JP3670907B2 - Assembled battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an assembled battery in which a large number of single cells are connected in series or in parallel. In particular, the present invention relates to an assembled battery that can detect that at least one of the many single cells constituting the assembled battery for an electric vehicle has abnormally heated.
[0002]
[Prior art]
An assembled battery in which a thermal sensor such as a PTC element is incorporated in a battery is widely known in order to detect an abnormal temperature rise of the battery and prevent an accident due to deterioration or heat generation of the battery.
[0003]
In addition, as a motor driving power source for an electric vehicle, a device capable of supplying a high voltage and a high current by electrically connecting a large number of single cells in series has been proposed. Also known is a power supply device for an electric vehicle in which a temperature sensor is incorporated, for example, one disclosed in Japanese Patent Application Laid-Open No. 10-270094.
[0004]
The power supply device disclosed in this publication is one in which a temperature sensor is attached to each of the single cells constituting the assembled battery, and an abnormal temperature rise of the single cell is detected by measuring the total resistance of the temperature sensor.
[0005]
[Problems to be solved by the invention]
However, since the power supply device described in this publication has temperature sensors attached to all of the single cells constituting the power supply device, temperature sensors corresponding to the number of single cells are required. In particular, since a power supply device that requires a high output and a high voltage, such as an electric vehicle, has an extremely large number of connected single cells, an extremely large number of temperature sensors connected to each single cell are required.
[0006]
As a result, the number of parts is increased, and the number of assembly steps such as connection of each temperature sensor is increased, resulting in a cost increase.
[0007]
Accordingly, the present invention provides an assembled battery that can detect an abnormal temperature rise of each unit cell while reducing the number of temperature sensors attached to the assembled battery in which a large number of unit cells are connected.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, the present invention provides a battery pack in which a plurality of cells are connected in series or in parallel, and is provided with a thermal sensor that detects the temperature of the battery cell in the vicinity of the battery cells constituting the battery pack. The thermal sensor has one thermal sensor arranged for one single cell, and a smaller number of thermal sensors than the number of connected single cells, thereby providing a single cell in which the thermal sensors are arranged close to each other, It is characterized in that it is connected in a mixed manner with single cells in which the thermal sensors are not arranged close to each other.
In addition, the unit cell in which the heat sensor is not disposed in proximity is provided with a heat collecting member that collects the temperature of the unit cell and transmits temperature information of the unit cell to the heat sensor.
The unit cell constituting the assembled battery is composed of a plurality of unit cells in which a thermal sensor is arranged and a unit cell in which a heat collecting member is arranged. Each of the thermal sensors is electrically connected in series with each other through a heat collecting member.
[0009]
The thermal sensor is a PTC element or a thermistor.
[0010]
In addition, the assembled battery is divided into a plurality of small blocks, each small block is configured by connecting a plurality of single cells, and each unit is configured to correspond to the small block of the assembled battery. The heat sensor arranged close to the battery is divided into a plurality of small blocks, and each small block is configured by connecting a plurality of heat sensors in series. Is provided, and the control unit calculates the output of the heat sensor for each small block.
[0012]
Further, the unit cell in which the thermal sensor is arranged and the unit cell in which the heat collecting member is arranged are connected to each other adjacent to each other.
[0013]
Further, the thermal sensor is characterized in that it is arranged at a position close to the unit cell on which the adjacent heat collecting member is arranged on the surface of the unit cell on which the thermal sensor is arranged.
[0014]
Further, the heat collecting member is characterized in that any one of iron, nickel, copper, aluminum or an alloy containing them is used as a main component.
[0016]
The unit cell constituting the assembled battery is composed of a plurality of unit cells in which the thermal sensor is arranged and a unit cell in which the heat collecting member is arranged, and the heat collecting member is arranged. The single cell is arranged between a plurality of single cells in which a thermal sensor is arranged.
[0017]
In addition, a heat sensor is disposed between adjacent unit cells, and a heat collecting member is disposed in each of the adjacent unit cells located on both sides of the heat sensor.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. In the assembled battery of the present invention, six cylindrical unit cells 1 are formed in a vertically long bar shape, and all the unit cells 1 are connected in series to form an assembled battery. Although the nickel hydride battery is used as the unit cell 1, a nickel-cadmium battery or a lithium ion battery may be used.
[0019]
Between the single cells 1, the dish-shaped connecting body 2 is spot-welded to the single cells 1, so that the adjacent single cells 1 are electrically connected in series and mechanically coupled. Then, positive and negative electrode terminals are respectively provided at both ends of the assembled battery to which the six unit cells 1 are connected. The positive electrode terminal 3 has a protrusion 31 at the center, while the negative electrode terminal 4 has a hole 41 at the center.
[0020]
Since the protruding portion 31 of the positive electrode terminal 3 can be inserted and connected to the hole 41 of the negative electrode terminal 4, the assembled batteries are further elongated in the vertical direction to be 12 or 18 pieces. It can be expanded. Further, when the battery packs are arranged side by side in parallel, the plus electrode terminal 3 and the minus electrode terminal 4 have different shapes, so that the arrangement direction can be prevented from being arranged incorrectly.
[0021]
An assembled battery composed of six unit cells 1 can be used as a power supply device by further arranging a plurality of the assembled batteries in a case or the like. This power supply device can increase the number of connected single cells according to the number of connected assembled batteries, and can be used for a power supply device for an electric vehicle that requires high output and high voltage.
[0022]
The assembled battery shown in FIG. 1 includes a thermal sensor 5 and a heat collecting member 6 on the surface of each unit cell 1. The thermal sensor 5 is, for example, a PTC element or the like whose resistance value changes according to a temperature change. In particular, the design is such that the change in resistance value increases as the temperature increases, and the resistance value is designed to change greatly in an atmosphere of 60 ° C. to 120 ° C. On the other hand, the heat collecting member 6 is made of any one of iron, nickel, copper, aluminum and an alloy containing them as a main material.
[0023]
This heat collecting member 6 can collect the heat of the mounted unit cell 1 and maintain the temperature. The heat of the single cell held by the heat collecting member 6 is transmitted from the heat collecting member 6 to the heat sensor 5, and the heat sensor 5 senses the heat of the single cell equipped with the heat collecting member 6. it can. Therefore, it is desirable that the thermal sensor 5 be provided as close to the heat collecting member 6 as possible.
[0024]
The assembled battery shown in FIG. 1 has four heat sensors 5 and two heat collecting members 6 attached to six unit cells 1. The four thermal sensors 5 are arranged on the surfaces of the unit cells 1 at both ends and the two unit cells 1 at the center among the six unit cells 1. The two heat collecting members 6 are disposed on the surfaces of the remaining two unit cells 1. Therefore, the heat collecting member 6 is arranged between the two heat sensors 5.
[0025]
The heat collecting member 6 is formed in a belt shape together with the heat sensor 5 and is laminated with a resin or the like so as to insulate the unit cell 1 from the outer can. The heat sensor 5 and the heat collecting member 6 which are laminated and formed in a band shape are in close contact with the unit cell 1 by a heat-shrinkable tube (not shown) together with the assembled cell constituted by the six unit cells 1. It is supposed to be. The heat collecting member 6 that is in close contact with the unit cell 1 can collect the heat of the unit cell 1. The size of the heat collecting member 6 is formed in the range of 3% to 60% of the surface area of the unit cell 1. If the size of the heat collecting member 6 is increased, the effect of collecting the heat of the unit cell 1 is increased, but conversely, the heat dissipation effect of the unit cell 1 may be reduced. The optimum value is set for the heat dissipation problem.
[0026]
The shape of the heat collecting member 6 includes a heat collecting portion 61 of the unit cell 1 and connecting leg portions 62 connected to the heat sensor 5 protruding from both ends of the heat collecting portion 61. The part 62 is affixed on the heat sensor 5. Furthermore, the heat collecting member 6 has, for example, a two-layer structure, and a material with low thermal conductivity is selected on the surface side not in contact with the inner surface side in contact with the unit cell 1. It is devised so that the collected heat does not escape.
[0027]
This assembled battery is a separate system from the unit cells 1 connected in series, and each thermal sensor 5 is electrically connected in series. FIG. 6 is a circuit example in which all of the thermal sensors 5 attached to each assembled battery are connected in series in a power supply apparatus provided with a plurality of assembled batteries. Further, instead of connecting them all in series, for example, each assembled battery, or two or three assembled batteries may be connected in series, and the whole may be connected in parallel.
[0028]
The resistance value of the heat sensor 5 connected in series changes due to an abnormal temperature rise of the unit cells to be mounted. If an abnormal temperature rise occurs even with a single cell, it can be detected to detect that there is an abnormality in the power supply device.
[0029]
Here, since the heat collecting member 6 is composed of a conductive member such as a metal, it can be used as a lead plate for connecting the heat sensors 5 to each other.
[0030]
FIG. 2 shows another embodiment in which the connecting leg 62 of the heat collecting member 6 to the heat sensor 5 is formed so as to cover the entire heat sensor 5. With this configuration, the heat collecting member 6 can transmit the collected temperature information to the heat sensor 5 more accurately.
[0031]
Further, FIGS. 3 and 4 show further different embodiments, in which three heat sensors 5 and three heat collecting members 6 are mounted among six unit cells. In this example, the heat collecting member 6 is adjacent to the heat sensor 5, and the heat sensor 5 and the heat collecting member 6 are alternately arranged. Thus, the number of heat sensors 5 can be reduced by changing and adjusting the number of heat sensors 5 and heat collecting members 6 with respect to the number of cells. As a result, the heat collecting member 6 is connected to the heat sensor 5 while being installed in the assembled battery, so that one heat sensor is arranged for every two cells, and one heat sensor is used for each cell. Two heat sensors are arranged for every three cells, two heat sensors are arranged to monitor three cells, and one heat sensor for every three cells The three cells can be monitored with one heat sensor.
[0032]
Furthermore, FIG. 5 shows a further different embodiment in which two heat sensors 5 and six heat collecting members 6 are provided for six unit cells 1. In the assembled battery shown in FIG. 5, the thermal sensor 5 is positioned between the two single cells 1 and is disposed at a position facing the dish-like connection body 2. And the heat collection member 6 is arrange | positioned on the surface of each of the six unit cells 1, and each connection leg part 62 of the adjacent heat collection member 6 is connected to the surface and the back surface of the said heat sensor 5, respectively. . Further, the central four unit cells excluding both ends of the six unit cells 1 are provided with a heat collecting member 6 in which two heat collecting portions 61 are integrally formed for every two unit cells. Yes. This heat collecting member 6 can arrange the heat collecting part 61 on the surface of the two unit cells 1 with one heat collecting member, and the number of heat collecting members can be reduced by that amount. The number of points and assembly man-hours can be reduced.
[0033]
As described above, the assembled battery shown in FIG. 5 is configured such that the heat collecting members 6 are arranged in all the unit cells 1 and the heat collecting members 6 are connected to the heat sensors 5 so that the two heat sensors 5 can all be used. It is possible to detect an abnormal temperature rise of the unit cell 1. In addition, the number which arrange | positions the heat sensor 5 between single cells can be changed suitably.
[0034]
Next, the embodiment of FIGS. 7 and 8 will be described. 7 and 8 do not use a heat collecting member, unlike the embodiments of FIGS. 1 to 6 described above. In the assembled battery shown in FIG. 7, a battery module 7 is configured for each of the six unit cells 1, and a plurality of battery modules 7 connected in series are used as one assembled battery.
[0035]
The number of battery modules 7 connected in one assembled battery can be arbitrarily adjusted. For example, 32 battery modules can be connected to connect 192 cells 1 or more. You can also. In addition, the number of single cells 1 constituting one battery module 7 can be arbitrarily adjusted, and can be more or less than six.
[0036]
In the battery module 7 in FIG. 7, six unit cells 1 are connected in series in a rod shape, and among these, two sensor cells 1 are provided with thermal sensors 5. The remaining four unit cells 1 are not provided with heat sensors 5. Similarly, in the other battery modules 7, the heat sensors 5 are arranged in two of the six unit cells 1. For this reason, compared with the case where the thermal sensor 5 is arrange | positioned with respect to all the single cells 1, the number of the thermal sensors 5 can be decreased. However, the arrangement interval and the number of arrangement of the thermal sensors 5 are not limited to this and can be arbitrarily set.
[0037]
Furthermore, the heat sensor 5 is configured such that a total of four heat sensors 5 are connected in series so that a small block is formed for every two battery modules 7. A small block is formed by the four heat sensors 5, and a plurality of the small blocks are formed. And the temperature of the thermal sensor 5 is detected for every small block.
[0038]
The thermal sensor 5 may be a PTC element or a thermistor. The PTC element has a characteristic that the resistance changes abruptly when it reaches the operating temperature. For example, when the operating temperature is 93 ° C., the abnormality cannot be detected until the temperature of the unit cell 1 reaches around 100 ° C. There is. For this reason, it may take time to detect an abnormal temperature rise.
[0039]
On the other hand, the thermistor has a characteristic in which the resistance value gradually changes from a low temperature (−20 ° C.) to a high temperature (150 ° C.). Abnormality detection can be accelerated by adjusting the setting. Further, since the thermistor is cheaper than the PTC element, the cost can be suppressed.
[0040]
FIG. 8 is a temperature detection circuit diagram in which a control unit ECU and a display device 8 are further connected to the assembled battery in FIG. The control unit ECU is configured to input temperature information of the heat sensor 5 configured to be divided into the small blocks described above.
[0041]
Then, the absolute temperature for each small block is detected and compared with a predetermined value set in advance in the control unit to detect an abnormal temperature rise. The default value is set to 60 ° C., for example. When an abnormal temperature rise for each small block is detected, the display device 8 displays which small block is in an abnormal state. For this reason, even if a large number of cells are connected to form an assembled battery, the location of the abnormality can be easily identified, and the abnormal range can be identified for each small block, so maintenance work such as replacement and repair can be performed. Easy to do.
[0042]
In addition, the control unit ECU can compare the temperature signal input for each small block for each block. Thereby, a temperature difference, that is, variation between the small blocks can be detected. For example, if the detection temperature of a certain small block is 80 ° C. and the detection temperature of the other small block is 45 ° C. to 50 ° C., it is abnormal when the temperature difference exceeds a specified value. It is determined that it is in a state, and it is detected that an abnormal unit cell 1 is mixed in the assembled battery. Also in this case, it is possible to display which small block is abnormal by the display device 8.
[0043]
In this way, in the embodiment of FIGS. 7 and 8, the thermal sensor 5 is divided into small blocks, and the control unit ECU performs abnormality detection for each small block. Anomaly detection in a narrow range of small blocks is possible while the number is smaller than the number. The control unit ECU inputs the battery temperature information, uses it as a parameter for self-discharge and charging efficiency, and manages the battery status such as the remaining capacity. Therefore, the temperature information is input for each small block. As a result, detailed calculation of the battery state is possible.
[0044]
【The invention's effect】
According to the present invention, in an assembled battery in which a large number of single cells are connected, the temperature of the single cells is adjusted by arranging the heat collecting member on the surface of the single cell and connecting the heat collecting member to the heat sensor. Can be collected and transferred to a thermal sensor. For this reason, the abnormal temperature rise of the unit cell can be detected by the heat collecting member. As a result, even if the number of heat sensors corresponding to the number of cells constituting the assembled battery is not attached, by combining this heat collecting member, all the units can be obtained even if the number of heat sensors is smaller than the number of cells. Abnormal temperature rise of the battery can be detected.
[0045]
As a result, the number of heat sensors can be reduced, the number of assembly steps and the number of parts can be reduced, and the cost can be reduced.
[0046]
In addition, according to the present invention, the thermal sensor is divided into small blocks, and the abnormality is detected for each small block by the control unit. Easy to do.
[Brief description of the drawings]
FIG. 1 is a perspective view of an assembled battery of the present invention. FIG. 2 is a perspective view of an assembled battery showing another embodiment. FIG. 3 is a perspective view of an assembled battery showing another embodiment. FIG. 5 is a perspective view of an assembled battery showing another embodiment. FIG. 6 is a connection circuit diagram of a thermal sensor. FIG. 7 is a plan view of the assembled battery showing another embodiment. Temperature detection circuit diagram of the assembled battery in FIG. 7 [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cell 2 Dish-shaped connection body 3 Positive electrode terminal 31 Protrusion part 4 Negative electrode terminal 41 Hole part 5 Thermal sensor 6 Heat collecting member 61 Heat collecting part 62 Connecting leg part 7 Battery module 8 Display device ECU Control unit

Claims (8)

In an assembled battery in which a large number of unit cells are connected in series or in parallel, a thermal sensor that detects the temperature of the unit cell is provided in the vicinity of the unit cell that constitutes the assembled battery. By arranging one thermal sensor and providing a smaller number of thermal sensors than the number of connected single cells, there is a mix of single cells with thermal sensors in close proximity and single cells without thermal sensors in close proximity. The unit cells that are connected to each other and that are not close to each other are provided with a heat collecting member that collects the temperature of the unit cells and transmits temperature information of the unit cells to the thermal sensor, and constitutes a battery assembly Is composed of a plurality of single cells in which a thermal sensor is arranged and a single cell in which a heat collecting member is arranged, and each heat sensor arranged in the single cell passes through the heat collecting member. In series with each other Battery pack which is characterized in that it is a gas connection.   The assembled battery according to claim 1, wherein the thermal sensor is a PTC element or a thermistor. The assembled battery is divided into a plurality of small blocks, each small block is configured by connecting a plurality of single cells, and the single battery is configured to correspond to the small blocks of the assembled battery. The heat sensors arranged close to each other are divided into a plurality of small blocks, and each small block is configured by connecting a plurality of heat sensors in series, and the output of each small block of the heat sensor is input. And a control unit that calculates the output of the thermal sensor for each small block. A unit cell thermal sensor is arranged, the battery pack according to claim 1, characterized in that the unit cell collector member is disposed are connected are adjacent to each other. Thermal sensors, of the surface of the unit cell thermal sensor is arranged, the battery pack according to claim 1, characterized in that it is arranged at a position close to the unit cell of arranging the heat-collecting member to be adjacent. Heat collection member, iron, nickel, copper, aluminum or the assembled battery according to claim 1, characterized in that it is configured either as the main component of the alloy containing them. The unit cell constituting the assembled battery is composed of a plurality of unit cells in which a thermal sensor is arranged and a unit cell in which a heat collecting member is arranged, and the heat collecting member is arranged. 2. The assembled battery according to claim 1 , wherein the unit cell is disposed between a plurality of unit cells on which the thermal sensor is disposed. With placing the heat sensors between adjacent unit cells, the battery pack according to claim 1, characterized in that a heat-collecting member to the respective cells of the adjacent positions on opposite sides of the heat sensor.

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