Battery Pack

Abstract

The present invention provides a battery pack, comprising: a battery module; a battery pack box, comprising a plurality of crossbeams and a plurality of longitudinal beams, the crossbeams and the longitudinal beams defining a plurality of module accommodating spaces for accommodating battery modules, and an isolation plate being provided on one side of each module accommodating space; a liquid cooling assembly, which is provided on the other side of the isolation plate, and the liquid cooling assembly and the battery module are heat-conducted through the isolation plate. Both the crossbeams and the longitudinal beams have overlapping ribs, and a heat insulation plate is provided on the overlapping ribs, and the isolation plate is placed on the heat insulation plate, and a heat insulation plate is also provided below the crossbeams at both ends and between the lower cover. There is a first gap between the isolation plate corresponding to each module accommodating space and the inner side surface of the corresponding crossbeam, and there is a second gap between the isolation plate corresponding to each module accommodating space and the inner side surface of the corresponding longitudinal beam. By adopting the solution of the present invention, a battery pack with a heat-insulating box structure is provided, which reduces the impact of the environment on the battery and achieves a uniform temperature effect for the battery pack.

Description

Technical Field

[0001] The present invention relates to the technical field of battery packs, and in particular to a battery pack box and a battery pack that realize the function of heat preservation and temperature equalization. Background Art

[0002] The large temperature difference of lithium-ion power batteries will directly cause some defects: (1) inconsistent battery attenuation, even causing accelerated battery aging; (2) large errors in battery status estimation, even causing the vehicle to be unable to drive; (3) reduced battery pack cooling / heating efficiency, extended pre-cooling / preheating time, increased energy consumption, and even causing the vehicle to be unable to drive. In severe cases, there will be risks of fire and explosion.

[0003] If the battery temperature is too low, the available battery capacity and available battery power will be reduced. When the vehicle is sold and used in colder areas, the battery pack needs to be equipped with a thermal insulation structure in order to delay the impact of low temperatures on the available battery capacity and available battery power. Higher battery temperatures will accelerate battery aging. In the hot summer environment, for vehicles equipped with battery packs with liquid cooling systems, when the vehicle is powered off, the environment will heat the battery, causing the battery temperature to even exceed 40°C. Therefore, for power batteries, whether the temperature is too high, too low, or the temperature difference is too large, it will have a great adverse effect on the performance of the power battery and even the vehicle.

[0004] In the prior art, in order to achieve dry-wet separation of the battery module and the liquid cooling system in the battery pack, a dry-wet separation battery pack is provided. Figure 1 As shown. The battery pack includes an upper cover 101, a battery module 103, a first heat-conducting layer 104, a dry-wet separation isolation plate 105, a second heat-conducting layer 106, a liquid cooling plate 107 and a lower cover 108 from top to bottom, and a side plate 102 is provided on the side of the battery pack. The upper cover 101, the side plate 102 and the isolation plate 105 constitute a first connected domain. The battery pack components other than the cooling pipeline and the cooling pipeline accessories are located in the first connected domain. The first connected domain mainly contains battery modules, BMS (Battery Management System), high and low voltage wiring harnesses, etc. The lower cover 108, the isolation plate 105 and the side plate 102 constitute a second connected domain. The cooling pipeline and the cooling pipeline accessories are located in the second connected domain. The second connected domain mainly contains battery cooling pipes, cooling plates and auxiliary supports, thermal conductive sheets, etc. Liquid caused by anti-cooling liquid leakage and condensation cannot be sprayed or flowed from the second connected domain to the first connected domain.

[0005] However, this dry-wet separation battery pack has the defect of being easily affected by the ambient temperature. Specifically, since the dry-wet separation isolation plate 105 of the battery pack is directly connected to the lower cover of the battery pack and is an aluminum profile structure, the external environment will exchange heat with the module through the heat transfer path formed by these aluminum profile structures. If there is no thermal isolation design, the dry-wet separation battery pack is more susceptible to environmental influences than the non-dry-wet separation liquid-cooled battery pack using the same material, and the temperature difference of this battery pack will be greater. Summary of the invention

[0006] In view of the problems in the prior art, an object of the present invention is to provide a battery pack with a heat-insulating box structure to reduce the impact of the environment on the battery and achieve a uniform temperature effect.

[0007] An embodiment of the present invention provides a battery pack, comprising: a battery module; a battery pack case, the battery pack case comprising a plurality of cross beams and a plurality of longitudinal beams, the plurality of cross beams and the plurality of longitudinal beams defining a plurality of module accommodating spaces, the battery modules being placed in the module accommodating spaces, a side surface of each of the module accommodating spaces being provided with an isolation plate, a first gap being provided between the isolation plate corresponding to each of the module accommodating spaces and an inner side surface of the corresponding cross beam, and a second gap being provided between the isolation plate corresponding to each of the module accommodating spaces and an inner side surface of the corresponding longitudinal beam; a liquid cooling assembly being provided on a side of the isolation plate away from the battery module, the liquid cooling assembly and the battery module being heat-conducted through the isolation plate.

[0008] Optionally, the first gap and the second gap are filled with heat insulating material.

[0009] Optionally, a longitudinal beam lap rib is provided on the inner side surface of the longitudinal beam, and the longitudinal beam lap rib includes a lap portion, the lap portion is located below the isolation plate, and a first heat insulation board is provided between the upper surface of the lap portion and the lower surface of the isolation plate.

[0010] Optionally, the longitudinal beam lap rib further includes an extension portion located between the lap portion and the longitudinal beam, the lap portion is bent downward relative to the extension portion, the extension portion is arranged flush with the isolation plate, and the second gap is provided between the extension portion and the isolation plate.

[0011] Optionally, a cross beam lap rib is provided on the inner side surface of the cross beam, and the cross beam lap rib is located below the isolation plate.

[0012] Optionally, the cross beam includes end cross beams located at both ends of the battery pack body, and a second heat insulation plate is arranged between the cross beam lap ribs of the end cross beam and the isolation plate.

[0013] Optionally, the crossbeam further includes a middle crossbeam located between the end crossbeams, and a distance H1 between an isolation plate corresponding to the end crossbeam and a lower end surface of the end crossbeam is smaller than a distance H2 between an isolation plate corresponding to the middle crossbeam and a lower end surface of the middle crossbeam.

[0014] Optionally, it further includes a lower cover arranged below the liquid cooling assembly, and a third heat insulation plate is arranged between the lower end surface of the end cross beam and the lower cover.

[0015] Optionally, the end cross beam at one end of the battery pack body includes a first cross beam and a second cross beam, the first cross beam, the second cross beam and the longitudinal beam define an accessory accommodating space, an accessory isolation plate is provided on one side of the accessory accommodating space, and the edges of the accessory isolation plate are respectively in contact with the inner side surfaces of the first cross beam, the second cross beam and the longitudinal beam.

[0016] Optionally, the liquid cooling assembly includes liquid cooling plate units corresponding one to one with the battery modules, a lower cover is provided below the liquid cooling assembly, the crossbeam passes through the gap between the liquid cooling plate units and is supported on the lower cover; an upper cover is provided above the battery pack body, and the upper cover covers both the module accommodating space and the accessory accommodating space.

[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure.

[0018] The battery pack provided by the present invention has the following advantages:

[0019] The present invention provides a battery pack with a heat-insulating box structure. Through the isolation between the isolation plate and the longitudinal beams and cross beams of the battery pack box, the heat is isolated from being transferred from the circumferential surface of the isolation plate to the cross beams and longitudinal beams, and the heat is isolated from being transferred from the cross beams and longitudinal beams to the isolation plate, thereby reducing the impact of the environment on the battery, mitigating the heating effect of the environment on the battery, and achieving the temperature equalization effect of the battery pack, reducing the battery aging speed, and increasing the available capacity and service life of the battery; the overall structure is simple and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objectives and advantages of the present invention will become more apparent from a reading of the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0021] Figure 1 It is a structural schematic diagram of a battery pack in the prior art;

[0022] Figure 2 is an exploded view of a battery pack according to an embodiment of the present invention;

[0023] Figure 3is a schematic structural diagram of a battery pack box according to an embodiment of the present invention;

[0024] Figure 4 yes Figure 3 Enlarged view of point A in the middle;

[0025] Figure 5 is a schematic diagram of the cooperation between the longitudinal beam and the isolation plate according to an embodiment of the present invention;

[0026] Figure 6 yes Figure 5 An enlarged view of the matching part between the middle longitudinal beam and the isolation plate;

[0027] Figure 7 is a schematic diagram of the cooperation between the longitudinal beam, the liquid cooling plate and the lower cover according to an embodiment of the present invention;

[0028] Figure 8 yes Figure 7 Enlarged view of point B in the middle;

[0029] Fig. 9 is a schematic diagram of the cooperation between the sixth crossbeam and the isolation plate according to an embodiment of the present invention;

[0030] Fig.10 is a schematic diagram of the cooperation between the third cross beam and the isolation plate according to an embodiment of the present invention;

[0031] Fig.11 It is a schematic diagram of the cooperation between the first crossbeam, the second crossbeam and the isolation plate according to an embodiment of the present invention;

[0032] Fig.12 is a schematic diagram of the sixth crossbeam cooperating with the liquid cooling plate and the lower cover according to an embodiment of the present invention;

[0033] Fig.13 is a schematic diagram of the cooperation between the third crossbeam, the liquid cooling plate and the lower cover according to an embodiment of the present invention;

[0034] Fig.14 It is a schematic diagram of the cooperation between the first crossbeam, the second crossbeam, the liquid cooling plate and the lower cover according to an embodiment of the present invention;

[0035] Fig.15 A temperature drop curve diagram for testing a battery pack in the prior art;

[0036] Fig.16 The figure is a temperature drop curve diagram for testing the battery pack of the present invention.

[0037] Reference numerals:

[0038] Prior art

[0039] 101 Upper cover 105 Isolation board

[0040] 102 side plate 106 second heat conducting layer

[0041] 103 Battery Module 107 Liquid Cooling Plate

[0042] 104 first heat conducting layer 108 lower cover

[0043] The present invention

[0044] 1 Upper cover 422 Second longitudinal beam

[0045] 2 Battery module 43 Isolation board

[0046] 3 Thermal pad 44 Stringer lap rib

[0047] 4 Battery pack box 441 extension

[0048] 41 beam 442 overlap

[0049] 411 first beam 45 first heat insulation board

[0050] 412 Second beam 46 Beam lap rib

[0051] 413 third beam 47 second heat insulation board

[0052] 414 fourth beam 48 module accommodation space

[0053] 415 Fifth beam 49 Accessory storage space

[0054] 416 Sixth beam 5 liquid cooling assembly

[0055] 42 longitudinal beam 6 lower cover

[0056] 421 First longitudinal beam 7 Third heat insulation board DETAILED DESCRIPTION

[0057] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0058] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus their repeated description will be omitted.

[0059] like Figure 2As shown, in order to solve the above technical problems, an embodiment of the present invention provides a battery pack, including a battery pack module 2, a battery pack case 4 and a liquid cooling assembly 5. The battery pack case 4 includes a plurality of cross beams 41 and a plurality of longitudinal beams 42, and the plurality of cross beams 41 and the plurality of longitudinal beams 42 define a plurality of module accommodating spaces 48, and the battery module 2 is placed in the module accommodating space 48, and an isolation plate 43 is provided on the lower side of each module accommodating space 48. The liquid cooling assembly 5 is arranged below the battery pack case 4, and the liquid cooling assembly 5 and the battery module 2 are heat-conducted through the isolation plate 43.

[0060] In this embodiment, an upper cover 1 is further provided above the module accommodating space 48. The battery module 2 is located in the module accommodating space 48 defined by the upper cover 1, the cross beam 41, the longitudinal beam 42 and the isolation plate 43, and the liquid cooling assembly 5 is separated from the battery module 2 by the isolation plate 43 to prevent the antifreeze liquid in the liquid cooling assembly 5 from leaking and condensing and causing the liquid to spray or flow into the module accommodating space 48. The battery module 2 in the battery pack case 4 is heat-conducted with the liquid cooling assembly 5 through the isolation plate 43. In this embodiment, a thermally conductive gasket 3 is further provided between the battery module 2 and the corresponding isolation plate 43, and the battery module 2 is heat-conducted with the liquid cooling assembly 5 through the thermally conductive gasket 2 and the isolation plate 43 in turn.

[0061] like Figure 2 As shown, in this embodiment, the liquid cooling assembly 5 includes a plurality of liquid cooling plate units corresponding one to one with the battery module 2, and there is a certain gap between two adjacent liquid cooling plate units for the crossbeam 41 to pass through. A lower cover 6 is provided under the liquid cooling assembly, and the crossbeam 41 passes through the gap between the liquid cooling plate units and is supported on the lower cover 6, thereby supporting the entire battery pack body 4 and the battery module 2 together with the longitudinal beam 42.

[0062] like Figure 3As shown, in this embodiment, the battery pack box 4 includes six crossbeams 411 to 416 and two longitudinal beams 421 and 422. However, the present invention is not limited thereto, and the number of crossbeams 41 and longitudinal beams 42 can be selected and set as needed. In this embodiment, the first crossbeam 411, the second crossbeam 412, the first longitudinal beam 421 and the second longitudinal beam 422 define an accessory accommodating space 49, in which battery module accessories are placed. Here, battery module accessories refer to other components in the battery pack other than the battery module, such as a battery management system (BMS), a high-voltage electrical box, and the like. The third crossbeam 413, the fourth crossbeam 414, the fifth crossbeam 415, the sixth crossbeam 416, the first longitudinal beam 421 and the second longitudinal beam 422 define four module accommodating spaces 48. The specific number of module accommodating spaces 48 can be selected according to the number of battery modules 2 actually used. The upper cover 1 covers both the accessory accommodating space 49 and the module accommodating space 48 to form a closed battery pack accommodating cavity. The upper cover 1 can also be arranged in sections according to the settings of each accommodating space.

[0063] like Figure 4 As shown, in order to avoid heat conduction between the isolation plate 43 and the crossbeam 41 and the longitudinal beam 42, there is a first gap G1 between the isolation plate 43 corresponding to each of the module accommodating spaces 48 and the inner side of the crossbeam 41 defining the module accommodating space 48, and there is a second gap G2 between the isolation plate 43 corresponding to each of the module accommodating spaces 48 and the inner side of the longitudinal beam 42 defining the module accommodating space 48, thereby avoiding heat transfer from the isolation plate 43 to the crossbeam 41 and the longitudinal beam 42, improving the overall temperature uniformity of the battery pack, and also avoiding the heat of the crossbeam 41 and the longitudinal beam 42 from being transferred to the battery module 2 through the isolation plate 43, reducing the influence of the ambient temperature. The size of the first gap G1 can be the same as or different from the size of the second gap G2. In order to make the structure simple and unified, in one embodiment, the values ​​of the first gap G1 and the second gap G2 are the same, and can be selected within the range of 0.5mm to 1.5mm, for example, G1 = G2 ≈ 1mm. The first gap and the second gap may be filled with air or may be filled with heat insulating materials such as rubber, sponge, etc.

[0064] In this embodiment, an isolation plate 43 is also provided on the lower side of the accessory accommodating space 49, and the edges of the isolation plate 43 can be respectively in contact with the inner side of the first cross beam 411, the inner side of the second cross beam 412, and the inner side of the longitudinal beam 42. In other embodiments, at least one side gap can be provided between the edge of the isolation plate 43 and the inner side of the first cross beam 411, the inner side of the second cross beam 412, and the inner side of the longitudinal beam 42.

[0065] like Figure 5 and Figure 6As shown, the inner side surface of the longitudinal beam 42 is provided with a longitudinal beam lap rib 44, and the longitudinal beam lap rib 44 includes a lap portion 442, and the lap portion 442 is located below the isolation plate 43, and a first heat insulation board 45 is provided between the upper surface of the lap portion 442 and the lower surface of the isolation plate 43. The thermal conductivity of the first heat insulation board 45 is preferably less than 1.5 W / mK, and is used to block the transfer of heat between the end surface of the isolation plate 43 and the longitudinal beam 42. In this embodiment, the longitudinal beam lap rib 44 also includes an extension portion 441 located between the lap portion 442 and the longitudinal beam 42, the lap portion 442 is bent downward relative to the extension portion 441, the extension portion 441 is arranged flush with the isolation plate 43, and the second gap is provided between the extension portion 441 and the isolation plate 43 to isolate the heat transfer between the isolation plate 43 and the longitudinal beam 42.

[0066] The height of the first heat insulation board 45 is H, and the height H must be such that after the liquid cooling assembly 5 is installed under the battery pack box 4, there will be no interference between the longitudinal beam lap rib 44 and the liquid cooling assembly 5. Figure 7 and Figure 8 As shown, there is a gap between the liquid cooling assembly 5 and the longitudinal beam lap rib 44, ensuring that there is no interference between the liquid cooling assembly 5 and the longitudinal beam lap rib 44. The first heat insulation board 45 is preferably made of a heat insulation material with a certain hardness, such as a flame retardant plastic, which can withstand the pressure caused by the deformation of the thermal gasket 3 material without obvious compression, ensuring good thermal contact between the thermal gasket 3 and the battery module 2, and between the thermal gasket 3 and the isolation board 43. The first heat insulation board 45 can be pre-assembled with the longitudinal beam lap rib 44 to form a component, and then assembled with the isolation board 43; or the first heat insulation board 45 can be first assembled with the isolation board 43 to form a component, and then assembled with the longitudinal lap rib 44.

[0067] like Figures 9-11 As shown, the inner side of the cross beam 41 is provided with a cross beam lap rib 46, and the cross beam lap rib 46 is located below the isolation plate 43. In this embodiment, the cross beam includes end cross beams located at both ends of the battery pack case 4 and a middle cross beam located between the end cross beams. In this embodiment, the end cross beams include a first cross beam 411 and a second cross beam 412 located at one end of the battery pack case 4 and defining an accessory accommodating space 49, and a sixth cross beam 416 located at the other end of the battery pack case 4, and the middle cross beam includes a third cross beam 413, a fourth cross beam 414 and a fifth cross beam 415.

[0068] like Fig. 9 and Fig.11 As shown in FIG. 1 , a second heat insulation board 47 is disposed between the cross beam lap ribs 46 of the first cross beam 411, the second cross beam 412 and the sixth cross beam 416 and the isolation board 43. Fig.10As shown, the beam lap rib 46 of the middle beam, taking the third beam 413 as an example, is in direct contact with the end surface of the isolation plate 43. According to heat transfer theory, the heat exchange rate between the battery module 4 located between the second beam 412 and the third beam 413 and the battery module 4 located between the fifth beam 415 and the sixth beam 416 and the environment is much greater than the heat exchange rate between the battery module 4 at other positions and the environment. This design can balance the speed of heat exchange between the battery modules 4 at different positions and the environment, and achieve a module temperature equalization effect. The material of the second insulation board 47 can be selected from the same material as the first insulation board 45, and the second insulation board 47 can also be in a segmented form. The height of the second insulation board 47 is also preferably the same as the height of the first insulation board 45 to achieve a unified and simple structure.

[0069] The structure of the sixth cross beam 416 and the isolation plate 43 is as follows: Fig. 9 As shown, the distance between the isolation plate 43 corresponding to the sixth crossbeam 416 and the lower end surface of the sixth crossbeam 416 is H1. The structure of the middle crossbeam and the isolation plate 43 is as follows: Fig.10 As shown, taking the third crossbeam 413 as an example, the structures of the fourth crossbeam 414 and the fifth crossbeam 415 are the same as the structure of the third crossbeam 413, and the distance between the isolation plate 43 corresponding to the middle crossbeam and the lower end surface of the middle crossbeam is H2. The structure of the first crossbeam 411 and the second crossbeam 412 cooperating with the isolation plate 43 is as shown in FIG. Fig.11 As shown, the spacing between the isolation plate 43 corresponding to the first beam 411 and the second beam 412 and the lower end surface of the first beam 411 and the second beam 412 is H1. In one embodiment, the spacing H2 is greater than the spacing H1, and the difference between the spacing H2 and the spacing H1 can be 1mm to 3mm. According to heat transfer theory, the heat exchange rate between the battery module 4 located between the second beam 412 and the third beam 413 and the battery module 4 located between the fifth beam 415 and the sixth beam 416 and the environment is much greater than the heat exchange rate between the battery module 4 at other positions and the environment. Therefore, Figures 12-14 As shown, a third heat insulation board 7 is respectively arranged between the lower end surfaces of the first crossbeam 411, the second crossbeam 412 and the sixth crossbeam 416 and the lower cover 6. The height of the third heat insulation board 7 is the same as the value of H2-H1. The thermal conductivity of the third heat insulation board 7 is less than 1.5W / mK. After the heat of the battery module 4 is transferred to the crossbeam 41, the third heat insulation board 7 between the crossbeam 41 and the lower cover 6 can prevent the heat from being transferred to the lower cover 6 and then dissipated into the environment. This design can balance the speed of heat exchange between the battery modules 4 at different positions and the environment, and achieve a uniform temperature effect for the battery modules. It is recommended to use structural glue for the third heat insulation board 7, which can simultaneously achieve better sealing, better thermal insulation effect and better assembly strength.

[0070] like Fig.15 and Fig.16 As shown, there are temperature drop curves of simulation tests using a battery pack in the prior art and a battery pack of the present invention.

[0071] Here, a battery pack with 96 cells is used as an example for simulation, and the average temperature of the upper surface of each cell is taken as the research object, so there are 96 research objects; the simulation model adopts a natural convection transient model, the battery pack is placed in the air, and the natural convection heat transfer is solved by itself. The initial temperature of the battery pack is 20°C, and the ambient temperature is -20°C; the thickness of the insulation structure adhesive layer is H2-H3=4 mm, H1-H3=4 mm; the thickness of the insulation board is H=2 mm; G1=G2=1 mm, and the thermal conductivity of the insulation material is 2.0W / mK;

[0072] Among them, T_max means that there is a maximum value among the 96 research objects, that is, the maximum value of the average temperature on the upper surface of the battery cell; T_min means that there is a maximum value among the 96 research objects, that is, the maximum value of the average temperature on the upper surface of the battery cell; T_diff means the temperature difference, that is, T_diff = T_max-T-min;

[0073] The data comparison of the battery pack in the prior art (without the heat insulation board and the heat insulation structure adhesive layer) and the battery pack in the present invention (with the heat insulation board and the heat insulation structure adhesive layer) is shown in Table 1 below:

[0074] Table 1

[0075] Time to cool down to 0 degrees Celsius Maximum temperature difference T_diff Prior art 11210 seconds 7.90 degrees Celsius The present invention 14780 seconds 4.48 degrees Celsius The heat insulation and temperature uniformity effect of the present invention 32% longer time 43% reduction in temperature difference

[0076] From the comparison in Table 1, it can be seen that by adopting the thermal insulation box structure of the present invention and adding a thermal insulation board and a thermal insulation structural adhesive layer in the battery pack, the thermal insulation effect of the battery pack can be greatly improved, the time for the battery pack to cool down to 0°C can be delayed, and the maximum temperature difference can be significantly reduced, thereby greatly reducing the impact of the environment on the battery.

[0077] In summary, compared with the prior art, the battery pack provided by the present invention has the following advantages:

[0078] The present invention provides a battery pack with a heat-insulating box structure. Through the isolation between the isolation plate and the longitudinal beams and cross beams of the battery pack box, the heat is isolated from being transferred from the circumferential surface of the isolation plate to the cross beams and longitudinal beams, and the heat is isolated from being transferred from the cross beams and longitudinal beams to the isolation plate, thereby reducing the impact of the environment on the battery, mitigating the heating effect of the environment on the battery, and achieving the temperature equalization effect of the battery pack, reducing the battery aging speed, and increasing the available capacity and service life of the battery; the overall structure is simple and practical.

[0079] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A battery pack, characterized in that: include: Battery module; A battery pack case, the battery pack case comprising a plurality of cross beams and a plurality of longitudinal beams, the plurality of cross beams and the plurality of longitudinal beams defining a plurality of module accommodating spaces, the battery modules being placed in the module accommodating spaces, a side surface of each of the module accommodating spaces being provided with an isolation plate, a first gap being provided between the isolation plate corresponding to each of the module accommodating spaces and the inner side surface of the corresponding cross beam, and a second gap being provided between the isolation plate corresponding to each of the module accommodating spaces and the inner side surface of the corresponding longitudinal beam; A liquid cooling assembly is arranged on a side of the isolation plate away from the battery module, and the liquid cooling assembly and the battery module are heat-conducted through the isolation plate; The first gap and the second gap are filled with heat insulation material; The inner side surface of the cross beam is provided with a cross beam overlapping rib, and the cross beam overlapping rib is located below the isolation plate.

2. The battery pack according to claim 1, characterized in that: The inner side surface of the longitudinal beam is provided with a longitudinal beam lap rib, and the longitudinal beam lap rib includes a lap portion, the lap portion is located below the isolation plate, and a first heat insulation board is provided between the upper surface of the lap portion and the lower surface of the isolation plate.

3. The battery pack according to claim 2, characterized in that: The longitudinal beam lap rib further includes an extension portion located between the lap portion and the longitudinal beam, the lap portion is bent downward relative to the extension portion, the extension portion is arranged flush with the isolation plate, and the second gap is provided between the extension portion and the isolation plate.

4. The battery pack according to claim 1, characterized in that: The cross beam includes end cross beams located at both ends of the battery pack body, and a second heat insulation plate is arranged between the cross beam lap ribs of the end cross beam and the isolation plate.

5. The battery pack according to claim 4, characterized in that: The crossbeam also includes a middle crossbeam located between the end crossbeams, and a distance H1 between the isolation plate corresponding to the end crossbeam and the lower end surface of the end crossbeam is smaller than a distance H2 between the isolation plate corresponding to the middle crossbeam and the lower end surface of the middle crossbeam.

6. The battery pack according to claim 5, characterized in that: It also includes a lower cover arranged below the liquid cooling assembly, and a third heat insulation board is arranged between the lower end surface of the end cross beam and the lower cover.

7. The battery pack according to claim 4, characterized in that: The end cross beam at one end of the battery pack body includes a first cross beam and a second cross beam, and the first cross beam, the second cross beam and the longitudinal beam define an accessory accommodating space, and the accessory accommodating space is used to accommodate a battery management system and a high-voltage electrical box. An accessory isolation plate is provided on one side of the accessory accommodating space, and the edges of the accessory isolation plate are respectively in contact with the inner side surfaces of the first cross beam, the inner side surfaces of the second cross beam and the inner side surfaces of the longitudinal beam.

8. The battery pack according to claim 7, characterized in that: The liquid cooling assembly includes liquid cooling plate units corresponding to the battery modules one by one, a lower cover is provided below the liquid cooling assembly, and the crossbeam passes through the gaps between the liquid cooling plate units and is supported on the lower cover; An upper cover is arranged above the battery pack box, and the upper cover covers both the module accommodating space and the accessory accommodating space.

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