
The battery case has a rectangular parallelepiped shape having a bottom surface, a pair of narrow short side surfaces and a pair of wide long side surfaces, and includes a connecting member at each of the upper and lower ends of the pair of short side surfaces,
The connecting member includes a through-hole penetrating in the width direction of the short side surface,
The shape of the through hole is a substantially oval shape that is flatter than a perfect circle,
The through-hole is pressed in the direction of the long axis of the substantially elliptical shape of the through-hole by the connecting rod,
An assembled battery in which at least one of the directions in which the through-hole is pressed is different from any of the other pressed directions. The assembled battery according to claim 1, wherein the through hole is formed such that a direction of a major axis of the substantially elliptical shape of the through hole is inclined with respect to the bottom surface of the battery case.   The assembled battery according to claim 2, wherein a direction in which the through hole is pressed is a direction toward the battery case.   The assembled battery according to claim 2, wherein a direction in which the through hole is pressed is a direction away from the battery case. The assembled battery according to any one of claims 1 to 4, wherein the through hole is formed in a tapered shape toward a central portion of the battery case in a direction of a major axis of a substantially elliptical shape.

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