JP2010182441A - Structure for connecting voltage detection circuit with battery cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for connecting a voltage detection circuit with a battery cell capable of high-precision voltage detection. <P>SOLUTION: An electrode terminal 21 of each battery cell 20 has a connection hole 23 provided. Alternatively, a signal wire 34 of the voltage detection circuit has a press-fit terminal 30 connected. As an elastic swollen part 33 fitted at an electrode connection 32 of the press-fit terminal 30 ingresses into the connection hole 23 of the electrode terminal 21 while being elastically contracted by the same, and gets in elastic contact with an inner peripheral face of the connection hole 23 by being expanded with resilience, the electrode terminal 21 is electrically connected with the voltage detection circuit through the press-fit terminal 30 and the signal wire 34. In such a structure, variations of contact resistance can be alleviated as compared with a conventional structure, so that a more stable and higher-accuracy voltage detection can be achieved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a connection structure between a voltage detection circuit and a battery cell.

In a vehicle battery module, a high voltage is obtained by connecting a large number of battery cells in series in order to increase the output. When a plurality of battery cells are connected in series, if battery characteristics such as battery voltage are not uniform between the battery cells, there is a problem in that the battery is overdischarged or overcharged, leading to deterioration or breakage of the battery. Therefore, in a battery module for a vehicle, charging and discharging are stopped before the voltage of each battery cell is detected and the battery is overdischarged or overcharged.
As a structure for connecting a voltage detection terminal to a battery cell, for example, a structure in which a bus bar connecting an electrode portion of an adjacent battery cell and a voltage detection terminal are fastened together by a nut is known (patent) Reference 1).

JP 2000-333343 A

However, in the above structure, the bus bar is interposed between the battery cell and the voltage detection terminal. For this reason, the contact resistance on the contact surface between the terminal and the bus bar varies due to the difference in the surface state of the voltage detection terminal or the bus bar or the variation in the contact area between them due to manufacturing tolerances. For this reason, there exists a problem that a highly accurate voltage detection cannot be performed.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a connection structure between a voltage detection circuit and a battery cell capable of highly accurate voltage detection.

The connection structure between the voltage detection circuit and the battery cell according to the present invention is connected to a battery cell including an electrode part provided with a connection hole, and a voltage detection wiring, and is inserted into the connection hole and the electrode part. And a detection terminal provided with an electrode connection portion that is electrically connected.
The electrical connection may be performed using a press-fit terminal as the detection terminal, or may be performed by fixing the electrode connection portion of the detection terminal in the connection hole by brazing such as soldering.

  According to the present invention, variation in contact resistance can be reduced as compared with the conventional configuration, and more stable and highly accurate voltage detection is possible.

External perspective view of joint terminal in embodiment 1 The bottom view of the joint terminal in Embodiment 1 The top view of the joint terminal in Embodiment 1 Side view of joint terminal in embodiment 1 Exploded view of joint terminal in embodiment 1 External perspective view of a joint terminal to which a press-fit terminal and a signal wire are fixed in the first embodiment The top view of the joint terminal to which the press-fit terminal and the electric wire for signal in Embodiment 1 were fixed. Side view of the joint terminal to which the press-fit terminal and the signal wire in Embodiment 1 are fixed. The front view which shows the state before connection with the joint terminal in Embodiment 1, and a press fit terminal, and a battery cell. The front view which shows the state after the connection of the joint terminal in Embodiment 1, and a press fit terminal, and a battery cell. External perspective view of battery module in embodiment 2. Side sectional view which shows the state after the connection of the press-fit terminal and battery cell in Embodiment 2. The front view which shows the state after the connection of the press fit terminal and battery cell in other embodiment. The front view which shows the state after the connection of the detection terminal and battery cell in other embodiment Side sectional view which shows the state after the connection of the detection terminal and battery cell in other embodiment

<Embodiment 1>
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS.
In the present embodiment, the connection structure between the voltage detection circuit and the battery cell of the present invention is applied to a battery module 1 mounted on an electric vehicle, a hybrid vehicle, or the like. In the battery module 1, the positive and negative electrode terminals 21 of adjacent battery cells 20 are electrically connected by the joint terminal 10.

  The battery cell 20 includes a main body portion 22 formed in a columnar shape as a whole, and positive and negative electrode terminals 21 provided so as to protrude perpendicularly to one end surface and the other end surface in the axial direction of the main body portion 22. (See FIGS. 9 and 10). The plurality of battery cells 20 are arranged such that adjacent battery cells 20 are opposite in the axial direction (positive and negative electrode terminals 21 are arranged adjacent to each other), and are held together by a holding member (not shown). Has been.

  The electrode terminal 21 is made of metal (copper, copper alloy, aluminum, aluminum alloy, etc.), and is formed by a known method such as cutting, casting, or forging. The positive and negative electrode terminals 21 are formed in substantially the same shape and size, and the protruding ends of the electrode terminals 21 are each provided with a spherical head portion 21A.

  The joint terminal 10 is formed by, for example, pressing a metal plate material such as copper, copper alloy, stainless steel (SUS) into a predetermined shape. Hereinafter, in each component, the front side in the connection direction with respect to the electrode terminal 21 (the lower side in FIG. 1) is the lower side, the rear side in the connection direction (the upper side in the same direction) is the upper side, and the right side in FIG. Will be described.

  The joint terminal 10 has a pair of connection portions 11A and 11B that are respectively connected to the positive and negative electrode terminals 21 of the adjacent battery cells 20. 1 is referred to as a first connection portion 11A, and the left connection portion is referred to as a second connection portion 11B.

  As shown in FIG. 2, each of the first connecting portion 11A and the second connecting portion 11B has a substantially U shape, and has a pair of opposing walls 12 that can be elastically displaced in the approaching / separating direction (opposing direction). ing. Each facing wall 12 has a substantially rectangular plate shape that is long in the left-right direction (substantially orthogonal to the connection direction with respect to the electrode terminal 21). One end of the pair of opposing walls 12 in the left-right direction is connected to each other, and each opposing wall 12 extends in a cantilevered manner in the same direction from each other's connecting portion (hereinafter referred to as a bent portion 13). It has a form to do. The distance between the pair of opposing walls 12 in the natural state is set to be smaller than the maximum width dimension of the head 21 </ b> A of the electrode terminal 21. Note that the first connection portion 11A and the second connection portion 11B have substantially the same shape and size.

  The end of each connection portion 11A, 11B opposite to the bent portion 13 is a portion where the electrode terminal 21 comes into contact, and in this contact portion, a hole portion into which the head 21A of the electrode terminal 21 can be fitted. 14 is provided. The hole part 14 is provided in both of the pair of opposing walls 12 of each connection part 11A, 11B, and is formed by punching each opposing wall 12 in the wall thickness direction.

  The pair of hole portions 14 provided in each of the connection portions 11A and 11B are disposed at positions facing each other, and have substantially the same shape and size. The hole 14 provided in the first connection portion 11A has a substantially circular shape, and the hole 14 provided in the second connection portion 11B has an oval shape that is long in the left-right direction (see FIG. 5). In the hole edge of the hole portion 14 of the second connection portion 11B, the central portion in the left-right direction has a straight line shape extending in the left-right direction, and both end portions have a symmetrical arc shape. The hole 14 is provided at a substantially central position in the lateral direction (vertical direction) of each facing wall 12.

  Each opposing wall 12 is formed with a guide groove 15 for guiding the electrode terminal 21 from the lower edge (the edge on the front side in the connection direction with respect to the electrode terminal 21) to the hole 14. The guide grooves 15 are provided in all the opposing walls 12 having the hole portions 14 and are formed by punching the opposing walls 12 in the wall thickness direction. The guide grooves 15 provided in the joint terminal 10 are all substantially the same shape and size.

  As shown in FIG. 2, the first connection portion 11 </ b> A and the second connection portion 11 </ b> B are arranged in the opposite orientation in the left-right direction, in other words, the bent portion 13 of both the connection portions 11 </ b> A and 11 </ b> B The end portions on the side where the hole portions 14 are provided are connected to each other via the connecting portion 16 in a posture in which the end portions are arranged at the right end or the left end of the joint terminal 10.

  The connecting portion 16 has a substantially rectangular plate shape that is long in the left-right direction, and the longitudinal dimension thereof is substantially the same as the longitudinal dimension of the first connecting portion 11A and the second connecting portion 11B. The first connecting portion 11A is connected to the right end side of the connecting portion 16, the second connecting portion 11B is connected to the left end side, and the first connecting portion 11A and the second connecting portion 11B are the ends opposite to the bent portion 13. The parts protrude to the right and left of the connecting part 16, respectively. The guide groove 15 and the hole portion 14 are located on the right side and the left side of the connecting portion 16.

  One opposing wall 12 of the pair of opposing walls 12 of each connecting portion 11A, 11B is connected to the connecting portion 16. The opposing walls 12 of the connecting portions 11A and 11B are connected to approximately half of the length direction of both edges extending in the longitudinal direction of the connecting portion 16, respectively. In addition, the bending part 13 and the other opposing wall 12 of each connection part 11A, 11B are not connected with the connection part 16, but are in a free state.

  In the joint terminal 10 described above, a metal plate material is punched into a predetermined shape (see FIG. 5), and then the connection portions 11A and 11B are bent substantially perpendicularly to the connection portion 16 and the connection portions 11A and 11B. Are each bent into a U shape. In FIG. 5, the bending position is indicated by a one-dot chain line.

  A press-fit terminal 30 for connecting the signal wire 34 of the voltage detection circuit (not shown) and the electrode terminal 21 of the battery cell 20 is fixed to the joint terminal 10 and integrated (see FIG. 6 to 8).

  The press-fit terminal 30 has a shape in which an elongated square bar is bent into an L shape as a whole by pressing and bending a metal plate having excellent conductivity. One side of the L-shape in the press-fit terminal 30 is a wire connection portion 31 connected to the signal wire 34. On the other hand, the other side is an electrode connecting portion 32 connected to the electrode terminal 21 of the battery cell 20, and an elastic bulging portion 33 is formed at the tip thereof. The elastic bulging portion 33 is cut at the center in the width direction along the length direction at a position slightly on the center side of the tip of the electrode connection portion 32, and both side portions of the cut portion bulge outward in the width direction. It can be opened and closed elastically in the width direction.

  The press-fit terminal 30 is connected to one of the pair of electrode terminals 21 and 21 connected to the pair of connection portions 11A and 11B. In the present embodiment, an example in which the electrode terminal 21 is connected to the first connection portion 11A is shown. The electrode connecting portion 32 is suspended between the pair of opposing walls 12 in the first connecting portion 11 </ b> A, and the elastic bulging portion 33 is positioned between the pair of hole portions 14. In other words, the elastic bulging portion 33 is arranged at a position that aligns with the connection hole 23 (described later) of the electrode terminal 21 connected to the first connection portion 11A in a state where the press-fit terminal 30 is connected to the electrode terminal 21. Has been. On the other hand, the electric wire connection part 31 is distribute | arranged along the upper surface (back side surface of the fitting direction with respect to the electrode terminal 21) of the connection part 16 in the joint terminal 10, and is being fixed by welding, for example.

  The signal wire 34 connected to the press-fit terminal 30 has a configuration in which the outer periphery of a conductor 35 made of a stranded wire is covered with a resin coating 36. The resin coating 36 is peeled off at the terminal portion of the signal wire 34 to expose the conductor 35, and the exposed portion is connected to the wire connection portion 31 of the press-fit terminal 30 by, for example, crimping.

  On the other hand, in the electrode terminal 21 connected to the first connection portion 11A in the battery cell 20, the connection hole 23 into which the elastic bulging portion 33 of the press-fit terminal 30 can be inserted has a protruding end side (joint side) of the electrode terminal 21 (joint An opening is provided in front of the terminal 10 in the fitting direction. The inner diameter of the connection hole 23 is slightly smaller than the lateral width of the portion with the largest bulge in the width direction in the elastic bulge portion 33 of the press-fit terminal 30.

Next, an operation of connecting the joint terminal 10 and the press-fit terminal 30 fixed to the electrode terminal 21 will be described.
First, the plurality of battery cells 20 are arranged so that the positive and negative electrode terminals 21 are adjacent to each other.
Next, the joint terminal 10 is oriented so that the connecting portion 16 is on the upper side and the connecting portions 11A and 11B are on the lower side, and the connecting portions 11A and 11B are arranged above the electrode terminals 21. (See FIG. 9).

  In this state, the joint terminal 10 is moved downward (battery cell 20 side), and the heads 21 </ b> A of the electrode terminals 21 are inserted into the guide grooves 15. When the head 21A and the inner wall of the guide groove 15 in the joint terminal 10 come into contact with each other, the pair of opposing walls 12 are elastically displaced from each other in the separation direction. When the joint terminal 10 is further pushed in, the head portions 21A are fitted into the hole portions 14, respectively, and at the same time, the pair of opposing walls 12 are elastically restored in the approaching direction, and the hole edges of the hole portions 14 are the outer periphery of the head portion 21A. It is in a state of being pressed against the surface.

  At the same time, the elastic bulging portion 33 of the press-fit terminal 30 enters the connection hole 23 of the electrode terminal 21 while being elastically contracted. In the connection hole 23, the elastic bulging portion 33 expands with a restoring force and elastically contacts the inner peripheral surface of the connection hole 23. Thereby, the press-fit terminal 30 is electrically connected to the electrode terminal 21.

  Thus, the joint terminal 10 is connected to the positive and negative electrode terminals 21, and the battery cells 20 are connected in series. At the same time, the electrode terminal 21 is electrically connected to the voltage detection circuit via the press-fit terminal 30 and the signal wire 34.

  As described above, according to the present embodiment, the connection hole 23 is provided in the electrode terminal 21 of the battery cell 20. On the other hand, a press-fit terminal 30 is connected to the signal wire 34 of the voltage detection circuit. The press-fit terminal 30 is inserted into the connection hole 23 of the electrode terminal 21 while the elastic bulge portion 33 provided in the electrode connection portion 32 is elastically contracted, and the elastic bulge portion 33 is restored to the inside of the connection hole 23. The electrode terminal 21 is electrically connected to the electrode terminal 21 by expanding and elastically contacting the inner peripheral surface of the connection hole 23. As a result, the electrode terminal 21 is electrically connected to the voltage detection circuit via the press-fit terminal 30 and the signal wire 34. According to such a configuration, variation in contact resistance can be reduced as compared with the conventional configuration, and more stable and highly accurate voltage detection can be performed.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 11 shows the battery module 40 of the present embodiment. In the present embodiment, the positive and negative electrode portions 52 of adjacent battery cells 50 are electrically connected by the bus bar 60.

  The battery cell 50 includes a main body 51 formed in a cylindrical shape as a whole and a pair of positive and negative electrodes 52. The electrode portion 52 is provided on one end surface and the other end surface of the main body portion 51, and is formed in a disk shape having an outer diameter slightly smaller than the outer diameter of the main body portion 51, and the surface of the electrode terminal 53 And a bolt portion 54 that vertically protrudes along the axial direction of the battery cell 50.

  The plurality of battery cells 50 are arranged in two rows so that the battery cells 50 adjacent to each other are reversed. Both ends of these battery cells 50 are sandwiched and fixed by a pair of holding plates 41 and 41. Each holding plate 41 is provided with a holding hole 42 penetrating in the thickness direction and allowing the tip of the main body 51 of the battery cell 50 and the electrode terminal 53 to be inserted therethrough. Each battery cell 50 is inserted into the holding hole 42, and the surface of the electrode terminal 53 slightly protrudes from the outer surface of the holding plate 41 (the surface opposite to the surface facing the other holding plate 41). It is fixed with.

  A bus bar 60 that electrically connects the electrode portions 52 of the two adjacent battery cells 50 and 50 is disposed on the outer surface of the holding plate 41. The bus bar 60 is formed of a metal in a plate shape, and is provided with bolt insertion holes 61 that can penetrate the bolt portion 54 through the thickness direction. The bus bar 60 includes bolt insertion holes 61 and 61 that connect the bolt part 54 of the positive electrode part 52 in one battery cell 50 and the bolt part 54 of the negative electrode part 52 in another battery cell 50 adjacent thereto. And is fixed onto the electrode terminal 53 by screwing nuts 55, 55 from above. The positive electrode portion 52 of the other battery cell 50 is connected to the negative electrode portion 52 of the adjacent battery cell 50 in the same manner, though not shown in detail. By repeating this sequentially, the plurality of battery cells 50 are connected in series as a whole.

  The bolt part 54 of the battery cell 50 is provided with a connection hole 56 that opens to the protruding end side of the bolt part 54, and a press-fit terminal 70 is connected thereto. The press-fit terminal 70 is formed into an elongated rectangular bar shape as a whole by pressing a metal plate having excellent conductivity, and one end of the press-fit terminal 70 is a wire connecting portion 71 connected to the signal wire 74. ing. The signal wire 74 has a configuration in which the outer periphery of a conductor 75 made of a stranded wire is covered with a resin coating 76. At the terminal portion of the signal wire 74, the resin coating 76 is peeled off to expose the conductor 75, and this exposed portion is connected to the wire connecting portion 71 of the press-fit terminal 70 by, for example, crimping.

  On the other hand, the other end portion is an electrode connecting portion 72 connected to the electrode portion 52 of the battery cell 50, and an elastic bulging portion 73 is formed at the tip thereof. The elastic bulging portion 73 is cut in the widthwise central portion along the length direction at a position slightly on the center side of the tip of the electrode connecting portion 72, and both side portions of the cut portion bulge outward in the width direction. It can be opened and closed elastically in the width direction. Note that the inner diameter of the connection hole 56 described above is slightly smaller than the lateral width of the portion of the elastic bulging portion 73 of the press-fit terminal 70 that has the largest bulge in the width direction.

  When connecting the press-fit terminal 70 to the electrode portion 52, the elastic bulging portion 73 of the press-fit terminal 70 is caused to enter the connection hole 56 provided in the bolt portion 54 of the electrode portion 52 while being elastically contracted. Then, the elastic bulging portion 73 expands by a restoring force inside the connection hole 56 and elastically contacts the inner peripheral surface of the connection hole 56, whereby the press-fit terminal 70 is electrically connected to the electrode portion 52. The Thereby, the electrode part 52 is electrically connected to the voltage detection circuit via the press-fit terminal 70 and the signal wire 74.

  As described above, according to the present embodiment, in the battery cell 50, the connection hole 56 is provided in the bolt portion 54 of the electrode portion 52. On the other hand, a press-fit terminal 70 is connected to the signal wire 74 of the voltage detection circuit. The press-fit terminal 70 is inserted into the connection hole 56 of the electrode part 52 while the elastic bulge part 73 provided in the electrode connection part 72 is elastically contracted, and the elastic bulge part 73 is restored to the inside of the connection hole 56. And is electrically connected to the electrode portion 52 by elastically contacting the inner peripheral surface of the connection hole 56. Thereby, the electrode part 52 is electrically connected to the voltage detection circuit via the press-fit terminal 70 and the signal wire 74. According to such a configuration, variation in contact resistance can be reduced as compared with the conventional configuration, and more stable and highly accurate voltage detection can be performed.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the first embodiment, the wire connecting portion 31 is fixed to the connecting portion 16 of the joint terminal 10 by welding. However, the fixing method is not limited to the above embodiment, and for example, brazing such as soldering. It does not matter.

(2) In the first embodiment, the press-fit terminal 30 is fixed to the joint terminal 10, but the press-fit terminal 30 is not fixed to the joint terminal 10 as shown in FIG. It doesn't matter.

(3) In the first embodiment, the terminal connected to the signal wire 34 of the voltage detection circuit is not necessarily a press-fit terminal. For example, as shown in FIG. 14, the electrode connection portion 81 may be a detection terminal 80 formed in a rod shape. In such a case, for example, after the electrode connection portion 81 is inserted into the connection hole 23 of the electrode terminal 21, molten solder or the like is poured into the gap between the inner wall of the connection hole 23 and the electrode connection portion 81, and is cooled and solidified. The detection terminal 80 can be fixed and connected to the electrode terminal 21.

(4) Similarly, in the second embodiment, the terminal connected to the signal wire 74 of the voltage detection circuit is not necessarily a press-fit terminal. For example, as shown in FIG. It may be a detection terminal 80 formed in a rod shape. In such a case, similarly to the above (3), the detection terminal 80 can be fixed and connected to the electrode portion 52 by soldering or the like.

20, 50 ... Battery cell 21 ... Electrode terminal (electrode part)
23, 56 ... connection holes 30, 70 ... press-fit terminals (detection terminals)
32, 72, 81 ... Electrode connecting portions 34, 74 ... Signal wires (voltage detection wires)
52 ... Electrode unit 80 ... Detection terminal

Claims (3)

A battery cell comprising an electrode part provided with a connection hole;
A detection terminal provided with an electrode connection portion connected to the voltage detection wiring and inserted into the connection hole and electrically connected to the electrode portion;
A connection structure between a voltage detection circuit and a battery cell. The connection structure between the voltage detection circuit and the battery cell according to claim 1, wherein the detection terminal is a press-fit terminal. The connection structure between the voltage detection circuit and the battery cell according to claim 1, wherein the electrode connection portion is fixed by brazing in the connection hole.

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