Patent ID: 12209675

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. For reference numbers in the drawings, the same or similar reference numbers are used to designate the same or similar parts. In the following description, various operating parameters and components are described in various embodiments. These specific parameters and components are included herein by way of example only and are not meant to be limiting.

The embodiments of the present disclosure are described below. However, it is to be understood that the disclosed embodiments are merely examples and that other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure. As will be understood by those of ordinary skill in the art, various features shown and described with reference to any one figure may be combined with features shown in one or more other figures to produce embodiments not expressly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desirable for certain particular applications or implementations

In this document, relational terms, such as first and second and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

As used herein, the term “and/or”, when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed.

One or more embodiments of the present disclosure will be described below with reference to the accompanying drawings. The flowchart is used to illustrate an example of a process executed by a system. It should be understood that the execution of the flowchart does not need to be performed in sequence, and one or more steps may be omitted, or one or more executed steps may be added, and one or more steps may be performed sequentially or in reverse order, and even in some embodiments concurrently.

As mentioned in the background, the pressure relief valves can be used for pressure exchange between the closed containers and the outside to achieve a desired pressure balance. With the rapid development of electrified vehicles due to their advantages in reducing fuel consumption and exhaust emissions, the pressure relief valves are commonly used on battery packs to facilitate sealing of battery packs and gas exchange at different rates under different pressures.

In one or more embodiments, the inventors of the present disclosure propose a pressure relief valve that may have one or more advantages of structural robustness, connection convenience, and testing convenience. In one or more embodiments, the present disclosure provides a battery pack, which can maintain bidirectional gas exchange and pressure balance of the breathable film under conventional pressure conditions, and can effectively reduce the pressure in the battery pack under thermal shock change caused by rapid heat generation. In one example, when the internal pressure of the battery pack is 0.5 kilopascals, air flow path provided by the pressure relief valve should at least provide an air exchange capacity greater than 1 liter per min.

Referring toFIG.1, one example of an electrified vehicle12to which a battery pack according to the present disclosure can be applied is shown. Although depicted as a hybrid electric vehicle (HEV), it should be understood that the battery pack according to the present disclosure may be applied to other types of electrified vehicle, such as plug-in deep hybrid electric vehicles (PHEVs), pure electric vehicles (BEVs), full hybrid electric vehicles (FHEVs), etc.

In one embodiment, a powertrain10is a power-split powertrain system that employs a first drive system and a second drive system. The first drive system includes a combination of an engine14and a generator18(i.e., a first electric machine). The second drive system includes at least a motor22(i.e., a second electric machine), the generator18, and a battery assembly. In this example, the second drive system is considered an electric drive system of the powertrain10. The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels28of the electrified vehicle12. Although a power-split configuration is shown in this illustrative embodiment, this disclosure extends to any hybrid electric vehicle including full hybrids, parallel hybrids, series hybrids, mild hybrids or micro hybrids. The engine14and the generator18may be connected through a power transfer unit30. In addition to planetary gear set, other types of power transfer units may be used to connect the engine14to the generator18. In a non-limiting embodiment, the planetary gear set includes a ring gear32, a sun gear34, and a carrier assembly36.

The generator18can be driven by the engine14through the power transfer unit30to convert kinetic energy to electrical energy. The generator18can alternatively function as a motor to convert electrical energy into kinetic energy, thereby outputting torque to a shaft38connected to the power transfer unit30. Because the generator18is operatively connected to the engine14, the speed of the engine14can be controlled by the generator18.

The ring gear32of the power transfer unit30may be connected to a shaft40, which is connected to vehicle drive wheels28through a second power transfer unit44. The second power transfer unit44may include a gear set having a plurality of gears46. Other power transfer units may also be suitable. The gears46transfer torque from the engine14to a differential48to ultimately provide traction to the vehicle drive wheels28. The differential48may include a plurality of gears that enable the transfer of torque to the vehicle drive wheels28. In one embodiment, the second power transfer unit44is mechanically coupled to an axle50through the differential48to distribute torque to the vehicle drive wheels28.

The battery assembly24is an example type of battery assembly for an electrified vehicle. The battery assembly24may provide power to drive a motor, and in regenerative braking, the motor22and generator18may output power to the battery assembly24for storage. The battery assembly24may include a high voltage battery pack, which may include a plurality of battery arrays. In the following embodiments, battery packs that can be incorporated into the above-described example electrified vehicles are provided.

FIG.2is a top view of a pressure relief valve100according to one or more embodiments of the present disclosure. As shown in the figure, the pressure relief valve100has a valve cover120and a protective wall140arranged on the outside of the valve cover120in a radial direction R. In order to facilitate the description of embodiments below, the direction extending perpendicular to the plane where the top view of the pressure relief valve100is located is set as axial direction A. It can be understood that in other embodiments, the pressure relief valve100can be directly connected to a battery pack without an additional air guide device. The configuration of the pressure relief valve100will be described below with reference to further drawings.

FIG.3is an exploded structural diagram of the pressure relief valve100for the battery pack according to an embodiment of the present disclosure. It should be understood by those skilled in the art that although the structure of the pressure relief valve in the present disclosure is applied to the battery pack of the vehicle, various pressure relief valves can also be applied to any suitable scenario where pressure balance inside and outside the container is required.

Referring toFIG.3, in one or more embodiments of the present disclosure, the pressure relief valve100is provided. The pressure relief valve100has a valve body110extending substantially in the axial direction A and the valve cover120matched with the valve body and having a plurality of exhaust holes1201for gas exchange. The pressure relief valve100also has a flexible element130positioned between the valve body110and the valve cover120. In combination with an embodiment of the flexible element130inFIG.5, it can be seen that the flexible element130has a flange1303extending in its circumferential direction. The flange1303is at least partially arranged in a groove arranged in the circumferential direction of a projection portion1105of the valve body110, and the valve cover120presses the flange1303into the groove to realize the positioning of the flexible element. It can be understood that the positioning of the flexible element130can also be realized by bonding, welding and other joint methods known in the art.

The flexible element130has a compression portion1301. The flexible element130also has a through hole1302as shown inFIG.3. A breathable film150is also arranged between the valve cover120and the flexible element130, and the breathable film150covers the through hole1302. In one or more embodiments of the present disclosure, the breathable film150only allows two-way passage of gas, and can prevent moisture and dust from entering the interior of the pressure relief valve100. Depending on the sealing requirements, the appropriate waterproof and breathable film on the market can be selected. In one or more embodiments of the present disclosure, the breathable film150is connected to the flexible element130through a connecting ring160. It can be understood by those skilled in the art that the breathable film150can be connected to the flexible element130through the connecting ring160using connection methods known in the art, including but not limited to bonding, welding, and so on, so as to cover the through hole1302arranged on the flexible element130.

In the described embodiment, the breathable film150is welded to the through hole1302at the bottom area of the flexible element130along the direction shown in the figure. It can be understood that in other embodiments, the through hole1302can be formed at an upper part, or the through hole1302can be formed at any suitable position such as the middle area of the flexible element130.

In the described embodiment, the valve body110has a flange structure1101extending in the circumferential direction. The flange structure1101is generally annular planar, and can have a relatively smooth surface to facilitate the fitting of the connection surfaces. It can be understood by those skilled in the art that depending on the surfaces to be engaged during application, the flange structure can also have other structural variants.

In the described embodiment, the flange structure1101has an edge larger than the size of the valve cover120and a plurality of clamping grooves1102in its circumferential direction. The valve cover120can be connected with the valve body110through a buckle or other suitable structure. In one embodiment of the present disclosure, after the valve cover120is connected with the valve body110, an exhaust port1202on the valve cover120forms another fluid channel between the valve cover120and the valve body110. In one or more embodiments of the present disclosure, the projection portion1105of the valve body110has an generally M-shaped joint portion1106that is adapted to the valve cover120. The shape adaptive M-shaped joint make the connection between the valve cover120and the valve body110have higher strength.

In one example, breaking torque between the two exceeds 15 newton meters, and the M-shaped joint portion1106can also provide parallel fluid channels at the side of the valve body110. As shown inFIG.6, when water vapor L2enters, it can enter the side of the flexible element130close to the valve cover120, that is, the outside of the breathable film150, from the opening of the valve cover located above as shown by the dot-dash line inFIG.6. Since the breathable film150is a waterproof breathable film, this channel can prevent moisture from entering. It can also be understood that the water vapor L2may enter from the side as shown by the dash line inFIG.6. Due to the guidance and blocking of a guide surface1313provided by a concave part1311of the flexible element130, the water vapor L2entering from the side will be discharged from the side of the valve body110along the guide surface1313, thus preventing the water vapor L2from entering the interior of the pressure relief valve100.

Further referring toFIG.3, in order to install the pressure relief valve100to a component to be connected, at the axially downward end of the pressure relief valve100, a connecting portion1103can be extended from the flange structure1101, and the connecting portion1103can have an external thread structure, so as to be configured for connecting to the component to be connected.

In one embodiment, the pressure relief valve100can be directly connected to a battery pack through the connecting portion1103, while the flange structure1101is located outside the battery pack housing. A groove1104is arranged around the connecting portion1103, and a gasket180is partially arranged in the groove1104. The gasket180is separated from the connecting portion1103to prevent the connecting portion1103or the edge of the through hole of the component to be connected from disturbing the gasket180during installation. The groove1104helps to stabilize the positioning of the gasket180, and the gasket180can rests against the surface to be engaged to achieve stable sealing. In the described embodiment, the gasket180also has a plurality of spaced projecting ribs1801to achieve a stable fit in the groove1104. In the described embodiment, the gasket180can be an EPDM (Ethylene Propylene Diene Monomer) gasket.

As shown inFIG.3, the pressure relief valve100also has a bias spring170positioned between the valve cover120and the flexible element130. In the embodiment containing the bias spring170, the flexible element130is offset by the bias spring170to rest against an upward facing surface of the valve body110in the axial direction A. In another embodiment of the present disclosure, the pressure relief valve100does not have a bias spring, but the flexible element130is directly pressed against the upward facing surface of the valve body110in the axial direction A by the valve cover120. In one or more embodiments of the present disclosure, a mount1203for the bias spring170is arranged on an inner side of the valve cover120, so that the bias spring170can be more accurately positioned around the mount1203to maintain the proper installation position.

In one or more embodiments of the present disclosure, the pressure relief valve100also has the protective wall140arranged around the valve body110. The protective wall140has a generally flat cylindrical structure, and the protective wall140has an inner surface and an outer surface. The protective wall140is clamped with the clamping grooves1102of the flange structure1101through a plurality of clamping parts1401arranged on one end thereof. Those skilled in the art can understand that the connection between the protective wall140and the flange structure1101can also be realized by welding, bonding and other connection methods known in the art. The protective wall140may be used for connecting with external components to be connected.

As shown inFIG.6, when conducting a waterproof performance test of the pressure relief valve100, for example, in the waterproof grade test of IP9K, when a high-pressure water gun sprays high-pressure liquid L1from different directions as shown by the thick arrows inFIG.6, the protective wall140and the valve cover120ensure that the high-pressure liquid will not directly enter the gas path of the pressure relief valve100, so that the pressure relief valve100can meet the waterproof performance requirements of IP9K.

Next, as shown inFIG.4, a schematic diagram of the connection state between the pressure relief valve100and a shielding pipe200is shown, wherein the pressure relief valve100is shown in the form of a sectional view taken along X-X direction ofFIG.2. As shown in the figure, in the described embodiment, the shielding pipe200is connected to the thread on the outer surface of the protective wall140through the thread on its inner surface to realize the connection between the shielding pipe200and the pressure relief valve100. It should be understood by those skilled in the art that other well-known connection methods such as welding, clamping, bonding, etc. can also be used for the connection of the shielding pipe200and the pressure relief valve100. By connecting the shielding pipe200, the pressure relief valve100can effectively isolate the high-temperature gas from the surrounding parts when relieving under the high-pressure state. It should also be understood by those skilled in the art that, in addition to the shielding pipe200in the above embodiment, other components can also be used to connect with the protective wall140to achieve different technical purposes, for example, connecting to HVAC (Heating Ventilation and Air Conditioning) system of the vehicle through other pipes to achieve heat exchange with the HVAC system of the vehicle.

Next, in combination with the X-X direction sectional view of the flexible element130shown inFIG.5, in one or more embodiments of the present disclosure, the flexible element130has a compression portion1301arranged around the outer side of the through hole1302generally in the radial direction. The compression portion1301is made of rubber material. It can be understood by those skilled in the art that other elastic materials known in the art can also be used for the compression portion in the embodiments of the present disclosure. The flexible element130has a circumferential wall portion1304that surrounds the through hole1302and extends upward from the bottom in the axial direction A. The compression portion1301is arranged on at least a portion of the circumferential wall portion1304. The compression portion1301is arranged as a concave part1311extending inwards and a convex part1312extending outwards from the circumferential wall portion1304in the radial direction R. In the described embodiment, the compression portion1301has one concave part1311and one convex part1312arranged on the circumferential wall portion1304in an axial direction. Along the axial direction of the valve body, the concave part1311and the convex part1312form a compression portion1301with an approximate S-shaped section shape. When the internal pressure of the battery pack increases, the S-shaped compression portion1301, which is composed of the concave part1311and the convex part1312, can undergo deformation along the axial direction to make the flexible element130and the valve body110produce relative displacement, thereby forming a fluid channel between the flexible element130and the valve body110to complete the pressure relief of the battery pack. It can be understood that the compression portion1301, that includes one concave part1311and one convex part1312in the above embodiments, is only an example of the compression portion of the present disclosure, and in other embodiments of the present disclosure, the compression portion1301may include only one concave part or one convex part, or a plurality of concave parts and convex parts spaced in the axial direction. The pressure for opening the fluid channel can be effectively adjusted by installing compression portions1301with different numbers of concave parts and convex parts.

As shown inFIG.5, in one or more embodiments of the present disclosure, guide pins1305extending downward in the axial direction are arranged at bottom of the flexible element130, and the guide pins1305are accommodated in fitting holes arranged on the valve body110so as to make the flexible element130more stable when it is displaced relative to the valve body110, without tilting to one side, thus affecting the gas discharge. In the described embodiment, the flexible element130includes two guide pins1305. Those skilled in the art can understand that the flexible element130with two guide pins1305is only an example, and the number of guide pins1305can be increased or decreased as needed. In addition, a plurality of ribs1306are arranged on the outside of the bottom of the flexible element130and extends on the outer surface of its bottom. When the flexible element130butts against the valve body110, the friction between the flexible element130and the valve body110is increased through the plurality of ribs1306, so that the flexible element130is better positioned on the bottom surface of the valve body110. It can be understood by those skilled in the art that the ribs can also be arranged on the radial outer side of the flexible element, and the beneficial effect of better positioning the flexible element130can also be obtained by butting the rib arranged on the radial outer side with the inner surface of the projection portion1105of the valve body110. In one or more embodiments of the present disclosure, an O-ring190is sleeved on the outer surface of the projection portion1105. The O-ring190is partially sleeved with a groove (not shown in the figure) arranged on the outer surface of the projection portion1105. The depth of the groove is less than the diameter of the O-ring190, so that the O-ring190is partially located outside the groove. When performing the leak test of the pressure relief valve100, an air supply pipe can be sleeved on the outside of the O-ring190to facilitate the leak test. In one embodiment of the leak test, the air supply pipe provides 4 kilopascals of gas pressure towards the outside of the pressure relief valve. In order to provide sufficient flow of gas during the leak test, the air flow channel of the pressure relief valve100should meet the requirement of at least 50 liters per min of gas flow rate under 4 kilopascals of gas pressure.

After the pressure relief valve100is installed on the component to be connected, such as the battery pack, as shown inFIG.7A, the breathable film150forms a first fluid channel C1for direct gas exchange between the battery pack and the external environment, while the flexible element130forms a second fluid channel C2for gas exchange between the battery pack and the external environment. When the internal pressure of the pressure relief valve is less than a set pressure threshold, only the first fluid channel C1remains open, and gas G can flow to the breathable film150through the through hole1302, thus flowing to the external environment through the first fluid channel C1.

When the internal temperature of the battery pack rises rapidly (for example, due to rapid charging, high output power, etc.), the internal pressure may rise rapidly. When the internal pressure rises rapidly beyond the set pressure threshold, as shown inFIG.7B, compared withFIG.7A, when the internal gas pressure of the battery pack increases, the thickness of the compression portion1301is compressed as a whole, making the flexible element130move relative to the valve body110, so that the flexible element130is separated from the valve body110to open the second fluid channel C2. The internal gas can be discharged simultaneously through the first fluid channel C1and the second fluid channel C2to rapidly reduce the internal pressure. It can be understood that the pressure threshold can be set according to the structure of the compression portion1301and the number of concave parts1311and convex parts1312. The setting requirement of the pressure threshold can be met by adjusting the structure of the compression portion1301and/or the number of concave parts1311and convex parts1312.

In combination with the example of gas flow inFIG.6,FIG.7AandFIG.7B, when the air pressure difference on both sides of the pressure relief valve100is below the threshold, the gas can be exchanged on both sides of the breathable film150, that is, only the first fluid channel C1allows the gas to form gas exchange between the inner and outer sides of the pressure relief valve100. In one embodiment of the present disclosure, the pressure threshold is 6.5 kilopascals. When the air pressure inside the pressure relief valve100increases rapidly and exceeds the threshold due to the discharge of a large amount of gas F from the battery pack, the compression portion1301of the flexible element130is compressed and separated from the valve body110, so that the second fluid channel C2opens rapidly, the first fluid channel C1and the second fluid channel C2thus jointly discharge the gas F in the battery pack, and maintain stable air pressure on both sides of the pressure relief valve100. The greater the pressure inside the battery pack, the greater the degree of compression of the compression portion1301, and thus the greater the degree of opening of the second fluid channel C2, and the faster the gas can be discharged from the inside of the pressure relief valve100. The gas discharged from the first fluid channel C1can be discharged through an exhaust hole1201on the valve cover120and the exhaust port1202on the side of the valve cover120, while the gas discharged from the second fluid channel C2can also be discharged through the exhaust hole1201and the exhaust port1202. In one or more embodiments of the present disclosure, when the internal pressure increases due to the rapid increase of the internal temperature of the battery pack, the first fluid channel C1and the second fluid channel C2jointly provide sufficient air flow channels for the pressure relief of the battery pack, for example, when the internal pressure is 7 kilopascals, the air flow capacity of more than 12 liters per second is provided.

In the described embodiment, the gas discharged from the exhaust hole1201and the exhaust port1202may be high-temperature gas. After the gas is discharged from the pressure relief valve100, it arrives at the shielding pipe200and is collected directionally by the shielding pipe200. The shielding pipe200provides the guidance and orientation function of high-temperature gas, so that the centralized treatment of the high-temperature gas can be achieved without causing the vehicle parts near the battery pack to be exposed to high temperatures.

On the premise that it is technically feasible, the technical features listed above for different embodiments can be combined with each other to form other embodiments within the scope of the present disclosure.

In this application, the use of the disjunctive is intended to include the conjunctive. The use of definite or indefinite articles is not intended to indicate cardinality. In particular, a reference to “the” object or “a” and “an” object is intended to denote also one of a possible plurality of such objects. Further, the conjunction “or” may be used to convey features that are simultaneously present instead of mutually exclusive alternatives. In other words, the conjunction “or” should be understood to include “and/or”. The terms “includes,” “including,” and “include” are inclusive and have the same scope as “comprises,” “comprising,” and “comprise” respectively.

The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of protection given to this disclosure can only be determined by studying the following claims.