Battery pack

Abstract

Provided is a structure for protecting a monitoring unit from heat from a high-voltage heat-generating component or the like in a configuration in which, in a battery pack 1 mounted on a mechanical apparatus such as an electric vehicle, a high-voltage heat-generating component 4 is disposed at an end on one side of battery modules 3 arranged side by side on a bottom surface of a lower case 2 of the battery pack 1, the monitoring unit 6 is disposed on a pedestal 5 provided above the high-voltage heat-generating component 4, and an upper side of the entire battery pack 1 is covered and packed with an upper cover 7.SOLUTION: In a battery pack having a configuration in which battery modules are arranged side by side on a bottom surface of a lower case, a high-voltage heat generating component is disposed adjacent to the battery module at an end on one side of the bottom surface of the lower case, a monitoring unit is disposed on a pedestal provided above the high-voltage heat generating component, and an upper side of the whole is covered and packed with an upper cover, a flow blocking 10a 10, a side 10b, and a side wall extending along an edge of the pedestal are provided between the edge of the pedestal on the one side and the upper cover.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to the structure of a battery pack mounted on a mechanical device such as an electric vehicle, and more particularly to a structure for protecting a monitoring unit that monitors the state of cells in the battery pack from heat. [Background technology]

[0002] Various configurations have been proposed for preventing heat damage to the internal components of battery packs (electricity storage devices) installed in electric vehicles (PHEVs, BEVs, FCVs, HEVs, etc.). For example, Patent Document 1 proposes that in an electricity storage device having a multi-story structure with a battery stack and high-voltage components arranged on each floor, a heat-shielding member be placed between the battery stack and the floor above so as to face the battery stack, thereby suppressing heat damage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2023-141941 Summary of the Invention [Problem to be solved by the invention]

[0004] In a typical in-vehicle battery pack such as the one described above, as shown in FIG. 1 , several battery modules 3 are arranged side by side on the bottom surface of the lower case (lower case 2) of the battery pack 1. At one end of the battery pack, typically the end toward the front of the vehicle, high-voltage heat-generating components 4, such as a system main relay (SMR), a direct current relay (DCR), and fuses, are packaged in a junction box (J / B). A base 5 is formed above the battery modules 4, and a monitoring unit 6 that monitors the status of the battery modules and performs various controls is mounted on the base 5. The entire assembly is covered from above by an upper cover 7. In this configuration, the monitoring unit 6 must operate normally below its heat-resistant temperature. However, the monitoring unit 6 on the base 5 may be exposed to high temperatures due to natural convection of hot air rising from below the base 5 from the high-voltage components 4, or, in the case of a vehicle with an engine mounted in front of the battery pack (such as a PHEV or HEV), due to heat from the engine compartment hitting the front surface of the battery pack. Therefore, as described above, in the case of an on-board battery pack in which the monitoring unit is positioned in front of the battery pack above high-voltage heat-generating components, it is preferable to provide a configuration that protects the monitoring unit from the high-voltage heat-generating components and heat from the front of the vehicle.

[0005] In view of the above circumstances, the main object of the present invention is to provide a structure that protects the monitoring unit from heat from the high-voltage heat-generating components and also from heat from outside the battery pack, in a configuration in which high-voltage heat-generating components are placed at one end of battery modules arranged side by side on the bottom surface of the lower case within a battery pack to be mounted on machinery and equipment such as an electric vehicle, a monitoring unit is placed on a base attached above the high-voltage heat-generating components, and the entire assembly is covered and packaged from above with an upper cover. [Means for solving the problem]

[0006] According to one aspect of the present invention, the above problem can be solved by providing a battery pack having a configuration in which battery modules are arranged side by side on the bottom surface of a lower case, high-voltage heat-generating components are arranged adjacent to the battery modules at one end of the bottom surface of the lower case, a monitoring unit is arranged on a base attached above the high-voltage heat-generating components, and the entire assembly is covered on the top side with an upper cover and packaged, This is achieved by the battery pack having a flow barrier extending along the edge of the base between the edge of the base on the one side and the upper cover.

[0007] In the above configuration, the "lower case" may be a housing with an open top. The battery modules may be composed of a stack of stacked battery cells, with various components required for operation attached. These are arranged side by side on the bottom surface of the lower case, as described above. Furthermore, the high-voltage heat-generating components mentioned above are arranged at one end of the bottom surface of the lower case on which the battery modules are arranged side by side. A base is provided above the battery modules, and a monitoring unit is placed on the base. The entire assembly is then covered with an upper cover, the edge of which is connected to the upper edge of the lower case, and the above-mentioned components are packaged together. Here, the lower case, base, and upper case are made of a material commonly used in this field, such as steel plate. The base may be fastened to the side of the lower case by screws or the like. The high-voltage heat-generating components are housed in a J / B, which may be fastened to the lower case or the base by screws or the like.

[0008] In the battery pack of the present invention having the above-described configuration, a flow-shielding wall is provided between the edge of the base on one side of the bottom surface of the lower case and the upper cover, extending along the edge of the base. The flow-shielding wall may be formed of a plate-like member made of any material that can withstand the temperature environment inside the battery pack (approximately 150°C or less), typically a steel plate of an appropriate thickness. With this configuration, the airflow crossing between the edge of the base and the upper cover is blocked, thereby preventing high-temperature air rising from high-voltage heat-generating components or high-temperature air from one side of the lower case outside the battery pack from reaching the area around the monitoring unit on the base, thereby protecting the monitoring unit from such heat.

[0009] The battery pack of the present invention is typically mounted under the floor of an electric vehicle, and the one side may be the front of the electric vehicle. In this case, the transfer of heat from the front of the vehicle to the battery pack to the monitoring unit is suppressed.

[0010] In the above-described configuration of the present invention, more specifically, in one embodiment, the flow barrier may be formed by connecting the lower edge and upper edge of a single plate-like member to the edge of the base and the upper cover, respectively, so that the wall is formed without any gaps.

[0011] In another aspect of the above-described configuration of the present invention, the flow shielding wall may include a first flow shielding wall extending upward from the edge of the base. In this configuration, the first flow shielding wall is connected only to the edge of the base, making installation easy (connecting the flow shielding wall to both the edge of the base and the upper cover requires the upper cover to be placed on the lower case while the flow shielding wall is attached to the edge of the base and the upper cover, which is somewhat difficult). Furthermore, even if vibration or load input is applied to the upper cover or base, the vibration or load input is not transmitted to the base or upper cover, thereby improving durability. Note that when only the first flow shielding wall is provided as the flow shielding wall, its upper edge may be formed as close as possible to the upper cover. This is because the high-temperature air rising from the high-voltage heat-generating components below the base tends to rise but is difficult to fall, so if the upper edge of the first flow barrier is positioned high, it becomes difficult for the high-temperature air to overcome the first flow barrier and reach the monitoring unit.

[0012] Furthermore, in the above-described configuration of the present invention, the flow shielding wall may further include a second flow shielding wall extending from the upper cover to below the upper edge of the first flow shielding wall at a position closer to the monitoring unit than the first flow shielding wall. With this configuration, high-temperature air rising from the high-voltage heat-generating component below the base rises along the second flow shielding wall rather than descending after passing the upper edge of the first flow shielding wall, so that most of the air does not reach the monitoring unit, thereby protecting the monitoring unit from high-temperature air. Furthermore, since the second flow shielding wall is connected to the upper cover but not to the base, installation is easy, and even if vibrations or load inputs are applied to the upper cover or base, the vibrations or load inputs are not transmitted to the base or upper cover, thereby improving durability.

[0013] Furthermore, in the above-described configuration of the present invention, the flow blocking walls may be provided on a surface facing one side of the bottom surface of the lower case of the monitoring unit and on both side surfaces thereof. That is, the flow blocking walls may be provided on three sides around the periphery of the monitoring unit. This makes it possible to more effectively prevent air heated by heat rising from high-voltage heat-generating components or heat from one side of the external lower case of the battery pack from reaching the monitoring unit. [Effects of the Invention]

[0014] Thus, according to the present invention, in a battery pack mounted on machinery and equipment such as an electric vehicle, high-voltage heat-generating components are placed at the end of one side of battery modules arranged side by side on the bottom surface of the lower case, a monitoring unit is placed on a base attached above the high-voltage heat-generating components, and the entire assembly is covered from above and packaged with an upper cover, the flow of air heated by heat from the high-voltage heat-generating components or even heat from outside the battery pack toward the monitoring unit is blocked or suppressed by the air-blocking wall placed between the edge of the base and the upper cover, thereby preventing the monitoring unit from being exposed to high temperatures.

[0015] Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention. [Brief explanation of the drawings]

[0016] [Figure 1] Figure 1(A) and (B) are a schematic plan view and a side cross-sectional view of the battery pack. Figure 1(C) shows the simulation results of the temperature distribution inside the battery pack (whiter indicates higher temperature H, and blacker indicates lower temperature L; the same applies below). [Figure 2] FIG. 2(A) is a side cross-sectional view of a battery pack to which one aspect of this embodiment is applied, and FIG. 2(B) shows the results of a simulation of the temperature distribution in the battery pack in the structure of (A). [Figure 3]FIG. 3(A) is a side cross-sectional view of a battery pack to which another aspect of this embodiment is applied, and FIG. 3(B) shows the results of a simulation of the temperature distribution within the battery pack in the structure of (A). [Figure 4] Figures 4(A) and (B) are side cross-sectional views of a battery pack to which another aspect of this embodiment is applied, and the simulation results of the temperature distribution within the battery pack. Figures 4(C) and (D) are side cross-sectional views of a battery pack to which another aspect of this embodiment is applied, and the simulation results of the temperature distribution within the battery pack. Figures 4(E) and (F) are side cross-sectional views of an example battery pack in which the flow barrier extending from the base edge is long and the flow barrier extending from the upper cover is short, and the simulation results of the temperature distribution within the battery pack. Figures 4(G) and (H) are side cross-sectional views of an example battery pack in which there is no flow barrier extending from the base edge, and the simulation results of the temperature distribution within the battery pack. [Figure 5] Figures 5(A) and (B) show a side cross-sectional view of an example battery pack in which the flow barrier extending from the base edge is long and there is no flow barrier extending from the upper cover, and the simulation results of the temperature distribution within the battery pack. [Figure 6] FIG. 6 is a schematic cross-sectional view of a monitoring unit in which flow barrier walls surround the monitoring unit on three sides. [Explanation of symbols]

[0017] 1... battery pack, 2... lower case, 3... battery module, 4... high-voltage heat-generating component, 5... base, 6... monitoring unit, 7... upper cover, 8... exhaust pipe, 10... flow barrier, 10a... first flow barrier, 10b... second flow barrier BEST MODE FOR CARRYING OUT THE INVENTION

[0018] The present invention will now be described in detail with reference to some preferred embodiments thereof with reference to the accompanying drawings, in which like reference numerals indicate like parts.

[0019] Battery pack configuration The battery pack to which this embodiment is applied may be a battery pack mounted under the floor of machinery and equipment such as an electric vehicle. As shown in FIGS. 1A and 1B, the battery pack 1 to which this embodiment is applied has battery modules 3, each consisting of stacked battery cells, arranged side by side on the bottom surface of a lower case 2, which is a housing with an open top. A high-voltage heat-generating component 4 is disposed at one end of the bottom surface of the lower case 2. The high-voltage heat-generating component 4 may be a group of circuit devices, such as SMRs, DCRs, and fuses, through which a large current flows, packaged in a J / B. Above the high-voltage heat-generating component 4, a base 5 is provided by fastening a plate-like member to the side surface of the lower case 2 by screws or the like, approximately parallel to the bottom surface of the lower case 2. A monitoring unit 6 is disposed on the base 5, which includes an SBM (SENSOR Battery Voltage: measuring battery voltage) that monitors and controls the status of the battery modules 3 and the high-voltage heat-generating component 4, and a battery ECU (Electric Control Unit: controlling battery charging and discharging).

[0020] In the configuration of the battery pack 1 as described above, as shown schematically in Figure 1(B), the air ha heated by the heat generated by the high-voltage heat-generating components 4 rises from the high-voltage heat-generating components 4 by natural convection, and in the case of an electric vehicle or the like that has an engine mounted in front of the battery pack 1, the air ha in the front parts of the upper case 7 and lower case 2 that has been heated by the heat generated by the exhaust pipe 8 etc. (see Figure 1(A)) located in front of the battery pack 1 moves rearward. Therefore, in a configuration in which the monitoring unit 6 is placed directly on the base 5, the hot air ha from the high-voltage heat-generating components 4 and the front parts of the upper case 7 and lower case 2 reaches the monitoring unit 6 directly, and the area around the monitoring unit 6 becomes hot, as shown in Figure 1(C). Therefore, in this embodiment, as described below, a flow barrier is provided between the edge of the base 5 and the upper case 7 to block or suppress the flow of air, thereby preventing or suppressing high-temperature air ha from reaching the area around the monitoring unit 6 and protecting the monitoring unit 6 from heat.

[0021] Structure with flow barrier A shield wall for protecting the monitoring unit 6 from heat may be provided between the edge of the base 5 and the upper case 7 in several ways, as will be described below.

[0022] (1) As shown in FIG. 2(A), the flow barrier 10 provided between the edge of the base 5 on the outer side of the lower case 2 and the upper case 7 may be configured by a single plate-like member whose surface extends substantially vertically along the edge of the base 5, with its upper and lower ends connected to the edge of the base 5 and the inner wall of the upper case 7, respectively, so as to completely cover the space between the edge of the base 5 on the outer side of the lower case 2 and the upper case 7. The plate-like member constituting the flow barrier 10 may be formed from any material that can withstand the temperature environment (approximately 150°C or less) within the battery pack, typically a steel plate of an appropriate thickness. In this configuration, as shown in FIG. 2(B), the flow barrier 10 blocks high-temperature air from the side opposite to the high-voltage power generation components 4 and battery modules 3, thereby suppressing a rise in temperature around the monitoring unit 6. Although not shown, the flow barrier wall 10 may be provided not only on the edge of the base 5 opposite the battery module 3 side, but also between the edge on the battery module 3 side and the upper case 7.

[0023] (2) As shown in Fig. 3(A), the flow barrier 10 provided between the edge of the base 5 and the upper case 7 may include a first flow barrier 10a extending upward from the edge of the base 5, and a second flow barrier 10b extending downward from the inner wall of the upper case 7 on a side closer to the monitoring unit 6 than the first flow barrier 10a, in a direction along the edge of the base 5. In this case, as shown in the figure, the second flow barrier 10b is formed so that its lower end extends below the upper end of the first flow barrier 10a. The distance between the upper edge of the first flow barrier 10a and the lower edge of the second flow barrier 10b may be, but is not limited to, 5 to 10 mm. In this configuration, when air flows from outside the first flow barrier 10a toward the monitoring unit 6, the air must pass over the upper end of the first flow barrier 10a and then descend to the lower end of the second flow barrier 10b before it can reach the monitoring unit 6. In this regard, high-temperature air ha, which has been heated by the heat of the high-voltage heat-generating component 4 or the heat from outside the battery pack, tends to rise but is difficult to descend, so that the high-temperature air ha that has reached the first flow barrier 10a rises over the upper end of the first flow barrier 10a and then rises along the second flow barrier 10b without descending to the lower end of the second flow barrier 10b. 3(A), even if the first flow shielding wall 10a and the second flow shielding wall 10b are not connected, as shown in FIG. 3(B), the high-temperature air ha hardly reaches the lower end of the second flow shielding wall 10b and does not flow around the monitoring unit 6, thereby suppressing a rise in temperature of the monitoring unit 6. Furthermore, in the case of the above configuration, the first flow shielding wall 10a and the second flow shielding wall 10b are not connected, and the first flow shielding wall 10a and the second flow shielding wall 10b are connected to the edge of the base 5 and the inner wall of the upper case 7, respectively, making installation easy, and even if vibrations or load input are applied to the upper cover 7 or the base 5, the vibrations or load input are not transmitted to the base 5 or the upper cover 7, making them less susceptible to damage, thereby improving durability. Although not shown, the first and second flow barrier walls 10a, 10b may be provided not only on the edge of the base 5 opposite the battery module 3 side, but also between the edge on the battery module 3 side and the upper case 7.

[0024] In the case of a configuration as described above in which a first flow shielding wall 10a extending upward from the edge of the base 5 and a second flow shielding wall 10b formed from the inner wall of the upper case 7 on a side closer to the monitoring unit 6 than the first flow shielding wall 10a so that its lower end extends to a position lower than the upper end of the first flow shielding wall 10a, it is desirable to minimize the amount of air passing between the first and second flow shielding walls 10a, 10b, so it is preferable that the gap between the first and second flow shielding walls 10a, 10b be as small as possible, taking into account interference, tolerances, etc.

[0025] Furthermore, in the case of a configuration in which the first flow shielding wall 10a and the second flow shielding wall 10b are provided as described above, research by the inventors of this embodiment has revealed that it is preferable for the overlapping portion of the first flow shielding wall 10a and the second flow shielding wall 10b to be as far away from the upper case 7 as possible, and that it is preferable for the second flow shielding wall 10b to be as long as possible, taking into account interference, tolerances, etc. More specifically, according to a simulation of the temperature distribution inside the battery pack when the high-voltage heat-generating component 4 inside the battery pack generates heat and the outside of the battery pack is heated, it was observed that when the lower end of the second flow barrier 10b is separated from the upper case 7, as shown in Figures 3(A), 4(A), and 4(C), the high-temperature air that hits the connection between the second flow barrier 10b and the upper case 7 is unlikely to reach the lower end of the second flow barrier 10b, even with the inertia of the flow, and the high-temperature air hardly exceeds the second flow barrier 10b, so that the area around the monitoring unit 6 is kept at a low temperature, as shown in Figures 3(B), 4(B), and 4(D). On the other hand, when the second flow shielding wall 10b is short, as shown in Figure 4(E), after the high-temperature air hits the connection between the second flow shielding wall 10b and the upper case 7, the inertia of the flow causes it to easily go over the lower end of the second flow shielding wall 10b, and as a result, as shown in Figure 4(F), it was observed that the high-temperature air reaches the periphery of the monitoring unit 6, causing the temperature to rise around the monitoring unit 6. From this, it became clear that it is preferable for the second flow shielding wall 10b to be as long as possible, with its lower end being as far away from the upper case 7 as possible.

[0026] Furthermore, as shown in Figure 4(G), even if the second flow barrier 10b is long, if the first flow barrier 10a is not present, it has been confirmed that high-temperature air heated by the high-voltage heat-generating component 4 enters above the base 5 from the lower end of the second flow barrier 10b, as shown in Figure 4(H), causing high temperatures around the monitoring unit 6.

[0027] (3) According to research by the inventors of this embodiment, it has been observed that even when there is no second flow shielding wall 10b as shown in Fig. 5(A), when the first flow shielding wall 10a extends close to the upper case 7, it is possible to suppress the temperature rise around the monitoring unit 6 to a certain extent as shown in Fig. 5(B). Therefore, in one aspect of this embodiment, the flow shielding wall may be the only first flow shielding wall 10a extending upward from the edge of the base 5.

[0028] (4) As already mentioned, the flow barriers may be provided not only on the edge of the base 5 opposite the battery module 3 side, but also on the edge on the battery module 3 side. Furthermore, as shown in Fig. 6, the flow barriers 10, 10a, 10b may also be provided on both side surfaces of the monitoring unit 6, i.e., in the direction from the edge (F) of the base 5 opposite the battery module 3 side to the edge (R) on the battery module 3 side. This is expected to better suppress the temperature rise around the monitoring unit 6.

[0029] The above description has been made in relation to the embodiments of the present invention, but it will be apparent that many modifications and changes will be readily apparent to those skilled in the art, and the present invention is not limited to the above-described exemplary embodiments, but can be applied to various devices without departing from the concept of the present invention.

Claims

1. A battery pack having a configuration in which battery modules are arranged side by side on the bottom surface of a lower case, high-voltage heat-generating components are arranged adjacent to the battery modules at one end of the bottom surface of the lower case, a monitoring unit is arranged on a base attached above the high-voltage heat-generating components, and the entire assembly is covered with an upper cover and packaged, The battery pack further includes a flow barrier extending along the edge of the base between the edge of the base on the one side and the upper cover.

2. 2. The battery pack of claim 1, wherein the battery pack is mounted under a floor of an electric vehicle, and the one side is a front side of the electric vehicle.

3. 2. The battery pack of claim 1, wherein the flow barrier includes a first flow barrier extending upward from an edge of the base.

4. 4. The battery pack of claim 3, wherein the flow barrier further includes a second flow barrier extending from the upper cover to a position lower than the upper edge of the first flow barrier at a position closer to the monitoring unit than the first flow barrier.

5. 5. The battery pack according to claim 1, wherein the flow-blocking walls are provided on a surface of the lower case of the monitoring unit facing one side of the bottom surface and on both side surfaces of the surface.

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