JP2014103031A - Bus bar substrate and battery module using bus bar substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bus bar substrate capable of suppressing power consumption as much as possible by reducing contact resistance between the bus bar substrate and an electrode terminal of a battery cell, and also to provide a battery module using this bus bar substrate.SOLUTION: In a bus bar substrate 10, a plurality of protrusions 30 are provided in a shaft member and a bus bar part is provided in the protrusion 30. Such a configuration enables an electrode terminal of a battery cell and the bus bar part to be brought into contact with each other without gaps by obtaining mechanical flexibility between them. As a result, contact resistance between the electrode terminal and the bus bar part is reduced, and when utilized in a battery module, power consumption of the battery module can be suppressed.

Description

  The present invention relates to a bus bar substrate and a battery module using the bus bar substrate.

  As an electric vehicle, a hybrid vehicle, and a stationary battery module, a plurality of battery cells such as lithium ion batteries, nickel metal hydride batteries, and other secondary batteries are connected by bus bars and wires, respectively, and the positive and negative electrodes of these battery cells There is known a structure in which a battery module is formed together with a control circuit for managing a voltage between terminals.

  Since such a connection structure has a large number of parts and is a connection work for the live parts, there is a possibility of causing a short circuit and an erroneous connection of the bus bar during the work.

  As a solution, for example, in Patent Document 1, a plurality of bus bars and a conductive member connected to a control circuit are integrally molded, thereby reducing the number of parts and eliminating short circuits and erroneous connection work. And improve safety.

JP 2002-170535 A

  By the way, the battery cell which comprises a battery module is diversified in various uses, and a magnitude | size and a dimension tolerance differ. In the structure in which the bus bar is embedded in the molded part as in the above-mentioned document 1, the mechanical freedom is limited, and when the battery module is assembled by arranging the individual battery cells, the bus bar is An inclination or a gap in the contact surface between the substrate and the battery cell terminal is generated. For this reason, the contact between the bus bar substrate and the terminal electrode becomes insufficient, and the contact resistance value increases, so that there is a problem that a long time is likely to occur due to the management and adjustment work of the resistance value.

  The present invention has been made in view of the above circumstances, and a bus bar substrate capable of reducing the contact resistance value between the bus bar substrate and the electrode terminal of the battery cell, and shortening the working time, and this An object of the present invention is to provide a battery module using a bus bar substrate.

  In order to achieve the above object, the bus bar substrate of the present invention has a first feature in that a plurality of protrusions are formed on a shaft member, and the protrusions support the bus bar at a substantially central portion of the bus bar. To do.

  According to the present invention having the above characteristics, since the protruding portion is formed on the shaft member and the bus bar is supported at the substantially central portion, the flexibility is maintained with respect to the movement in the three-axis direction, and between the individual battery cells. Even if there is a dimensional difference, the mechanical freedom between the electrode terminal of the battery cell and the bus bar portion can be maintained, so that contact can be made without any gaps. As a result, there is no gap between the electrode terminal and the bus bar portion. The contact resistance can be reduced.

  Furthermore, the bus bar substrate according to the present invention is characterized in that a plurality of protrusions are formed in a comb shape on one side of the shaft member, and adjacent lengths of the protrusions are alternately different. .

  According to the present invention having the above characteristics, the bus bar substrate composed of the shaft member and the comb-shaped protrusion is disposed along one side surface of the battery module because of the shape characteristics. That is, the shaft portion of the shaft member is disposed outside the battery electrode. Accordingly, since the shape of the battery is not limited, the shape and dimensions of the shaft member and the protruding portion have a degree of freedom that can be set according to design and use needs. Furthermore, since a wide space can be secured between the upper surface electrodes of the battery cell, resistance to convection of the air in the battery module by the shaft member and the protruding portion is reduced. That is, it has a shape advantageous for heat dissipation of the battery cell.

  Furthermore, the bus bar substrate according to the present invention has a third feature in that a plurality of projecting portions are formed in a branch shape on both sides of the shaft member, and the projecting portions on both sides are alternately shifted. To do.

  According to the present invention having the above characteristics, since the projecting portions are provided on both sides of the shaft member, the shaft member is located at the center of the battery cell, so that the right and left arrangement balance is improved and the relative rigidity is achieved by downsizing. The mechanical freedom between the battery cell electrode terminal and the bus bar portion can be maintained while increasing the contact resistance, so that the contact can be made without any gaps. As a result, the contact resistance between the electrode terminal and the bus bar portion is reduced. can do.

  Furthermore, the battery module according to the present invention includes any one of the bus bar substrates described above and a plurality of battery cells, and is connected to the electrode terminals of the plurality of battery cells by the bus bar portions of the bus bar substrate. It is characterized by.

  According to the present invention of the above feature, the bus bar substrate according to any one of the above and a plurality of battery cells, wherein the plurality of battery cells are connected by the electrode terminals of the plurality of battery cells and the bus bars of the bus bar substrate. Even when height and size variations due to dimensional tolerances and types occur between battery cells or when vibration is applied to the battery module, the battery cell electrode terminals and busbars maintain mechanical flexibility. Therefore, the contact resistance between the electrode terminal and the bus bar portion is reduced, and as a result, a battery module with reduced power consumption can be provided.

  According to the bus bar substrate of the present invention, a bus bar substrate capable of reducing the contact resistance between the bus bar and the electrode terminal of the battery cell and reducing the working time, and a battery module using the bus bar substrate are provided. can do.

It is a figure which shows the bus bar board | substrate of Embodiment 1. FIG. It is a figure which shows the bus bar board | substrate of Embodiment 2. FIG. FIG. 6 is an enlarged view of a connection part according to the second embodiment. It is a figure which shows the bus bar board | substrate of Embodiment 3. FIG. It is a figure which shows the bus bar board | substrate of the modification 1 which concerns on Embodiment 2. FIG. It is a figure which shows the bus bar board | substrate of the modification 2 which concerns on Embodiment 3. FIG. It is a figure of Example 1 which shows the battery module using the bus bar board | substrate of Embodiment 2. FIG. It is a figure which shows the screw which connects a bus bar and an electrode terminal. It is a figure which shows the shape and structure of a battery cell. It is a figure of Example 2 which shows the battery module using the bus bar board | substrate of Embodiment 3. FIG. It is a figure of Example 3 which shows the battery module using the bus bar board | substrate of the modification 1 which concerns on Embodiment 2. FIG. It is a figure of Example 4 which shows the battery module using the bus bar board | substrate of the modification 2 which concerns on Embodiment 3. FIG. 10 is a diagram illustrating an application example 1 according to Embodiment 3. FIG. 10 is a diagram illustrating an application example 2 according to Embodiment 3. FIG. It is a figure which shows the conventional bus bar board | substrate as a comparative example. It is a figure which shows the battery module using the bus bar board | substrate of a comparative example.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. In the case where only a part of the configuration is described in each embodiment, the other embodiments described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly show that each embodiment can be combined specifically, but also a combination of the embodiments even if not clearly indicated, unless there is a problem with the combination. Is possible.

(First embodiment)
FIG. 1 is a diagram illustrating a shape serving as a basic unit of the configuration of the bus bar substrate 10 according to the first embodiment. As shown in the figure, a protrusion 30 is provided on the shaft member 20 of the bus bar substrate 10, and a bus bar 40 is provided at the tip of the protrusion 30. The protrusion 30 is integrally formed so as to extend from the shaft member 20, and supports the center of the bus bar 40. The material of the shaft member and the protruding portion is preferably a flame-retardant resin that can be molded such as ABS (acrylonitrile butadiene styrene) or PBT (poly butylene terephthalate).

  As shown in FIG. 1, the protrusion 30 integrally formed so as to extend from the shaft member 20 has flexibility, and the bus bar 40 provided at the tip of the protrusion 30 is connected to the terminal connection portion 31 later. When it is connected and fixed to the electrode terminal 101 described (see FIG. 7C for a specific structure), it is easily deformed and bent to easily follow the fixed state of the bus bar 40 and the electrode terminal 101. That is, with this configuration, when the bus bar substrate 10 is manufactured by integral molding, the electrode terminals 101 of a plurality of adjacent rectangular battery cells 100 (see FIG. 7A for a specific structure) described later are provided. The contact resistance of the bus bar 40 to be connected can be reduced, and the performance can be improved.

(Second Embodiment)
FIG. 2 is a diagram illustrating a configuration of the bus bar substrate 11 according to the second embodiment. As shown in the figure, the shaft member 20 of the bus bar substrate 11 is provided with a comb-like protrusion 32, and the adjacent lengths of the protrusions 30 are different from each other. A bus bar 41 is provided at the tip of the comb-shaped protrusion 32. The comb-shaped protrusion 32 is integrally formed so as to extend from the shaft member 20 and supports the center of the bus bar 41. A difference from the bus bar substrate 10 according to the first embodiment shown in FIG. 1 is that a plurality of protrusions 30 constituting the basic unit shape are provided on one side of the shaft member 20 and arranged in the shape of a comb-like protrusion 32. . The shape of the bus bar 40 is also different, but there is no particular functional difference. Here, the comb shape means that a plurality of comb teeth (protrusion portions 30) protrude from a single band-shaped base portion (shaft member 20) serving as a base.

  Further, by producing the bus bar substrate 11 having the comb-like protrusions 32 as shown in FIG. 2, it corresponds to the battery module 110 composed of a plurality of rectangular battery cells 100 (see FIG. 7A for a specific structure) described later. Thus, the integrated bus bar substrate 11 can be realized. The bus bar substrate 11 of FIG. 2 has different lengths adjacent to each other, and the shaft member 20 can be disposed outside the electrode terminals 101 arranged in the battery module 110. In order not to be restricted by the shape of the battery cell 100, the shape and size of the shaft member 20 and the protruding portion 30 have a degree of freedom that can be set according to design and usage requirements. Therefore, by manufacturing the bus bar substrate 11 in such a shape, the bus bar substrate 11 having a small contact resistance between the terminal connection portion 31 and the electrode terminal 101 and a practical shape can be realized.

  FIG. 3 is an enlarged view of the connecting portion 50 between the shaft member 20 and the comb-like protruding portion 32. As shown in FIG. 3, only the connection part 50 of the short protrusion part is provided with a counterbore part 60, and by reducing the width of the protrusion part 30, the three-axis displacement directions 62, 63, 64 are made flexible, and the long protrusion By providing a movable range equivalent to the portion, the electrode terminal 101 and the bus bar 41 can maintain a mechanical degree of freedom between them, and can be brought into contact with no gap. Thereby, the contact resistance between the terminal connection part 31 and the electrode terminal 101 can be made small.

(Third embodiment)
FIG. 4 is a diagram illustrating a configuration of the bus bar substrate 12 according to the third embodiment. This is a bus bar substrate 12 in which protrusions 30 are arranged on both sides of the shaft member 20. 4 differs from the bus bar substrate 12 according to the third embodiment shown in FIG. 4 and the bus bar substrate 11 according to the second embodiment shown in FIG. 2 in that a plurality of protrusions 30 are provided on both sides of the shaft member 20, That is, it is arranged in the shape of the protruding portion 33. Here, the term “branch shape” means that a plurality of comb teeth (protrusions 30) protrude from both ends of one band-shaped base (shaft member 20) serving as a base.

  In this case, since the shaft member 20 is positioned at the center in the short direction of a plurality of adjacent rectangular battery cells 100 (see FIG. 8 for a specific structure) which will be described later, the protrusions arranged on both sides of the shaft member 20 The portions 30 are almost equal in length and shorter. Therefore, the movement of each bus bar 40 becomes equal, the rigidity of the entire bus bar substrate 12 increases, and the contact resistance between the terminal connection portion 31 and the electrode terminal 101 can be stably reduced.

  Furthermore, in the third embodiment, it is desirable that the branch-like protrusions 33 are arranged alternately from the shaft member 20. With such a configuration, the branch-like protrusions 33 are asymmetrical with respect to the shaft member 20, so that the load applied to the connection part 50 is distributed in a well-balanced manner, and deterioration of the strength of the bus bar substrate 12 can be suppressed.

  Next, other fourth and fifth embodiments according to the second and third embodiments of the present invention will be described with reference to FIGS. In these embodiments, measures are taken to further increase the rigidity of the bus bar substrate 11 and the bus bar substrate 12.

  Further, the assembly can be performed using the same process as that of the conventional integrally formed busbar substrate 17, and the working time can be shortened without providing a new process. The first to third embodiments. The same effect can be obtained.

(Fourth embodiment)
FIG. 5 is a diagram showing a fourth embodiment obtained by modifying the second embodiment. In this configuration, the bus bar substrate 13 is formed in such a manner that the shaft member 20 extends in an annular shape so as to surround the comb-shaped protruding portion 32 and the tip portion of the comb-shaped protruding portion 32 and the annular portion 21 are connected.

  With such a configuration, compared to the cantilever-like embodiment 2, the ring-shaped extension and the tip portion of the comb-shaped protrusion 32 and the annular portion 21 are connected, so that the rigidity of the bus bar substrate 11 is further increased and the handling becomes easier. The contact resistance between the terminal connecting portion 31 and the electrode terminal 101 can be reduced by the flexible shape effect of the protruding portion 30 as compared with the conventional integral molding type.

(Fifth embodiment)
FIG. 6 is a diagram showing a fifth embodiment obtained by modifying the third embodiment. In this configuration, the shaft member 20 is a bus bar substrate 14 that extends annularly on both sides so as to surround the branch-shaped protrusion 33 and connects the tip of the branch-shaped protrusion 33 and the annular portion 21.

  With such a configuration, the busbar substrate 10 is more rigid than the cantilevered embodiment 3 and can be easily handled, and the terminal connection portion 31 and the electrode terminal are formed by the flexible shape effect of the branch-like protruding portion 33. The contact resistance with 101 can be reduced as compared with the conventional integral molding type.

  Below, the application example of the battery module which concerns on the 5th Embodiment of this invention is demonstrated. The following application is merely an example.

(Application 1)
<Battery module>
FIG. 11 is a diagram illustrating an application example 1 of the fifth embodiment of the present invention. In this configuration, the bus bar substrate 14 is formed of a printed circuit board, the bus bar 40 is formed of a thick copper of 0.5 mm or more, and a multilayer substrate in which the circuit portion is formed with a normal pattern thickness of 12 to 35 microns is adopted. As a result, a large-current power supply circuit component (fuse 200, output control circuit 210) can be simultaneously mounted on the bus bar substrate 15 other than the region of the projecting portion 30 supporting the bus bar 40 to form a module.

  As a result, when the fuse 200, the output control circuit 210, the circuit connector 220, and the like are provided on the bus bar substrate 15, even if a failure occurs in the battery module 110, a battery system that stops the function as a battery is This can be realized on the substrate 15.

(Application example 2)
FIG. 12 is a diagram illustrating an application example 2 of the fifth embodiment. Similar to Application Example 1, the printed circuit board is used, and the temperature detection element 230 and the voltage monitoring unit 240 are provided on the bus bar substrate 16 to form a temperature and cell voltage monitoring circuit.

  As a result, the battery system can be configured to monitor the temperature of the battery cell and control the voltage.

  The effects of the present invention will be described more specifically with reference to the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

Example 1
FIG. 7A is a diagram of Example 1 in which twelve battery cells 100 are connected in series using the bus bar substrate 11 of the second embodiment to form a battery module 110. The battery module 110 is configured by connecting the electrode terminal 101 of the battery cell 100 shown in FIG. 7C and the terminal connection portion 31 provided on the bus bar 41 by screwing or the like. Taking FIG. 7A as an example, the battery module 110 having a series structure can be obtained by connecting the electrode terminals 101 of 12 battery cells 100 to the bus bar 40 with screws 102 shown in FIG. 7B. In the case of the series structure, if the length of the bus bar substrate 11 is appropriately changed, the number of battery cells 100 to be connected can be increased or decreased, and the battery module 110 having a desired voltage can be obtained.

  In the battery module 110 of FIG. 7A, since the comb-shaped protrusion 32 of the bus bar substrate 11 is supported in a cantilever manner on the shaft member 20, the height and size of the individual battery cells 100 vary depending on dimensional tolerances and usage. Even when this occurs or when vibration is applied to the battery module, the comb-shaped protrusion 32 flexes flexibly. Therefore, the terminal connection part 31 and the electrode terminal 101 can be contacted without a gap, and the contact resistance between the terminal connection part 31 and the electrode terminal 101 can be reduced. Therefore, the battery module 110 with low contact resistance can be configured. In addition, although the case 120 which accommodates the some battery cell 100 connected in series is used, even if it does not use, the effect similar to the above is acquired by using the bus bar board | substrate of this embodiment.

(Example 2)
FIG. 8 shows a battery module 110 manufactured in the same manner as in Example 1 except that a plurality of adjacent rectangular battery cells 100 are connected and replaced with modules by using the bus bar substrate 12 of the third embodiment. did.

(Example 3)
FIG. 9 shows a battery module 110 manufactured in the same manner as in Example 1 except that a plurality of adjacent rectangular battery cells 100 are connected and replaced with modules by using the bus bar substrate 13 of the fourth embodiment. did. In addition, by making the shaft member 20 annular, not only the rigidity of the bus bar substrate 11 is increased, but also the strength of the entire battery module can be improved. In particular, the bus bar substrate 13 having a shape in which the shaft member is extended annularly as in the present embodiment is a battery module mounted on a moving body such as a car or a battery module having a large number of battery cells. Thus, it is suitable for a battery module that requires strength.

Example 4
FIG. 10 shows a battery module 110 manufactured in the same manner as in Example 1 except that a plurality of adjacent rectangular battery cells 100 are connected and replaced with modules using the bus bar substrate 14 of the fifth embodiment. did. Similar to Example 3, it is suitable for a battery module that requires strength.

(Comparative example)
As a comparative example, FIG. 13 shows a bus bar substrate 17 which is a connection by a conventional molded bus bar.

Twelve batteries were connected in series to each of the above examples and comparative examples, and the average value and variation Σ of the interelectrode resistance before and after the bus bar substrate connection in each battery module and the working time thereof were measured. The measurement results are shown in Table 1 below.

  From the results shown in Table 1, the average contact resistance value of 12 batteries was reduced in any of the examples as compared with the conventional example. In particular, in Example 2, it was possible to suppress the comparative example to about a quarter at 0.050 / 0.126 mΩ and the variation Σ to about a fifth at 0.0137 / 0.0722 mΩ.

  Further, the work time was shortened from about 35 minutes to 18 to 20 minutes, including the measurement work, because no screw re-tightening work for improving the contact resistance value occurred.

  Further, regarding the difference in effect due to the shape of each bus bar substrate, the contact resistance is Example 2 → 1 → 4 → 3, the variation is Example 2 → 4 → 1 → 3, and the working time is Example 3 → 4 → 2 → A ranking of effect data of 1 was obtained.

  As a result, it was confirmed that the reliability (contact resistance value and resistance value variation) in connection quality was greatly improved and the effect of shortening the working time was great.

  As described above, the bus bar substrate according to the present invention is suitable when mounted on a battery module in which a plurality of batteries are connected in series or in parallel.

10, 11, 12, 13, 14, 15, 16, 17 ... busbar substrate 20 ... shaft member 21 ... annular part 30 ... projection part 31 ... terminal connection part 32 ... comb -Like protruding part 33 ... branch-like protruding part 40, 41, 42 ... busbar 50 ... connection part 60 ... counterbore part 70 ... branch-like protruding part 100 ... battery cell 101 ... Electrode terminal 110 ... Battery module 120 ... Battery case 200 ... Fuse 210 ... Output control circuit 230 ... Temperature detection element 240 ... Voltage monitor unit 250 ... Temperature detection circuit 260 ...・ Terminal voltage monitor circuit

Claims (4)

  A bus bar substrate for connecting between electrode terminals of battery cells, wherein a plurality of projecting portions are formed on a shaft member, and the projecting portions support the bus bar at a substantially central portion of the bus bar. .   The bus bar substrate according to claim 1, wherein a plurality of protrusions are formed in a comb shape on one side of the shaft member of the substrate, and adjacent lengths of the protrusions are different from each other.   The bus bar substrate according to claim 1, wherein a plurality of projecting portions are formed in a branch shape on both sides of the shaft member of the substrate, and the projecting portions are alternately shifted.   A bus bar substrate according to any one of claims 1 to 3 and a plurality of battery cells, wherein electrode terminals of the plurality of battery cells are connected by the bus bar substrate. Battery module.

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