JP2007280898A - Terminal connection structure, power storage mechanism, and electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terminal connection structure capable of cutting off the current certainly when an excessive current flows, while securing a constant strength and current flow at a normal time, and a power storage mechanism including this structure, and an electric vehicle. <P>SOLUTION: The terminal connection structure protects a battery when an excessive current flow by disconnecting connection and is provided with a first conductive member 421, a second conductive member 422 connected electrically to the first conductive member 421, and a blow-out part 423 between the first and the second conductive members 421, 422. In this case, the blow-out part 423 comprises a first and a second blow-out parts 423A, 423B formed so as to be arranged in a row along the joining face of the first and the second conductive members 421, 422. Then, the first blow-out part 423A has a relatively higher bonding strength than the second blow-out part 423B, and the second blow-out part 423B has a relatively lower melting point than the first blow-out part 423A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a terminal connection structure, a power storage mechanism, and an electric vehicle, and more particularly, to a terminal connection structure that protects an electrical device by releasing connection when an excessive current flows, and a power storage mechanism and an electric vehicle including the structure.

Conventionally, an assembled battery formed by combining a plurality of battery cells is known.
For example, Japanese Patent Laying-Open No. 2005-183070 (Patent Document 1) discloses an assembled battery having a terminal connection structure in which a copper terminal and an aluminum terminal are partially overlapped and connected to each other. Here, the central part of the overlapping part of the copper terminal and the aluminum terminal is joined by ultrasonic welding.

  Japanese Patent Laid-Open No. 10-188946 (Patent Document 2) discloses a battery having a fusible piece that melts when an excessive current flows.

  In JP 2001-338635 A (patent document 3), an electrode fixing part and an electric wire fixing part are fixed with a locking pin, and when an excessive current flows, the locking pin is blown out. The structure of is disclosed.

Japanese Patent Laying-Open No. 2002-260630 (Patent Document 4) discloses that a heating pressure welding method is used for joining an aluminum electrode and a copper lead wire.
JP 2005-183070 A Japanese Patent Laid-Open No. 10-188946 JP 2001-338635 A JP 2002-260630 A

  In a battery pack as described in Patent Document 1, when a large current flows between the terminals due to a short circuit or the like, a large current flows through the battery, and the battery function may be impaired. Therefore, it is desirable to provide a terminal connection structure capable of interrupting an excessive current when it flows. On the other hand, from the viewpoint of ensuring stable operation of electrical equipment, a terminal connection structure that ensures a certain level of strength and conductivity is normally desired. Even with the connection structures described in Patent Documents 2 to 4, the above two requirements cannot be sufficiently satisfied.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to ensure that when an excessive current flows while ensuring a certain level of strength and electrical conductivity during normal operation, the current is reliably supplied. It is an object to provide a terminal connection structure that can be cut off, a power storage mechanism including the structure, and an electric vehicle.

  The terminal connection structure according to the present invention is a terminal connection structure that protects an electrical device by releasing the connection when an excessive current flows, and is electrically connected to the first conductive member and the first conductive member. A second conductive member, and a fusing part formed between the first and second conductive members. Here, the fusing part includes a first fusing part and a second fusing part formed so as to be aligned along the joint surface of the first and second conductive members. The first fusing part has a relatively high bonding strength with respect to the second fusing part, and the second fusing part has a relatively low melting point with respect to the first fusing part.

  According to the above configuration, by providing the first fusing part with high bonding strength, the bonding strength between the first and second conductive members can be ensured at a certain level or more. On the other hand, when an excessive current flows, the second fusing part having a low melting point is first melted, and the current is concentrated on the first fusing part. And heat_generation | fever in a 1st fusing part becomes large, and a 1st fusing part also melt | dissolves. As a result, the current flowing between the first and second conductive members is interrupted. As described above, it is possible to provide a terminal connection structure that can reliably cut off an electric current when an excessive current flows while ensuring a certain strength and energization in a normal state.

  In the terminal connection structure, preferably, the area of the second fusing part on the joint surface between the first and second conductive members is larger than the area of the first fusing part.

  Thereby, after a 2nd fusing part melt | dissolves, an electric current can be concentrated on a 1st fusing part more effectively. As a result, the heat generation in the first melted part after the second melted part is melted is increased, and the first melted part can be more reliably dissolved.

  In the terminal connection structure, as one example, the second fusing part includes a conductive bonding material having a melting point lower than that of the first fusing part. As one example, the first fusing part includes a part formed by bringing the base materials of the first and second conductive members into contact with each other.

  The power storage mechanism according to the present invention is a power storage mechanism formed by paralleling a plurality of power storage cells having connection terminals, and includes a bus bar that electrically connects the connection terminals of the plurality of power storage cells. The bus bar includes the terminal connection structure described above. The electric vehicle according to the present invention includes the above-described power storage mechanism.

  Thereby, a constant strength and energization are ensured in normal times, and an electric storage mechanism having a bus bar that reliably cuts off current when an excessive current flows and an electric vehicle equipped with the electric storage mechanism are obtained.

  According to the present invention, it is possible to obtain a terminal connection structure that reliably cuts off a current when an excessive current flows while ensuring a certain strength and energization in a normal state.

  Embodiments of the present invention will be described below. Note that the same or corresponding parts are denoted by the same reference numerals, and the description thereof may not be repeated.

  Note that in the embodiments described below, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified. In the following embodiments, each component is not necessarily essential for the present invention unless otherwise specified. In addition, when there are a plurality of embodiments below, it is planned from the beginning to appropriately combine the features of each embodiment unless otherwise specified.

  FIG. 1 is a diagram showing a hybrid vehicle (HV) including a power storage mechanism to which a terminal connection structure according to one embodiment of the present invention is applied. In the present specification, the “electric vehicle” is not limited to the hybrid vehicle, and for example, a fuel cell vehicle and an electric vehicle are also included in the “electric vehicle”. An engine as an “internal combustion engine” to be described later may be a gasoline engine or a diesel engine. A capacitor may be used instead of a secondary battery as a “storage mechanism” described later.

  Referring to FIG. 1, hybrid vehicle 1 includes an engine 100, a motor generator 200, a PCU (Power Control Unit) 300, a battery 400 that is a chargeable / dischargeable secondary battery, a power split mechanism 500, a differential, and the like. It includes a mechanism 600, a drive shaft 700, and drive wheels 800L and 800R that are front wheels.

  As shown in FIG. 1, engine 100, motor generator 200, PCU 300, and power split mechanism 500 are arranged in the engine room. Motor generator 200 and PCU 300 are connected by a cable 300A. PCU 300 and battery 400 are connected by a cable 400A. A power output device including engine 100 and motor generator 200 is connected to differential mechanism 600 through power split mechanism 500. Differential mechanism 600 is coupled to drive wheels 800L and 800R via drive shaft 700.

  Next, the configuration of the motor generator 200 and its periphery will be described in more detail with reference to FIG.

  Referring to FIG. 2, motor generator 200 includes motor generators 210 and 220. Motor generators 210 and 220 are rotating electrical machines having at least one function of an electric motor and a generator. A speed reduction mechanism 550 is provided between the power split mechanism 500 and the differential mechanism 600. Differential mechanism 600 is connected to drive shaft 700 via drive shaft receiving portion 650. Motor generators 210 and 220, power split mechanism 500, reduction mechanism 550 and differential mechanism 600 are provided in casing 900.

  Motor generators 210 and 220 are electrically connected to cables 300A1 and 300A2 via terminal blocks 910 and 920 provided in housing 900, respectively. The other ends of the cables 300A1 and 300A2 are connected to the PCU 300. PCU 300 is electrically connected to battery 400 via cable 400A. Thereby, battery 400 and motor generators 210 and 220 are electrically connected.

  Power split device 500 is constituted by a plurality of planetary gears, for example, and has a power split function and a speed reduction function. Here, the ring gear in the plurality of planetary gears may be constituted by one cylindrical member.

  When the hybrid vehicle travels, the power output from the engine 100 is transmitted to the shaft 150 and divided into two paths by the power split mechanism 500.

  One of the two paths is a path that is transmitted from the speed reduction mechanism 550 to the drive shaft receiving portion 650 via the differential mechanism 600. The driving force transmitted to the drive shaft receiving portion 650 is transmitted as a rotational force to the drive wheels 800L and 800R via the drive shaft 700, thereby causing the vehicle to travel.

  The other is a path for driving the motor generator 210 to generate power. Motor generator 210 generates power using the engine power distributed by power split device 500. The electric power generated by the motor generator 210 is properly used according to the running state of the vehicle and the state of the battery 400. For example, during normal traveling and sudden acceleration of the vehicle, the electric power generated by motor generator 210 is directly used as electric power for driving motor generator 220. On the other hand, under the conditions determined in battery 400, the electric power generated by motor generator 210 is stored in battery 400 via an inverter and a converter (not shown) provided in PCU 300.

  Motor generator 220 is driven by at least one of the electric power stored in battery 400 and the electric power generated by motor generator 210. The driving force of motor generator 220 is transmitted from reduction mechanism 550 to drive shaft receiving portion 650 via differential mechanism 600. By doing so, the driving force of engine 100 can be assisted by the driving force from motor generator 220, or hybrid vehicle 1 can be driven only by the driving force from motor generator 220.

  On the other hand, during regenerative braking of hybrid vehicle 1, drive wheels 800L and 800R are rotated by the inertial force of the vehicle body. Motor generator 220 is driven through drive shaft receiving portion 650, differential mechanism 600 and reduction mechanism 550 by the rotational force from drive wheels 800 </ b> L and 800 </ b> R. At this time, the motor generator 220 operates as a generator. Thus, motor generator 220 functions as a regenerative brake that converts braking energy into electric power. The electric power generated by the motor generator 220 is stored in the battery 400 via an inverter (not shown) provided in the PCU 300.

  FIG. 3 is a diagram showing a battery cell 410 included in the battery 400. With reference to FIG. 3, the battery cell 410 has a battery case 411 and a connection terminal 412 including a positive electrode terminal 412C and a negative electrode terminal 412A. The battery cell 410 is composed of a lithium ion battery. A battery element is formed inside the battery case 411. The positive terminal 412C and the negative terminal 412A are formed so as to extend from the inside of the battery case 411 to the outside. The positive electrode terminal 412C and the negative electrode terminal 412A protrude outside the battery case 411 from positions separated from each other.

  FIG. 4 is a diagram illustrating a state in which the battery 400 is formed by stacking the battery cells 410. Referring to FIG. 4, battery 400 includes a plurality of battery cells 410 and a bus bar 420. The bus bar 420 electrically connects the positive terminal 412C and the negative terminal 412A of the adjacent battery cells 410.

  FIG. 5 is a cross-sectional view showing the terminal connection structure according to the present embodiment. Referring to FIG. 5, the terminal connection structure according to the present embodiment is applied to bus bar 420. The connection structure may be applied to all bus bars 420 or may be applied to some bus bars 420. In the example of FIG. 5, the bus bar 420 includes a first conductive member 421, a second conductive member 422, and a fusing part 423. The first and second conductive members 421 and 422 include, for example, copper or aluminum. The first and second conductive members 421 and 422 are electrically connected via a fusing part 423. Thereby, the connection structure between terminals is realized.

  The fusing part 423 includes a first fusing part 423A as a “high strength part” and a second fusing part 423B as a “low melting point part”. The first and second fusing parts 423A and 423B are formed so as to be aligned along the joint surfaces of the first and second conductive members 421 and 422. The first fusing part 423A has a relatively high strength relative to the second fusing part 423B, and the first fusing part 423A ensures the strength of the terminal connection structure to a certain level or more. Further, the second fusing part 423B has a relatively low melting point with respect to the first fusing part 423A, and is easily blown when the temperature rises. The first fusing part 423A is configured by, for example, welding, ultrasonic welding, pressure welding, or the like. In other words, in the example of FIG. 5, the first fusing part 423A is formed by bringing the base materials of the first and second conductive members 421 and 422 into contact with each other. On the other hand, the second fusing part 423B is composed of a conductive bonding material (for example, solder, conductive adhesive, etc.) having a melting point lower than that of the first fusing part 423A. Note that, on the joint surface between the first and second conductive members 421 and 422, the second fusing part 423B is formed to have a larger area than the first fusing part 423A.

  Battery 400 is a high-voltage power storage mechanism of, for example, 200 V or higher. Here, if a large current flows through the bus bar 420 due to a short circuit in the battery 400, there is a concern that the function of the battery 400 may be impaired. On the other hand, the bus bar 420 including the fusing part 423 protects the battery 400 by interrupting a large current by the following action.

  When a large current flows through the bus bar 420, the first and second conductive members 421, 422 and the fusing part 423 generate heat rapidly. Thereby, first, the second fusing part 423B having a relatively low melting point is dissolved. Then, the short circuit current concentrates on the first fusing part 423A, and the first fusing part 423A further generates heat. As a result, the first fusing part 423A having a relatively high melting point is also fused, and the short-circuit current is interrupted. As described above, the bus bar 420 normally melts and cuts off the current when a large current flows while ensuring a certain strength and electrical conductivity during normal operation.

  FIG. 6 is a view showing a bus bar 420 according to a modification of FIG. Referring to FIG. 6, in the present modification, first fusing part 423A is formed of a conductive bonding material having a melting point higher than that of second fusing part 423B. Even with such a configuration, the same effect as described above can be obtained.

  According to the terminal connection structure according to the present embodiment, by providing the first fusing part 423A having a high bonding strength, the bonding strength between the first and second conductive members 421 and 422 can be ensured at a certain level or more. On the other hand, when an excessive current flows, the first and second fusing parts 423A and 423B are melted, and the current flowing between the first and second conductive members 421 and 422 is interrupted. As described above, the terminal connection structure according to the present embodiment is capable of surely cutting off the current when an excessive current flows while ensuring a certain level of strength and conductivity during normal operation. .

  Further, in the terminal connection structure, by making the area of the second fusing part 423B larger than the area of the first fusing part 423A, the second fusing part 423B is melted and then more effectively formed into the first fusing part 423A. Current can be concentrated. As a result, the heat generation in the first fusing part 423A after the second fusing part 423B is fused increases, and the first fusing part 423A can be more reliably dissolved.

  The above configuration is summarized as follows. That is, the terminal connection structure according to the present embodiment is a terminal connection structure that eliminates the connection when an excessive current flows and protects the battery 400 as the “electrical device”, and includes the first conductive member 421 and the terminal connection structure. The second conductive member 422 electrically connected to the first conductive member 421 and the fusing part 423 formed between the first and second conductive members 421 and 422 are provided. Here, the fusing part 423 includes first and second fusing parts 423 </ b> A and 423 </ b> B formed so as to be aligned along the joint surfaces of the first and second conductive members 421 and 422. The first fusing part 423A has a relatively high bonding strength with respect to the second fusing part 423B, and the second fusing part 423B has a relatively low melting point with respect to the first fusing part 423A.

  The battery 400 as the “power storage mechanism” according to the present embodiment is formed by paralleling a plurality of battery cells 410 as “power storage cells” having a positive terminal 412C and a negative terminal 412A as “connection terminals”. In addition, a bus bar 420 that electrically connects the positive terminal 412C and the negative terminal 412A in the plurality of battery cells 410 is provided. The bus bar 420 includes the terminal connection structure described above.

  The battery 400 is an example of an “electric device”, and the “electric device” is not limited to this. As other “electric devices” mounted on the vehicle, for example, motor generators 210 and 220, PCU 300, and the like are conceivable. Furthermore, the “electric device” does not necessarily have to be mounted on the vehicle.

  Although the embodiments of the present invention have been described above, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the hybrid vehicle containing the electrical storage mechanism with which the terminal connection structure which concerns on one embodiment of this invention is applied. It is a figure explaining the drive unit in the hybrid vehicle shown by FIG. It is the figure which showed the electrical storage cell contained in the electrical storage mechanism with which the terminal connection structure which concerns on one embodiment of this invention is applied. It is the figure which showed the electrical storage mechanism with which the terminal connection structure which concerns on one embodiment of this invention is applied. It is sectional drawing which showed the terminal connection structure which concerns on one embodiment of this invention. It is sectional drawing which showed the modification of the terminal connection structure which concerns on one embodiment of this invention.

Explanation of symbols

  1 hybrid vehicle, 100 engine, 150 shaft, 200, 210, 220 motor generator, 300 PCU, 300A, 300A1, 300A2, 400A cable, 400 battery, 410 battery cell, 411 battery case, 412 connection terminal, 412A negative electrode terminal, 412C Positive electrode terminal, 420 bus bar, 421 first conductive member, 422 second conductive member, 423 fusing part, 423A first fusing part, 423B second fusing part, 500 power split mechanism, 550 reduction mechanism, 600 differential mechanism, 650 drive shaft Receiving part, 700 drive shaft, 800L, 800R driving wheel, 900 housing, 910, 920 terminal block.

Claims (6)

It is a terminal connection structure that protects electrical equipment by removing the connection when an excessive current flows,
A first conductive member;
A second conductive member electrically connected to the first conductive member;
A fusing part formed between the first and second conductive members,
The fusing part includes a first fusing part and a second fusing part formed so as to be aligned along the joint surface of the first and second conductive members,
The first fusing part has a relatively high bonding strength with respect to the second fusing part,
The second fusing part is a terminal connection structure in which the melting point is relatively low with respect to the first fusing part.   2. The terminal connection structure according to claim 1, wherein an area of the second fusing part on a joint surface between the first and second conductive members is larger than an area of the first fusing part.   The terminal connection structure according to claim 1, wherein the second fusing part includes a conductive bonding material having a melting point lower than that of the first fusing part.   4. The terminal connection structure according to claim 1, wherein the first fusing portion includes a portion formed by bringing the base materials of the first and second conductive members into contact with each other and joining them. 5. . A power storage mechanism formed in parallel with a plurality of power storage cells having connection terminals,
A bus bar for electrically connecting the connection terminals in the plurality of the storage cells,
The said bus-bar is an electrical storage mechanism containing the terminal connection structure in any one of Claims 1-4.   An electric vehicle comprising the power storage mechanism according to claim 5.

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