Battery pack and vehicle

Abstract

The invention discloses a battery pack and a vehicle. The battery pack comprises a battery box body, a battery pack upper cover matched with the battery box body and a double-layer battery cell module which is arranged in the battery box body and composed of an upper-layer battery cell module and a lower-layer battery cell module, the lower-layer battery cell module is arranged in an inverted mode, a liquid cooling plate is arranged between the double-layer battery cell module, and the liquid cooling plate is arranged between the upper-layer battery cell module and the lower-layer battery cell module. And meanwhile, carrying out liquid cooling on the upper-layer battery cell module and the lower-layer battery cell module. All battery cells of the battery pack can be effectively cooled under the condition that the height of the battery pack is not changed, and when the battery pack is applied to a battery system in a commercial vehicle, the problems that the battery cells of a battery pack of an existing commercial vehicle are high and the liquid cooling effect is poor can be solved, and the problems that the cost is high and the height is increased due to the addition of a liquid cooling plate are solved. The total energy density of the box body is reduced, and the space utilization rate is low.

Description

Technical Field

[0001] The present invention relates to the technical field of battery packs, and in particular to a battery pack and a vehicle. Background Art

[0002] With the rapid development of the new energy industry, the application of power battery systems is becoming more and more extensive. In recent years, the energy density of battery packs has received more and more attention from vehicle manufacturers, and at the same time, the demand for fast charging has become more and more obvious. However, the traditional structural form cannot take away the heat generated by the fast charging of the battery cell. If a liquid cooling plate is added for heat dissipation, the cost of the battery pack will inevitably increase, and the energy density will be reduced. Therefore, there is an urgent need for a structural form that can ensure energy density and support fast charging. The traditional light truck battery pack is a square structure, and its length is limited by the frame space. It is impossible to increase the power and increase the endurance, which limits the development of new energy vehicles in the direction of light trucks.

[0003] The existing commercial vehicle battery pack structure is generally a single-layer battery cell equipped with a bottom liquid cooling plate to cool the bottom of the battery cell. In the development process in recent years, the height of the battery cells has been relatively high, and is generally around 200mm, with a maximum of 218mm. One of the problems caused by the increase in the height of the battery cell is that when the bottom of the battery cell is liquid-cooled, the temperature difference between the top and bottom is large, which affects the cycle life of the battery cell. However, if the heat is dissipated by adding liquid cooling plates, adding top liquid cooling plates and side liquid cooling plates, the cost will increase and the overall energy density of the box will decrease. At the same time, the space height that a light truck frame can accommodate a battery pack is about 340mm, and the existing commercial vehicle battery cells (about 200mm in height) will result in low space utilization.

[0004] In short, traditional commercial vehicle battery packs generally have taller cells, which can maximize the power and occupy more frame space. The traditional liquid cooling structure at the bottom of the battery pack cools the battery pack by cooling the bottom of the cell on one side. For battery modules in special operating conditions (such as fast charging), the cells will release more heat. At this time, the temperature of the bottom liquid cooling coolant is low, which will cause a large temperature difference between the top and the bottom, affecting the cycle life of the battery pack. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings and defects of the prior art and to provide a battery pack that uses a layer of liquid cooling plate to simultaneously cool two layers of shorter battery cell modules and a vehicle equipped with the battery pack.

[0006] One aspect of the present invention provides a battery pack, comprising a battery case, a battery pack cover matched with the battery case, and a double-layer battery cell module composed of an upper battery cell module and a lower battery cell module placed in the battery case, wherein the lower battery cell module is arranged inverted, and a liquid cooling plate is arranged between the double-layer battery cell modules, and the upper battery cell module and the lower battery cell module are liquid-cooled at the same time.

[0007] The bottom surface of the battery cell of the upper battery cell module is fixedly connected to the upper surface of the liquid cooling plate, and the bottom surface of the battery cell of the lower battery cell module is fixedly connected to the lower surface of the liquid cooling plate.

[0008] The battery box is composed of a box frame and a bottom guard plate connected to the box frame; the box frame and the bottom guard plate are independently processed and formed and then assembled and connected together through a detachable structure.

[0009] Wherein, supporting bosses are arranged on both sides of the bottom of the box frame, the bottom guard plate is located between the two supporting bosses, and the bottom surface of the bottom guard plate is lower than the bottom surface of the supporting bosses and is in a suspended state.

[0010] Wherein, the liquid cooling plate is fixedly connected to the inner wall of the box frame by adopting a detachable structure.

[0011] Wherein, the upper parts of the two opposite inner side walls of the box frame are respectively provided with a connecting boss for connecting the liquid cooling plate, and the two sides of the liquid cooling plate are fixedly connected to the connecting boss by means of bolt connection.

[0012] There is a protruding portion in the middle of one end of the battery box, so that the battery box has a convex U-shaped structure as a whole.

[0013] Among them, one end of the liquid cooling plate is provided with a cooling medium inlet and outlet interface, and the cooling medium inlet and outlet interface is detachably connected to the inlet and outlet liquid pipes. The inlet and outlet liquid pipes are arranged in the end side space formed by the protrusion, and are detachably connected to the medium inlet and outlet joints installed on the end plate of the protrusion.

[0014] Wherein, the box frame is made of aluminum profile, and the bottom guard plate is made of steel plate or composite material.

[0015] Another aspect of the present invention provides a vehicle including the battery pack.

[0016] The battery pack of the present invention has a double-layer battery cell module consisting of an upper battery cell module and a lower battery cell module arranged in its battery case, the lower battery cell module is arranged inverted, and a liquid cooling plate is arranged between the double-layer battery cell modules, and the upper battery cell module and the lower battery cell module are liquid-cooled at the same time. Such a technical scheme can achieve effective cooling of all the battery cells of the battery pack while keeping the height of the battery pack unchanged. When used in a commercial vehicle battery system, it can solve the problems of high battery cells and poor liquid cooling effect in existing commercial vehicle or light truck battery packs, as well as the problems of high cost and increased height due to the addition of liquid cooling plates, reduced overall energy density of the box, and low space utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an exploded view of the overall structure of the battery pack according to an embodiment of the present invention.

[0018] Figure 2 It is a schematic diagram of the assembly of the liquid cooling plate and the upper battery cell module of the battery pack according to an embodiment of the present invention.

[0019] Figure 3 It is a schematic diagram of the battery pack of an embodiment of the present invention after the battery cell modules are assembled and put into a box as a whole.

[0020] Figure 4 It is a schematic diagram of putting the battery cell modules of the battery pack of an embodiment of the present invention into a box and closing the battery cover.

[0021] Figure 5 It is a schematic diagram of a battery pack box frame of an embodiment of the present invention connected to a liquid cooling plate and inverted to install a lower battery cell module and a bottom guard plate.

[0022] Figure 6 It is a schematic diagram of assembling an upper layer battery cell module after assembling a lower layer battery cell module according to an embodiment of the present invention.

[0023] Figure 7 It is a partial schematic diagram of the box frame and the front end of the liquid cooling plate of the battery pack according to an embodiment of the present invention.

[0024] Figure 8 It is a side view after the box frame, bottom protective plate, lower battery cell module and liquid cooling plate of the battery pack of an embodiment of the present invention are assembled together.

[0025] Fig. 9 It is an overall schematic diagram of the battery pack of an embodiment of the present invention after the box frame, bottom protective plate, lower battery cell module and liquid cooling plate are assembled together. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] See also Figures 1 to 9 As shown, a battery pack includes a battery case, a battery pack cover 1 matched with the battery case, and a double-layer battery cell module composed of an upper battery cell module 2 and a lower battery cell module 4 placed in the battery case, wherein the lower battery cell module is invertedly arranged, and a liquid cooling plate 3 is arranged between the double-layer battery cell modules, and the upper battery cell module and the lower battery cell module are liquid-cooled at the same time.

[0028] By setting up a double-layer battery cell module, all the battery cells in the battery pack can be effectively cooled without changing the height of the battery pack. When used in the battery system of commercial vehicles or light trucks, it can solve the problems of high battery cells and poor liquid cooling effect in existing commercial vehicle battery packs, as well as the problems of high cost and increased height due to the addition of liquid cooling plates, reduced overall energy density of the box, and low space utilization.

[0029] In the embodiment of the present application, the battery pack uses a liquid cooling plate to cool the upper and lower layers of the battery cell modules at the same time, which can effectively reduce the problem of large temperature difference between the top and bottom caused by liquid cooling at the bottom of the battery cell. Moreover, by reducing the height of the battery cell, the problem of large temperature difference between the top and bottom caused by fast charging / high rate discharge can be reduced; and the use of an independent liquid cooling plate has stronger adaptability.

[0030] In addition, since a single-layer liquid cooling plate is used to cool two layers of modules at the same time, it can save material costs, increase the volume grouping rate, and solve the problem of insufficient energy density of the battery pack; it can also reduce the height of the entire battery pack to adapt to more vehicle models.

[0031] The traditional square battery pack is installed on the light truck frame, which is limited by the frame installation space and cannot increase the power by increasing the length. In the embodiment of the present application, the battery pack is set as a double-layer battery module structure, which can make more reasonable use of the height direction of the vehicle. For example, the height space of the light truck battery compartment is about 330mm, and the maximum height of the battery cell can be made 218mm. Single-layer battery cells cannot reasonably use the space.

[0032] In some embodiments, the bottom surface of the battery cell of the upper battery cell module is fixedly connected to the upper surface of the liquid cooling plate, and the bottom surface of the battery cell of the lower battery cell module is fixedly connected to the lower surface of the liquid cooling plate, such as by bonding and fixing with a thermal conductive structural adhesive and / or by bolting. If a thermal conductive structural adhesive is used to bond the battery cell module to the liquid cooling plate, a certain structural strength can be provided, and good thermal conductivity can be achieved; bolting can also be used to provide secondary reinforcement of the structural strength.

[0033] In some embodiments, the battery case is composed of a case frame 5 and a bottom guard plate 6 connected to the case frame; the case frame 5 and the bottom guard plate 6 are independently processed and formed and then assembled and connected together through a detachable structure. In one embodiment, the bottom guard plate and the case frame are pre-assembled to form a battery case, or are provided as an integral battery case assembly. The bottom guard plate and the case frame can be integrated together to form a case in a variety of ways, such as by using FDS (Flow Drill Screwing, flow drill threaded connection technology), welding, bonding or bolting.

[0034] When assembling the battery pack, the liquid cooling plate can be first bonded and / or bolted to the lower battery cell module. After the thermal conductive structural adhesive used for bonding the lower battery cell module is cured, turn it over to assemble the upper battery cell module; after the thermal conductive structural adhesive of the upper battery cell module is cured again, lift the liquid cooling plate and the two layers of battery cell modules into the box at the same time. After the overall structure of the battery cell module and the liquid cooling plate is placed in the box, bolts can be used to bolt the liquid cooling plate and the box wall together; then install quick-plug water pipes, other electrical parts and connecting bars, BMS, etc.; finally, install the battery pack cover to complete the assembly of the battery pack.

[0035] In another embodiment, the liquid cooling plate and the box frame are pre-formed, but without a preset assembly structure, the liquid cooling plate and the box frame are first assembled and connected together, and then the battery cells are assembled. When assembling the battery cell module, first invert the battery pack box frame, first install and fix the lower battery cell module, and after the lower battery cell module is installed and fixed, install the bottom guard plate to the bottom of the box frame; then flip the whole thing over, and install the upper battery cell module to the upper surface of the liquid cooling plate; then install the quick-plug water pipe, other electrical parts and connecting bars, BMS, etc.; finally install the battery pack cover to complete the assembly of the battery pack.

[0036] In the embodiment of the present application, the bottom guard plate, liquid cooling plate, and box frame are all supplied separately. At the production site, one of the above two assembly forms can be selected according to the production line / equipment conditions of the production site, and the adaptability is strong.

[0037] In some embodiments, support bosses 56 are arranged on both sides of the bottom of the side wall 53 of the box frame 5, and the bottom is the lowest point of the battery pack. The bottom guard plate 6 is located between the two support bosses 56, and the bottom surface of the bottom guard plate is lower than the bottom surface of the support boss and is in a suspended state. With such a technical solution, when the battery is placed normally, the bottom guard plate can be suspended to avoid wear on the bottom guard plate during installation and transportation. At the same time, the protrusions of the bolts / screws used in the installation of the bottom guard plate can be avoided, causing the bolts and screws to be stressed. The bottom guard plate is connected to the box frame with bolts / screws. The upper and lower ends of the box frame are open, and the outer wall formed around the end and tail connection serves as the side plate or enclosure of the battery box.

[0038] In some embodiments, the liquid cooling plate is fixedly connected to the inner wall of the box frame using a detachable structure. A preferred implementation is that the liquid cooling plate is connected to the inner wall of the box frame using bolts / screws for easy installation and maintenance.

[0039] In some embodiments, the upper portions of the two opposite inner side walls of the box frame each have a connecting boss 52 for connecting the liquid cooling plate, and the two side structures 31 of the liquid cooling plate (such as a connecting plate) are fixedly connected to the connecting boss 52 by bolt connection, and the connecting boss 52 is arranged along the length direction of the box frame 5 in two strips, which are arranged relatively on the two inner side walls of the box frame, wherein the two side structures 31 of the liquid cooling plate are arranged as corresponding long strip structures.

[0040] The connecting boss 52 is preferably located near the top of the box frame, and more preferably is a solid structure, which can provide sufficient structural strength for the battery box. With such a technical solution, after the liquid cooling plate is fixed to the box frame, a space for the lower battery module is formed between the lower surface of the liquid cooling plate and the bottom guard plate, and a space for the upper battery module is formed between the upper surface of the liquid cooling plate and the upper cover of the battery box. The upper surface of the entire liquid plate and the upper end of the box frame are preferably close to being level.

[0041] In some embodiments, the battery box has a protrusion 50 in the middle of one end side, so that the battery box as a whole has a convex structure, and the protrusion is formed by connecting two side panels 54 and an end panel 55. The two side panels 54 are connected to the end surface of the box frame and connected to the end panel 55, forming a small rectangular space inside. Figure 7 As shown, correspondingly, the shape of the battery pack upper cover, box frame and bottom guard plate are prefabricated into a convex structure, and a convex-shaped battery box is formed after assembly.

[0042] At the front end of the convex-shaped battery box, that is, in the space corresponding to the convex part, the restricted position on the frame can be avoided, and electrical components and BMS can be placed, so that the space utilization is more reasonable. Furthermore, in the convex part of the battery pack, the frame structure is provided with upper and lower reinforcement structures, such as the upper reinforcement plate and the lower reinforcement plate 57, which can be used to install the upper cover / bottom guard plate of the battery pack while enhancing the structural strength; it can also be used to fix the wiring harness, so that the space utilization rate is higher. There is a medium inlet and outlet connector 51 on the end panel 55 of the convex part.

[0043] In some embodiments, one end of the liquid cooling plate 3 has a cooling medium inlet and outlet interface 32, and the cooling medium inlet and outlet interface is detachably connected to the inlet and outlet liquid pipe 7. The inlet and outlet liquid pipe 7 is arranged in the end side space formed by the protrusion, and is detachably connected to the medium inlet and outlet joint 51 installed on the end panel of the protrusion. In the embodiment of the present application, the medium inlet and outlet joint 51 on the protrusion at the front end of the liquid cooling plate and the battery pack is connected to the inlet and outlet liquid pipe 7, especially using a quick-insert inlet and outlet liquid pipe, which is simple and reliable to assemble and saves labor costs. The medium inlet and outlet joint 51 on the protrusion can be adjusted according to the space of the entire vehicle without changing the design of the liquid cooling plate.

[0044] In some embodiments, the box frame is made of aluminum profiles, and the bottom guard plate is made of steel plates or composite materials. In the embodiments of the present application, the side walls of the box frame are connected to the solid structure of the bosses to increase the structural strength of the battery pack. The bottom is made of high-strength steel or composite materials. Compared with aluminum profiles, the bottom guard plate has stronger structural strength. Furthermore, the strength can be enhanced by adding processes such as bending. The space between the bottom guard plate and the battery cell is large enough to support the bottom impact. Combined with the setting of the supporting boss at the bottom, there will be no danger due to bottom support or bottom scraping during use. Compared with the commonly used aluminum profile box bottom plate, it has higher safety performance and solves the problem of danger caused by bottom impact of the battery pack.

[0045] Another aspect of the present invention provides a vehicle including the battery pack, wherein the vehicle is a commercial vehicle, in particular a light truck.

[0046] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0047] Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is therefore intended that all changes falling within the meaning and range of equivalent elements of the claims are included in the present invention.

[0048] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A battery pack, characterized in that: It includes a battery case, a battery pack cover matched with the battery case, and a double-layer battery cell module composed of an upper battery cell module and a lower battery cell module placed in the battery case, wherein the lower battery cell module is invertedly arranged, and a liquid cooling plate is arranged between the double-layer battery cell modules, and the upper battery cell module and the lower battery cell module are liquid-cooled at the same time.

2. The battery pack according to claim 1, characterized in that: The bottom surface of the battery cells of the upper battery cell module is fixedly connected to the upper surface of the liquid cooling plate, and the bottom surface of the battery cells of the lower battery cell module is fixedly connected to the lower surface of the liquid cooling plate.

3. The battery pack according to claim 1, characterized in that: The battery box body is composed of a box body frame and a bottom guard plate connected to the box body frame; the box body frame and the bottom guard plate are independently processed and formed, and then assembled and connected together through a detachable structure.

4. The battery pack according to claim 3, characterized in that: Support bosses are arranged on both sides of the bottom of the box frame, the bottom guard plate is located between the two support bosses, and the bottom surface of the bottom guard plate is lower than the bottom surface of the support bosses and is in a suspended state.

5. The battery pack according to claim 1, characterized in that: The liquid cooling plate is fixedly connected to the inner wall of the box frame by adopting a detachable structure.

6. The battery pack according to claim 5, characterized in that: The upper parts of the two opposite inner side walls of the box frame are respectively provided with a connecting boss for connecting the liquid cooling plate, and the two sides of the liquid cooling plate are fixedly connected to the connecting boss by means of bolt connection.

7. The battery pack according to claim 1, characterized in that: A protruding portion is provided in the middle of one end side of the battery box, so that the battery box as a whole has a convex-shaped structure.

8. The battery pack according to claim 7, characterized in that: One end of the liquid cooling plate is provided with a cooling medium inlet and outlet interface, and the cooling medium inlet and outlet interface is detachably connected to an inlet and outlet liquid pipe. The inlet and outlet liquid pipe is arranged in the end side space formed by the protrusion and is detachably connected to a medium inlet and outlet joint installed on the end plate of the protrusion.

9. The battery pack according to claim 3, characterized in that: The box frame is made of aluminum profiles, and the bottom guard plate is made of steel plates or composite materials.

10. A vehicle, characterized in that A battery pack comprising any one of claims 1 to 9.

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