JP2015220003A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure excellent temperature detection accuracy by suppressing the impact of outdoor air flowing into a smoke exhaust duct.SOLUTION: A battery pack 10 includes a battery stack 20 formed by stacking a plurality of batteries 21 having a safety valve 22, a smoke exhaust duct 14 for leading the gas discharged from the safety valve 22, and a temperature sensor 15 installed in the duct. The smoke exhaust duct 14 is provided with a windbreak wall 38 covering at least the duct exhaust port side 14a of a temperature sensor 15.

Description

  The present invention relates to a battery pack, and more particularly, to a battery pack including a smoke exhaust duct and a temperature sensor.

  Patent Document 1 discloses a battery pack including a battery stack in which a plurality of batteries having safety valves are stacked, and a smoke exhaust duct for guiding gas discharged from the safety valves to the outside due to internal short circuit of the batteries or the like. ing. In the battery pack, a temperature sensor for detecting the temperature of the battery is provided in the vicinity of the smoke exhaust duct. Patent Document 2 discloses a battery pack in which a temperature sensor is disposed in a flow path through which cooling air flows.

JP 2010-80135 A Japanese Patent Laid-Open No. 2003-187772

  By the way, since the surface temperature of the battery tends to be high in the vicinity of the safety valve, the temperature sensor is preferably provided in the vicinity of the safety valve. The temperature sensor is particularly preferably provided in the smoke exhaust duct so that the temperature of the hot gas discharged from the safety valve can be detected. However, since the smoke exhaust duct communicates with the outside of the battery pack, if a temperature sensor is provided in the exhaust duct, outside air may flow from the exhaust port of the duct and hit the temperature sensor, reducing the accuracy of temperature detection. is there. In particular, in the case of a battery pack mounted on a vehicle, outside air tends to flow into the smoke exhaust duct when the vehicle is traveling, and the detection value tends to become unstable.

  The battery pack according to the present invention includes a battery stack in which a plurality of batteries having safety valves are stacked, a smoke exhaust duct for guiding gas discharged from the safety valve to the outside of the battery pack, and the smoke exhaust duct. A battery pack including an installed temperature sensor, wherein the smoke exhaust duct is provided with a windbreak wall that covers at least a duct exhaust port side of the temperature sensor.

  In the battery pack according to the present invention, the temperature sensor is covered by the windbreak wall or by the windbreak wall and the side wall of the smoke exhaust duct except for the upstream side of the duct (the side opposite to the duct exhaust port side). It is preferable that

  According to the battery pack of the present invention, since the temperature sensor is installed in the smoke exhaust duct in the vicinity of the safety valve of the battery, it is easy to detect an increase in the battery temperature, and the high temperature gas discharged from the safety valve is reduced. It can be detected quickly. Further, since the smoke exhaust duct is provided with a windproof wall that covers at least the duct exhaust port side of the temperature sensor, it is possible to suppress the influence of outside air flowing into the smoke exhaust duct and to ensure good temperature detection accuracy. .

It is a figure which shows the battery pack which is an example of embodiment of this invention. It is AA sectional view taken on the line of FIG. It is the B section enlarged view of FIG. It is a figure (front view) which extracts and shows the sensor installation part and windbreak wall which are examples of the embodiment of the present invention. It is the figure (perspective view seen from the bottom) which extracts and shows the sensor installation part which is an example of embodiment of this invention, and a windbreak wall.

An example of an embodiment of the present invention will be described in detail below.
The drawings referred to in the embodiments are schematically described, and the dimensional ratios of components drawn in the drawings may be different from the actual products. Specific dimensional ratios and the like should be determined in consideration of the following description.

  In the present specification, the description of “substantially **” is intended to include what is recognized as substantially the same as the same as the case where the description is given by taking substantially the same as an example. In the following, for convenience of explanation, the side on which the safety valve of the battery is provided is referred to as “above” the battery pack (battery stack / battery), but the relationship between each component of the battery pack and the direction is not limited. A direction in which a plurality of batteries are stacked and a direction orthogonal to the vertical direction are defined as a horizontal direction (or a horizontal direction).

  In the embodiment, the battery pack is described as being mounted on a vehicle. Examples of the vehicle include a hybrid vehicle and an electric vehicle. The battery pack of the embodiment is used as a power source that supplies power to a motor that is a power source of a vehicle, for example.

  Hereinafter, a battery pack 10 as an example of an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing a battery pack 10. In FIG. 1, the upper cover 12 and the lower cover 13 are indicated by a two-dot chain line. 2 is a cross-sectional view taken along line AA in FIG.

  As shown in FIGS. 1 and 2, the battery pack 10 includes a stack assembly 11, an upper cover 12, and a lower cover 13. The upper cover 12 and the lower cover 13 are covers that cover the stack assembly 11. The two covers cover almost the entire stack assembly 11 to form a case that accommodates the assembly. For example, the upper cover 12 covers the top surface and some side surfaces of the stack assembly 11, and the lower cover 13 covers the bottom surface and some side surfaces of the stack assembly 11. The number of stack assemblies 11 accommodated in the case is not particularly limited, and may be one or plural (for example, two).

  The stack assembly 11 includes a battery stack 20 in which a plurality of batteries 21 are stacked, and a bus bar module 30 that electrically connects the batteries 21 of the stack. In the example shown in FIG. 1, a battery stack 20 is configured by stacking a large number of substantially rectangular parallelepiped batteries 21 in one direction, and the one direction is the longitudinal direction of the battery stack 20. The bus bar module 30 is provided on the top surface 20a of the battery stack 20, and includes, for example, a frame 31 (see FIG. 2) that is a housing of the module, a terminal connection portion 32 (see FIG. 2) that is a wiring member, and a terminal connection. And a cover 33 that covers the portion 32 and the like.

  Each battery 21 constituting the battery stack 20 has terminals 23 and 24 (see FIG. 2) which are a positive terminal and a negative terminal, respectively. The terminals 23 and 24 are provided on the left and right of a later-described safety valve 22 on the top surface 21a of the battery 21, for example. The plurality of batteries 21 are preferably arranged with their left and right directions reversed between adjacent batteries 21 so that the terminals 23 and 24 are alternately arranged along the longitudinal direction of the battery stack 20. The terminal connection part 32 of the bus bar module 30 preferably connects a plurality of batteries 21 in series. For example, the terminal 23 of one adjacent battery 21 and the terminal 24 of the other battery 21 are connected.

  The battery stack 20 preferably has a partition member 25 (see FIG. 1) between the two batteries 21. The partition member 25 is made of an insulating material such as resin and functions as a spacer. Moreover, it is preferable that the partition member 25 has a flow path for flowing a coolant such as cooling air. In the present embodiment, the upper end of the partition member 25 projects upward from the top surface 21 a of the battery 21.

  For example, end plates (not shown) are arranged at both ends of the battery stack 20 in the longitudinal direction. In the present embodiment, two restraining rods 26 are provided on the top surface 20a side of the battery stack 20, and two restraining rods 27 (see FIG. 2) are provided on the bottom surface 20b side. The restraining rods 26 and 27 extend, for example, in the longitudinal direction of the battery stack 20, and both ends are attached to the end plates. Each constraining rod applies a force (constraining force) for pressing each end plate against the battery 21.

  The number of the batteries 21 constituting the battery stack 20 is not particularly limited, and can be appropriately set according to a required output. The battery 21 is, for example, a secondary battery such as a nickel metal hydride battery or a lithium ion battery, or a capacitor such as an electric double layer capacitor, and is preferably a secondary battery. The battery 21 has a safety valve 22 that opens when gas is generated inside the battery due to an internal short circuit or the like and the internal pressure increases. In the present embodiment, a safety valve 22 is provided in the approximate center of the top surface 21a of each battery 21. The safety valve 22 is formed, for example, by locally reducing the thickness of the outer package of the battery 21 and is designed to break when the internal pressure of the battery 21 exceeds a predetermined threshold.

  In the present embodiment, the two restraining rods 26 are arranged on the left and right sides of the safety valve 22 with a space between each other. The upper cover 12 is provided with a leg portion 12a (see FIG. 2) that engages with the restraining rod 26. By attaching the leg portion 12a to the restraining rod 26, the upper cover 12 and the top surface 20a of the battery stack 20 are provided. Between the two restraining rods 26, a smoke exhaust duct 14 to be described later is formed.

  As shown in FIGS. 1 and 2, the battery pack 10 includes a smoke exhaust duct 14 for guiding the high temperature gas discharged from the safety valve 22 of the battery 21 to the outside of the battery pack 10, and a temperature installed in the duct. Sensor 15.

  The smoke exhaust duct 14 preferably extends along the direction in which the plurality of batteries 21 are stacked (the longitudinal direction of the battery stack 20) and has one duct exhaust port 14a. In the present embodiment, as described above, the gap provided between the top surface 20 a of the battery stack 20 and the upper cover 12 serves as the smoke exhaust duct 14. The smoke exhaust duct 14 has, for example, a duct exhaust port 14a at one end in the longitudinal direction, and the other end in the longitudinal direction is closed. It is preferable that the smoke exhaust duct 14 has no opening other than the duct exhaust port 14a, and is designed so that substantially all of the high-temperature gas is exhausted from only one duct exhaust port 14a to the outside of the vehicle. Hereinafter, the longitudinal direction one end side of the smoke exhaust duct 14 provided with the duct exhaust port 14a is referred to as “duct downstream side”, and the longitudinal direction other end side of the smoke exhaust duct 14 is referred to as “duct upstream side”.

  The temperature sensor 15 may be provided in a state where the temperature measuring unit is in contact with the top surface 21 a located in the vicinity of the safety valve 22 so that the battery surface temperature in the vicinity of the safety valve 22 can be detected in the smoke exhaust duct 14. Is preferred. A conventionally well-known sensor can be used for the temperature sensor 15, for example, a thermistor is used. The temperature of the battery 21 detected by the temperature sensor 15 is transmitted to, for example, a control device (not shown) and used for controlling the battery pack 10 and the like. Further, the temperature sensor 15 detects the temperature of the hot gas discharged from the safety valve 22 and flowing through the smoke exhaust duct 14.

  In the present embodiment, the temperature sensor mounting unit 34 (hereinafter referred to as “mounting unit 34”) of the bus bar module 30 is disposed in the smoke exhaust duct 14, and the temperature sensor 15 is provided in the sensor installation portion 36 of the unit. Further, the two restraining rods 26 serve as side walls of the smoke exhaust duct 14, and the interval between the rods defines the width of the smoke exhaust duct 14. When a gap exists between the restraining rod 26, the upper cover 12, and the battery stack 20, a seal member that closes the gap may be provided. The two restraining rods 26 are preferably provided substantially parallel to each other. Thereby, the smoke exhaust duct 14 having a substantially constant width is formed.

  The mounting unit 34 is disposed in the smoke exhaust duct 14 as described above. The attachment unit 34 is connected to, for example, the frame 31 by a connecting portion 37 that extends beyond the restraining rod 26 and into the smoke exhaust duct 14. By integrating the attachment unit 34 with the bus bar module 30, the assembly of the stack assembly 11 is facilitated.

  The attachment unit 34 includes, for example, a base portion 35 extending along the longitudinal direction of the smoke exhaust duct 14 and a sensor installation portion 36 provided at a part of the base portion 35. The base 35 has a substantially U-shaped cross section in the width direction, and is provided over substantially the entire length of the smoke exhaust duct 14. The cable of the temperature sensor 15 passes through the base 35 and is drawn out of the battery pack 10.

  The mounting unit 34 may be disposed at the center in the width direction of the smoke exhaust duct 14, but is preferably disposed so as to be in contact with one of the restraining rods 26, that is, in contact with the side wall of the smoke exhaust duct 14. Thereby, for example, the flow of the high-pressure gas discharged from the safety valve 22 can be made smooth, and the side wall of the smoke exhaust duct 14 functions as a windbreak wall as will be described later, so that the windbreak wall 38 can be reduced. The width of the mounting unit 34 is preferably 30% or less of the width of the smoke exhaust duct 14.

  The sensor installation part 36 is provided at least on the downstream side of the smoke exhaust duct 14. The sensor installation part 36 is provided in the vicinity of the duct exhaust port 14a, for example, in a range of 10% or less of the length of the smoke exhaust duct 14 from the duct exhaust port 14a. Thereby, the hot gas discharged | emitted from the safety valve 22 can be detected rapidly. Although it is possible to install the temperature sensors 15 in all the batteries 21, it is preferable to install them in some of the batteries 21 from the viewpoint of cost reduction and the like. For example, the sensor installation parts 36 are provided at three locations near the both ends in the longitudinal direction of the smoke exhaust duct 14 and in the middle part.

  The shape of the sensor installation part 36 can be appropriately changed according to the shape of the temperature sensor 15 and the like. The sensor installation part 36 is provided on the bottom surface of the base part 35, for example, and has a structure into which the temperature sensor 15 can be inserted. On the sensor installation part 36, for example, a cover 39 is provided to protect the cable of the temperature sensor 15. Hereinafter, a surface of the sensor installation portion 36 that is substantially in contact with the restraining rod 26 is referred to as a back surface portion, and a surface located on the opposite side of the back surface portion is referred to as a front surface portion.

  Hereinafter, the structure around the sensor installation part 36 to which the temperature sensor 15 is attached will be described in detail with reference to FIGS. FIG. 3 is an enlarged view showing a portion B (near the sensor installation portion 36) in FIG. 4 and 5 are views showing the sensor installation portion 36 and the windbreak wall 38 extracted, FIG. 4 is a view of the sensor installation portion 36 as viewed from the front side, and FIG. 5 is a view of the sensor installation portion 36 from below. It is a perspective view.

  As shown in FIGS. 3 to 5, the smoke exhaust duct 14 is provided with a windbreak wall 38 that covers at least the duct exhaust port 14 a side of the temperature sensor 15. The windbreak wall 38 plays a role of preventing the outside air flowing into the smoke exhaust duct 14 from the duct exhaust port 14a from hitting the temperature sensor 15 and ensuring good temperature detection accuracy. Since the temperature sensor 15 is attached to the sensor installation part 36 of the attachment unit 34, the windbreak wall 38 is provided around the sensor installation part 36. The windbreak wall 38 is a panel that protrudes downward from the bottom surface of the base portion 35 located around the sensor installation portion 36.

  For example, the windbreak wall 38 may be provided only around the sensor installation portion 36 located on the downstream side of the smoke exhaust duct 14 that is easily affected by outside air, but is preferably provided around all the sensor installation portions 36. In the example shown in FIG. 1, the windbreak walls 38 covering the sensor installation portions 36 have substantially the same shape, but the shapes of the windbreak walls 38 may be different from each other.

  The windbreak wall 38 is provided at least on the duct exhaust port 14a side (duct downstream side) of the sensor installation part 36 in the periphery of the sensor installation part 36 (temperature sensor 15). Furthermore, the windbreak wall 38 is preferably provided so as to cover the front portion of the sensor installation portion 36. On the other hand, it is preferable not to provide the windbreak wall 38 on the upstream side of the duct of the sensor installation portion 36. In this embodiment, since the back surface part of the sensor installation part 36 is arrange | positioned in contact with the side wall of the smoke exhaust duct 14, the said side wall functions as a windbreak wall.

  That is, the windproof wall 38 and the side wall of the smoke exhaust duct 14 surround the sensor installation portion 36 except for the upstream side of the duct. Thereby, most of the outside air flowing in from the duct exhaust port 14a can be prevented from hitting the temperature sensor 15, and for example, a part of the outside air entering the periphery of the sensor installation portion 36 through the gap of the windbreak wall 38 is It flows to the upstream side of the duct without creating an airflow vortex around 36. Moreover, since the hot gas discharged from the safety valve 22 and flowing downstream of the duct is not blocked by the windbreak wall, the hot gas can be detected quickly.

  The windbreak wall 38 has a substantially L shape as a whole, and is provided substantially in parallel with the first wall portion 38 a located on the downstream side of the duct of the sensor installation portion 36 and the side wall of the smoke exhaust duct 14. It is preferable to include a second wall portion 38b that covers the front portion of the first wall portion. The angle formed by the first wall portion 38a and the second wall portion 38b with respect to the sensor installation portion 36 side is larger than 90 °, for example, in order to smooth the flow of the incoming external air and suppress the generation of the air vortex. An angle is preferred. It is preferable that the first wall portion 38 a extends to a position that is substantially in contact with the side wall of the smoke exhaust duct 14.

  The wind barrier 38 is provided across, for example, the two batteries 21. As described above, the partition member 25 protruding above the top surface 21 a is disposed between the adjacent batteries 21, so that the partition wall 25 is avoided on the second wall portion 38 b of the windbreak wall 38. The recess 38c is formed. It is preferable that the first wall portion 38 a and the second wall portion 38 b extend below at least the upper end of the partition member 25. On the other hand, it is preferable to provide a gap between the windbreak wall 38 and the top surface 21a. Thereby, for example, the influence of the outside air on the temperature detection can be suppressed while ensuring the flowability of the high temperature gas around the sensor installation portion 36 without hindering the contact of the temperature sensor 15 with the battery surface.

  As described above, according to the battery pack 10 having the above configuration, since the temperature sensor 15 is installed in the smoke exhaust duct 14, it is easy to detect the temperature rise of the battery 21 and is discharged from the safety valve 22. Hot gas can be detected quickly. On the other hand, because the smoke exhaust duct 14 communicates with the outside of the vehicle, a pressure difference is generated inside and outside the exhaust duct 14 when the vehicle is traveling (the interior of the duct is low), and the outside air easily flows into the duct, so that temperature detection accuracy is achieved. It will contribute to lowering. According to the battery pack 10, since the windbreak wall 38 that covers the temperature sensor 15 is provided, it is possible to suppress the influence of outside air and ensure good temperature detection accuracy.

  In the battery pack 10, the sensor installation portion 36 except for the upstream side of the duct is surrounded by a windbreak wall 38 and the like, so that outside air hits the temperature sensor 15 without generating an airflow vortex around the sensor installation portion 36. Can be greatly suppressed. When the windbreak wall is provided in the entire periphery including the duct upstream side of the sensor installation part 36, it is possible to prevent the temperature sensor 15 from being exposed to outside air as compared with the case where no windbreak wall is provided. On the other hand, as compared with the case where the upstream side of the duct is opened, air vortices are likely to be generated around the sensor installation portion 36, and the outside air is likely to hit the temperature sensor 15.

  The above embodiment can be appropriately changed in design, and various modifications other than those described above are possible. For example, in the above embodiment, the smoke exhaust duct 14 is formed by using the upper cover 12 and the restraining rod 26. However, a smoke exhaust duct may be formed by separately providing a wall that covers the safety valve 22. Further, it is possible to provide a structure for attaching the temperature sensor 15 and a windbreak wall on the upper cover 12 or the top surface 20a of the battery stack 20.

  DESCRIPTION OF SYMBOLS 10 Battery pack, 11 Stack assembly, 12 Upper cover, 12a Leg part, 13 Lower cover, 14 Smoke duct, 14a Duct exhaust port, 15 Temperature sensor, 20 Battery stack, 20a, 21a Top surface, 20b Bottom surface, 21 Battery, 22 Safety valve, 23, 24 terminal, 25 Partition member, 26, 27 Restraint rod, 30 Bus bar module, 31 Frame, 32 Terminal connection part, 33, 39 Cover, 34 Temperature sensor mounting unit, 35 Base part, 36 Sensor installation part, 37 Connection part, 38 Windbreak wall, 38a 1st wall part, 38b 2nd wall part, 38c Concave part.

Claims (1)

A battery stack in which a plurality of batteries having safety valves are stacked;
A smoke exhaust duct for guiding the gas discharged from the safety valve to the outside of the battery pack;
A temperature sensor installed in the smoke exhaust duct;
A battery pack comprising:
The battery pack, wherein the smoke exhaust duct is provided with a windbreak wall that covers at least a duct exhaust port side of the temperature sensor.

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