Power battery pack and vehicle

Abstract

The invention provides a power battery pack and a vehicle. The power battery pack comprises a shell, a top cover, a plurality of battery modules and a cooling unit, the top cover is attached to the shell, the battery modules and the cooling unit are contained in the shell and sealed by the top cover, the shell comprises a bottom plate and a frame which are attached to each other, and the bottom plate and / or the frame are / is provided with an anti-collision structure; and the cooling unit is constructed into an integrated cooling plate, and the cooling plate comprises a liquid inlet and a liquid outlet which are formed in the outer part of the shell. According to the power battery pack, the shell and the cooling unit of the power battery pack are at least improved, so that the mechanical strength and the impact resistance of the battery pack are improved, the risk of leakage of cooling liquid in the battery pack is completely eradicated, and potential safety hazards are avoided. Through further improved design of the battery module, the wiring harness layout and the like in the battery pack, the power battery pack disclosed by the invention can obtain at least one beneficial effect of good mechanical property, high cooling efficiency, high-temperature and high-voltage short-circuit protection and the like in a cost-saving and reliable manner.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicles, in particular to the field of power battery systems for new energy vehicles, and more specifically to a power battery pack and a vehicle using the power battery pack. Background Art

[0002] With the increasing popularity of new energy vehicles, higher and higher requirements are constantly being put forward for the battery pack technology, which is its key technology. First of all, the battery pack shell that carries the battery module plays a vital role in the safety and protection of the power battery pack. The battery pack shell usually includes a sealed bottom plate, a frame and a cover plate, thereby enclosing the battery module in the shell. In addition, in order to avoid thermal runaway, a cooling unit is provided in the battery pack. The cooling unit usually adopts multiple harmonica tube structure cooling plates or extruded cooling plates or oversized / ultra-small stamping plates combined with multiple cooling tubes, and different cooling lines and battery modules are connected through multiple cooling tubes.

[0003] After the battery pack is assembled to the lower body sheet metal of the vehicle, the usually aluminum or steel shell is difficult to meet the requirements of the battery pack bottom being hit by stones or gravel when driving at high speed, and it is difficult to ensure that the cooling unit still maintains cooling function after being hit by the bottom. At the same time, multiple cooling plates and multiple cooling pipes are difficult to ensure high cooling efficiency, good sealing performance and good manufacturing consistency.

[0004] Patent document WO2023001474A1 discloses a high-voltage battery pack, which ensures the safety of the battery module by designing different heights of the battery pack shell and setting a buffer structure. Patent document JP6617933B2 discloses an exhaust structure for 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. Summary of the invention

[0005] The purpose of the present disclosure is to solve the problems existing in the above-mentioned prior art and to provide a power battery pack, which proposes improvements in the shell design, battery module layout, wiring harness arrangement, cooling system and other aspects of the battery pack in a cost-effective and reliable manner, so as to meet the safety of use with improved mechanical strength under various adverse conditions of use.

[0006] To this end, according to one aspect of the present disclosure, a power battery pack is provided, comprising a shell, a top cover attached to the shell, and a plurality of battery modules and a cooling unit accommodated in the shell and sealed by the top cover, wherein the shell comprises a bottom plate and a frame attached to each other, the bottom plate and / or the frame being provided with an anti-impact structure; and the cooling unit is constructed as an integrated cooling plate, the cooling plate comprising a liquid inlet and a liquid outlet arranged on the outside of the shell.

[0007] According to the above technical concept, the present disclosure may further include any one or more of the following optional forms.

[0008] In certain optional forms, the anti-collision structure of the bottom plate is configured to include a plurality of recessed portions recessed toward the interior of the power battery pack, and reinforcing ribs arranged between the plurality of recessed portions.

[0009] In some optional forms, each of the recessed portions is constructed in a hemispherical shape and is provided with a connecting hole so as to be suitable for being attached to the cooling unit by a sealing screw.

[0010] In some optional forms, the frame includes side beams extending in the longitudinal direction and end beams extending in the 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.

[0011] In some optional forms, the plurality of hollow portions are stacked in a vertical direction.

[0012] In some optional forms, the cooling plate is provided with a plurality of thermal conductive pads corresponding to the plurality of battery modules respectively.

[0013] In certain optional forms, the multiple battery modules are arranged to be symmetrically distributed with respect to the longitudinal center line of the power battery pack and with the same poles facing each other, and the power battery pack includes a high-voltage wiring harness and a low-voltage wiring harness, wherein the high-voltage wiring harness is arranged along the longitudinal center line.

[0014] In certain optional forms, the high-voltage wiring harness includes a central main high-voltage wiring harness and a plurality of sub-high-voltage wiring harnesses distributed along and connected to the central main high-voltage wiring harness, the central main high-voltage wiring harness is connected to both ends of the power battery pack in the longitudinal direction, and the plurality of sub-high-voltage wiring harnesses correspond to the plurality of battery modules.

[0015] In certain optional forms, the low-voltage wiring harness includes a main low-voltage wiring harness corresponding to the plurality of battery modules, and a central low-voltage wiring harness arranged along the longitudinal center line and connected to both ends of the power battery pack in the longitudinal direction.

[0016] In certain optional forms, the power battery pack includes a central channel extending along the longitudinal centerline to accommodate and position the high-voltage wiring harness, and the central channel is made of mica.

[0017] In certain optional forms, the power battery pack includes a cover plate arranged between the top cover and the plurality of battery modules, wherein the cover plate is adapted in shape to the top cover and is made of mica.

[0018] In some optional forms, the power battery pack includes a battery management unit and a plurality of battery cell monitoring units, and the plurality of battery cell monitoring units are distributed on one side of the power battery pack or at both ends along the longitudinal direction.

[0019] According to another aspect of the present disclosure, a vehicle is provided, comprising the above-mentioned power battery pack, wherein the power battery pack is suitable for being attached to a lower body sheet metal of the vehicle.

[0020] The present disclosure improves the mechanical strength and impact resistance of the battery pack by at least improving the housing and cooling unit of the power battery pack, and eliminates the risk of coolant leakage in the battery pack, thereby avoiding safety hazards. Through further improved designs of the battery module and wiring harness layout in the battery pack, the power battery pack of the present disclosure can achieve at least one beneficial effect such as good mechanical properties, high cooling efficiency, high temperature and high pressure short circuit protection in a cost-effective and reliable manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features and advantages of the present disclosure will be better understood through the following detailed description of the optional embodiments in conjunction with the accompanying drawings, in which the same reference numerals identify the same or similar components, wherein:

[0022] Figure 1 is a top schematic diagram of a power battery pack according to an embodiment of the present disclosure;

[0023] Figure 2 is an exploded schematic diagram of a power battery pack according to an embodiment;

[0024] Figure 3 yes Figure 2 The top schematic diagram of the power battery pack shown is without the top cover and cover plate;

[0025] Figure 4 is an exploded schematic diagram of a frame and internal support beams according to one embodiment;

[0026] Figure 5 is a schematic cross-sectional view of a side beam and associated components according to one embodiment;

[0027] Figure 6 is a schematic diagram of a cooling unit according to one embodiment;

[0028] Figure 7 is a schematic diagram of a base plate according to one embodiment;

[0029] Figure 8 is a schematic cross-sectional view of a recessed portion of a base plate and associated components;

[0030] Fig. 9 is a schematic diagram of a high voltage wiring harness according to one embodiment;

[0031] Fig.10 is a schematic diagram of a low voltage wiring harness according to one embodiment. DETAILED DESCRIPTION

[0032] The implementation and use of the embodiments are discussed in detail below. However, it should be understood that the specific embodiments discussed are merely exemplary of specific ways to implement and use the present disclosure, and are not intended to limit the scope of the present disclosure. When describing the structural positions of the various components, such as up, down, top, bottom, etc., the expressions of directions are not absolute, but relative. When the various components are arranged as shown in the figure, these directional expressions are appropriate, but when the positions of the various components in the figure change, these directional expressions also change accordingly.

[0033] In this document, unless otherwise clearly specified and limited, the terms "installation", "attachment", "connection", "fixation" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in this document can be understood according to the specific circumstances.

[0034] In this article, "front" and "rear" are relative to the front and rear directions of the vehicle. In addition, the "lateral direction" refers to the direction of relatively smaller size, also known as the width direction, the "longitudinal direction" refers to the direction of relatively larger size, also known as the length direction, and the "vertical direction" refers to the direction generally perpendicular to the ground.

[0035] In this article, a vehicle refers to a new energy vehicle that uses a power battery pack as an operating power source and / or a driving power source, including but not limited to a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle.

[0036] Generally, the power battery pack for a vehicle includes a battery module or battery cell, a battery management system, a battery pack housing and corresponding accessories. The battery pack housing, as a carrier of the battery module, plays a vital role in the safety and protection of the power battery pack. After the power battery pack is installed on the lower body sheet metal of the vehicle, once the vehicle is subjected to a collision, the collision force may be transmitted from the lower body sheet metal to the battery pack housing, thereby squeezing the battery module and causing safety hazards. When the vehicle is driving at high speed, objects such as stones and gravel on the ground may also directly collide with the battery pack housing to cause scratches, wear, and even cracks. For this reason, the existing battery pack housing mainly adopts, for example, a steel housing to improve the mechanical strength, but its weight is large, which is not conducive to the lightweight design of the whole vehicle. In addition, when, for example, an internal short circuit occurs in an iron-lithium battery under extreme conditions, the battery temperature will rise sharply and thermal runaway will occur, endangering the safety of life and property. For ternary lithium (NCM) batteries, which have higher energy density and have become the development trend of new energy vehicles, their chemical properties are unstable and their high-temperature safety is poor. How to reduce the risk of thermal runaway and improve cooling efficiency is particularly important.

[0037] The present disclosure proposes an improved power battery pack design based on the above requirements. Figure 1 and Figure 2 As shown, 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, and 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, to avoid damage caused by impact and thus affect the cooling effect of the cooling unit 300. Furthermore, the cooling unit 300 is also advantageously constructed as an integrated cooling plate 310, combined with Figure 3 and Figure 6 As shown, the cooling plate 310 is an integral design with a coolant pipeline built in, for example, formed by welding or crimping two large-sized aluminum plates to each other, and includes a liquid inlet 330 and a liquid outlet 340 arranged on the outside of the shell. The liquid inlet 330 and the liquid outlet 340 can be formed on one side of the cooling plate 310, and provide positioning and sealing connections, for example, in the form of a flange 320 to eliminate interface leakage. In this way, the risk of coolant leakage of the cooling unit 300 inside the battery pack is eliminated, safety hazards are avoided, and the integral large-sized cooling plate 310 also provides higher cooling efficiency.

[0038] In some embodiments, the cooling plate 310 is provided with a plurality of thermal pads 350 corresponding to the plurality of battery modules 200, such as a thermal conductive medium such as thermal conductive glue that improves thermal conductivity. Each battery module 200 can be attached to the cooling plate 310 through the corresponding thermal pad 350, further improving the cooling efficiency.

[0039] In the illustrated embodiment, the combination Figure 2 and Figure 4 , the frame 130 includes a side beam 131 extending in the longitudinal direction D1 and an end beam extending in the transverse direction D2, wherein the end beam includes a front beam 132 and a rear beam 133. Here, the side beam 131, the front beam 132 and the rear beam 133 provide the main mechanical strength as the structural beams of the shell 110. Advantageously, the shell 110 also includes a plurality of support beams arranged in the side beams 131 and the end beams to further provide structural support. The support beams, for example, include a longitudinal beam 134 extending in the longitudinal direction D1, and a plurality of cross beams 135 extending in the transverse direction D2 and spaced apart in the longitudinal direction D1. It should be understood that the number and distribution of the support beams vary depending on different needs and are not limited to those shown in the figure.

[0040] 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 beam 131. Figure 5 As shown, the side beam 131 is sealedly connected to the bottom plate 140 at the welding portion 150 by a welding process, such as friction stir welding (FSW) or metal inert gas welding (MIG). Figure 5 It can be seen that the multiple hollow portions 131a are advantageously stacked along the vertical direction D3, so that a compact structural size can provide reliable mechanical strength while achieving a weight reduction effect. When the battery pack is hit from the side, the hollow portion 131a can collapse and deform evenly, which helps to absorb and disperse part of the impact energy and protect the battery module inside the shell. It should be understood that the cross-sectional shape of the hollow portion 131a is not limited to that shown in the figure. For example, it can also be circular, elliptical or other polygonal shapes, as long as it is suitable for reliable and uniform transmission and absorption of 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.

[0041] In some embodiments, the anti-collision structure of the bottom plate 140 can be configured as a plurality of recessed portions 141 that are recessed toward the inside of the power battery pack, such as Figure 7 As shown, reinforcing ribs 142 are arranged between the plurality of recessed portions 141, and 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 needs. Advantageously, each recessed portion 141 is configured as a hemispherical shape and is provided with a connecting hole 143, so as to be suitable for being attached to the cooling plate 310 of the cooling unit 300 by a sealing screw. Figure 8The sealing screw 160 that is arranged at the recessed portion 141 to connect the bottom plate 140 to the cooling plate 310 is exemplarily shown. The sealing screw not only ensures the airtightness of the battery pack, but also helps to improve the mechanical strength of the various recessed portions at the bottom of the shell. In this way, when the bottom plate 140 is hit by a high-speed rock at the bottom, the recessed 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, and avoids affecting the cooling function of the cooling unit, thereby improving the durability of the cooling unit. Moreover, the reinforcing ribs 142 also further provide the mechanical strength of the bottom plate 140.

[0042] Since an 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 an extruded aluminum profile or an aluminum stamping plate, which can provide reliable and effective mechanical strength and cooling efficiency in a cost-effective manner.

[0043] In addition to providing an anti-collision structure for the housing and an integrated cooling plate design for the cooling unit, the present disclosure also advantageously arranges multiple battery modules 200 to be symmetrically distributed with respect to the longitudinal center line C of the power battery pack and with the same poles facing each other, see Figure 3 Especially for ternary lithium battery systems, the risk of thermal runaway is relatively high. The battery modules are arranged with the same poles facing each other, that is, the pole ears are led out on the same side, and the copper bars connecting the modules are arranged in the center of the battery pack. This provides more possibilities for the effective implementation of high temperature and high voltage short circuit protection.

[0044] Specifically, Figure 2 and Figure 3 In the illustrated embodiment, 12 battery modules 200 symmetrically distributed in two rows are exemplarily shown. It should be understood that other numbers of battery modules are optional depending on different needs. The junction box 400 and the battery management system (BMS) 500 can be arranged on one side of the battery pack, as shown in the figure on one side along the longitudinal direction D1, and the charging connector 600 can be arranged on the other opposite side. The power battery pack includes a high-voltage wire harness 710 and a low-voltage wire harness 720, wherein the high-voltage wire harness 710 is advantageously arranged along the longitudinal center line C. In this way, the length of the wire 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 a low-voltage wire harness to be responsible for collecting and monitoring the voltage, current, temperature and other state parameters of the battery cell, and the battery management unit 510 receives and evaluates the monitored state parameters to provide battery protection and is responsible for managing power, temperature, etc. Advantageously, the plurality of cell monitoring units 520 are arranged to be distributed on one side of the power battery pack or at both ends along the longitudinal direction. Figure 2As shown in , for example, four cell monitoring units 520 may be arranged on one side of the longitudinal direction D1 of the battery pack, and another four cell monitoring units 520 may be arranged adjacent to the battery management unit 510 on the opposite side. Compared with the prior design in which the cell monitoring units are arranged adjacent to the battery modules in a one-to-one correspondence, the solution disclosed in the present invention can ensure that the control components are not damaged by heat for as long as possible when thermal runaway occurs.

[0045] Combination Fig. 9 As shown, 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 and connected to 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 along the longitudinal direction D1, that is, connecting the junction box 400, the battery management system 500 and the charging connector 600 on the other side, and the plurality of sub-high-voltage harnesses 712 correspond to the plurality of battery modules 200. Similarly, in combination Fig.10 As shown, the low-voltage harness 720 includes a main low-voltage harness 721 corresponding to a plurality of battery modules 200, and a central low-voltage harness 722 connected to both ends of the power battery pack along the longitudinal direction D1 along the longitudinal center line, so as to complete the mutual connection between each battery cell monitoring unit and the battery management unit, and connect the external junction box interface and the junction box inside the battery pack. As described above, the multiple battery modules disclosed in the present invention are configured to lead out the pole ears with the same poles, and the copper bars connected between each module are arranged in the central position 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 bar and reduces the cost, but also reduces the number and probability of components affected when the short-circuit thermal runaway phenomenon occurs, and can also avoid the risk of short circuit when the side beam is deformed.

[0046] In certain embodiments, Figure 2 and Figure 3 As shown, the power battery pack of the present disclosure includes a central groove 810 extending along the longitudinal center line C to accommodate and position the high-voltage wire harness 710, and the central groove 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 groove 810 can be isolated to prevent the conductive medium generated when the battery module on one side is thermally runaway from affecting the battery module on the other side.

[0047] In some embodiments, the power battery pack further includes a cover plate 820 disposed between the top cover 120 and the plurality of battery modules 200. Figure 2 As shown, the cover plate 820 is made of mica and matches the shape of the top cover 120. When thermal runaway occurs, the hot gas and conductive medium ejected from the battery cell may arc with the top cover, and the cover plate 820 advantageously avoids the adverse effects of this situation.

[0048] The power battery pack disclosed in the present invention improves the impact resistance, cooling performance, fire resistance and safety performance of the power battery pack through design optimization in terms of shell structure, battery module layout, cooling unit, high and low voltage wiring harness layout, and high temperature and high voltage short circuit protection. The above components in the power battery pack have simple structures and are easy to implement, and are applicable to various forms of power battery packs.

[0049] It should be understood here that the embodiments shown in the figures only show the optional shapes, sizes and arrangements of the various components of the power battery pack, but they are only for illustration and not limitation. Other shapes, sizes and arrangements may also be adopted without departing from the spirit and scope of the present disclosure.

[0050] The technical content and technical features of the present disclosure have been disclosed above. However, it can be understood that under the creative ideas of the present disclosure, technicians in this field can make various changes and improvements to the above disclosed concepts, but they all belong to the protection scope of the present disclosure. The description of the above implementation mode is illustrative rather than restrictive, and the protection scope of the present disclosure is determined by the claims.

Claims

1. A power battery pack, comprising 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), characterized in that: The housing (110) includes 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 constructed 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, characterized in that: The anti-collision structure of the bottom plate (140) is configured to include a plurality of recessed portions (141) recessed toward the inside of the power battery pack (100), and reinforcing ribs (142) arranged between the plurality of recessed portions (141).

3. The power battery pack according to claim 2, characterized in that: Each of the recessed portions (141) is constructed in a hemispherical shape and is provided with a connecting hole (143) so as to be suitable for being attached to the cooling unit (300) via a sealing screw (160).

4. The power battery pack according to claim 1, characterized in that: The frame (130) comprises a side beam (131) extending in a longitudinal direction (D1) and end beams (132, 133) extending in a transverse direction (D2), and the anti-collision structure of the frame (130) is constructed as a plurality of hollow parts (131a) formed at least on the side beam (131).

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

6. The power battery pack according to claim 1, characterized in that: The cooling plate (310) is provided with a plurality of thermal conductive pads (350) respectively corresponding to the plurality of battery modules (200).

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

8. The power battery pack according to claim 7, characterized in that: The high-voltage wiring harness (710) includes a central main high-voltage wiring harness (711) and a plurality of sub-high-voltage wiring harnesses (712) distributed along the central main high-voltage wiring harness (711) and connected to the central main high-voltage wiring harness (711), wherein the central main high-voltage wiring harness (711) is connected to both ends of the power battery pack (100) along the longitudinal direction (D1), and the plurality of sub-high-voltage wiring harnesses (712) correspond to the plurality of battery modules (200).

9. The power battery pack according to claim 7, characterized in that: The low-voltage wiring harness (720) includes a main low-voltage wiring harness (721) corresponding to the plurality of battery modules (200), and a central low-voltage wiring harness (722) arranged along the longitudinal center line (C) and connected to both ends of the power battery pack (100) along the longitudinal direction (D1).

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

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

12. The power battery pack according to claim 1, characterized in that: The power battery pack (100) comprises a battery management unit (510) and a plurality of battery cell monitoring units (520), wherein the plurality of battery cell monitoring units (520) are distributed on one side of the power battery pack (100) or at both ends along a longitudinal direction (D1).

13. A vehicle, characterized in that: The vehicle comprises a power battery pack (100) according to any one of claims 1 to 12, the power battery pack (100) being suitable for being attached to a lower body sheet metal of the vehicle.

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