Power battery pack and vehicle

Abstract

The present disclosure provides a power battery pack and a vehicle. The power battery pack comprises a housing, a top cover attached to the housing, and a plurality of battery modules and a cooling unit accommodated in the housing and sealed by the top cover, wherein the housing comprises a bottom plate and a frame attached to each other, and the bottom plate and / or the frame are provided with an anti-collision structure; and the cooling unit is constructed as an integrated cooling plate, and the cooling plate comprises a liquid inlet and a liquid outlet arranged outside the housing. By at least improving the housing and the cooling unit of the power battery pack, the present disclosure improves the mechanical strength and impact resistance of the battery pack, eliminates the risk of coolant leakage in the battery pack and avoids potential safety hazards. By further improving the designs of the battery modules and the layout of the wiring harness in the battery pack, the power battery pack disclosed by the present disclosure can obtain at least one beneficial effect such as good mechanical performance, high cooling efficiency, high temperature and high voltage short circuit protection and the like in a cost-effective and reliable way.

Description

[0001] POWER BATTERY PACK AND VEHICLE

[0002] This invention claims the priority of the Chinese patent application 202311288996.6 filed on September 27, 2023, of which the content (Text, Drawings and Claims) is incorporated by reference.

[0003] TECHNICAL FIELD

[0004] The present disclosure relates to the field of vehicle, in particular to the field of power battery systems of new energy vehicles. More specifically, it relates to a power battery pack and a vehicle using the same.

[0005] BACKGROUND

[0006] With the increasing popularity of the new energy vehicles, the higher and higher requirements are put forward for the key technology, i.e. battery pack technology. First of all, a housing of the battery pack carrying battery modules plays a vital role in the safety and protection of the power battery pack. The housing of the battery pack usually includes a bottom plate, a frame and a cover plate which are hermetically connected, so that the battery modules are enclosed in the housing. In addition, in order to avoid thermal runaway, the battery pack is provided with a cooling unit therein, which is usually composed of a plurality of harmonica tube structure cooling plates, extrusion cooling plates or ultra-large / ultra-small stamping plates combined with a plurality of cooling pipes, and different cooling pipelines and battery modules are connected through the plurality of cooling pipes.

[0007] After the battery pack is assembled to a lower vehicle body sheet metal of the vehicle, it is difficult for the housing, usually made of aluminum or steel, to meet the requirement that the bottom of the battery pack can withstand the impact of stones or gravels when driving at high speed, and it is difficult to ensure that the cooling unit still maintains the cooling function after being impacted at the bottom. At the same time, it is difficult to ensure high cooling efficiency, good sealing performance and good manufacturing consistency with the plurality of cooling plates and the plurality of cooling pipes.

[0008] Patent document W02023001474A1 discloses a high-voltage battery pack, and the safety of the battery modules is ensured by designing different heights of the housing of the battery pack and setting a buffer structure. Patent document JP6617933B2 discloses an exhaust structure of an electric vehicle, which adopts a natural air cooling system. However, the existing solutions still need to be improved in terms of safety and mechanical strength.

[0009] SUMMARY

[0010] The purpose of the present disclosure is to solve the above-mentioned problems existing in the prior art, and provide a power battery pack to meet the use safety with improved mechanical strength under various unfavorable use conditions by improving the housing design, battery module layout, wiring harness layout, cooling system and other aspects of the battery pack in a cost-effective and reliable way

[0011] To this end, according to one aspect of the present disclosure, a power battery pack is provided. The power battery pack comprises a housing, a top cover attached to the housing, and a plurality of battery modules and a cooling unit accommodated in the housing and sealed by the top cover, wherein the housing comprises a bottom plate and a frame attached to each other, and the bottom plate and / or the frame are provided with an anti-collision structure; and the cooling unit is configured as an integrated cooling plate, and the cooling plate comprises a liquid inlet and a liquid outlet arranged outside the housing.

[0012] According to the above technical concept, the present disclosure may further include any one or more of the following alternative forms.

[0013] In some alternative forms, the anti-collision structure of the bottom plate is configured to comprise a plurality of concave portions recessed toward the inside of the power battery pack and reinforcing ribs arranged among the concave portions.

[0014] In some alternative forms, each of the concave portions is configured in a hemispherical shape and is provided with a connecting hole for being attached to the cooling unit by a sealing screw.

[0015] In some alternative forms, the frame comprises side beams extending in a longitudinal direction and end beams extending in a transverse direction, and the anti-collision structure of the frame is configured as a plurality of hollow portions formed at least on the side beams.

[0016] In some alternative forms, the plurality of hollow portions are stacked along a vertical direction.

[0017] In some alternative forms, the cooling plate is provided with a plurality of heat conducting pads respectively corresponding to the plurality of battery modules.

[0018] In some alternative forms, the plurality of battery modules are arranged symmetrically with respect to a longitudinal center line of the power battery pack and have the same poles facing each other, and the power battery pack comprises a high-voltage harness and a low- voltage harness, wherein the high-voltage harness is arranged along the longitudinal center line.

[0019] In some alternative forms, the high-voltage harness comprises a central main-high- voltage harness and a plurality of sub-high-voltage harnesses distributed along the central main-high-voltage harness and connected to the central main-high-voltage harness, wherein the central main-high-voltage harness is connected to both ends of the power battery pack along the longitudinal direction, and the plurality of sub-high-voltage harnesses correspond to the plurality of battery modules.

[0020] In some alternative forms, the low-voltage harness comprises a main-low-voltage harness corresponding to the plurality of battery modules and a central low-voltage harness arranged along the longitudinal center line and connected to both ends of the power battery pack along the longitudinal direction.

[0021] In some alternative forms, the power battery pack comprises a central channel extending along the longitudinal center line to accommodate and position the high-voltage harness, and the central channel is made of mica.

[0022] In some alternative forms, the power battery pack comprises a cover plate arranged between the top cover and the plurality of battery modules, and the cover plate is matched with the top cover in shape and made of mica.

[0023] In some alternative forms, the power battery pack comprises a battery management unit and a plurality of battery cell monitoring units, and the plurality of battery cell monitoring units are distributed at one side of the power battery pack (100) or at both ends of the power battery pack (100) in the longitudinal direction.

[0024] According to another aspect of the present disclosure, a vehicle is provided. The vehicle comprises the above-mentioned power battery pack, and the power battery pack is adapted to be attached to a lower vehicle body sheet metal of the vehicle.

[0025] By at least improving the housing and the cooling unit of the power battery pack, the present disclosure improves the mechanical strength and impact resistance of the battery pack, eliminates the risk of coolant leakage in the battery pack, and avoids potential safety hazards. By further improving the designs of the battery modules and the layout of the wiring harness in the battery pack, the power battery pack disclosed by the present disclosure can obtain at least one beneficial effect such as good mechanical performance, high cooling efficiency, high temperature and high voltage short circuit protection and the like in a cost-effective and reliable way.

[0026] BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features and advantages of the present disclosure will be better understood by the following alternative embodiments described in detail in conjunction with the accompanying drawings, in which the same reference numerals identify the same or similar parts, in the drawings:

[0028] Fig. 1 is a schematic top view of a power battery pack according to an embodiment of the present disclosure;

[0029] Fig. 2 is an exploded schematic view of a power battery pack according to an embodiment;

[0030] Fig. 3 is a schematic top view of the power battery pack shown in Fig. 2 with a top cover and a cover plate removed;

[0031] Fig. 4 is an exploded schematic view of a frame and an internal support beam according to an embodiment;

[0032] Fig. 5 is a schematic sectional view of a side beam and associated components according to an embodiment;

[0033] Fig. 6 is a schematic view of a cooling unit according to an embodiment;

[0034] Fig. 7 is a schematic view of a bottom plate according to an embodiment;

[0035] Fig. 8 is a schematic sectional view of a concave portion of the bottom plate and associated components;

[0036] Fig. 9 is a schematic view of a high-voltage harness according to an embodiment;

[0037] Fig. 10 is a schematic view of a low-voltage harness according to an embodiment.

[0038] DETAILED DESCRIPTION

[0039] The implementation and usage of the embodiments will be discussed in detail below. However, it should be understood that the specific embodiments discussed herein are merely illustrative of specific ways to implement and use the present disclosure without limiting the scope of the present disclosure. In the description for the structural positions of various components, representations of directions such as "upper", "lower", "top" and "bottom" are not absolute, but relative. When the various components are arranged as shown in the drawings, these representations of directions are appropriate. However, when the positions of the various components in the drawings are changed, these representations of directions are also changed accordingly.

[0040] In this context, unless otherwise specified, the terms such as "installation", "attach", "connection" and "fix" should be understood broadly For example, it can be fixed connection, detachable connection or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meanings of the above terms in this context can be understood according to specific situations.

[0041] In this context, "front" and "rear" are relative to the front-rear direction of the vehicle. In addition, "transverse direction" refers to a direction with relatively small size, which can also be called width direction, "longitudinal direction" refers to a direction with relatively large size, which can also be called length direction, and "vertical direction" refers to a direction generally perpendicular to the ground.

[0042] In this context, vehicle is new energy vehicle that uses power battery pack as operating power and / or driving power, including but not limited to pure electric vehicle, hybrid vehicle or extended-range vehicle.

[0043] Usually, the power battery pack for the vehicle includes battery modules or battery units, battery management system, battery pack housing and corresponding accessories. As the carrier of the battery modules, the battery pack housing plays a vital role in the safety and protection of the power battery pack. After the power battery pack is installed on the lower vehicle body sheet metal of the vehicle, once the vehicle experiences a collision, the collision force may be transferred from the lower vehicle body sheet metal to the battery pack housing, which will further squeeze the battery modules and cause potential safety hazards. When the vehicle is driving at high speed, stones, gravels and other objects on the ground may also directly collide with the battery pack housing, resulting in scratching, abrasion and even crack. For this reason, the existing battery pack housing mainly adopts, for example, steel housing to improve the mechanical strength, but its heavy weight is not conducive to the lightweight design of the whole vehicle. In addition, for example, when an internal short circuit occurs in a lithium iron battery under extreme conditions, the temperature of the battery will rise sharply and thermal runaway will occur, endangering the safety of life and property. For lithium ternary (NCM) battery with higher energy density, which has become the development trend of new energy vehicles, its chemical performance is unstable and its high- temperature safety is poor. How to reduce the risk of thermal runaway and improve the cooling efficiency is particularly important.

[0044] Based on the above requirements, the present disclosure proposes an improved design of the power battery pack. First, as shown in Figs. 1 and 2, a power battery pack 100 according to an embodiment of the present disclosure includes a housing 110, a top cover 120 attached to the housing 110, and a plurality of battery modules 200 and a cooling unit 300 accommodated in the housing 110 and sealed by the top cover 120, wherein the housing 110 includes a bottom plate 140 and a frame 130 attached to each other. Advantageously, the bottom plate 140 and / or the frame 130 are provided with an anti-collision structure to ensure the mechanical strength and impact resistance of the housing 110, so as to avoid impact damage and thus affect the cooling effect of the cooling unit 300. Further, the cooling unit 300 is also advantageously configured as an integral cooling plate 310. As shown in combination with Figs. 3 and 6, the cooling plate 310 is of an integral design with coolant pipes inside, for example, formed by welding or crimping two large-size aluminum plates with each other, and includes a liquid inlet 330 and a liquid outlet 340 arranged outside the housing. The liquid inlet 330 and the liquid outlet 340 may be formed at one side of the cooling plate 310 and provide positioning and sealing connection, for example, in the form of a flange 320, to eliminate interface leakage. In this way, the risk that the coolant of the cooling unit 300 leaks inside the battery pack is eliminated, and potential safety hazards can be avoided. The integral large-size cooling plate 310 also provides high cooling efficiency.

[0045] In some embodiments, the cooling plate 310 is provided with a plurality of heat conducting pads 350 respectively corresponding to the plurality of battery modules 200, such as thermal grease and other heat conducting mediums for improving the thermal conductivity. Each battery module 200 can be attached to the cooling plate 310 through the corresponding heat conducting pad 350, thereby further improving the cooling efficiency.

[0046] In the illustrated embodiment, with reference to Figs. 2 and 4, the frame 130 includes side beams 131 extending in a longitudinal direction DI and end beams extending in a transverse direction D2, wherein the end beams include a front beam 132 and a rear beam 133. Here, the side beams 131, the front beam 132 and the rear beam 133 are formed as structural beams of the housing 110 to provide main mechanical strength. Advantageously, the housing 110 further includes a plurality of support beam arranged in the side beams 131 and the end beams to further provide structural support. The support beams include, for example, a longitudinal beam 134 extending in the longitudinal direction DI, and a plurality of transverse beams 135 extending in the transverse direction D2 and distributed at intervals in the longitudinal direction DI. It should be understood that the number and distribution of the support beams can be varied according to different requirements and are not limited to those shown in the figures.

[0047] In some embodiments, the anti-collision structure of the frame 130 can be configured as a plurality of hollow portions 131a formed at least on the side beams 131. As shown in Fig. 5, the side beam 131 is hermetically connected with the bottom plate 140 at the welding portion 150 by a welding process, such as friction stir welding (FSW) or metal inertia gas (MIG). As can be seen from Fig. 5, the plurality of hollow portions 131a are advantageously stacked in a vertical direction D3, so that it is possible to provide reliable mechanical strength and play a role in reducing weight with a compact structural size. When the battery pack is impacted from the side, the hollow portions 131a can collapse and deform uniformly, which helps to absorb and disperse portion of the impact energy and protect the battery modules inside the housing. It should be understood that the cross-sectional shape of the hollow portion 131a is not limited to that shown in the figure, and it can be, for example, circle, ellipse or other polygons, as long as it is suitable for reliably and uniformly transmitting and absorbing impact energy. Alternatively, the front beam 132 and / or the rear beam 133 can also form a similar hollow structure to provide a certain deformation capacity, thereby absorbing impact energy.

[0048] In some embodiments, the anti-collision structure of the bottom plate 140 can be configured as a plurality of concave portions 141 recessed toward the inside of the power battery pack, as shown in Fig. 7, and reinforcing ribs 142 are arranged among the concave portions 141. Two reinforcing ribs 142 are exemplarily shown in the figure. The number, size and arrangement of the reinforcing ribs can be provided according to actual requirements. Advantageously, each of the concave portions 141 is configured in a hemispherical shape and is provided with a connection hole 143 to be suitable for being attached to the cooling plate 310 of the cooling unit 300 by a sealing screw. Fig. 8 exemplarily illustrates a sealing screw 160 arranged at the concave portion 141 to connect the bottom plate 140 with the cooling plate 310. The sealing screw not only ensures the air tightness of the battery pack, but also helps to improve the mechanical strength of each concave portion at the bottom of the housing. In this way, when the bottom plate 140 is impacted by the bottom stone at high speed, the concave portion 141 provides an impact buffer space, which reduces the energy brought by the impact force to a certain extent, ensures the mechanical integrity of the battery pack, avoids affecting the cooling function of the cooling unit, and improves the durability of the cooling unit. Moreover, the reinforcing ribs 142 further provide the mechanical strength of the bottom plate 140.

[0049] Since the anti-collision structure is provided on the bottom plate 140 and / or the frame 130, the housing 110 of the power battery pack of the present disclosure can still be made of aluminum, such as extruded aluminum profiles or aluminum stamped plates, which can provide reliable and effective mechanical strength and cooling efficiency in a cost-effective manner.

[0050] In addition to providing the anti-collision structure of the housing and the integral cooling plate design of the cooling unit, the present disclosure also advantageously arranges the plurality of battery modules 200 symmetrically with respect to a longitudinal center line C of the power battery pack and with the same poles facing each other, as shown in Fig. 3. Especially for the ternary lithium battery system, the risk of thermal runaway is high. The battery modules are arranged with the same poles facing each other, that is, the lugs are led out on the same side, and the copper bars connected between the modules are arranged in the center of the battery pack, which provides more possibilities for the effective implementation of high temperature and high voltage short circuit protection.

[0051] Specifically, in the embodiment shown in Figs. 2 and 3, twelve battery modules 200 symmetrically distributed in two rows are exemplarily illustrated. It should be understood that other numbers of the battery modules are optional depending on different requirements. A junction box 400 and a battery management system (BMS) 500 may be arranged at one side of the battery pack, as shown in the figure, along the longitudinal direction DI, and a charging connector 600 may be arranged at the opposite side. The power battery pack includes a high- voltage harness 710 and a low-voltage harness 720, wherein the high-voltage harness 710 is advantageously arranged along the longitudinal center line C. In this way, the length of the wiring harness is reduced and the cost is saved. The battery management system 500 includes a battery management unit 510 and a plurality of battery cell monitoring units 520, wherein the battery cell monitoring unit 520 is connected to each battery module through the low- voltage harness to collect and monitor voltage, current, temperature and other state parameters of the battery cell. The battery management unit 510 receives and evaluates the monitored state parameters to provide battery protection and manage power, temperature and the like. Advantageously, the plurality of battery cell monitoring units 520 are configured to be distributed at one side of the power battery pack or at both ends of the power battery pack in the longitudinal direction. As shown in Fig. 2, for example, four cell monitoring units 520 may be arranged on one side of the battery pack in the longitudinal direction DI, and another four cell monitoring units 520 may be arranged on the opposite side adjacent to the battery management unit 510. Compared with the existing design that the battery cell monitoring unit and the battery module are adjacently arranged in one-to-one correspondence, the solution of the present disclosure can ensure that the control component is not harmed by heat for as long as possible when thermal runaway occurs.

[0052] Referring to Fig. 9, in some embodiments, the high-voltage harness 710 includes a central main-high-voltage harness 711 and a plurality of sub-high-voltage harnesses 712 distributed along the central main-high-voltage harness 711 and connected with the central main-high-voltage harness 711, wherein the central main-high-voltage harness 711 is connected to both ends of the power battery pack in the longitudinal direction DI, that is, the junction box 400, the battery management system 500 and the charging connector 600 on the other side are connected with the central main-high-voltage harness 711, and the plurality of sub-high-voltage harnesses 712 correspond to the plurality of battery modules 200. Similarly, as shown in Fig. 10, the low-voltage harness 720 includes a main-low-voltage harness 721 corresponding to the plurality of battery modules 200, and a central low-voltage harness 722 connected to both ends of the power battery pack in the longitudinal direction DI along the longitudinal center line, so as to complete the interactive connection of each battery cell monitoring unit and the battery management unit, and connect external junction box interface with the junction box inside the battery pack. As mentioned above, the plurality of battery modules in the present disclosure are arranged with the same poles facing each other and lead out the lugs, and the copper bars connected among the modules are arranged in the center of the battery pack. In this way, the design of the central high and low voltage harness not only saves the length of the copper bars, reduces the cost, but also reduces the number and probability of components affected by short-circuit thermal runaway phenomenon, and can also avoid the risk of short-circuit when the side beam is deformed.

[0053] In some embodiments, as shown in Figs. 2 and 3, the power battery pack of the present disclosure includes a central channel 810 extending along the longitudinal center line C to accommodate and position the high-voltage harness 710, and the central channel is preferably made of mica. In this way, the short circuit on the high-voltage circuit is effectively reduced, and the battery modules symmetrically distributed on both sides of the central channel 810 can be isolated, so as to avoid the influence of the conductive medium generated by the battery module at one side when thermal runaway occurs on the battery module at the other side.

[0054] In some embodiments, the power battery pack further includes a cover plate 820 arranged between the top cover 120 and the plurality of battery modules 200. As shown in Fig. 2, the cover plate 820 is matched with the top cover 120 in shape and made of mica. When thermal runaway occurs, the hot gas and conductive medium emitted by the battery cell may arc with the top cover, and the cover plate 820 advantageously avoids the adverse effects of this situation.

[0055] The power battery pack disclosed by the present disclosure improves the impact resistance, cooling performance, fire resistance and safety performance of the power battery pack through the design optimization of housing structure, battery module layout, cooling unit, high and low voltage harness layout and also high temperature and high voltage short circuit protection. The above-mentioned components in the power battery pack are simple in structure and easy to implement, and are suitable for various forms of power battery packs.

[0056] Here, it should be understood that the embodiments shown in the figures only show the optional shapes, sizes and arrangements of various components of the power battery pack according to the present disclosure which are merely illustrative and not restrictive. Other shapes, sizes and arrangements can be adopted without departing from the spirit and scope of the present disclosure.

[0057] The technical contents and technical features of the present disclosure have been disclosed above. However, it can be understood that those skilled in the art can make various changes and improvements to the above disclosed concept, but all the changes and improvements fall within the scope of protection of the present disclosure. The description of the above embodiments is illustrative and not restrictive, and the scope of protection of the present disclosure is defined by the claims.

Claims

CLAIMS1. A power batery pack comprising a housing (110), a top cover (120) atached to the housing (110), and a plurality of battery modules (200) and a cooling unit (300) accommodated in the housing (110) and sealed by the top cover (120), wherein the housing (110) comprises a bottom plate (140) and a frame (130) attached to each other, and the bottom plate (140) and / or the frame (130) are provided with an anti-collision structure; and the cooling unit (300) is configured as an integrated cooling plate (310), and the cooling plate (310) comprises a liquid inlet (330) and a liquid outlet (340) arranged outside the housing (110).

2. The power battery pack according to claim 1, wherein the anti-collision structure of the bottom plate (140) is configured to comprise a plurality of concave portions (141) recessed toward the inside of the power battery pack (100) and reinforcing ribs (142) arranged among the concave portions (141).

3. The power battery pack according to claim 2, wherein each of the concave portions (141) is configured in a hemispherical shape and is provided with a connecting hole (143) for being attached to the cooling unit (300) by a sealing screw (160).

4. The power battery pack according to claim 1, wherein the frame (130) comprises side beams (131) extending in a longitudinal direction (DI) and end beams (132, 133) extending in a transverse direction (D2), and the anti-collision structure of the frame (130) is configured as a plurality of hollow portions (131a) formed at least on the side beams (131).

5. The power battery pack according to claim 4, wherein the plurality of hollow portions (131a) are stacked along a vertical direction (D3).

6. The power battery pack according to claim 1, wherein the cooling plate (310) is provided with a plurality of heat conducting pads (350) respectively corresponding to the plurality ofbattery modules (200).

7. The power battery pack according to claim 1, wherein the plurality of battery modules (200) are arranged symmetrically with respect to a longitudinal center line (C) of the power battery pack (100) and have the same poles facing each other, and the power battery pack (100) comprises a high-voltage harness (710) and a low-voltage harness (720), and wherein the high-voltage harness (720) is arranged along the longitudinal center line (C).

8. The power battery pack according to claim 7, wherein the high-voltage harness (710) comprises a central main-high-voltage harness (711) and a plurality of sub -high-voltage harnesses (712) distributed along the central main-high-voltage harness (711) and connected to the central main-high-voltage harness (711), and wherein the central main-high-voltage harness (711) is connected to both ends of the power battery pack (100) along the longitudinal direction (DI), and the plurality of sub-high-voltage harnesses (712) correspond to the plurality of battery modules (200).

9. The power battery pack according to claim 7, wherein the low-voltage harness (720) comprises a main-low-voltage harness (721) corresponding to the plurality of battery modules (200) and a central low-voltage harness (722) arranged along the longitudinal center line (C) and connected to both ends of the power battery pack (100) along the longitudinal direction (DI).

10. The power battery pack according to claim 7, wherein the power battery pack (100) comprises a central channel (810) extending along the longitudinal center line (C) to accommodate and position the high-voltage harness (710), and the central channel (810) is made of mica.

11. The power battery pack according to claim 1, wherein the power battery pack (100) comprises a cover plate (820) arranged between the top cover (120) and the plurality of battery modules (200), and the cover plate (820) is matched with the top cover (120) in shape and made of mica.

12. The power battery pack according to claim 1, wherein the power battery pack (100) comprises a battery management unit (510) and a plurality of battery cell monitoring units (520), and the plurality of battery cell monitoring units (520) are distributed at one side of the power battery pack (100) or at both ends of the power battery pack (100) in the longitudinal direction (DI).

13. A vehicle comprising a power battery pack (100) according to any one of claims 1 to 12, and the power battery pack (100) is adapted to be attached to a lower vehicle body sheet metal of the vehicle.

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