JP5971562B2 - Short-circuit protection device for battery monitoring system - Google Patents

Description

The present invention relates to a short-circuit protection device in the battery-monitoring system.

  Conventionally, a hybrid vehicle or an electric vehicle is generally equipped with a battery monitoring device for monitoring a charging state of the battery. The following patent document 1 can be mentioned to such a technique. Here, a battery that is an assembled battery in which a plurality of battery cells are arranged is disclosed. Each battery cell is electrically connected in series so that a high output voltage can be obtained. The electrodes of adjacent battery cells are connected by a bus bar. A voltage detection terminal is overlaid on each bus bar, and is connected to either the positive electrode or the negative electrode of each battery cell. One end of a detection wire is connected to each voltage detection terminal. Terminal fittings are also connected to the other ends of the detection wires, and each terminal fitting is inserted into the connector and connected to a battery monitoring device (ECU). The connector on the side of the battery monitoring device connected to each detection wire is generally installed on the board in the ECU, and the terminal fitting drawn from this connector penetrates through the through hole formed in the printed board By being soldered, it is electrically connected to a circuit formed on the printed circuit board.

JP 2012-199007 A

  By the way, the battery monitoring device includes the above-described connector and an electrolytic solution (hereinafter, the electrolytic solution is an electrically conductive material in which an ionic substance such as salt water or a solution in the battery is dissolved in a polar solvent such as water. In the case where it is assumed that the terminal fitting is immersed in a solution having a liquid crystal structure, the terminal fittings may be short-circuited via the electrolytic solution on the printed circuit board. In such a case, an overcurrent flows between the terminal fittings, and the connector may generate heat before it becomes abnormal. In addition, depending on the part, copper ions are eluted from the terminal fitting (generally made of a copper alloy), resulting in so-called terminal thinning, and an increase in resistance due to a decrease in cross-sectional area through which current passes. For this reason, the situation of exacerbating the fever situation was also considered.

The present invention was completed based on the above situation, and an object thereof is to provide a short-circuit protection device in the resolver Tteri monitoring system can effectively corresponds to a situation of short circuit.

The short circuit protection device in the battery monitoring device of the present invention connects a battery, which is an assembled battery composed of a plurality of battery cells, and a battery monitoring device for detecting the voltage of the battery by a plurality of electric wires with terminals. In the battery monitoring system to
The electric wire with terminal is covered with an insulating coating in the middle, the insulating coating is removed at both ends, and the core wire is exposed, and the copper for connecting the exposed core wire to the battery monitoring device side An alloy terminal fitting is connected, and the core wire is formed of aluminum or aluminum alloy having a higher ionization tendency than the terminal fitting, and the connection portion of the exposed core wire with the terminal fitting is the terminal fitting. It is the structure which served as the fusing part melt | dissolved when the caulking part and electric corrosion generate | occur | produce with respect to.

According to the present invention , when the terminal fitting is immersed in the electrolyte on the battery monitoring device side, the short circuit may continue between the terminal fittings. However, in that case, since the wire core is made of aluminum or aluminum alloy, the terminal metal fitting made of copper alloy starts to elute and heats up earlier than the time when it generates heat, leading to early fusing. Therefore, it can be avoided that an overcurrent flows through the terminal fitting.

The perspective view which shows the outline of a battery monitoring system The perspective view which shows the state before each electric wire for a detection is connected to a battery. The perspective view which shows the electric wire for detection in the state where the terminal metal fitting was attached to both ends Flat sectional view showing a state where the core wire that has been crimped by the wire barrel is melted Sectional side view which shows the state by which the core wire connected to the terminal metal fitting of the upper stage was cut in the state where the male and female connector housings are fitted

< Example>
Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an electrical connection state between the battery B mounted on the hybrid vehicle and the battery monitoring device M side. The battery B of the present embodiment is an assembled battery composed of a plurality of battery cells 1. Each battery cell 1 has a pair of electrodes 2 (a positive electrode and a negative electrode) on its upper surface, and is aligned in close contact so that the surfaces on which the electrodes 2 are formed face the same direction when combined. At this time, the positive electrode and the negative electrode are alternately positioned along the alignment direction. Further, the electrodes 2 adjacent to each other in the arrangement direction are connected by a bus bar 3.

  The bus bar 3 is made of, for example, a conductive metal plate material such as copper, copper alloy, and stainless steel, and has a pair of through holes, although not shown in detail. And by making a through-hole penetrate each electrode 2 adjacent in the arrangement direction, the adjacent electrodes 2 are connected to each other via the bus bar 3, thereby all the battery cells 1 are connected in series.

  In addition, as shown in FIG. 1, one electrode (electrodes at the diagonal position of the assembled battery: hereinafter referred to as a single electrode 1a) of the battery cells 1 arranged at both ends in the arrangement direction among all the battery cells 1 is a bus bar. No connection with 3 is made.

  A detection wire W (terminal) as shown in FIG. 3 is connected to one electrode (for example, the positive electrode side) of both electrodes 2 connected by each bus bar 3 and both single electrodes 1a not connected to the bus bar 3. Cable).

  The detection electric wire W is composed of a core wire 4 made of a plurality of strands and an insulating coating 5 covering the core wire 4. Each strand of the core wire 4 is made of aluminum or an aluminum alloy. A predetermined length of the insulation coating 5 at both ends of the detection wire W is removed, and the core wire 4 is exposed. The exposed core wire 4 is provided with first and second terminal fittings 6 and 7, respectively. The first terminal fitting 6 on the side connected to the electrode 2 of the battery B is formed of a copper alloy plate material such as copper or brass. The first terminal fitting 6 is formed of an electrode connection portion 6A and a wire connection portion 6B for the detection wire W. An insertion hole 8 is formed in the electrode connection portion 6 </ b> A so as to open in a circular shape, and is inserted into the electrode 2 while being superimposed on the upper surface of the bus bar 3, and is fastened and fixed by a nut 9.

  As shown in FIG. 1, when the first terminal fitting 6 is connected to the electrode 2, the protruding direction of the protruding piece 10 formed at one end of the electrode connecting portion 6 </ b> A is the alignment direction of the battery cells 1. The direction is perpendicular to the direction. In the electrode connecting portion 6 </ b> A, the edge opposite to the protruding piece 10 is bent upward along the one side edge of the bus bar 3 to form a bent edge 11. A connecting piece 12 protrudes from the central portion in the width direction of the bent edge 11 in a direction opposite to the protruding piece 10 and continues to the above-described electric wire connecting portion 6B. The electric wire connection portion 6B is formed of an insulation barrel 13 that is caulked to the insulating coating 5 of the detection electric wire W, and a wire barrel 14 that is caulked to the core wire.

  As shown in FIG. 1, the detection wires W are collected at the center of the upper surface of the battery B, routed along the alignment direction of the battery cells 1, and extended to the battery monitoring device M side. ing.

  A second terminal fitting 7 is attached to the end of each detection wire W opposite to the first terminal fitting 6. The second terminal fitting 7 is formed by bending a copper or copper alloy plate, and a known female terminal fitting is used. That is, the second terminal fitting 7 has a terminal connection portion 7A having a rectangular tube shape at the front end portion, and a wire connection portion 7B formed at the rear side thereof. Similar to the first terminal fitting 6, the electric wire connecting portion 7 </ b> B is formed of an insulation barrel 15 that is caulked to the insulating coating 5 of the detection electric wire W and a wire barrel 16 that is caulked to the core wire 4. The second terminal fitting 7 is inserted into each cavity 18 of the female connector housing 17.

  On the other hand, the battery monitoring device (ECU) M has a function of measuring the voltage of each battery cell 1. The battery monitoring device M is disposed inside a box body (not shown), and a printed circuit board 19 and a male connector housing 20 mounted on the printed circuit board 19 are incorporated therein.

  The female connector housing 17 described above can be fitted to the male connector housing 20 on the printed circuit board 19. A plurality of male terminal fittings 21 are attached inside the male connector housing 20. As shown in FIG. 5, one end side of each male terminal fitting 21 protrudes in parallel in the male connector housing 20, and the other end side protrudes from the back side of the male connector housing 20. A portion of each male terminal fitting 21 that protrudes from the male connector housing 20 is bent at a substantially right angle in the middle, and then inserted into the through hole 22 of the printed circuit board 19 and soldered on the back surface side of the printed circuit board 19. A voltage detection circuit formed on the printed circuit board 19 is connected.

  Next, the function and effect of the present embodiment configured as described above will be described. In a state where the battery B side and the battery monitoring device M side are connected via the detection electric wire W, for example, assuming that the male and female connector housings are both immersed in the electrolyte, a short circuit occurs on the second terminal fitting 7 side. And an excessive current flows through the detection wire W.

  At the same time, in the female connector housing 17, elution of the core wire 4 proceeds at the connection portion (the portion where the core wire 4 is caulked with the wire barrel 16) between the detection electric wire W and the second terminal fitting 7. That is, in the wire barrel 16 of the second terminal fitting 7, since the wire barrel 16, which is a copper or copper alloy portion, is in contact with the core wire 4 made of aluminum or aluminum alloy, electrolytic corrosion occurs here. . In that case, due to the difference in ionization tendency, elution is performed exclusively on the core wire 4 side which is a material having a higher ionization tendency. Moreover, as is well known, when the electrolytic solution adheres to the site where the dissimilar metals are in contact with each other, the elution rate of the core wire 4 is faster than that of the single body, and the connection to the wire barrel portion 16 is relatively short. Can cause a situation (melting). 4 and 5 show a state in which the entire area where the core wire 4 is exposed forward from the wire barrel 16 is eluted and electrical continuity with the second terminal fitting 7 cannot be obtained. As a result, an excessive current does not continue to flow through the detection wire W, the connectors 17 and 20 do not become abnormally hot, and the battery cell 1 is also protected. Thus, the core wire 4 exposed from the insulating coating 5 has a function as a caulking portion that is caulked by the wire barrel 16 and a fusing portion that is fused.

  In addition, if the state immersed in electrolyte solution is eliminated at the early stage before the cutting of the detection electric wire W occurs, the situation of the short circuit is once eliminated. However, even if the immersion state by the electrolytic solution is eliminated, the copper oxide (CuO) powder deposited on the male terminal fitting 21 bridges the bridge BR (see FIG. 5) between the adjacent male terminal fittings 21. As a result, the short-circuit state continues and abnormal heat generation is unavoidable at the fitting portion between the connector housings 17 and 20. However, as described above, the corrosion rate when copper is immersed in an electrolytic solution and the corrosion rate when the aluminum core wire 4 in contact with a dissimilar metal is immersed in an electrolytic solution are the latter rates. It ’s faster. Therefore, there is a high possibility that the detection wire W is melted at the wire barrel 16 before the bridge BR made of copper oxide powder is formed, and therefore a short circuit occurs after the immersion state by the electrolytic solution is eliminated. Are thought to be rare.

  Further, when the battery B is immersed in the electrolytic solution in addition to the connector, the core wire 4 can be melted also on the first terminal fitting 6 side. If double fusing sites are set in this way, a short circuit can be reliably avoided. Further, when the connection state with the first terminal fitting 4 is released by fusing, the detection wire W moves on the battery B, and the exposed tip portion of the core wire 4 touches the peripheral bus bar 3 to cause a short circuit. However, since the exposed aluminum core wire 4 is immediately exposed to air, an oxide film (aluminum oxide) is immediately formed to ensure electrical insulation, so the above-mentioned concerns can be eliminated.

DESCRIPTION OF SYMBOLS 1 ... Battery cell 4 ... Core wire 5 ... Cover 6 ... 1st terminal metal fitting 7 ... 2nd terminal metal fitting 16 ... Wire barrel of 2nd terminal metal fitting 17 ... Female connector housing 19 ... Printed circuit board 20 ... Male connector housing 21 ... Male terminal metal fitting B ... Battery M ... Battery monitoring device W ... Electric wire

Claims (1)

In a battery monitoring system in which a battery, which is an assembled battery composed of a plurality of battery cells, and a battery monitoring device for detecting the voltage of the battery are connected by a plurality of electric wires with terminals,
  The electric wire with terminal is covered with an insulating coating in the middle, the insulating coating is removed at both ends, and the core wire is exposed, and the copper for connecting the exposed core wire to the battery monitoring device side An alloy terminal fitting is connected, and the core wire is formed of aluminum or aluminum alloy having a higher ionization tendency than the terminal fitting, and the connection portion of the exposed core wire with the terminal fitting is the terminal fitting. A short-circuit protection device in a battery monitoring system, characterized in that it is configured to serve as both a caulking portion and a fusing portion that is fused when electric corrosion occurs.

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