Power battery pack and engineering vehicle

Abstract

The present disclosure relates to the field of power batteries, and relates to a power battery pack and an engineering vehicle, for use in improving the structure of the power battery pack and realizing high capacity and high voltage of the power battery pack. The power battery pack comprises a case, a bracket assembly, and a plurality of battery cell assemblies. The case comprises a first storage cavity; the bracket assembly is located in the first storage cavity; the bracket assembly comprises a plurality of layers of second storage cavities; each battery cell assembly comprises a plurality of battery cells; and the battery cell assemblies are placed in the second storage cavity of each bracket. The power battery pack formed by the described technical solution is provided with a plurality of layers of battery cell assemblies, so that a single power battery pack has a high voltage, a high capacity, and high structural strength. A single power battery pack can provide a high-voltage platform for a vehicle, without requiring external series connection of additional battery packs, thereby simplifying the high-voltage architecture of a battery system and reducing the number of battery packs in the battery system.

Description

Power battery packs and engineering vehicles

[0001] Cross-references to related applications

[0002] This disclosure is based on and claims priority to CN application No. 202510091901.4, filed on January 21, 2025, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates to the field of power batteries, specifically to a power battery pack and an engineering vehicle. Background Technology

[0004] Currently, for large construction machinery and heavy trucks, the overall voltage platform is 800V and above, which requires more than 250 series-connected battery cells, with a battery system capacity of 1,000 to 3,000 kWh. Here, "voltage platform" refers to the voltage range of the battery during charging and discharging.

[0005] The overall battery system requires a large amount of power and high voltage, while the individual battery packs that make up the overall battery system have a small amount of power and low voltage. In order to form an overall battery system that meets the requirements, a large number of battery packs need to be connected in series and parallel, and in some cases, even dozens of battery packs are needed.

[0006] The inventors have discovered that the prior art has at least the following problems: due to the large number of battery packs included in the whole battery system, the whole battery system is complicated to assemble, heavy, and occupies a large amount of external space. Summary of the Invention

[0007] This disclosure proposes a power battery pack and an engineering vehicle to improve the structure of the power battery pack and achieve high capacity and high voltage.

[0008] This disclosure provides a power battery pack in some embodiments, including:

[0009] The enclosure includes a first storage cavity;

[0010] A bracket assembly is located within the first storage cavity; the bracket assembly includes multiple layers of second storage cavities; and

[0011] Multiple battery cell assemblies, each of the battery cell assemblies comprising multiple battery cells, and the battery cell assembly being placed in the second storage cavity of each of the brackets.

[0012] In some embodiments, the bracket assembly includes a first bracket, a second bracket, and a third bracket stacked together; the first bracket and the second bracket are fixedly connected, and the second bracket and the third bracket are fixedly connected; the height of each of the battery cell assemblies is lower than the height of the first bracket, the second bracket, and the third bracket.

[0013] In some embodiments, the height of the second storage cavity of each of the first bracket, the second bracket, and the third bracket is 0.8 mm to 1.2 mm higher than the height of the cell assembly.

[0014] In some embodiments, the first bracket, the second bracket, and the third bracket each include at least one second storage cavity, and at least one of the battery cell assemblies is fixed in each second storage cavity.

[0015] In some embodiments, the first bracket and the second bracket each include:

[0016] A first cold plate is configured to cool the cell assembly located within the second storage cavity;

[0017] Two first end plates, the two first end plates being separately fixed at both ends of the first cold plate along its length; and

[0018] Two first side plates, two first end plates, and two first side plates form a closed side wall; the two first side plates are dispersedly fixed to the first cold plate, and both first side plates are located between the two first end plates; the first cold plate, each of the first end plates, and each of the first side plates together form the second storage cavity.

[0019] In some embodiments, the first bracket and the second bracket each further include:

[0020] At least one first partition is fixedly connected to the first cold plate. The first partition divides the second storage cavity into a plurality of first storage sub-cavities, and each first storage sub-cavity contains one of the battery cell assemblies.

[0021] In some embodiments, at least one of the first side plates is provided with a first groove;

[0022] Wherein, the length direction is along the direction from one of the first end plates to the other first end plate, and along the length direction, the cell assemblies located in two adjacent first storage sub-cavities are connected in series by a first connecting part, the first connecting part being located in the first groove or on the side of the first groove away from the cell assembly.

[0023] In some embodiments, at least one of the first end plates is provided with a second groove;

[0024] Wherein, the width direction is perpendicular to the length direction, and along the width direction, the battery cell assemblies located in two adjacent first storage sub-cavities are connected in series through a second connecting part, which is located in the second groove or on the side of the second groove away from the battery cell assembly.

[0025] In some embodiments, along the length direction, each of the cell assemblies located in two adjacent first storage sub-cavities includes a plurality of cells, wherein one cell assembly includes an odd number of cells and the other cell assembly includes an even number of cells.

[0026] In some embodiments, the number of the first partitions is two, and the two first partitions are arranged in a cross-shaped manner.

[0027] In some embodiments, the first end plate, the first side plate, and the first partition plate have the same height, and each is 0.8 to 1.2 mm higher than the height of the battery cell assembly.

[0028] In some embodiments, the third bracket includes:

[0029] The second cold plate is configured to cool the cell assembly located within the second storage cavity;

[0030] Two second end plates, which are separately fixed at both ends of the second cold plate along its length; and

[0031] Two second side plates, two second end plates, and two second side plates form a closed side wall; two second side plates are separately fixed to the second cold plate, and both second side plates are located between the two second end plates; the second cold plate, each of the second end plates, and each of the second side plates together form the second storage cavity of the third bracket.

[0032] In some embodiments, the third bracket further includes:

[0033] At least one second partition is fixedly connected to the second cold plate. The second partition divides the second storage cavity of the third bracket into multiple second storage sub-cavities, and each second storage sub-cavity contains one of the battery cell assemblies.

[0034] In some embodiments, at least one of the second side plates is provided with a third groove;

[0035] Wherein, the length direction is along the direction from one of the second end plates to the other second end plate, and along the length direction, the cell assemblies located in two adjacent second storage sub-cavities are connected in series by a third connecting part, the third connecting part being located in the third groove or on the side of the third groove away from the cell assembly.

[0036] In some embodiments, at least one of the second end plates is provided with a fourth groove;

[0037] Wherein, the width direction is perpendicular to the length direction, and along the width direction, the cell assemblies located in two adjacent second storage sub-cavities are connected in series through a fourth connecting part, which is located in the fourth groove or on the side of the fourth groove away from the cell assembly.

[0038] In some embodiments, along the length direction, each of the cell assemblies located in two adjacent second storage sub-cavities includes a plurality of cells, wherein one cell assembly includes an odd number of cells and the other cell assembly includes an even number of cells.

[0039] In some embodiments, the number of the second partition is two, and the two second partitions are arranged in a cross pattern.

[0040] In some embodiments, the second end plate and the second partition plate are at the same height, and both are 0.8 to 1.2 mm higher than the height of the battery cell assembly;

[0041] The height of the second side plate is lower than the height of the second end plate and the second partition.

[0042] In some embodiments, the bottom surface of the battery cell assembly located in the second storage cavity of the first bracket is fixedly connected to the inner wall of the bottom surface of the first bracket, and the top surface of the battery cell assembly is fixedly connected to the outer wall of the bottom surface of the second bracket.

[0043] In some embodiments, the bottom surface of the battery cell assembly located in the second storage cavity of the second bracket is fixedly connected to the inner wall of the bottom surface of the second bracket, and the top surface of the battery cell assembly is fixedly connected to the outer wall of the bottom surface of the third bracket.

[0044] In some embodiments, the power battery pack further includes:

[0045] A pull plate is located at the top of the bracket assembly, and the pull plate is fixedly connected to both the bracket assembly and the housing.

[0046] This disclosure also provides an engineering vehicle, including a power battery pack provided by any of the technical solutions in this disclosure.

[0047] In some embodiments, the engineering vehicle is one of the following: a loader or a grader.

[0048] The power battery pack provided by the above technical solution has a first storage cavity in its casing, with the bracket assembly and cell assembly located inside the first storage cavity. Multiple layers of second storage cavities are formed by the bracket assembly, with each layer containing cell assemblies. The entire power battery pack includes multiple layers of cell assemblies, with each layer containing fewer cell assemblies. This increases the overall height of the power battery pack while reducing its length and width in the plane. Because the cell assemblies are placed inside the second storage cavities—meaning they do not protrude from the highest point of the cavity wall—they do not bear the weight of other cell assemblies above them in the vertical direction. Therefore, the multiple layers of cell assemblies do not cause excessive load on the lower cell assemblies, preventing safety hazards or damage. The structure of the power battery pack is optimized, contributing to high capacity and high voltage. The power battery pack formed by the above technical solution, due to the multiple layers of cell assemblies, has high voltage and high capacity per cell, and high structural strength. A single power battery pack can meet the high voltage platform of the entire vehicle, eliminating the need for other battery packs to be connected in series externally. This simplifies the high voltage architecture of the battery system and reduces the number of battery packs in the system. Attached Figure Description

[0049] Figure 1 is a three-dimensional exploded view of a power battery pack provided in some embodiments of this disclosure.

[0050] Figure 2 is a schematic diagram showing the arrangement of the first bracket and the cell assembly of the power battery pack provided in some embodiments of this disclosure.

[0051] Figure 3 is a three-dimensional structural schematic diagram of the first bracket of the power battery pack provided in some embodiments of this disclosure.

[0052] Figure 4 is a schematic diagram showing the arrangement of the first bracket, the second bracket, and the cell components inside each of the power battery packs provided in some embodiments of this disclosure.

[0053] Figure 5 is a three-dimensional structural schematic diagram of the second bracket of the power battery pack provided in some embodiments of this disclosure.

[0054] Figure 6 is a schematic diagram showing the arrangement of the first bracket, second bracket, third bracket and the cell components inside each of the power battery packs provided in some embodiments of this disclosure.

[0055] Figure 7 is a three-dimensional structural diagram of the third bracket of the power battery pack provided in some embodiments of this disclosure.

[0056] Figure 8 is a schematic diagram of the three-dimensional structure of the pull plate of the power battery pack provided in some embodiments of this disclosure.

[0057] Figure 9 is a schematic diagram of the pull plate mounting structure of a power battery pack provided in some embodiments of this disclosure.

[0058] Figure 10 is a schematic diagram showing the connection relationship of the first bracket, the second bracket, and the third bracket of the power battery pack provided in some embodiments of this disclosure.

[0059] Reference numerals: 1. Housing; 2. Bracket assembly; 3. Cell assembly; 4. Pull plate; 5. Hook; 6. Seal; 11. First storage cavity; 12. Housing body; 13. Housing cover; 14. Inspection port; 15. Inspection plate; 20. Second storage cavity; 21. First bracket; 22. Second bracket; 23. Third bracket; 24. First cold plate; 25. First end plate; 26. First side plate; 27. First partition; 28. First connecting part; 29. ​​Second connecting part; 210. Third connecting part; 211. Fourth connecting part; 212. Total negative output copper busbar; 213. Interlayer connecting copper busbar; 214. Total positive output copper busbar; 200. First storage sub-cavity; 201. Second storage sub-cavity; 250. First groove; 240. Second groove; 231. Second cold plate; 232. Second end plate; 233. Second side plate; 234. Second partition plate; 235. Third groove; 236. Fourth groove; 237. Lifting hole. Detailed Implementation

[0060] The technical solutions provided in this disclosure will be described in more detail below with reference to Figures 1 to 10. The descriptions of exemplary embodiments are merely illustrative and are in no way intended to limit this disclosure or its application or use. This disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make this disclosure thorough and complete, and to fully express the scope of this disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0061] The terms “first,” “second,” and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as “including” or “contains” mean that the element preceding the word covers the element listed after the word, and do not exclude the possibility of covering other elements as well.

[0062] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0063] All terms used in this disclosure, including technical or scientific terms, have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0064] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment shall be considered part of the specification.

[0065] The dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Common structural elements or elements of the same kind are given the same reference numerals in the various drawings, and repeated descriptions of them are omitted where appropriate.

[0066] In the following description of specific embodiments, for ease of explanation, an XYZ coordinate system is established in Figure 1, where the X direction is the length direction of the power battery pack, which is approximately the left-right direction in Figure 1; the Y direction is the width direction of the power battery pack, which is approximately the up-down direction in Figure 1; and the Z direction is the height direction of the power battery pack, which is also the up-down direction in Figure 1.

[0067] Figure 1 is a three-dimensional exploded view of a power battery pack provided in some embodiments of this disclosure. Figure 2 is a schematic diagram of the arrangement relationship between the first bracket and the cell assembly of the power battery pack provided in some embodiments of this disclosure. Figure 3 is a three-dimensional structural schematic diagram of the first bracket of the power battery pack provided in some embodiments of this disclosure.

[0068] Referring to Figure 1, some embodiments of this disclosure provide a power battery pack, including a housing 1, a bracket assembly 2, and multiple cell assemblies 3. The housing 1 includes a first storage cavity 11; the bracket assembly 2 is located within the first storage cavity 11. The bracket assembly 2 includes multiple layers of second storage cavities 20, as shown in Figure 3; each cell assembly 3 includes multiple cells, and each second storage cavity 20 of the bracket houses a cell assembly 3.

[0069] The housing 1 is used to support and install the bracket assembly 2 and each battery cell assembly 3. The housing 1 is made of castings, which have strong load-bearing capacity and high structural strength to meet the load-bearing requirements of engineering vehicles such as loaders and graders that operate under relatively complex working conditions.

[0070] In some embodiments, the housing 1 includes a housing body 12 and a housing cover 13. The housing body 12 is made of casting, and the housing cover 13 is made of casting or composite material. The housing body 12 has an opening at the top, and the housing cover 13 is disposed at the opening of the housing body 12. The housing body 12 and the housing cover 13 are detachably connected. By opening the housing cover 13, the battery cell assembly 3 and the bracket assembly 2 can be placed inside the housing body 12, or the aforementioned components can be removed. When the housing cover 13 is closed, the entire power battery pack is a closed whole, and the battery cell assembly 3 and the bracket assembly 2 inside the power battery pack are fixedly connected, making the entire power battery pack structure very stable.

[0071] In order to make the installation of the cover 13 more secure, in addition to being fixedly connected to the body 12, the cover 13 is also detachably fixedly connected to the third bracket 23 at the top of the bracket assembly 2, for example by bolt connection. This connection method increases the number of connection points of the cover 13, making the installation of the cover 13 more secure and reliable.

[0072] Referring again to Figure 1, for ease of maintenance, multiple access ports 14 are provided on the enclosure body 12. Each access port 14 is detachably equipped with an access panel 15. By opening the access panel 15, the internal components of the enclosure body 12 can be inspected and maintained. As shown in Figure 1, taking four access ports 14 as an example, the four access ports 14 are arranged side by side, and each access port 14 is equipped with an access panel 15. Each access panel 15 is configured to be opened and closed independently.

[0073] Referring again to Figure 1, in some embodiments, the bracket assembly 2 includes a first bracket 21, a second bracket 22, and a third bracket 23 stacked together; the first bracket 21 and the second bracket 22 are fixedly connected, and the second bracket 22 and the third bracket 23 are fixedly connected; the height of each cell assembly 3 is lower than the respective height of the first bracket 21, the second bracket 22, and the third bracket 23.

[0074] Referring to Figure 1, a layer of battery cell assembly 3 is fixedly mounted on the first bracket 21, a layer of battery cell assembly 3 is fixedly mounted on the second bracket 22, and a layer of battery cell assembly 3 is fixedly mounted on the third bracket 23. The entire power battery pack has three layers of battery cell assembly 3. Each layer includes one or more battery cell assemblies 3. Of course, as needed, in other embodiments, the entire power battery pack has two or more layers of battery cell assembly 3.

[0075] Referring again to Figure 1, in some embodiments, the height of the second storage cavity 20 of each of the first bracket 21, second bracket 22, and third bracket 23 is 0.8mm to 1.2mm higher than the height of the cell assembly 3, for example, 0.8mm, 1mm, and 1.2mm. After the cell assembly 3 is placed in the second storage cavity 20 of each of the first bracket 21, second bracket 22, and third bracket 23, the top surface of the cell assembly 3 is slightly lower than the highest point of each of the first bracket 21, second bracket 22, and third bracket 23. Since the height of the cell assembly 3 is slightly lower than the brackets of the bracket assembly 2, the cell assembly 3 will not support other components located above it. The first bracket 21 is located at the bottom of the bracket assembly 2, the second bracket 22 is located in the middle of the bracket assembly 2, and the third bracket 23 is located at the top of the bracket assembly 2. The first bracket 21 supports and carries the second bracket 22 and the third bracket 23, and the second bracket 22 supports and carries the third bracket 23. The cell assembly 3 supported by the first bracket 21 does not support the second bracket 22, the third bracket 23 above it, or the cell assemblies 3 they support; these components are supported by the first bracket 21. The cell assembly 3 supported by the second bracket 22 does not support the third bracket 23 above it or the uppermost cell assembly 3; these components are supported by the second bracket 22. The cover 13 located on top of the third bracket 23 and the pull plate 4 described later are supported by the third bracket 23. The uppermost cell assembly 3 essentially does not bear the weight of these components.

[0076] Referring to Figures 1, 3, 5, and 7, in some embodiments, the first bracket 21, the second bracket 22, and the third bracket 23 each include at least one second storage cavity 20, and at least one battery cell assembly 3 is fixed in each second storage cavity 20. In some embodiments described later, the first bracket 21, the second bracket 22, and the third bracket 23 each include a second storage cavity 20, and each second storage cavity 20 is divided into four smaller cavities by a partition, with one battery cell assembly 3 placed in each smaller cavity. The battery cell assemblies 3 in the four smaller cavities of the same second storage cavity 20 are connected in series and parallel to form a whole. The battery cell assemblies 3 in all second storage cavities 20 are also connected in series and parallel to form a whole. The battery cell assemblies 3 in each layer are first connected in series and parallel to form a whole, and then the battery cell assemblies 3 in each layer are connected in series and parallel to form the final whole. That is, in the second storage cavity 20 of the first bracket 21, the second bracket 22 and the third bracket 23, each cell assembly 3 first forms a single layer through series and parallel connection; then, the single layers corresponding to the three brackets form the total electrical circuit of the power battery pack through series and parallel connection.

[0077] Referring to Figures 2 and 3, the first bracket 21 is divided into four first storage sub-cavities 200 by the first partition 27, which will be described later. The four first storage sub-cavities 200 are arranged in a 2x2 configuration, that is, there are two first storage sub-cavities 200 along the X direction and two first storage sub-cavities 200 along the Y direction. Each first storage sub-cavity 200 houses a battery cell assembly 3. The four first storage sub-cavities 200 are electrically connected to form a whole.

[0078] Furthermore, referring to Figure 2, multiple hooks 5 are distributed along the edge of the first bracket 21, with 4 to 8 hooks 5 as an example. These multiple hooks 5 facilitate the lifting of the first bracket 21 and the battery cell assembly 3 within it.

[0079] Referring to Figure 3, the first bracket 21 includes a first cold plate 24, two first end plates 25, and two first side plates 26. The first cold plate 24 is configured to cool the battery cell assembly 3 located in the second storage cavity 20. The two first end plates 25 are distributed and fixed at both ends of the first cold plate 24, specifically welded together. The two first end plates 25 and the two first side plates 26 form a closed sidewall; the two first side plates 26 are distributed and fixed to the first cold plate 24, specifically welded together, and both first side plates 26 are located between the two first end plates 25; the first cold plate 24, each of the first end plates 25, and each of the first side plates 26 together form the second storage cavity 20 of the second bracket 22.

[0080] The first cooling plate 24 is a water-cooled plate with internal water channels for cooling the battery cell assembly 3 inside the first bracket 21. The first cooling plate 24 serves as the bottom wall of the first bracket 21, supporting the individual battery cell assemblies 3 within it. The first cooling plate 24 is glued to the battery cell assembly 3, maintaining contact between them. The first cooling plate 24 effectively reduces the temperature of the battery cell assembly 3, providing excellent heat dissipation for the heat generated during operation.

[0081] Referring again to Figure 3, in some embodiments, the first bracket 21 further includes at least one first partition 27, for example, two first partitions 27. The first partition 27 along the X direction is a single plate, also referred to as a longitudinal beam; the first partition 27 along the Y direction is divided into two segments, also referred to as reinforcing plates, to avoid obstruction of the first partition 27 extending along the X direction. The first partition 27 is fixedly connected to the first cold plate 24, specifically by welding. The first partition 27 divides the second storage cavity 20 into multiple first storage sub-cavities 200, each of which is fixedly installed with a cell assembly 3, specifically by adhesive bonding.

[0082] Since the individual cell assemblies 3 supported by the first bracket 21 need to be electrically connected to form a whole, at least one first side plate 26 is provided with a first groove 250 to facilitate the electrical connection of the cell assemblies 3 located in two first storage sub-cavities 200 along the length direction, i.e., the X direction. The cell assemblies 3 located in two adjacent first storage sub-cavities 200 along the length direction are connected in series via a first connecting portion 28 (see Figure 2). The first connecting portion 28 is located in the first groove 250 or on the side of the first groove 250 opposite to the cell assemblies 3. The first connecting portion 28 is, for example, a copper busbar. The first groove 250 faces the first partition 27 extending along the Y direction. The first groove 250 is provided so that the cell assemblies 3 in two adjacent first storage sub-cavities 200 along the X direction can be conveniently electrically connected via the first connecting portion 28.

[0083] Referring again to Figures 2 and 3, the two battery cell assemblies 3 arranged along the width direction, i.e., the Y direction, on the first bracket 21 also require electrical connection. In some embodiments, at least one first end plate 25 is provided with a second groove 240; wherein, along the width direction, the battery cell assemblies 3 located in two adjacent first storage sub-cavities 200 are connected in series via a second connecting portion 29 (see Figure 2), the second connecting portion 29 being located in the second groove 240 or on the side of the second groove 240 opposite to the battery cell assemblies 3. The second connecting portion 29 is, for example, a copper busbar.

[0084] Referring to Figure 2, in some embodiments, the bottom surface of the battery cell assembly 3 within the second storage cavity 20 of the first bracket 21 is fixedly connected to the inner wall of the bottom surface of the first bracket 21, and the top surface of the battery cell assembly 3 is fixedly connected to the outer wall of the bottom surface of the second bracket 22. Specifically, the first bracket 21 includes four first storage sub-cavities 200, each containing one battery cell assembly 3, and each battery cell assembly 3 comprising multiple battery cells. The bottom surface of each battery cell assembly 3 is fixedly connected to the bottom wall of the first storage sub-cavity 200 by adhesive. The top surface of each battery cell assembly 3 is fixedly connected to the bottom wall of the second bracket 22, which will be described later, by adhesive.

[0085] Since the bottom walls of the first bracket 21 and the second bracket 22 are both water-cooled plates, they play a role in cooling. The cell assembly 3 in the first storage sub-cavity 200 of the first bracket 21 is sandwiched between the bottom walls of the first bracket 21 and the second bracket 22. The heat of the cell assembly 3 in the first storage sub-cavity 200 of the first bracket 21 is transferred to the cooling water inside the water-cooled plate through the bottom walls of the first bracket 21 and the second bracket 22, so as to effectively reduce the temperature of the cell assembly 3 in the first storage sub-cavity 200 of the first bracket 21. This ensures that the temperature of the cell assembly 3 in the first storage sub-cavity 200 of the first bracket 21 does not exceed the set temperature value during operation, thereby improving the temperature control effect of the power battery pack and enabling the power battery pack to work effectively.

[0086] Figure 4 is a schematic diagram showing the arrangement of the first bracket 21, the second bracket 22, and the cell assembly 3 inside each of the power battery packs provided in some embodiments of this disclosure. Figure 5 is a three-dimensional structural schematic diagram of the second bracket 22 of the power battery pack provided in some embodiments of this disclosure.

[0087] Referring to Figures 4 and 5, the second bracket 22 and the first bracket 21 have roughly the same structure. The second bracket 22 also includes a first cold plate 24, two first end plates 25, and two first side plates 26. The first cold plate 24 is configured to cool the battery cell assembly 3 located in the second storage cavity 20. The two first end plates 25 are dispersedly fixed to both ends of the first cold plate 24, specifically welded together. The two first end plates 25 and the two first side plates 26 form a frame with closed sidewalls at the bottom and sides and an open top. This frame has strong structural strength. The two first side plates 26 are dispersedly fixed to the first cold plate 24, specifically welded together. Both first side plates 26 are located between the two first end plates 25; the first cold plate 24, each first end plate 25, and each first side plate 26 together form the second storage cavity 20 of the second bracket 22.

[0088] The first cooling plate 24 of the second bracket 22 is a water-cooled plate with internal water channels for cooling the battery cell assembly 3 inside the second bracket 22. The first cooling plate 24 serves as the bottom wall of the second bracket 22, supporting the various battery cell assemblies 3 located within it. The first cooling plate 24 and the battery cell assembly 3 are fixedly connected by adhesive, maintaining contact. The first cooling plate 24 effectively reduces the temperature of the battery cell assembly 3, providing excellent heat dissipation for the heat generated during operation.

[0089] Referring again to Figures 4 and 5, in some embodiments, the second bracket 22 further includes at least one first partition 27, such as two first partitions 27 arranged crosswise, specifically perpendicularly. One first partition 27 extends along the X direction, and the other extends along the Y direction. The first partition 27 along the X direction is a single plate, while the first partition 27 along the Y direction is divided into two segments to avoid obstructing the first partition 27 extending along the X direction. The first partition 27 is fixedly connected to the first cold plate 24, specifically by welding. The first partition 27 divides the second storage cavity 20 into multiple first storage sub-cavities 200, each containing a battery cell assembly 3.

[0090] Since the four battery cell assemblies 3 supported by the second bracket 22 need to be electrically connected to form a whole, at least one first side plate 26 is provided with a first groove 250 to facilitate the electrical connection of the battery cell assemblies 3 located in the two first storage sub-cavities 200 along the length direction, i.e., the X direction. The battery cell assemblies 3 located in two adjacent first storage sub-cavities 200 along the length direction are connected in series via a first connecting portion 28, which is located in the first groove 250 or on the side of the first groove 250 opposite to the battery cell assemblies 3. The first groove 250 faces the first partition 27 extending along the Y direction. The first groove 250 facilitates the electrical connection of the battery cell assemblies 3 in two adjacent first storage sub-cavities 200 along the X direction via the first connecting portion 28.

[0091] Referring again to Figures 4 and 5, the two battery cell assemblies 3 arranged along the width direction (Y direction) on the second bracket 22 also require electrical connection. In some embodiments, at least one first end plate 25 of the second bracket 22 is provided with a second groove 240. The battery cell assemblies 3 located in two adjacent first storage sub-cavities 200 along the width direction are connected in series via a second connecting portion 29, which is located in the second groove 240 or on the side of the second groove 240 opposite to the battery cell assemblies 3. The electrical connection method of the four battery cell assemblies 3 supported by the second bracket 22 is the same as that of the four battery cell assemblies 3 supported by the first bracket 21 described above. The position of the second connecting portion 29 is not shown in Figures 4 and 5; please refer to Figure 2 for the position of the second connecting portion 29.

[0092] Referring to Figures 2 to 5, especially Figures 3 and 5, for the first bracket 21 and the second bracket 22, the first end plate 25, the first side plate 26, and the first partition plate 27 have the same height, and are all 0.8 to 1.2 mm higher than the height of the battery cell assembly 3. The first bracket 21 and the second bracket 22 are in direct contact and detachably fixedly connected. Specifically, first bolt holes a1 are provided on the first side plate 26, the first end plate 25, and the first partition plate 27 of the first bracket 21; and first through holes a2 are provided on the first side plate 26, the first end plate 25, and the first partition plate 27 of the second bracket 22. Long bolts P1 are used to pass through the first bolt holes a1 of the first side plate 26 of the first bracket 21 and the first through holes a2 of the first side plate 26 of the second bracket 22, respectively, to detachably fix the first bracket 21 and the second bracket 22.

[0093] For each cell assembly 3 supported by the first bracket 21 and the second bracket 22, in some embodiments, each cell assembly 3 located in two adjacent first storage sub-cavities 200 along the length direction includes multiple cells, with one cell assembly 3 including an odd number of cells and the other cell assembly 3 including an even number of cells. The total number of cells included in a row of cell assemblies 3 arranged along the length direction is odd. This numerical relationship allows the first connecting portion 28 of the two cell assemblies 3 arranged along the X direction of the first bracket 21 and the second bracket 22 to be located either in or outside the first groove 250, and the second connecting portion 29 of the two cell assemblies 3 arranged along the Y direction to be located either in or outside the second groove 240.

[0094] Referring to Figure 4, in some embodiments, the bottom surface of the battery cell assembly 3 located in the second storage cavity 20 of the second bracket 22 is fixedly connected to the inner wall of the bottom surface of the second bracket 22, specifically by adhesive bonding. The top surface of the battery cell assembly 3 is fixedly connected to the outer wall of the bottom surface of the third bracket 23, also by adhesive bonding.

[0095] The battery cell assembly 3, located in the second storage cavity 20 of the second bracket 22, is sandwiched between the bottom walls of the second bracket 22 and the third bracket 23. The bottom wall of the second bracket 22 is a water-cooled plate, and the bottom wall of the third bracket 23 is also a water-cooled plate. The battery cell assembly 3, located in the second storage cavity 20 of the second bracket 22, is sandwiched between the two water-cooled plates. The heat generated by the battery cell assembly 3 during operation is transferred to the cooling water inside the water-cooled plates through the bottom walls of the second bracket 22 and the third bracket 23.

[0096] Figure 6 is a schematic diagram showing the arrangement of the first bracket 21, the second bracket 22, the third bracket 23, and the cell assembly 3 inside each of the power battery packs provided in some embodiments of this disclosure. Figure 7 is a three-dimensional structural schematic diagram of the third bracket 23 of the power battery pack provided in some embodiments of this disclosure.

[0097] Referring to Figures 6 and 7, in some embodiments, the third bracket 23 includes a second cold plate 231, two second end plates 232, and two second side plates 233. The second cold plate 231 is configured to cool the battery cell assembly 3 located within the second storage cavity 20. The two second end plates 232 are dispersedly fixed to both ends of the second cold plate 231, specifically by welding. The two second end plates 232 and the two second side plates 233 form a closed sidewall; the two second side plates 233 are dispersedly fixed to the second cold plate 231, and both second side plates 233 are located between the two second end plates 232; the second cold plate 231, each of the second end plates 232, and each of the second side plates 233 together form the second storage cavity 20 of the third bracket 23.

[0098] Referring again to Figures 6 and 7, in some embodiments, the third bracket 23 further includes at least one second partition 234, which is fixedly connected to the second cold plate 231. The second partition 234 divides the second storage cavity 20 of the third bracket 23 into a plurality of second storage sub-cavities 201, and each second storage sub-cavity 201 contains a battery cell assembly 3.

[0099] Referring to Figure 7, there are two second partitions 234, which are arranged crosswise, specifically vertically. One second partition 234 extends along the X direction, and the other extends along the Y direction. The second partition 234 along the X direction is a single plate, while the second partition 234 along the Y direction is divided into two segments to avoid obstructing the second partition 234 extending along the X direction. The second partitions 234 are fixedly connected to the second cold plate 231, and divide the second storage cavity 20 into multiple second storage sub-cavities 201, each containing a battery cell assembly 3.

[0100] The cell assembly 3 in each second storage sub-cavity 201 is fixedly connected to the bottom wall of the third bracket 23 by adhesive. The heat generated by the cell assembly 3 during operation is transferred to the outside of the second bracket 22 through the bottom wall of the third bracket 23. Although the top of the cell assembly 3 in the third bracket 23 is not equipped with a water-cooling plate compared to the cell assembly 3 in the first bracket 21 and the second bracket 22, the heat of the entire power battery pack is guaranteed because only the top layer of cell assembly 3 in the entire power battery pack is not equipped with a water-cooling plate, while the top and bottom of the other layers of cell assembly 3 are equipped with water-cooling plates. The temperature of the entire power battery pack is effectively controlled during operation to achieve the reliability of the power battery pack operation.

[0101] Referring again to Figures 6 and 7, in some embodiments, at least one second side plate 233 is provided with a third groove 235. The length direction is along the path from one second end plate 232 to the other. Along this length direction, the battery cell assemblies 3 located in adjacent second storage sub-cavities 201 are connected in series via a third connecting portion 210. The third connecting portion 210 is located in the third groove 235 or on the side of the third groove 235 facing away from the battery cell assembly 3. The third connecting portion 210 is specifically a copper busbar. The height of the second side plate 233 is relatively low. In these embodiments, it is not necessary to additionally provide a third groove 235 on the second side plate 233; the empty portion above the second side plate 233 serves as the third groove 235.

[0102] Referring again to Figures 6 and 7, in some embodiments, at least one second end plate 232 is provided with a fourth groove 236. The width direction is perpendicular to the length direction. Along the width direction, the cell assemblies 3 located in two adjacent second storage sub-cavities 201 are connected in series via a fourth connecting portion 211. The fourth connecting portion 211 is located in the fourth groove 236 or on the side of the fourth groove 236 opposite to the cell assembly 3. The fourth connecting portion 211 is specifically a copper busbar.

[0103] In some embodiments, along the length direction, each cell assembly 3 located in two adjacent second storage sub-cavities 201 includes multiple cells, with one cell assembly 3 including an odd number of cells and the other cell assembly 3 including an even number of cells. Along the length direction, the total number of cells included in a row of cell assemblies 3 is odd. This numerical relationship ensures that the first connecting portions 28 of the two cell assemblies 3 arranged along the X direction of the third bracket 23 are located in or outside the first groove 250, and the second connecting portions 29 of the two cell assemblies 3 arranged along the Y direction are located in or outside the second groove 240. The first connecting portions 28 and the second connecting portions 29 are specifically copper busbar assemblies.

[0104] The multi-layer cell assembly 3 along the Y direction is electrically connected via interlayer connecting copper busbars 213. The total negative output copper busbar 212 of the power battery pack is located at one end of the power battery pack, and the total positive output copper busbar 214 is located at the other end of the power battery pack.

[0105] The four battery cell assemblies 3 located on the same floor, taking the left-right direction in Figure 1 as an example, have an odd number of cells in the two battery cell assemblies 3 on the left and an even number of cells in the two battery cell assemblies 3 on the right. This ensures that the series copper busbars of each battery cell assembly 3 are on the outside, facilitating installation and connection. Specifically, taking the direction shown in Figure 1 as an example, the series copper busbars of the three battery cell assemblies 3 refer to: two connecting copper busbars for the left and right battery cell assemblies 3 located on the same floor (because two rows of battery cell assemblies 3 are arranged along the Y direction), and one connecting copper busbar for the two battery cell assemblies 3 located on the right. A total negative output copper busbar 212 and a total positive output copper busbar 214 are provided on the left side.

[0106] For each layer of battery cell assembly 3, two rows of battery cell assemblies 3 are arranged along the Y direction. The number of battery cell assemblies 3 stacked in each row is odd. If the number of cells in a single battery cell assembly 3 is too large, a first partition 27 can be set in the middle position of the first bracket 21, a first partition 27 can be set in the middle position of the second bracket 22, and a second partition 234 can be set in the middle position of the third bracket 23 to strengthen the strength of the third bracket 23. After the second partition 234 is used to separate the battery cell assemblies 3 on the left side, the number of cells included is even, and the number of cells included in the battery cell assemblies 3 on the right side is odd. This makes the lengths of the first connecting part 28 and the third connecting part 210 on the outside, and the second connecting part 29 and the fourth connecting part 211 the shortest, which is convenient for the installation of copper busbars.

[0107] In some embodiments, the second end plate 232 and the second partition plate 234 are at the same height, and are both 0.8 mm to 1.2 mm higher than the height of the battery cell assembly 3, for example, 0.8 mm, 1 mm, and 1.2 mm. The height of the second side plate 233 is lower than the height of the second end plate 232 and the second partition plate 234. The second side plate 233 is provided with a lifting hole 237, as shown in Figure 7.

[0108] Referring again to Figures 5, 6, and 7, the second bracket 22 and the third bracket 23 are in direct contact and detachably fixedly connected. Specifically, a second bolt hole b1 is provided on the first end plate 25 of the second bracket 22, and a corresponding second through hole b2 is provided on the second end plate 232 of the third bracket 23. Long bolts are used to pass through the second bolt hole b1 of the first end plate 25 of the second bracket 22 and the second through hole b2 of the second end plate 232 of the third bracket 23, respectively, to detachably fix the second bracket 22 and the third bracket 23.

[0109] Referring to Figures 5 and 6, in addition, a threaded hole b4 is provided on the first end plate 25 of the second bracket 22, and a third through hole b3 is provided on the second partition plate 234 of the third bracket 23. A long bolt P2 is passed through the third through hole b3 and the threaded hole b4 to increase the stability of the connection between the second bracket 22 and the third bracket 23.

[0110] In addition, to increase the stability of the connection between the second bracket 22 and the third bracket 23, a third bolt hole c1 is provided on the first side plate 26 of the second bracket 22 (see Figure 5), and a corresponding fixing hole c2 is provided on the second side plate 233 of the third bracket 23 (see Figure 7). A short bolt P3 (see Figure 6) is used to pass through the third bolt hole c1 of the first side plate 26 of the second bracket 22 and the fixing hole c2 of the second side plate 233 of the third bracket 23, respectively, to detachably fix the second bracket 22 and the third bracket 23.

[0111] All threaded holes in this article are specifically designed to be rivet nut holes to increase the convenience and strength of the connection.

[0112] Figure 8 is a three-dimensional structural diagram of the pull plate 4 of the power battery pack provided in some embodiments of this disclosure. Figure 9 is a three-dimensional structural diagram of the installation of the pull plate 4 of the power battery pack provided in some embodiments of this disclosure.

[0113] Referring to Figures 1, 8, and 9, in some embodiments, the power battery pack further includes a pull plate 4, which is located on top of the bracket assembly 2 and is fixedly connected to both the bracket assembly 2 and the housing 1. Specifically, the pull plate 4 is fixedly connected to the top of the topmost cell assembly 3 by adhesive. Referring to Figure 8, the edge of the pull plate 4 is also provided with a protrusion M1, which has a screw hole or rivet nut. Correspondingly, a reinforcing plate M2 is provided on the inner wall of the housing 1, which has a screw hole. The pull plate 4 is fixedly connected to the inner wall of the housing 1 by bolts passing through the protrusion M1 and the reinforcing plate M2. A sealing element 6 is provided between the pull plate 4 and the housing 1 to enhance the sealing performance of the housing 1.

[0114] In addition, the edge of the pull plate 4 is provided with a first connecting hole N1, the second end plate 232 of the third bracket 23 is provided with a second through hole b2, and the first end plate 25 of the second bracket 22 is provided with a second bolt hole b1. Long bolts are used to pass through the first connecting hole N1, the second through hole b2 and the second bolt hole b1 to fix the pull plate 4, the third bracket 23 and the second bracket 22.

[0115] The middle part of the pull plate 4 is also provided with a second connecting hole N2, the second partition 234 of the third bracket 23 is provided with a third through hole b3, and the first end plate 25 of the second bracket 22 is provided with a threaded hole b4. Long bolts are used to pass through the second connecting hole N2, the third through hole b3 and the threaded hole b4 to fix the pull plate 4, the second partition 234 of the third bracket 23 and the first partition 27 of the second bracket 22.

[0116] The power battery pack includes three layers of cell components. The first bracket 21 at the bottom layer is fixed to the bottom of the housing 1. The second bracket 22 in the middle layer is fixedly connected to the first bracket 21. The third bracket 23 at the top layer is fixedly connected to the second bracket 22. A pull plate 4 is provided on the top of the cell component 3 at the top layer. The pull plate 4 is connected to the side wall of the housing 1 through a reinforcing plate M2 to prevent the three layers of cell components 3 from being stacked too high and shaking inside the housing 1. This increases the connection strength and rigidity between the three layers of cell components 3 and the housing 1.

[0117] Figure 10 is a schematic diagram showing the connection relationship of the first bracket, second bracket, and third bracket of the power battery pack provided in some embodiments of this disclosure. Referring to Figure 10, the first bracket 21 and the second bracket 22 are fixedly connected by long bolts. The long bolts pass through the first side plate 26 and the first end plate 25 of the second bracket 22 and are inserted into the first side plate 26 and the first end plate 25 of the first bracket 21. The second bracket 22 and the third bracket 23 are fixedly connected by long bolts and short bolts. The long bolts pass through the second end plate 232 of the third bracket 23 and are inserted into the first end plate 25 of the second bracket 22. Referring to Figure 7, the short bolts pass through the second side plate 233 of the third bracket 23 and are inserted into the first side plate 26 of the second bracket 22. By setting the second side plate 233 of the third bracket 23 to a lower height, the length of the connecting bolts between the second side plate 233 of the third bracket 23 and the first side plate 26 of the second bracket 22 is shortened, simplifying installation, saving materials, reducing installation difficulty, and improving installation strength.

[0118] Referring to Figure 10, the bolts P4 that fix the third bracket 23 to the second bracket 22, the bolt P3 that fixes the second bracket 22 to the first bracket 21, the bolt P1 that fixes the first bracket 21 to the bottom of the housing 1, and the bolt P2 are arranged in an alternating manner to achieve the connection and fixation between the power battery pack layers.

[0119] In the above technical solution, hooks 5 are provided on the edges of the first bracket 21, the second bracket 22, and the third bracket 23. After the battery cell assembly 3 is installed on the first bracket 21, the second bracket 22, and the third bracket 23 respectively, the bracket and the battery cell assembly 3 supported by it are hoisted into the housing 1 with the help of the hooks 5. After the hoisting is completed, the hooks 5 are removed.

[0120] In other embodiments, the first bracket 21, the second bracket 22, the third bracket 23, and their respective battery cell assemblies 3, along with the connection of related pipelines and lines, are assembled outside the housing 1, and then the entire assembly is hoisted into the housing 1. Although this solution requires high overall structural strength of the three-layer brackets, it significantly simplifies the installation process inside the housing.

[0121] In the above embodiments, two rows of battery cell assemblies 3 are used as an example in the width direction, i.e., the Y direction. Of course, in other embodiments, multiple rows of battery cell assemblies 3 are arranged, reducing the number of battery cell assemblies 3 stacked in the length direction to decrease the size of the power battery pack in the width direction. It should be noted that the more rows of battery cell assemblies 3 are arranged, the slightly lower the space utilization rate of the power battery pack due to the certain distance between the terminals of adjacent cells.

[0122] Some embodiments of this disclosure also provide an engineering vehicle, including a power battery pack provided by any of the technical solutions of this disclosure.

[0123] In some embodiments, the engineering vehicle is one of the following: a loader, a grader. In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this disclosure.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure and not to limit them; although this disclosure has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this disclosure or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of this disclosure, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in this disclosure.

Claims

1. A power battery pack, comprising: The housing (1) includes a first storage cavity (11); A bracket assembly (2) is located within the first storage cavity (11); the bracket assembly (2) includes multiple layers of second storage cavities (20); and Multiple battery cell assemblies (3), each of the battery cell assemblies (3) includes multiple battery cells, and the battery cell assembly (3) is placed in the second storage cavity (20) of each of the brackets.

2. The power battery pack according to claim 1, wherein the bracket assembly (2) includes a first bracket (21), a second bracket (22) and a third bracket (23) stacked together; the first bracket (21) and the second bracket (22) are fixedly connected, and the second bracket (22) and the third bracket (23) are fixedly connected; the height of each of the cell assemblies (3) is lower than the respective heights of the first bracket (21), the second bracket (22) and the third bracket (23).

3. The power battery pack according to claim 2, wherein the height of the second storage cavity (20) of each of the first bracket (21), the second bracket (22) and the third bracket (23) is 0.8 mm to 1.2 mm higher than the height of the cell assembly (3).

4. The power battery pack according to claim 2 or 3, wherein each of the first bracket (21), the second bracket (22) and the third bracket (23) includes at least one second storage cavity (20), and at least one of the battery cell assemblies (3) is fixed in each second storage cavity (20).

5. The power battery pack according to any one of claims 2-4, wherein the first bracket (21) and the second bracket (22) each comprise: A first cold plate (24) is configured to cool the cell assembly (3) located in the second storage cavity (20); Two first end plates (25) are respectively fixed at both ends of the first cold plate (24); and Two first side plates (26), two first end plates (25), and two first side plates (26) form a closed side wall; the two first side plates (26) are dispersedly fixed to the first cold plate (24), and the two first side plates (26) are located between the two first end plates (25); the first cold plate (24), each of the first end plates (25), and each of the first side plates (26) together form the second storage cavity (20).

6. The power battery pack according to claim 5, wherein the first bracket (21) and the second bracket (22) each further include: At least one first partition (27) is fixedly connected to the first cold plate (24). The first partition (27) divides the second storage cavity (20) into a plurality of first storage sub-cavities (200), and each first storage sub-cavity (200) contains one of the battery cell assemblies (3).

7. The power battery pack according to claim 6, wherein at least one of the first side plates (26) is provided with a first groove (250); in, Along the length direction from one of the first end plates (25) to the other first end plate (25), the battery cell assemblies (3) located in two adjacent first storage sub-cavities (200) are connected in series by a first connecting part (28), which is located in the first groove (250) or on the side of the first groove (250) away from the battery cell assembly (3).

8. The power battery pack according to claim 7, wherein at least one of the first end plates (25) is provided with a second groove (240); in, The width direction is perpendicular to the length direction. Along the width direction, the battery cell assembly (3) located in two adjacent first storage sub-cavities (200) are connected in series by a second connecting part (29). The second connecting part (29) is located in the second groove (240) or on the side of the second groove (240) away from the battery cell assembly (3).

9. The power battery pack according to claim 7 or 8, wherein each of the cell assemblies (3) located in two adjacent first storage sub-cavities (200) along the length direction comprises a plurality of cells, wherein the number of cells included in one of the cell assemblies (3) is odd and the number of cells included in the other cell assembly (3) is even.

10. The power battery pack according to any one of claims 6-9, wherein the number of the first separators (27) is two, and the two first separators (27) are arranged crosswise.

11. The power battery pack according to any one of claims 6-9, wherein the first end plate (25), the first side plate (26) and the first separator (27) have the same height and are all 0.8 to 1.2 mm higher than the height of the cell assembly (3).

12. The power battery pack according to any one of claims 2-11, wherein the third bracket (23) comprises: The second cold plate (231) is configured to cool the cell assembly (3) located in the second storage cavity (20); Two second end plates (232) are respectively fixed at both ends of the second cold plate (231); and Two second side plates (233), two second end plates (232), and two second side plates (233) form a closed side wall; the two second side plates (233) are dispersedly fixed to the second cold plate (231), and the two second side plates (233) are located between the two second end plates (232); the second cold plate (231), each of the second end plates (232), and each of the second side plates (233) together form the second storage cavity (20) of the third bracket (23).

13. The power battery pack according to claim 12, wherein the third bracket (23) further comprises: At least one second partition (234) is fixedly connected to the second cold plate (231). The second partition (234) divides the second storage cavity (20) of the third bracket (23) into a plurality of second storage sub-cavities (201), and each second storage sub-cavity (201) contains one of the battery cell assemblies (3).

14. The power battery pack according to claim 13, wherein at least one of the second side plates (233) is provided with a third groove (235); in, Along the length direction from one of the second end plates (232) to the other second end plate (232), the cell assemblies (3) located in two adjacent second storage sub-cavities (201) are connected in series by a third connection (210), which is located in the third groove (235) or on the side of the third groove (235) away from the cell assembly (3).

15. The power battery pack according to claim 14, wherein at least one of the second end plates (232) is provided with a fourth groove (236); in, The width direction is perpendicular to the length direction. Along the width direction, the battery cell assembly (3) located in two adjacent second storage sub-cavities (201) are connected in series by a fourth connecting part (211). The fourth connecting part (211) is located in the fourth groove (236) or on the side of the fourth groove (236) away from the battery cell assembly (3).

16. The power battery pack according to claim 14 or 15, wherein each of the cell assemblies (3) located in two adjacent second storage sub-cavities (201) along the length direction comprises a plurality of cells, wherein the number of cells included in one of the cell assemblies (3) is odd and the number of cells included in the other cell assembly (3) is even.

17. The power battery pack according to any one of claims 13-16, wherein the number of the second separator (234) is two, and the two second separators (234) are arranged crosswise.

18. The power battery pack according to any one of claims 13-16, wherein the second end plate (232) and the second separator (234) have the same height and are both 0.8 to 1.2 mm higher than the height of the cell assembly (3); The height of the second side plate (233) is lower than the height of the second end plate (232) and the second partition plate (234).

19. The power battery pack according to any one of claims 2-18, wherein the bottom surface of the cell assembly (3) located in the second storage cavity (20) of the first bracket (21) is fixedly connected to the inner wall of the bottom surface of the first bracket (21), and the top surface of the cell assembly (3) is fixedly connected to the outer wall of the bottom surface of the second bracket (22).

20. The power battery pack according to any one of claims 2-18, wherein the bottom surface of the cell assembly (3) located in the second storage cavity (20) of the second bracket (22) is fixedly connected to the inner wall of the bottom surface of the second bracket (22), and the top surface of the cell assembly (3) is fixedly connected to the outer wall of the bottom surface of the third bracket (23).

21. The power battery pack according to any one of claims 1-18, further comprising: A pull plate (4) is located on top of the bracket assembly (2), and the pull plate (4) is fixedly connected to the bracket assembly (2) and the housing (1).

22. An engineering vehicle comprising the power battery pack as described in any one of claims 1 to 21.

23. The engineering vehicle according to claim 22, wherein the engineering vehicle is one of the following: a loader, a grader.

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