JP7214569B2 - battery pack - Google Patents

Description

The present invention relates to a battery pack for use in hybrid vehicles and the like.

In recent years, hybrid vehicles, which have been under development, incorporate an ultra-thin three-phase alternating current machine in the flywheel housing of the diesel engine so that the three-phase alternating current machine assists the diesel engine.

That is, the three-phase AC machine used here operates as a starter when the engine is started, operates as a torque assist motor when the vehicle starts and accelerates, and operates as an electric brake when the vehicle is braked. As a result, the load on the diesel engine is reduced to improve fuel consumption, and the amount of air pollutants emitted from the diesel engine can be reduced.

Such a hybrid vehicle is equipped with an in-vehicle power supply for driving a motor. In this type of in-vehicle power supply, a battery stack, in which a large number of battery cells are assembled into a module, is vertically arranged in a battery pack. However, it is necessary to air-cool the battery cells of each battery stack as efficiently and uniformly as possible.

This is because a battery cell deteriorates due to overheating, and if some of the battery cells deteriorate and a difference in performance occurs between the battery cells, the entire battery cell group will be burdened. This is because the deterioration of the performance of the entire in-vehicle power supply device is accelerated.

For this reason, a plurality of battery stacks are arranged vertically and housed in a battery pack, and support portions provided at both width ends of each battery stack are fastened to the structure of the battery pack so that the battery stack floats from the bottom surface of the battery pack. Air is blown into the space secured below each battery stack by a blower and extracted upward through the space between the battery cells of each battery stack, thereby efficiently and evenly cooling the battery cells. ing.

In general, the battery pack as described above has a sealed structure, and it is necessary to eliminate fluctuations in internal pressure due to changes in temperature. It is necessary to pass through the battery pack at a plurality of locations using a breather using a ventilation filter.

Prior art document information relating to battery packs in this type of hybrid vehicle includes the following Patent Document 1 and the like.

JP 2019-8974 A

However, there is a natural limit to the breathability of a breather that uses a ventilation filter as described above, and in hybrid vehicles such as heavy-duty trucks, because of the large capacity of the battery pack, a large number of breathers must be installed. It is more realistic to open a very small number of through-holes without a ventilation filter to allow breathing, but simply opening the through-holes may cause high-pressure washing, splashing, etc. Therefore, when the battery pack is exposed to water, there is a risk that water may enter the interior of the battery pack.

In the case of conventional sealed battery packs, even if the condensed water generated inside flows down, it will not be drained and will accumulate on the bottom surface. As a result, the bottom surface moves around and undulates, which may cause the condensed water to splash on electrical parts such as battery cells, adversely affecting the electrical parts.

The present invention has been made in view of the above-mentioned actual situation. An object of the present invention is to provide a battery pack capable of realizing drainage.

The present invention accommodates a battery stack in which a large number of battery cells are modularized, floats and supports the battery stack from a bottom surface, and blows air into a space secured between the bottom surface and the battery stack by a blower. In the battery pack in which each battery cell is air-cooled by passing between the battery cells of the battery stack, a pit portion forming a stepped recess is provided on the bottom surface, and a through hole is opened in the bottom surface of the pit portion. In addition, the through hole is covered with an air-permeable layer made of a porous material.

By covering the through-holes with a ventilation layer made of a porous material in this way, the breathing volume is greatly increased compared to a conventional breather using a waterproof ventilation filter, and only a very small number of through-holes are required. It is possible to secure breathing volume, and even if the battery pack gets wet due to high-pressure washing or splashing, the ventilation layer can prevent water from entering the through holes directly. becomes.

Also, even if condensed water occurs inside the battery pack and flows down, the condensed water accumulates in the pit portion that forms a stepped depression on the bottom surface of the battery pack, and permeates the ventilation layer of the porous material here. Since the water is drained from the through hole at any time, the condensed water accumulated on the bottom of the battery pack can be prevented from moving around and rippling due to inertia, vibration, vehicle posture, etc. be done.

Furthermore, in the present invention, it is preferable that the ventilation layer is held on the bottom surface of the pit portion by a fixture so that the through hole is kept in a covered state, and that the fixture is provided with a waterproof wall facing the through hole, In this way, the fixture ensures that the through hole is covered with the ventilation layer, and the water shut-off wall reliably dams the high-pressure washing water, etc. that rushes into the through hole and loses its momentum. It is possible to quickly drain the water.

Further, in the present invention, it is preferable that the pit portion is divided as a cover body for detachably closing the maintenance inspection opening opened in the bottom surface. Simply by attaching and blocking the part, a step-down depression is easily formed, and at the same time, maintenance and inspection of electric parts such as a blower can be easily performed by setting a maintenance inspection opening.

Further, in the present invention, it is preferable to form the inner fins on the bottom surface so as to form a plurality of grooves for guiding the condensed water toward the pit portion. Since it flows down along the grooves of the internal fins and adheres to the walls of the internal fins due to surface tension, it is smoothly guided to the pit. Water is prevented from moving around the bottom surface and rippling.

In this case, if external fins are also formed on the lower surface so that the external fins function as a heat sink, the heat received by the internal fins through condensed water or air can be efficiently dissipated. It is possible to dissipate heat well to the outside of the battery pack.

According to the battery pack of the present invention described above, the following various excellent effects can be obtained.

(I) According to the invention of claim 1 of the present invention, it is possible to greatly increase the breathing volume compared to the conventional breather using a waterproof ventilation filter, and moreover, high-pressure washing and splashing (splashing water) are possible. ), etc., the ventilation layer can prevent direct water intrusion into the through-holes when the battery pack is submerged in water. Furthermore, the condensation water generated inside can be stored in the pit and drained quickly from the through hole, so that the condensation water accumulated on the bottom surface of the battery pack can be removed during driving. It is possible to avoid a situation where the bottom surface moves around and waves due to inertia, vibration, vehicle posture, etc., and there is a risk that condensed water will splash on electrical parts such as battery cells and adversely affect the electrical parts. can be eliminated.

(II) According to the invention of claim 2 of the present invention, it is possible to reliably maintain the covering state of the ventilation layer with respect to the through hole by means of the fixture, and moreover, to prevent high-pressure washing water or the like from vigorously entering the through hole. It is possible to reliably dam water with a cutoff wall, lose its momentum, and quickly drain water.

(III) According to the invention of claim 3 of the present invention, it is possible to easily form a step-down depression simply by attaching a container-shaped pit portion to the maintenance inspection opening opened in the bottom surface and closing the opening. Also, by setting the maintenance and inspection opening, maintenance and inspection work of electric parts such as a blower can be easily performed.

(IV) According to the invention of claim 4 of the present invention, the dew condensation water generated inside the battery pack is allowed to flow down the grooves of the internal fins, and remains adhered to the wall surfaces of the internal fins by surface tension. Since it can be smoothly guided to the pit area, it is possible to prevent the condensed water from moving around and waving on the bottom surface due to inertia, vibration, vehicle posture, etc. It is possible to more reliably eliminate the possibility that dew condensation water splashes and adversely affects the electrical parts.

(V) According to the fifth aspect of the present invention, external fins are also formed on the lower surface of the battery pack so that the external fins function as heat sinks. It is possible to efficiently dissipate the heat received through the battery pack and the air to the outside of the battery pack, thereby improving the air-cooling efficiency of each battery cell.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of the form which implements this invention. FIG. 2 is a perspective view showing details of a pit portion in FIG. 1; FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2; Figure 4 is a perspective view of a detail of the fixture of Figure 3; FIG. 2 is a partially cutaway perspective view of the internal fins and external fins of FIG. 1 ; FIG. 2 is a cross-sectional view showing how condensed water has flowed down on the wall surface of the internal fins of FIG. 1; FIG. 11 is a perspective view showing another embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of an embodiment of the present invention. In this embodiment, a plurality of battery stacks 1 are vertically arranged and housed in a battery pack 2, and the structure of the battery pack 2 Both width ends of each battery stack 1 are fixed so as to be floated from the bottom surface of the battery pack 2 to be supported. The air taken in by the blower 4 is sent to the lower side of each battery stack 1, and escapes upward from the lower side of each battery stack 1 through between the battery cells 5, thereby blowing the battery cells 5. Efficient and uniform air cooling is possible.

Further, the air released from each battery stack 1 flows through the flow path partitioned by the flow path partition plate 6, is guided in a direction away from the blower 4, and then turns back toward the blower 4 side. The air is exhausted to the outside from an exhaust port (not shown) that opens to the outside.

Here, a container-shaped pit portion 7 forming a stepped depression is provided on the bottom surface of the surplus space 3 in the battery pack 2. A maintenance and inspection opening 8 is formed for maintenance and inspection of the electrical parts, and the pit portion 7 is divided as a lid for detachably closing the maintenance and inspection opening 8 .

As shown in FIGS. 2 to 4, a through hole 9 is formed in the bottom surface of the pit portion 7, and the through hole 9 is covered with a ventilation layer 10 made of stainless wool (porous material). A ventilation layer 10 is held on the bottom surface of the pit portion 7 by a fixture 11 so as to keep the through hole 9 covered.

That is, the fixture 11 is provided with a water cutoff wall 11a facing the through hole 9, and the four corners of the water cutoff wall 11a are attached to the bottom surface of the pit portion 7 via support legs 11b. The ventilation layer 10 is sandwiched and held between the wall 11a and the bottom surface of the pit portion 7. As shown in FIG.

Further, as shown in FIGS. 1, 5, and 6, the bottom surface of the battery pack 2 is formed with internal fins 12 that form a plurality of grooves that guide the condensed water toward the pit portion 7. 2 is also formed with external fins 13 so that the external fins 13 function as a heat sink.

Since the battery pack 2 as described above employs a structure in which the through hole 9 is covered with the ventilation layer 10 made of stainless wool, it is more effective than the conventional breather using a waterproof ventilation filter. The breathing volume is greatly increased, and it is possible to secure the required breathing volume with only a very small number of through holes 9. Moreover, even if the battery pack 2 is exposed to water due to high-pressure washing or splashing, The ventilation layer 10 makes it possible to prevent water from entering the through hole 9 directly.

Further, even if dew condensation water occurs inside the battery pack 2 and flows down, the dew condensation water accumulates in the pit portion 7 forming a stepped recess on the bottom surface of the battery pack 2, where the ventilation layer 10 of stainless wool is formed. , and drained from the through hole 9 at any time, the condensed water accumulated on the bottom surface of the battery pack 2 moves around the bottom surface due to inertia, vibration, vehicle posture, etc. Situation is avoided.

At this time, the condensed water generated inside the battery pack 2 flows down along the grooves of the internal fins 12, and adheres to the wall surface of the internal fins 12 by surface tension (see FIG. 6), and is smoothly guided to the pit portion 7. As it dries up, it is possible to prevent the condensed water from moving here and there on the bottom surface due to inertia, vibration, vehicle posture, etc.

Therefore, according to the above-described embodiment, it is possible to greatly increase the breathing volume compared to the conventional breather using a waterproof ventilation filter, and moreover, the battery pack 2 is exposed to high-pressure washing, splashing (splashing water), and the like. Since the ventilation layer 10 can prevent direct water intrusion into the through-holes 9 when wet, pressure fluctuations can be achieved by ensuring the necessary breathing volume while preventing water intrusion with only a very small number of through-holes 9. In addition, the condensation water generated inside can be accumulated in the pit portion 7 and drained quickly from the through hole 9, so that the condensation water accumulated on the bottom surface of the battery pack 2 can be removed when the vehicle is running. It is possible to avoid a situation in which the bottom surface moves here and there due to inertia, vibration, vehicle posture, etc., and undulates. can be eliminated.

In particular, in the case of this embodiment, it is possible to reliably maintain the covering state of the ventilation layer 10 with respect to the through hole 9 by means of the fixture 11, and furthermore, the high-pressure washing water, etc., which has vigorously entered the through hole 9 can be prevented by the waterproof wall 11a. can reliably dam it up, lose its momentum and quickly drain water, furthermore, the dew condensation water generated inside the battery pack 2 is made to flow down the grooves of the internal fins 12, and the internal fins 12 Since the condensed water can be smoothly guided to the pit portion 7 while being adhered to the wall surface by surface tension, it is possible to prevent the condensed water from moving here and there on the bottom surface due to inertia, vibration, vehicle posture, etc. It is possible to more reliably eliminate the risk that the condensed water splashes on the electric parts such as the battery cell 5 and adversely affects the electric parts.

In addition, since the pit portion 7 is divided as a lid for detachably closing the maintenance inspection opening 8 opened in the bottom surface of the battery pack 2, the maintenance inspection opening 8 opened in the bottom surface of the battery pack 2 has a container-shaped pit. Only by attaching and closing the portion 7, a stepped recess can be easily formed, and by setting the maintenance inspection opening 8, maintenance and inspection work of electric parts such as the blower 4 can be easily performed.

Furthermore, since the external fins 13 are also formed on the lower surface of the battery pack 2 so that the external fins 13 function as heat sinks, the internal fins 12 efficiently dissipate heat received through condensed water and air. The heat can be effectively dissipated to the outside of the battery pack 2, and the air-cooling efficiency of each battery cell 5 can be improved more than before.

FIG. 7 shows another embodiment of the present invention. In the example shown here, a maintenance inspection opening 8 (see FIG. 1) opened in the bottom surface of the battery pack 2 (see FIG. 1) can be detachably attached. Regarding the pit part 7 which is divided and configured as a covering lid, through holes 9 are opened in a plurality of corners on the bottom surface of the pit part 7, and a permeable layer 10 is formed by using water permeable Ept Sealer (registered trademark) as a porous material. It is possible to use a porous material other than stainless wool as the ventilation layer 10 in this way.

It should be noted that the battery pack of the present invention is not limited to the above-described embodiments, and the porous material forming the air-permeable layer may be a coarse-mesh sponge or the like. It goes without saying that various modifications can be made within the scope of the invention.

REFERENCE SIGNS LIST 1 battery stack 2 battery pack 5 battery cell 7 pit section 8 maintenance inspection opening 9 through hole 10 ventilation layer 11 fixture 11a water stop wall 12 internal fin 13 external fin

Claims (5)

A battery stack containing a number of battery cells modularized is housed, the battery stack is floated from a bottom surface and supported, and air is blown into a space secured between the bottom surface and the battery stack by a blower to blow air into the battery stack. In the battery pack in which each battery cell is air-cooled by passing between the battery cells, a pit portion forming a stepped depression is provided in the bottom surface, a through hole is opened in the bottom surface of the pit portion, and the A battery pack characterized by covering a through-hole with an air-permeable layer made of a porous material. 2. The apparatus according to claim 1, wherein the ventilation layer is held on the bottom surface of the pit portion by a fixture so as to keep the through-hole covered, and the fixture is provided with a waterproof wall facing the through-hole. battery pack. 3. The battery pack according to claim 1 or 2, wherein the pit portion is divided as a cover for detachably closing the maintenance inspection opening opened in the bottom surface. 4. The battery pack according to claim 1, wherein the inner fins are formed on the bottom surface so as to form a plurality of grooves for guiding dew condensation water toward the pit portion. 5. The battery pack according to claim 4, wherein external fins are also formed on the lower surface so that the external fins function as a heat sink.

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