JP5022316B2 - Secondary battery device - Google Patents

Description

  The present invention relates to a secondary battery device including a plurality of secondary batteries, for example, mounted on a vehicle (moving body).

  Conventionally, in order to equalize the voltage of each secondary battery with respect to a plurality of secondary batteries connected in series, an equalization circuit (discharge circuit) connected in parallel to each secondary battery has been proposed. (See Patent Document 1). The equalization circuit includes a resistor (discharge resistor) and a switching element such as a transistor. Moreover, in order to protect a some secondary battery from dust, water, etc., it is normally accommodated in a box-shaped secondary battery box.

Japanese Patent Laid-Open No. 2002-354692

  However, when the equalization circuit is activated, the resistance generates heat. If the resistance and the control device that controls the equalization circuit are arranged close to each other, the control device may malfunction due to the heat of the resistance. is there.

  Accordingly, an object of the present invention is to provide a secondary battery device in which the control device of the equalization circuit is less susceptible to heat.

As means for solving the above-mentioned problems, the present invention provides a plurality of secondary batteries connected in series, a secondary battery box that accommodates the plurality of secondary batteries, and the voltages of the secondary batteries are equalized. And an equalization circuit for detecting the voltage of each secondary battery and a control device for controlling the operation of the equalization circuit, wherein the resistance of the equalization circuit is provided on one surface of the secondary battery box. And a heat transfer structure with the metal first panel of the secondary battery box constituting the one surface, and the control device is a surface different from the surface on which the resistor is disposed. together when placed in the side, it is attached to the second panel of the metal of the secondary battery box constituting the another aspect, wherein the first panel and the second panel, are separate members, this connected via the resin busbar plate A secondary battery system according to claim.

According to such a secondary battery device, the resistance of the equalization circuit forms a heat transfer structure with the panel of the secondary battery box, so that the heat of the resistance is suitably transmitted to the panel and radiates heat to the outside. Is done.
And since the control apparatus is arrange | positioned on the surface side different from the surface where the said resistance is arrange | positioned, it becomes difficult to transmit the heat | fever of resistance to a control apparatus. Therefore, the control device is not easily affected by heat.

  Further, the control device is a secondary battery device, wherein the control device is disposed on a surface side different from the surface of the secondary battery box corresponding to the terminal side of the secondary battery.

Here, when the secondary battery is charged and discharged, the terminal side usually tends to be at a high temperature.
According to such a secondary battery device, since the control device is arranged on a surface side different from the surface of the secondary battery box corresponding to the terminal side of the secondary battery, the control device further affects the influence of heat. It becomes difficult to receive.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of an equalization circuit can provide the secondary battery apparatus which is hard to receive to the influence of a heat | fever.

  First, an embodiment of the present invention will be described with reference to FIGS.

≪Configuration of secondary battery device≫
A secondary battery device 1 according to this embodiment shown in FIG. 1 is mounted on a fuel cell vehicle (not shown) on which a fuel cell stack (not shown) is mounted. The secondary battery device 1 is fixed to the front and rear frames 101 and 101 and the subframes 102 and 102 joined thereto in a center tunnel below a floor panel (not shown) below the rear seat.

  The front and rear frames 101 and 101 extend in the vehicle front-rear direction, and the subframes 102 and 102 extend in the vehicle width direction. An under panel 103 is attached to the lower surfaces of the front and rear frames 101 and 101 and the sub frames 102 and 102. A space surrounded by the front and rear frames 101 and 101, the sub frames 102 and 102, and the under panel 103 is As will be described later, it functions as the exhaust passage 37 (see FIG. 4).

The secondary battery device 1 is a device that discharges charging power to assist a fuel cell stack (not shown), or charges regenerative power from a travel motor or the like or surplus power of the fuel cell stack.
Such a secondary battery device 1 includes two assembled batteries A, A distributed to the left and right, a secondary battery box 30 that houses the assembled batteries A, A, and a secondary battery 11 that constitutes each assembled battery A. An equalization circuit 40 for equalizing the voltages of the (single cells), and an ECU 50 (Electronic Control Unit) that detects the voltage of each secondary battery 11 and controls the operation of the equalization circuit 40. ing.

<Battery assembly>
Each assembled battery A includes ten battery modules 10 (see FIG. 3), and each battery module 10 includes four lithium ion secondary batteries 11.
The four secondary batteries 11 constituting each battery module 10 are connected in series (see FIG. 4). More specifically, in each battery module 10, the two secondary batteries 11 and 11 are connected by a band 12, and the connected ones are connected in series by a bus bar 17 on the front side. The bus bar 17 is covered with a resin cap 14.
In FIG. 4, only one battery module 10 is schematically illustrated. Further, the secondary battery 11 and the flexible substrate 21 to be described later are integrally formed of a heat shrinkable tube (not shown) and are waterproof.

  The positive terminal 15 and the negative terminal 16 of the battery module 10 are disposed on the rear side of the vehicle and pass through a terminal hole 36b of a bus bar plate 36 described later (see FIG. 4). Adjacent battery modules 10 and 10 are connected in series by a metal bus bar 17 (see FIG. 3). That is, the plus terminal 15 (or minus terminal 16) of one battery module 10 protruding rearward from the bottom wall portion 36a of the bus bar plate 36 is connected to the minus terminal 16 (or plus) of another battery module 10 via the bus bar 17. Terminal 15) is electrically connected. Thereby, the some secondary battery 11 is electrically connected in series.

  In addition, the battery modules 10 and 10 arrange | positioned near the center upper part of FIG. 3 are connected in series via the always-on-type interruption | blocking circuit (not shown). The bus bar 17 is fixed to the plus terminal 15 and the minus terminal 16 by bolts 18 (see FIG. 4). Further, the plurality of secondary batteries 11 are stacked in a staggered manner with a predetermined gap therebetween.

  In each secondary battery 11, an elongated flexible substrate 21 is connected to a metal casing 19 that functions as a negative electrode (see FIGS. 4 and 5). More specifically, the flexible substrate 21 is provided with two metal tabs 22. The tabs 22 are welded to the casings 19 of the respective secondary batteries 11, whereby the casing 19 and the flexible substrate 21 are connected. Electrically connected. On the other hand, the rear end of the flexible substrate 21 is connected to the first substrate 25 via a connector.

Two circuits 23 and 24 connected to each tab 22 are printed on the flexible substrate 21 (see FIG. 5).
The circuit 23 is a circuit for detecting the voltage of the secondary battery 11, and is connected to the ECU 50 via the first board 25, the flat cable 26, the second board 27, and the harness 28 (see FIG. 6). The harness 28 is connected to the second substrate 27 via a harness connecting portion 28a provided on the rear surface of the rear panel 32.
The circuit 24 constitutes a part of the equalization circuit 40 and is connected to the resistor 41 and the transistor 42 of the second substrate 27 via the first substrate 25 and the flat cable 26 (see FIG. 6). .

<Secondary battery box>
The secondary battery box 30 is a box that houses a plurality of battery modules 10 in order to protect them from dust, water, etc., and includes a front panel 31, a rear panel 32, a right panel 33, a left panel 34, An upper panel 35 and a bus bar plate 36 are provided. The front panel 31, the rear panel 32, the right panel 33, the left panel 34, and the upper panel 35 are made of metal (for example, aluminum alloy), and the bus bar plate 36 is made of resin.

  The right panel 33 is formed with a cooling air inlet 33a for cooling the battery module 10 (secondary battery 11) that generates heat by charging and discharging. Similarly, the left panel 34 is formed with an inlet 34a. Yes. Then, the cooling air sucked from the intake ports 33a and 34a flows between the battery modules 10 (secondary batteries 11) to cool them, and then cools them through the exhaust passage 37 below the secondary battery box 30. It is designed to be discharged to the outside.

The bus bar plate 36 is a shallow box with an open rear side, and a plurality of terminal holes 36b through which the plus terminal 15 or the minus terminal 16 of the battery module 10 passes are formed in the bottom wall portion 36a.
The first substrate 25 relays the connection between the flexible substrate 21 and the second substrate 27 (see FIG. 6), and is attached to a boss (not shown) protruding from the bottom wall portion 36a of the bus bar plate 36. . An insulating sheet 29 is interposed between the first substrate 25 and the bus bar 17, and the first substrate 25 and the bus bar 17 are electrically insulated.

<Equalization circuit>
As shown in FIG. 6, the equalization circuit 40 is a circuit for equalizing the voltage of each secondary battery 11 and preventing overcharge and overdischarge of each secondary battery 11. 11 is connected in parallel.

  Each equalization circuit 40 includes a resistor 41 and a transistor 42 (switching element) that is ON / OFF controlled in accordance with a command from the ECU 50. The resistor 41 and the transistor 42 are connected in series. The resistor 41 and the transistor 42 are provided on the second substrate 27 on which a predetermined circuit is printed, and are directly connected to each secondary battery 11 via the circuit 24 of the flat cable 26, the first substrate 25, and the flexible substrate 21. (See FIG. 6). The second substrate 27 is accommodated in a substrate accommodating portion 39 provided on the front surface of the rear panel 32, and is protected from dust, water, and the like (see FIG. 4).

The resistor 41 is disposed on the rear surface of the second substrate 27. Between the resistor 41 and the rear panel 32, a heat transfer sheet 43 formed with, for example, silicone as a main component is interposed. The resistor 41 is thermally connected to the rear panel 32 via the heat transfer sheet 43. That is, the resistor 41 constituting the equalizing circuit 40 is disposed on the rear surface side constituting the secondary battery box 30 and forms a heat transfer structure with the rear panel 32 constituting the rear surface.
As a result, even when the transistor 42 is turned on and the equalization circuit 40 is activated and the resistor 41 generates heat, the heat of the resistor 41 is transferred to the rear panel 32 via the heat transfer sheet 43 and is externally transmitted from the rear panel 32 to the outside. The heat is suitably dissipated.

<ECU>
The ECU 50 is a control device that detects the voltage of each secondary battery 11 and controls the operation of the equalization circuit 40 in accordance with a program stored therein, and includes a CPU, a ROM, a RAM, various interfaces, and an electronic circuit. And so on.

  Moreover, ECU50 is arrange | positioned at the upper surface side of the secondary battery box 30, and is attached to the upper panel 35 which comprises this upper surface. The upper panel 35 is a separate panel from the front panel 31 and the rear panel 32 (corresponding surfaces) corresponding to the terminal side of the secondary battery 11 and the rear panel 32 on which the resistor 41 is disposed.

<ECU-voltage detection function>
The ECU 50 includes a voltage sensor and a scanning board (both not shown). The scanning board is connected to the harness 28, the second board 27, the flat cable 26, the first board 25, and the circuit 23 of the flexible board 21. Each secondary battery 11 is connected. The ECU 50 has a function of scanning all the secondary batteries 11 at a predetermined cycle and detecting the voltage of each secondary battery 11 by the voltage sensor. The ECU 50 also has a function of calculating the SOC (State Of Charge) of each secondary battery 11 based on the detected voltage of each secondary battery 11.

<ECU—Equalization circuit control function>
The ECU 50 is connected to the base terminal of each transistor 42 via the harness 28, and controls the operation of each equalization circuit 40 by controlling the ON / OFF signal to the transistor 42. .
For example, when the voltage (or SOC) of the secondary battery 11 is equal to or higher than a predetermined voltage (or predetermined SOC), the ECU 50 is connected in parallel to the secondary battery 11 to prevent overcharge of the secondary battery 11. An ON signal is sent to the transistor 42 constituting the equalization circuit 40 to operate the equalization circuit 40. When the equalization circuit 40 is activated, the resistor 41 generates heat.

≪Operation and effect of secondary battery device≫
According to such a secondary battery device 1, the following effects are obtained.
Since the resistor 41 of the equalization circuit 40 is thermally connected to the rear panel 32 via the heat transfer sheet 43, the heat of the resistor 41 can be suitably radiated to the outside. Therefore, heat radiation fins or the like may be formed on the rear surface of the rear panel 32 in order to promote heat radiation.

  The ECU 50 is attached to the upper panel 35 constituting the upper surface different from the rear surface where the resistor 41 is disposed, the front surface and the rear surface corresponding to the terminal side of the secondary battery 11, and the ECU 50 is affected by heat. It becomes difficult. Therefore, the ECU 50 will not overheat and will not malfunction. Further, since the ECU 50 is mounted on the upper panel 35, the ECU 50 can be suitably protected from water.

Since the resistance 41 and the like of the equalization circuit 40 and the ECU 50 are directly connected to each secondary battery 11 via the circuit 23 or the circuit 24 of the flexible substrate 21 without branching in the middle, the equalization Even if the ECU 50 detects the voltage of the secondary battery 11 while the circuit 40 is in operation, the voltage of the secondary battery 11 can be accurately detected without causing a voltage drop.
Incidentally, when detecting the voltage, a current of about several μA flows, and when the equalizing circuit 40 operates, a current of about several mA flows. Therefore, when the voltage detection circuit and the equalization circuit share a circuit with a small cross-sectional area, if a voltage is detected during the operation of the equalization circuit 40, the voltage drops greatly in the shared circuit portion with the small cross-sectional area. The voltage of the secondary battery 11 is erroneously detected.
Moreover, such a flexible substrate 21 is small and light, and the cross-sectional areas of the circuits 23 and 24 printed thereon can be easily changed.

  As mentioned above, although one suitable embodiment of the present invention was described, the present invention is not limited to the above-mentioned embodiment, and can be changed as follows, for example, in the range which does not deviate from the meaning of the present invention.

  In the above-described embodiment, the configuration in which the secondary battery device 1 is mounted on the fuel cell vehicle (moving body) is exemplified. However, for example, a configuration in which the secondary battery device 1 is incorporated in a stationary fuel cell system may be used. The battery device may be used alone.

It is a perspective view from the back of the rechargeable battery device concerning this embodiment. It is a disassembled perspective view of the secondary battery device concerning this embodiment. It is the figure which looked at the bus-bar plate which concerns on this embodiment from back. It is a longitudinal cross-sectional view of the secondary battery apparatus which concerns on this embodiment. It is a figure which shows the flexible substrate which concerns on this embodiment. It is an electric circuit diagram of the secondary battery device according to the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Secondary battery apparatus 10 Battery module 11 Secondary battery 30 Secondary battery box 40 Equalization circuit 41 Resistance 43 Heat-transfer sheet | seat 50 ECU (control apparatus)

Claims (2)

A plurality of secondary batteries connected in series;
A secondary battery box containing the plurality of secondary batteries;
An equalization circuit for equalizing the voltages of the respective secondary batteries;
A controller for detecting the voltage of each secondary battery and controlling the operation of the equalization circuit;
With
The resistance of the equalization circuit is disposed on one surface side of the secondary battery box, and forms a heat transfer structure with the metal first panel of the secondary battery box constituting the one surface,
The control device both when the resistor is located in a different side from the placed surface mounted to the second panel made of metal secondary battery box constituting the another aspect,
The secondary battery device, wherein the first panel and the second panel are separate members and are connected via a resin bus bar plate . The secondary battery device according to claim 1, wherein the control device is arranged on a surface side different from a surface of the secondary battery box corresponding to a terminal side of the secondary battery.

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