Power battery pack and engineering vehicle

Abstract

The invention discloses a power battery pack and an engineering vehicle, relates to the field of power batteries, and aims to improve the structure of the power battery pack and realize high electric quantity and high voltage of the power battery pack. The power battery pack comprises a box body, a bracket assembly and a plurality of battery cell assemblies, the box body comprises a first storage cavity; the bracket assembly is located in the first storage cavity. The bracket assembly comprises multiple layers of second storage cavities; each battery cell assembly comprises a plurality of battery cells, and the battery cell assembly is placed in the second storage cavity of each bracket. According to the power battery pack formed by the technical scheme, due to the arrangement of the multiple layers of battery cell assemblies, the single power battery pack is high in voltage, large in electric quantity and high in structural strength. A single power battery pack can meet a high-voltage platform of the whole vehicle, and other battery packs do not need to be connected in series outside, so that the high-voltage framework of the battery system is simplified, and the number of the battery packs in the battery system is reduced.

Description

Technical Field

[0001] The present invention relates to the field of power batteries, and in particular to a power battery pack and an engineering vehicle. Background Art

[0002] At present, for large-scale construction machinery and heavy trucks, the whole machine voltage platform is 800V and above, which requires the number of series-connected cells to be more than 250, and the battery system capacity to be between 1,000 and 3,000 kWh. The voltage platform refers to the voltage range of the battery during the charging and discharging process.

[0003] The battery system of the whole machine requires a large amount of power and a high voltage, while the single battery pack that forms the battery system of the whole machine has a small amount of power and a low voltage. In order to form a battery system that meets the requirements of the whole machine, a large number of battery packs need to be connected in series and in parallel, and in some cases even dozens of battery packs are needed.

[0004] The inventors have discovered that the prior art has at least the following problems: since the whole battery system includes a large number of battery packs, the whole battery system is complex to assemble, heavy and occupies a large external space. Summary of the invention

[0005] The present invention provides a power battery pack and an engineering vehicle, which are used to improve the structure of the power battery pack and achieve large power and high voltage of the power battery pack.

[0006] An embodiment of the present invention provides a power battery pack, including:

[0007] A box body, comprising a first storage cavity;

[0008] a bracket assembly located in the first storage cavity; the bracket assembly includes multiple layers of second storage cavities; and

[0009] A plurality of battery cell assemblies, each of which comprises a plurality of battery cells, and the battery cell assembly is placed in the second storage cavity of each bracket.

[0010] In some embodiments, the bracket assembly includes a stacked first bracket, a second bracket, and a third bracket; 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.

[0011] 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 battery cell assembly.

[0012] In some embodiments, each of the first bracket, the second bracket, and the third bracket includes at least one second storage cavity, and at least one battery cell assembly is fixed in each of the second storage cavities.

[0013] In some embodiments, the first bracket and the second bracket each include:

[0014] a first cold plate configured to cool the battery cell assembly located in the second storage cavity;

[0015] Two first end plates, the two first end plates are dispersedly fixed at two ends of the first cold plate; and

[0016] Two first side plates, two first end plates and two first side plates form a closed side wall; two first side plates are dispersedly fixed to the first cold plate, and two 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.

[0017] In some embodiments, the first bracket and the second bracket each further include:

[0018] At least one first partition, wherein the first partition is fixedly connected to the first cold plate, and the first partition divides the second storage cavity into a plurality of first storage sub-cavities, and each of the first storage sub-cavities contains one of the battery cell assemblies.

[0019] In some embodiments, at least one of the first side panels is provided with a first groove;

[0020] Among them, 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 battery cell assemblies located in two adjacent first storage sub-cavities are connected in series through a first connecting part, and the first connecting part is located in the first groove or on the side of the first groove away from the battery cell assembly.

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

[0022] Among them, 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, and the second connecting part is located in the second groove or on the side of the second groove away from the battery cell assembly.

[0023] In some embodiments, along the length direction, each of the battery cell assemblies located in two adjacent first storage subcavities each includes multiple battery cells, wherein the number of battery cells included in one of the battery cell assemblies is an odd number, and the number of battery cells included in the other battery cell assembly is an even number.

[0024] In some embodiments, the number of the first partitions is two, and the two first partitions are arranged crosswise.

[0025] In some embodiments, the first end plate, the first side plate, and the first partition plate have the same height, and are all 0.8 to 1.2 mm higher than the height of the battery cell assembly.

[0026] In some embodiments, the third bracket comprises:

[0027] a second cold plate configured to cool the battery cell assembly located in the second storage cavity;

[0028] Two second end plates, the two second end plates are dispersedly fixed at two ends of the second cold plate; and

[0029] Two second side plates, two second end plates and two second side plates form a closed side wall; two second side plates are dispersedly fixed to the second cold plate, and two second side plates are located between the two second end plates; the second cold plate, each second end plate and each second side plate together form a second storage cavity of the third bracket.

[0030] In some embodiments, the third bracket further comprises:

[0031] At least one second partition, the second partition is fixedly connected to the second cold plate, the second partition divides the second storage cavity of the third bracket into a plurality of second storage sub-cavities, each of the second storage sub-cavities contains one of the battery cell assemblies.

[0032] In some embodiments, at least one of the second side panels is provided with a third groove;

[0033] Among them, 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 battery cell assemblies located in two adjacent second storage sub-cavities are connected in series through a third connecting part, and the third connecting part is located in the third groove or on the side of the third groove away from the battery cell assembly.

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

[0035] Among them, the width direction is perpendicular to the length direction, and along the width direction, the battery cell assemblies located in two adjacent second storage sub-cavities are connected in series through a fourth connecting part, and the fourth connecting part is located in the fourth groove or on the side of the fourth groove away from the battery cell assembly.

[0036] In some embodiments, along the length direction, each of the battery cell assemblies located in two adjacent second storage subcavities each includes multiple battery cells, wherein the number of battery cells included in one of the battery cell assemblies is an odd number, and the number of battery cells included in the other battery cell assembly is an even number.

[0037] In some embodiments, the number of the second partitions is two, and the two second partitions are arranged crosswise.

[0038] In some embodiments, the second end plate and the second partition have the same height, and are both 0.8 to 1.2 mm higher than the height of the battery cell assembly;

[0039] The height of the second side plate is lower than that of the second end plate and the second partition plate.

[0040] In some embodiments, the bottom surface of the battery cell assembly 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.

[0041] In some embodiments, the bottom surface of the battery cell assembly 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.

[0042] In some embodiments, the power battery pack further includes:

[0043] A pull plate is located on the top of the bracket assembly, and the pull plate is fixedly connected to the bracket assembly and the box body.

[0044] An embodiment of the present invention further provides an engineering vehicle, comprising a power battery pack provided by any technical solution of the present invention.

[0045] In some embodiments, the engineering vehicle is one of the following: a loader, a grader.

[0046] The power battery pack provided by the above technical solution has a first storage cavity in the box, and the bracket assembly and the battery cell assembly are both located inside the first storage cavity. The bracket assembly forms a multi-layer second storage cavity, and the battery cell assembly can be placed in each layer of the second storage cavity. The battery cell assembly included in the entire power battery pack has multiple layers, and the number of battery cell assemblies included in each layer can be less. The height of the entire power battery pack is increased, and the length and width of the plane can be reduced. Since the battery cell assembly is placed inside the second storage cavity, that is, the battery cell assembly does not protrude from the highest point of the wall of the second storage cavity, in the height direction, the battery cell assembly does not bear the weight of other battery cell assemblies located above it, so the entire power battery pack will not cause the battery cell assembly located below to be overloaded due to the provision of multiple layers of battery cell assemblies, thereby causing safety hazards or being crushed. The structure of the power battery pack is optimized, which helps to achieve large power and high voltage of the power battery pack. The power battery pack formed by the above technical solution has a high voltage, large power, and high structural strength due to the provision of multiple layers of battery cell assemblies. A single power battery pack can meet the high-voltage platform of the entire vehicle, without the need to connect other battery packs in series externally, which simplifies the high-voltage architecture of the battery system and reduces the number of battery packs in the battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0048] Figure 1 A three-dimensional exploded schematic diagram of a power battery pack provided in an embodiment of the present invention.

[0049] Figure 2 A schematic diagram of the arrangement relationship between the first bracket and the battery cell assembly of the power battery pack provided in an embodiment of the present invention.

[0050] Figure 3 A schematic diagram of the three-dimensional structure of a first bracket of a power battery pack provided in an embodiment of the present invention.

[0051] Figure 4 A schematic diagram of the arrangement relationship of the first bracket, the second bracket and the battery cell assemblies inside each of the power battery packs provided in an embodiment of the present invention.

[0052] Figure 5 A schematic diagram of the three-dimensional structure of a second bracket of a power battery pack provided in an embodiment of the present invention.

[0053] Figure 6 A schematic diagram of the arrangement relationship of the first bracket, the second bracket, the third bracket and the battery cell assemblies inside each of the power battery packs provided in an embodiment of the present invention.

[0054] Figure 7 A schematic diagram of the three-dimensional structure of a third bracket of a power battery pack provided in an embodiment of the present invention.

[0055] Figure 8 A schematic diagram of the three-dimensional structure of a pull plate of a power battery pack provided in an embodiment of the present invention.

[0056] Fig. 9 A schematic diagram of the pull plate installation structure of a power battery pack provided in an embodiment of the present invention.

[0057] Fig.10 A schematic diagram of the connection relationship among the first bracket, the second bracket, and the third bracket of the power battery pack provided in an embodiment of the present invention.

[0058] Reference numerals:

[0059] 1. Box body; 2. Bracket assembly; 3. Cell assembly; 4. Pull plate; 5. Hook; 6. Seal;

[0060] 11. first storage chamber; 12. box body; 13. box cover; 14. inspection port; 15. inspection panel;

[0061] 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 connection part; 29, second connection part; 210, third connection part; 211, fourth connection part; 212, total negative output copper bar; 213, interlayer connection copper bar; 214, total positive output copper bar;

[0062] 200, first storage sub-cavity; 201, second storage sub-cavity;

[0063] 250, first groove; 240, second groove;

[0064] 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 DESCRIPTION

[0065] Combine the following Figures 1 to 10The technical solution provided by the present invention is described in more detail. The description of the exemplary embodiments is merely illustrative and is by no means intended to limit the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, the composition of the materials, the numerical expressions and the numerical values ​​described in these embodiments should be interpreted as being merely exemplary and not limiting.

[0066] The words "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements.

[0067] In the present disclosure, when a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the 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 intermediate device, or may not be directly connected to the other devices but have an intermediate device.

[0068] All terms used in the present disclosure, including technical terms or scientific terms, have the same meanings as those understood by ordinary technicians in the field to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0069] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment are considered part of the specification.

[0070] The dimensions of the various parts shown in the drawings are not drawn according to the actual proportional relationship. In the drawings, the same reference numerals are attached to common structural elements or structural elements of the same type, and their repeated descriptions are appropriately omitted.

[0071] In the description of the specific embodiments below, for the convenience of explanation, Figure 1 The XYZ coordinate system is established in the figure, where the X direction is the length direction of the power battery pack, which is roughly Figure 1 The left and right directions in the figure; the Y direction is the width direction of the power battery pack, which is approximately Figure 1In the up and down direction, the Z direction is the height direction of the power battery pack, which is also Figure 1 The up and down directions in .

[0072] Figure 1 A three-dimensional exploded schematic diagram of a power battery pack provided in an embodiment of the present invention. Figure 2 A schematic diagram of the arrangement relationship between the first bracket and the battery cell assembly of the power battery pack provided in an embodiment of the present invention. Figure 3 A schematic diagram of the three-dimensional structure of a first bracket of a power battery pack provided in an embodiment of the present invention.

[0073] See also Figure 1 The embodiment of the present invention provides a power battery pack, including a box body 1, a bracket assembly 2 and a plurality of battery cell assemblies 3. The box body 1 includes a first storage cavity 11; the bracket assembly 2 is located in the first storage cavity 11. The bracket assembly 2 includes a multi-layer second storage cavity 20, see Figure 3 Each battery cell assembly 3 includes a plurality of battery cells, and a battery cell assembly 3 is placed in the second storage cavity 20 of each bracket.

[0074] The box body 1 is used to carry and install the bracket assembly 2 and each battery cell assembly 3. The box body 1 can be made of a casting, which has a strong bearing capacity and high structural strength, and can meet the bearing requirements of engineering vehicles such as loaders and graders working under relatively complex working conditions.

[0075] In some embodiments, the box body 1 includes a box body 12 and a box cover 13. The box body 12 is made of a casting, and the box cover 13 can be made of a casting or a composite material. The top of the box body 12 is open, and the box cover 13 is arranged at the opening of the box body 12. The box body 12 and the box cover 13 are detachably connected. After opening the box cover 13, the battery cell assembly 3 and the bracket assembly 2 can be placed inside the box body 12, or the above components can be taken out. After covering the box cover 13, the entire power battery pack is a closed whole, the battery cell assembly 3 and the bracket assembly 2 inside the power battery pack are fixedly connected, and the entire power battery pack structure is very stable.

[0076] In order to make the installation of the box cover 13 more stable, in addition to being fixedly connected to the box body 12, the box cover 13 is also detachably fixedly connected to the third bracket 23 located at the top of the bracket assembly 2, for example, by bolts. This connection method can increase the connection position of the box cover 13, making the installation of the box cover 13 more stable and reliable.

[0077] Continue to see Figure 1 In order to facilitate maintenance, a plurality of inspection ports 14 are provided on the box body 12, and an inspection panel 15 is detachably mounted at each inspection port 14. By opening the inspection panel 15, the components inside the box body 12 can be inspected. Figure 1As shown, taking the setting of four inspection openings 14 as an example, the four inspection openings 14 are arranged side by side, and each inspection opening 14 is installed with an inspection panel 15, and each inspection panel 15 can be opened and closed separately.

[0078] Continue to see Figure 1 In some embodiments, the bracket assembly 2 includes a stacked first bracket 21, a second bracket 22 and a third bracket 23; 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 battery cell assembly 3 is lower than the height of the first bracket 21, the second bracket 22 and the third bracket 23.

[0079] See also Figure 1 , the first bracket 21 is fixedly mounted with a layer of battery cell assemblies 3, the second bracket 22 is also fixedly mounted with a layer of battery cell assemblies 3, and the third bracket 23 is also fixedly mounted with a layer of battery cell assemblies 3. The entire power battery pack is provided with three layers of battery cell assemblies 3. Each layer may include one or more battery cell assemblies 3. Of course, the entire power battery pack may also be provided with two or more layers of battery cell assemblies 3 as required.

[0080] Continue to see Figure 1 In some embodiments, 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 battery cell assembly 3, specifically 0.8 mm, 1 mm, and 1.2 mm. After the battery cell assembly 3 is placed in the second storage cavity 20 of each of the first bracket 21, the second bracket 22, and the third bracket 23, the top surface of the battery cell assembly 3 is slightly lower than the highest point of each of the first bracket 21, the second bracket 22, and the third bracket 23. Since the height of the battery cell assembly 3 is slightly lower than that of each bracket of the bracket assembly 2, the battery cell assembly 3 basically does not carry other components located above itself. 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 carry the second bracket 22, the third bracket 23 and the upper two layers of cell assemblies 3 located above it, and these components are carried by the first bracket 21. The cell assembly 3 supported by the second bracket 22 does not carry the third bracket 23 and the uppermost cell assembly 3 located above it, and these components are carried by the second bracket 22. The box cover 13 located on the top of the third bracket 23 and the pull plate 4 described later are carried by the third bracket 23. The cell assembly 3 located at the uppermost layer basically does not carry the weight of these components.

[0081] See also Figure 1 , Figure 3 , Figure 5 and Figure 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 below, 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 small cavities by a partition, and each small cavity is used to place a battery cell assembly 3. The battery cell assemblies 3 in the four small 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 the second storage cavities 20 are also connected in series and parallel to form a whole. The battery cell assemblies 3 of each layer are first connected in series and parallel to form a whole, and the battery cell assemblies 3 of each layer are then connected in series and parallel to form the final whole.

[0082] See also Figure 2 and Figure 3 The first bracket 21 is divided into four first storage sub-cavities 200 by a first partition 27 to be described later. The four first storage sub-cavities 200 are arranged in a 2X2 manner, 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 is individually placed with a battery cell assembly 3. The four first storage sub-cavities 200 are electrically connected to form a whole.

[0083] In addition, see Figure 2 A plurality of hooks 5 are dispersedly arranged at the edge of the first bracket 21, and 4 to 8 first hooks 5 are arranged as an example. The first bracket 21 and the battery cell assembly 3 located in the first bracket 21 can be conveniently lifted by the plurality of hooks 5.

[0084] See also 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 dispersedly fixed at both ends of the first cold plate 24, and can be fixed by welding. The two first end plates 25 and the 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 can be fixed by welding, and the two 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 first bracket 21.

[0085] The first cold plate 24 is a water-cooled plate, and a flow channel for water to pass through is provided inside the first cold plate 24, and the battery cell assembly 3 in the first bracket 21 is cooled through the first cold plate 24. The first cold plate 24 serves as the bottom wall of the first bracket 21, and supports each battery cell assembly 3 in the first bracket 21. The first cold plate 24 is fixedly connected to the battery cell assembly 3 by glue, and the two are in contact. The first cold plate 24 can effectively reduce the temperature of the battery cell assembly 3, and has a good heat dissipation effect on the heat generated during the operation of the battery cell assembly 3.

[0086] Continue to see Figure 3 In some embodiments, the first bracket 21 further includes at least one first partition 27, specifically two first partitions 27. The first partition 27 along the X direction is a whole plate, also called a longitudinal beam; the first partition 27 along the Y direction is divided into two sections, also called reinforcing plates, to avoid 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 a plurality of first storage sub-cavities 200, and a battery cell assembly 3 is fixedly installed in each first storage sub-cavity 200, specifically by glue.

[0087] Since the battery cell assemblies 3 supported by the first bracket 21 need to be electrically connected to form a whole, in order to facilitate the electrical connection of the battery cell assemblies 3 in the two first storage sub-cavities 200 along the length direction, i.e., the X direction, at least one first side plate 26 is provided with a first groove 250. In the length direction, the battery cell assemblies 3 in the two adjacent first storage sub-cavities 200 are electrically connected through the first connecting portion 28 (see Figure 2 ) are connected in series, and the first connection portion 28 is located in the first groove 250 or on the side of the first groove 250 away from the battery cell assembly 3. The first connection portion 28 is, for example, a copper bar. The first groove 250 is directly opposite to the first partition 27 extending along the Y direction. The first groove 250 is provided so that the battery cell assemblies 3 in two adjacent first storage sub-cavities 200 along the X direction are conveniently electrically connected through the first connection portion 28.

[0088] Continue to see Figure 2 and Figure 3 , the two battery cell assemblies 3 arranged along the width direction, i.e., the Y direction, on the first bracket 21 also need to be electrically connected. 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 through the second connecting portion 29 (see Figure 2 ) are connected in series, and the second connecting portion 29 is located in the second groove 240 or on the side of the second groove 240 away from the battery cell assembly 3. The second connecting portion 29 is, for example, a copper busbar.

[0089] See also Figure 2 In some embodiments, the bottom surface of the battery cell assembly 3 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 battery cell assembly 3 is fixedly connected to the outer wall of the bottom surface of the second bracket 22. The first bracket 21 specifically includes four first storage sub-cavities 200, each of which contains a battery cell assembly 3, and each battery cell assembly 3 includes a plurality of 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 glue. The top surface of each battery cell assembly 3 is fixedly connected to the bottom wall of the second bracket 22 described later by glue.

[0090] Since the bottom walls of the first bracket 21 and the second bracket 22 are both water-cooled plates, they can play a role in cooling down. The battery cell assembly 3 in the first storage sub-cavity 200 of the first bracket 21 is clamped by the bottom wall of the first bracket 21 and the bottom wall of the second bracket 22. The heat of the battery cell assembly 3 in the first storage sub-cavity 200 of the first bracket 21 can be transferred to the cooling water inside the water-cooled plate via the bottom wall of the first bracket 21 and the bottom wall of the second bracket 22, so as to effectively reduce the temperature of the battery cell assembly 3 in the first storage sub-cavity 200 of the first bracket 21, so that the temperature of the battery 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 ensuring the effective operation of the power battery pack.

[0091] Figure 4 Schematic diagram of the arrangement relationship of the first bracket 21, the second bracket 22 and the battery cell assemblies 3 therein of the power battery pack provided in an embodiment of the present invention. Figure 5 A schematic diagram of the three-dimensional structure of the second bracket 22 of the power battery pack provided in an embodiment of the present invention.

[0092] See also Figure 4 and Figure 5 The second bracket 22 has a substantially similar structure to the first bracket 21, and 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 at both ends of the first cold plate 24, and can be fixed by welding. The two first end plates 25 and the two first side plates 26 form a side wall with closed bottom and sides, and the top of the frame is open. This frame has a strong structural strength. The two first side plates 26 are dispersedly fixed to the first cold plate 24, and can be fixed by welding. The two first side plates 26 are both 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.

[0093] The first cold plate 24 of the second bracket 22 is a water-cooled plate, and a flow channel for water to pass through is provided inside the first cold plate 24, so as to cool the battery cell assembly 3 in the second bracket 22. The first cold plate 24 of the second bracket 22 serves as the bottom of the second bracket 22, and supports each battery cell assembly 3 in the second bracket 22. The first cold plate 24 of the second bracket 22 is fixedly connected with the battery cell assembly 3 by glue, and the two are in contact. The first cold plate 24 can effectively reduce the temperature of the battery cell assembly 3, and has a good heat dissipation effect on the heat generated during the operation of the battery cell assembly 3.

[0094] Continue to see Figure 4 and Figure 5 In some embodiments, the second bracket 22 further includes at least one first partition 27, specifically two first partitions 27, the two first partitions 27 are arranged crosswise, specifically vertically, one first partition 27 extends along the X direction, and the other first partition 27 extends along the Y direction. The first partition 27 along the X direction is a whole plate, and the first partition 27 along the Y direction is divided into two sections to avoid the first partition 27 extending along the X direction. The first partition 27 is fixedly connected to the first cold plate 24, specifically, it can be fixed by welding, and the first partition 27 divides the first storage cavity 11 into a plurality of first storage sub-cavities 200, and each first storage sub-cavity 200 has a battery cell assembly 3.

[0095] Since the four battery cell assemblies 3 supported by the second bracket 22 need to be electrically connected to form a whole, in order to facilitate the electrical connection of the battery cell assemblies 3 in the two first storage sub-cavities 200 along the length direction, i.e., the X direction, at least one first side plate 26 is provided with a first groove 250. Among them, along the length direction, the battery cell assemblies 3 in the two adjacent first storage sub-cavities 200 are connected in series through the first connecting portion 28, and the first connecting portion 28 is located in the first groove 250 or on the side of the first groove 250 away from the battery cell assembly 3. The first groove 250 is opposite to the first partition 27 extending along the Y direction. The first groove 250 is provided so that the battery cell assemblies 3 in the two adjacent first storage sub-cavities 200 along the X direction are conveniently electrically connected through the first connecting portion 28.

[0096] Continue to see Figure 4 and Figure 5, the two battery cell assemblies 3 arranged along the width direction, i.e., the Y direction, on the second bracket 22 also need to be electrically connected. In some embodiments, at least one first end plate 25 of the second bracket 22 is provided with a second groove 240; wherein, along the width direction, the battery cell assemblies 3 located in two adjacent first storage subcavities 200 are connected in series through a second connecting portion 29, and the second connecting portion 29 is located in the second groove 240 or on the side of the second groove 240 away from the battery cell assembly 3. The electrical connection method of the four battery cell assemblies 3 supported by the second bracket 22 is the same as the electrical connection method of the four battery cell assemblies 3 supported by the first bracket 21 described above. Figure 5 The position of the second connecting portion 29 is not shown in FIG. Figure 2 The position of the second connecting portion 29 in the middle.

[0097] See also Figures 2 to 5 , especially Figure 3 and Figure 5 For the first bracket 21 and the second bracket 22, the heights of the first end plate 25, the first side plate 26 and the first partition plate 27 are the same, 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 are detachably fixedly connected. Specifically, first bolt holes a1 can be respectively provided on the first side plate 26, the first end plate 25 and the first partition plate 27 of the first bracket 21; first through holes a2 can be correspondingly provided on the first side plate 26, the first end plate 25 and the first partition plate 27 of the second bracket 22, and long bolts P1 are respectively passed 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, so as to detachably fixly connect the first bracket 21 and the second bracket 22.

[0098] For each battery cell assembly 3 supported by the first bracket 21 and the second bracket 22, in some embodiments, along the length direction, each battery cell assembly 3 located in two adjacent first storage sub-cavities 200 includes a plurality of battery cells, wherein the number of battery cells included in one battery cell assembly 3 is an odd number, and the number of battery cells included in the other battery cell assembly 3 is an even number. The total number of battery cells included in a row of battery cell assemblies 3 arranged along the length direction is an odd number. This quantitative relationship can make the first connection parts 28 of the two battery cell assemblies 3 arranged along the X direction of the first bracket 21 and the second bracket 22 respectively located in the first groove 250 or outside the first groove 250, and the second connection parts 29 of the two battery cell assemblies 3 arranged along the Y direction are located in the second groove 240 or outside the second groove 240.

[0099] See also Figure 4In some embodiments, the bottom surface of the battery cell assembly 3 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 can be fixedly connected by glue. 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, and can also be fixedly connected by glue.

[0100] The battery cell assembly 3 in the second storage cavity 20 of the second bracket 22 is sandwiched by the bottom wall of the second bracket 22 and the bottom wall of the third bracket 23. The bottom wall of the second bracket 22 is a water-cooling plate, and the bottom wall of the third bracket 23 is also a water-cooling plate. The battery cell assembly 3 in the second storage cavity 20 of the second bracket 22 is sandwiched between two water-cooling plates, and the heat generated by the battery cell assembly 3 during operation can be transferred to the cooling water inside the water-cooling plate through the bottom wall of the second bracket 22 and the bottom wall of the third bracket 23.

[0101] Figure 6 A schematic diagram of the arrangement relationship of the first bracket 21, the second bracket 22, the third bracket 23 and the battery cell assemblies 3 therein of the power battery pack provided in an embodiment of the present invention. Figure 7 A schematic diagram of the three-dimensional structure of the third bracket 23 of the power battery pack provided in an embodiment of the present invention.

[0102] See also Figure 6 and Figure 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 in the second storage cavity 20. The two second end plates 232 are dispersedly fixed at both ends of the second cold plate 231, and can be specifically fixed by welding. The two second end plates 232 and the 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 both located between the two second end plates 232; the second cold plate 231, each second end plate 232 and each second side plate 233 together form the second storage cavity 20 of the third bracket 23.

[0103] Continue to see Figure 6 and Figure 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.

[0104] See also Figure 7There are two second partitions 234, which are arranged crosswise, specifically vertically, with one second partition 234 extending along the X direction and the other second partition 234 extending along the Y direction. The second partition 234 along the X direction is a whole plate, and the second partition 234 along the Y direction is divided into two sections to avoid the second partition 234 extending along the X direction. The second partition 234 is fixedly connected to the second cold plate 231, and the second partition 234 divides the second storage cavity 20 into a plurality of second storage sub-cavities 201, and each second storage sub-cavity 201 has a battery cell assembly 3.

[0105] The battery cell assembly 3 in each second storage sub-cavity 201 is fixedly connected to the bottom wall of the third bracket 23 by glue, and the heat generated during the operation of the battery cell assembly 3 is transferred to the outside of the second bracket 22 via the bottom wall of the third bracket 23. Although compared with the battery cell assemblies 3 in the first bracket 21 and the second bracket 22, the top of the battery cell assembly 3 in the third bracket 23 is not provided with a water cooling plate, but since only the top of the topmost layer of the battery cell assembly 3 in the entire power battery pack is not provided with a water cooling plate, and the tops and bottoms of the other layers of the battery cell assemblies 3 are provided with water cooling plates, the heat of the entire power battery pack is guaranteed, and the temperature of the entire power battery pack during operation can be effectively controlled to ensure the reliability of the operation of the power battery pack.

[0106] Continue to see Figure 6 and Figure 7 In some embodiments, at least one second side plate 233 is provided with a third groove 235. The length direction is along the direction from one of the second end plates 232 to the other second end plate 232. Along the length direction, the battery cell assemblies 3 located in two adjacent second storage sub-cavities 201 are connected in series through the 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 away from the battery cell assembly 3. The third connecting portion 210 can be a copper busbar. The height of the second side plate 233 can be set relatively low. In this embodiment, there is no need to set an additional third groove 235 on the second side plate 233. The vacant portion above the second side plate 233 can be used as the third groove 235.

[0107] Continue to see Figure 6 and Figure 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 battery cell assemblies 3 located in two adjacent second storage sub-cavities 201 are connected in series through the fourth connection portion 211. The fourth connection portion 211 is located in the fourth groove 236 or on the side of the fourth groove 236 away from the battery cell assembly 3. The fourth connection portion 211 can be a copper busbar.

[0108] In some embodiments, along the length direction, each battery cell assembly 3 located in two adjacent second storage sub-cavities 201 includes multiple battery cells, wherein the number of battery cells included in one battery cell assembly 3 is an odd number, and the number of battery cells included in the other battery cell assembly 3 is an even number. Along the length direction, the total number of battery cells included in a row of battery cell assemblies 3 is an odd number, that is, an odd number. This quantitative relationship can make the first connection portion 28 of the two battery cell assemblies 3 arranged along the X direction of the third bracket 23 located in the first groove 250 or outside the first groove 250, and the second connection portion 29 of the two battery cell assemblies 3 arranged along the Y direction located in the second groove 240 or outside the second groove 240. The first connection portion 28 and the second connection portion 29 can specifically adopt a copper bar group.

[0109] The two layers of battery cell assemblies 3 along the Y direction are electrically connected via the interlayer connecting copper bar 213. The total negative output copper bar 212 of the power battery pack is located at one end of the power battery pack, and the total positive output copper bar 214 is located at the other end of the power battery pack.

[0110] The four battery cell components 3 located on the same layer are Figure 1 Taking the left and right directions as an example, the two battery cell assemblies 3 on the left have an odd number of battery cells, and the two battery cell assemblies 3 on the right have an even number of battery cells, which ensures that the series copper busbars of the three battery cell assemblies 3 are all outside, making installation and connection easier. Figure 1 Taking the direction shown as an example, the series copper bar group of three battery cell assemblies 3 refers to: two connecting copper bars of two battery cell assemblies 3 on the left and right sides of the same layer (because two rows of battery cell assemblies 3 are arranged along the Y direction), and one connecting copper bar of two battery cell assemblies 3 on the right side. The total negative output copper bar 212 and the total positive output copper bar 241 are arranged on the left side.

[0111] For each layer of battery cell assemblies 3, two rows of battery cell assemblies 3 are arranged along the Y direction, and the number of stacked battery cell assemblies 3 in each row is an odd number. If the number of single battery cell assemblies 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 separated, the number of battery cells included in the battery cell assembly 3 on the left is an even number, and the number of battery cells included in the battery cell assembly 3 on the right is an odd number. In this way, the first connecting part 28 and the third connecting part 210 are ensured to be on the outside, and the length of the second connecting part 29 and the fourth connecting part 211 is the shortest, which is convenient for the installation of the copper busbar.

[0112] In some embodiments, the second end plate 232 and the second partition plate 234 have the same height, and are both 0.8 mm to 1.2 mm higher than the height of the battery cell assembly 3, such as 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 may be provided with a hoisting hole 237, see Figure 7 .

[0113] Continue to see Figure 5 , Figure 6 and Figure 7 The second bracket 22 and the third bracket 23 are in direct contact and detachably fixedly connected. Specifically, a second bolt hole b1 can be provided on the first end plate 25 of the second bracket 22, and a corresponding second through hole b2 can be provided on the second end plate 232 of the third bracket 23. Long bolts are used to penetrate 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, so as to detachably fixly connect the second bracket 22 and the third bracket 23.

[0114] See also Figure 5 and Figure 6 In addition, a third bolt hole b2 is provided on the first end plate 25 of the second bracket 22, and a third through hole b3 is correspondingly provided on the second partition plate 234 of the third bracket 23. A long bolt P2 passes through the third through hole b3 and the third bolt hole b2 to increase the stability of the connection between the second bracket 22 and the third bracket 23.

[0115] In addition, in order to increase the stability of the connection between the second bracket 22 and the third bracket 23, a third bolt hole c1 can be provided on the first side plate 26 of the second bracket 22 (see Figure 5 ), a fixing hole c2 is correspondingly provided on the second side plate 233 of the third bracket 23 (see Figure 7 ), use short bolt P3 (see Figure 6 ) 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.

[0116] Each threaded hole in this article can specifically adopt a rivet nut hole to increase the convenience and strength of connection.

[0117] Figure 8 A schematic diagram of the three-dimensional structure of a pull plate 4 of a power battery pack provided in an embodiment of the present invention. Fig. 9 A schematic diagram of the three-dimensional structure of the installation of the pull plate 4 of the power battery pack provided in an embodiment of the present invention.

[0118] See also Figure 1 , Figure 8 and Fig. 9 In some embodiments, the power battery pack further includes a pull plate 4, which is located at the top of the bracket assembly 2, and the pull plate 4 is fixedly connected to the bracket assembly 2 and the box body 1. Specifically, the pull plate 4 is fixedly connected to the top of the battery cell assembly 3 located at the top layer by glue. Figure 8 The edge of the pull plate 4 is also provided with a raised portion M1, which is provided with a screw hole or a rivet nut, and the inner wall of the box body 1 is correspondingly provided with a reinforcing plate M2, which is correspondingly provided with a screw hole, and the pull plate 4 is fixedly connected to the inner wall of the box body 1 by passing a bolt through the raised portion M1 and the reinforcing plate M2. A sealing member 6 is provided between the pull plate 4 and the box body 1 to enhance the sealing performance of the box body 1.

[0119] In addition, a first connecting hole N1 is provided at the edge of the pull plate 4, a second through hole b2 is correspondingly provided at the second end plate 232 of the third bracket 23, a second bolt hole b1 is provided on the first end plate 25 of the second bracket 22, and a long bolt is passed through the first connecting hole N1, the second through hole b2 and the second bolt hole b1 to fix the pull plate 4 and the third bracket 23 and the second bracket 22.

[0120] A second connecting hole N2 is also provided in the middle of the pull plate 4, and a third through hole b3 is correspondingly provided on the second partition 234 of the third bracket 23, and a third bolt hole b2 is provided on the first end plate 25 of the second bracket 22. Long bolts are passed through the second connecting hole N2, the third through hole b3 and the third bolt hole b2 to fix the pull plate 4 and the second partition 234 of the third bracket 23 and the first partition 27 of the second bracket 22.

[0121] The power battery pack includes a three-layer battery cell module. The first bracket 21 located at the bottom layer is fixed to the bottom of the box body 1, the second bracket 22 located at the middle layer is fixedly connected to the first bracket 21, and the third bracket 23 located at the top layer is fixedly connected to the second bracket 22. A pull plate 4 is provided on the top of the battery cell assembly 3 located at the top layer. The pull plate 4 is connected to the side wall of the box body 1 through a support plate to prevent the three-layer battery cell assembly 3 from being too high and shaking inside the box body 1, thereby increasing the connection strength and rigidity between the three-layer battery cell assembly 3 and the box body 1.

[0122] Fig.10 A schematic diagram of the connection relationship between the first bracket, the second bracket, and the third bracket of the power battery pack provided in an embodiment of the present invention. Fig.10 The first bracket 21 and the second bracket 22 are fixedly connected by long bolts, which penetrate 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, which penetrate the second end plate 232 of the third bracket 23 and are inserted into the first end plate 25 of the second bracket 22. Figure 7, the short bolts penetrate the second side plate 233 of the third bracket 23 and are inserted into the first side plate 26 of the second bracket 22. The second side plate 233 of the third tray is set to be relatively short, which can shorten the length of the connecting bolts between the second side plate 233 of the third tray and the first side plate 26 of the second tray, simplify the installation, save materials, reduce the difficulty of installation, and ensure the installation strength.

[0123] See also Fig.10 The bolts P4 that fix the third bracket 23 and the second bracket 22, the bolts P3 that fix the second bracket 22 and the first bracket 21, the bolts P1 and the bolts P2 that fix the first bracket 21 and the bottom of the box body 1 are arranged alternately to achieve the connection and fixation between the power battery pack layers.

[0124] 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 each layer of the first bracket 21, the second bracket 22 and the third bracket 23, the bracket and the battery cell assembly 3 supported by the hook 5 are hoisted into the box body 1. After the hoisting is completed, the hoisting can be removed.

[0125] In other embodiments, the first bracket 21, the second bracket 22, the third bracket 23 and the respective battery cell assemblies 3 can be assembled outside the box body 1, and the pipelines can be assembled, and then hoisted into the box body 1 as a whole. This places higher requirements on the structural strength of the three-layer battery cell module, but the installation operation can be completed in one hoisting.

[0126] In the above-mentioned embodiments, two rows of battery cell assemblies 3 are arranged in the width direction, i.e., the Y direction. Of course, multiple rows of battery cell assemblies 3 can also be arranged, but the size of the power battery pack in the length direction is reduced by reducing the number of battery cell assemblies 3 stacked in the width direction. It should be noted that the more rows of battery cell assemblies 3 are arranged, the lower the space utilization rate of the power battery pack may be due to the need to ensure a certain distance between adjacent battery cell poles.

[0127] An embodiment of the present invention further provides an engineering vehicle, comprising a power battery pack provided by any technical solution of the present invention.

[0128] In some embodiments, the engineering vehicle is one of the following: a loader, a grader.

[0129] In the description of the present invention, it is necessary to understand that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the protection content of the present invention. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0130] In the description of the present invention, each technical feature may be combined with other technical features where feasible.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power battery pack, characterized in that: include: The box body (1) comprises a first storage chamber (11); A bracket assembly (2) is located in the first storage cavity (11); the bracket assembly (2) comprises a multi-layer second storage cavity (20); and A plurality of battery cell assemblies (3), each of the battery cell assemblies (3) comprising a plurality of battery cells, and the battery cell assembly (3) is placed in the second storage cavity (20) of each bracket.

2. The power battery pack according to claim 1, characterized in that: The bracket assembly (2) comprises a first bracket (21), a second bracket (22) and a third bracket (23) which are stacked; 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; and the height of each of the battery cell assemblies (3) is lower than the height of each of the first bracket (21), the second bracket (22) and the third bracket (23).

3. The power battery pack according to claim 2, characterized in that: The height of each of the second storage cavities (20) 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 battery cell assembly (3).

4. The power battery pack according to claim 2, characterized in that: The first bracket (21), the second bracket (22) and the third bracket (23) each comprise at least one second storage cavity (20), and at least one battery cell assembly (3) is fixed in each of the second storage cavities (20).

5. The power battery pack according to claim 2, characterized in that: The first bracket (21) and the second bracket (22) each include: A first cold plate (24) configured to cool the battery cell assembly (3) located in the second storage cavity (20); Two first end plates (25), the two first end plates (25) being fixed at two 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, characterized in that: The first bracket (21) and the second bracket (22) each further include: At least one first partition plate (27), the first partition plate (27) being fixedly connected to the first cold plate (24), the first partition plate (27) dividing the second storage cavity (20) into a plurality of first storage sub-cavities (200), each of the first storage sub-cavities (200) containing one of the battery cell assemblies (3).

7. The power battery pack according to claim 6, characterized in that: At least one of the first side plates (26) is provided with a first groove (250); The length direction is a direction from one of the first end plates (25) to another of the first end plates (25), and along the length direction, the battery cell assemblies (3) located in two adjacent first storage sub-cavities (200) are connected in series via a first connecting portion (28), and the first connecting portion (28) is located in the first groove (250) or on a side of the first groove (250) facing away from the battery cell assembly (3).

8. The power battery pack according to claim 7, characterized in that: At least one of the first end plates (25) is provided with a second groove (240); The width direction is perpendicular to the length direction, and 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), and the second connecting portion (29) is located in the second groove (240) or on a side of the second groove (240) facing away from the battery cell assembly (3).

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

10. The power battery pack according to claim 6, characterized in that: The number of the first partition plates (27) is two, and the two first partition plates (27) are arranged crosswise.

11. The power battery pack according to claim 6, characterized in that: 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).

12. The power battery pack according to claim 2, characterized in that: The third bracket (23) comprises: A second cold plate (231) configured to cool the battery cell assembly (3) located in the second storage cavity (20); Two second end plates (232), the two second end plates (232) being dispersedly fixed at two 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 a second storage cavity (20) of the third bracket (23).

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

14. The power battery pack according to claim 13, characterized in that: At least one of the second side plates (233) is provided with a third groove (235); The length direction is along the direction from one of the second end plates (232) to the other second end plate (232), and along the length direction, the battery cell assemblies (3) located in two adjacent second storage sub-cavities (201) are connected in series via a third connecting portion (210), and the third connecting portion (210) is located in the third groove (235) or on a side of the third groove (235) facing away from the battery cell assembly (3).

15. The power battery pack according to claim 14, characterized in that: At least one of the second end plates (232) is provided with a fourth groove (236); The width direction is perpendicular to the length direction, and along the width direction, the battery cell assemblies (3) located in two adjacent second storage sub-cavities (201) are connected in series via a fourth connecting portion (211), and the fourth connecting portion (211) is located in the fourth groove (236) or on a side of the fourth groove (236) facing away from the battery cell assembly (3).

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

17. The power battery pack according to claim 13, characterized in that: The number of the second partition plates (234) is two, and the two second partition plates (234) are arranged crosswise.

18. The power battery pack according to claim 13, characterized in that: The second end plate (232) and the second partition plate (234) have the same height, and are both 0.8 to 1.2 mm higher than the height of the battery cell assembly (3); The height of the second side plate (233) is lower than the heights of the second end plate (232) and the second partition plate (234).

19. The power battery pack according to claim 2, characterized in that: The bottom surface of the battery 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 battery 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 claim 2, characterized in that: 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), and 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).

21. The power battery pack according to claim 1, characterized in that: Also includes: The pull plate (4) is located on the top of the bracket assembly (2), and the pull plate (4) is fixedly connected to the bracket assembly (2) and the box body (1).

22. An engineering vehicle, characterized in that: A power battery pack comprising any one of claims 1 to 21.

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

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