Battery pack and battery pack manufacturing method

Abstract

The invention belongs to the technical field of batteries, and discloses a battery pack and a battery pack manufacturing method. The battery pack specifically comprises a cooling plate assembly and a plurality of battery cell modules stacked from top to bottom, the cooling plate assembly is arranged between every two adjacent battery cell modules, and the cooling plate assembly comprises a first cooling plate and a second cooling plate; the first cooling plate supports the bottom of the upper battery cell module in the two adjacent battery cell modules, and the second cooling plate covers the top of the lower battery cell module in the two adjacent battery cell modules; the mechanical strength of the first cooling plate is greater than the mechanical strength of the second cooling plate. According to the battery pack, the multiple layers of battery cells can be well cooled, the cooling effect is better, the function of improving the bearing capacity of the cooling system can be achieved at low cost, and the cooling and heat dissipation effects are not affected.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery pack and a method for manufacturing the battery pack. Background Art

[0002] With the gradual development of the new energy vehicle industry, not only electric passenger cars have begun to be used, but more electric commercial vehicles will appear in the near future, such as pure electric vans, pure electric trucks and even pure electric heavy trucks. Due to the different structures of the entire vehicle, the battery packs of current passenger cars are mostly assembled with single-layer cells, so only a single-layer cold plate or side liquid cooling is required to meet the normal operation of the battery pack. However, since commercial vehicles cannot install the battery pack directly on the chassis of the car and can only be hung on the beam of the car, the battery pack often requires three or even four layers of cells to be stacked to meet the power usage requirements, so a three-layer or even four-layer liquid cooling system is required. The current liquid cooling system cannot adapt to the cooling needs of multi-layer cells, and can only meet the cooling of single-layer cells. The cooling effect of the cells in the middle layer of the multi-layer cells is not good, resulting in continuous accumulation of heat in the middle layer cells and eventually high-temperature failure, which reduces the cycle life of the cells and poses a greater safety risk.

[0003] Therefore, there is an urgent need to provide a battery pack and a method for manufacturing a battery pack so as to solve the above-mentioned technical problems in the prior art. Summary of the invention

[0004] The object of the present invention is to provide a battery pack that can cool multi-layer battery cells, improve the cooling effect of battery cell modules in the middle part of the multi-layer battery cells, and improve the reliability and service life of the multi-layer battery cells.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The battery pack specifically includes a cooling plate assembly and a plurality of battery cell modules stacked from top to bottom, wherein the cooling plate assembly is arranged between two adjacent battery cell modules, wherein: the cooling plate assembly includes a first cooling plate and a second cooling plate, the first cooling plate supports the bottom of the battery cell module located above the two adjacent battery cell modules, and the second cooling plate covers the top of the battery cell module located below the two adjacent battery cell modules; the mechanical strength of the first cooling plate is greater than that of the second cooling plate.

[0007] Optionally, the battery pack further includes a connecting pipeline, which includes a water inlet pipeline and a water outlet pipeline. The first cooling plate and the second cooling plate both include a water inlet and a water outlet connected to their interiors. The water inlet pipeline is connected to the water inlet, and the water outlet pipeline is connected to the water outlet pipe.

[0008] Optionally, the water inlet pipeline and the water outlet pipeline both include a connecting main pipe and a plurality of connecting branch pipes, the connecting branch pipes are arranged between the first cooling plate below any of the battery cell modules and the second cooling plate above the battery cell module, the connecting main pipe is connected to a plurality of the connecting branch pipes, and the connecting main pipe is provided with a water inlet main port or a water outlet main port.

[0009] Optionally, the middle parts of several of the above-mentioned connecting branch pipes are connected in parallel to the same above-mentioned connecting main pipe.

[0010] Optionally, the water inlet and the water outlet are both provided with water nozzle joints, the connecting branch pipe is fixedly connected to the water nozzle joints, and in any adjacent first cooling plate and second cooling plate, the water nozzle joint of the first cooling plate and the water nozzle joint of the second cooling plate are arranged relative to each other.

[0011] Optionally, the first cooling plate and the second cooling plate both include a protrusion, the protrusion extends out of the first cooling plate or the second cooling plate along the second direction, and the water inlet and the water outlet are arranged on the protrusion.

[0012] Optionally, a buffer gasket is sandwiched between the stacked first cooling plate and the second cooling plate.

[0013] Optionally, a ratio of the total thickness of the buffer gasket to the first cooling plate, or a ratio of the total thickness of the buffer gasket to the second cooling plate is 0.05 to 0.5.

[0014] Optionally, along the vertical direction, the first cooling plate located at the bottom includes a mounting structure, and the mounting structure and the first cooling plate located at the bottom are in the same plane.

[0015] Optionally, the mounting structure includes a pressed edge at the edge of the bottom first cooling plate, so that the coverage area of ​​the bottom first cooling plate is larger than the coverage area of ​​other first cooling plates or the coverage area of ​​the second cooling plates.

[0016] Optionally, the thickness of the first cooling plate is greater than the thickness of the second cooling plate.

[0017] Optionally, the ratio of the thickness of the first cooling plate to the thickness of the second cooling plate is not greater than 5 / 2.

[0018] Optionally, the first cooling plate comprises an extruded plate, and the second cooling plate comprises a stamped plate.

[0019] Optionally, there are at least three cooling plate assemblies, and along the vertical direction, the top cooling plate assembly includes the second cooling plate, and the bottom cooling plate assembly includes the first cooling plate; the cooling plate assembly between the top cooling plate assembly and the bottom cooling plate assembly includes the first cooling plate and the second cooling plate stacked from top to bottom.

[0020] Another object of the present invention is to provide a method for manufacturing a battery pack, which is used to manufacture a battery pack as described in any of the above solutions, comprising the steps of:

[0021] S1. Prepare cooling plates: produce the required first cooling plates and second cooling plates; S2. Assemble to form cooling plate components: place one of the first cooling plates at the bottom to form the cooling plate component at the bottom; place one of the second cooling plates at the top to form the cooling plate component at the top; stack one of the first cooling plates and one of the second cooling plates from top to bottom to form a middle cooling plate component; S3. Assemble to form: space a number of middle cooling plate components between the cooling plate component at the top and the cooling plate component at the bottom, with a preset distance between two adjacent cooling plate components, and sandwich the battery cell module between two adjacent cooling plate components.

[0022] Beneficial effects:

[0023] The battery pack in the present invention is formed by stacking a number of battery cell modules up and down, and a cooling plate assembly is arranged between two adjacent battery cell modules, wherein the mechanical strength of the first cooling plate in the cooling plate assembly is greater than the mechanical strength of the second cooling plate, and the first cooling plate support is arranged below the battery cell module, and plays a supporting role while cooling the battery cell module, thereby improving the mechanical strength of the battery pack, and the second cooling plate cover is arranged above the battery cell module, and only plays a cooling role, thereby improving the heat dissipation capacity of the battery pack. The battery pack realizes good cooling of the multi-layer battery cell modules, and the cooling effect is better, and can realize the function of improving the carrying capacity and mechanical strength of the battery pack at a low cost, and the cooling and heat dissipation effect will not be affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is an axonometric diagram of a battery pack provided in a specific embodiment of the present invention;

[0025] Figure 2 is a side view of a liquid cooling system provided by a specific embodiment of the present invention;

[0026] Figure 3 is an axonometric diagram of a liquid cooling system provided in a specific embodiment of the present invention;

[0027] Figure 4 yes Figure 3 A partial enlarged view of the middle A;

[0028] Figure 5 It is a schematic diagram of the liquid cooling channel of the second cooling plate or the first cooling plate provided in a specific embodiment of the present invention.

[0029] In the figure:

[0030] 10. Battery cell module; 11. Battery box; 12. Partition;

[0031] 100, connecting pipeline; 101, water inlet; 102, water outlet; 103, connecting main pipe; 104, connecting branch pipe; 110, water inlet pipeline; 120, water outlet pipeline;

[0032] 200, cooling plate assembly; 201, water inlet; 202, water outlet; 203, raised portion; 204, faucet joint; 205, liquid cooling channel; 210, first cooling plate; 212, mounting structure; 220, second cooling plate. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0036] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0037] The first direction described in this embodiment is Figure 2 and Figure 3 The X direction is the vertical height direction and the stacking direction of the battery module 10; the second direction is Figure 2 and Figure 3 The Y direction in the figure is the horizontal direction and the length direction of the cooling plate assembly 200.

[0038] like Figure 1 As shown, in this embodiment, a battery pack is first provided, which specifically includes a battery case 11 and a liquid cooling system. The liquid cooling system is composed of a plurality of cooling plate assemblies 200. An accommodating space for accommodating a battery cell module 10 is formed between two adjacent cooling plate assemblies 200 of the liquid cooling system. The connecting pipe 100 is used to connect the cooling plate assemblies 200. At the same time, a partition 12 is used to divide the battery case 11 into two spaces, and the cooling plate assemblies 200 and the connecting pipe 100 are placed in the above two spaces. The cooling plate assembly 200 is fixed to the battery case 11 by riveting or welding. The battery pack uses the liquid cooling system in this embodiment, which can realize the cooling of the multi-layer battery cell module 10, improve the cooling effect of the battery cell module 10 in the middle part of the multi-layer battery cell module 10, and improve the reliability and service life of the multi-layer battery cell module 10.

[0039] Specifically, the battery cell module 10 is formed by stacking a plurality of battery cell units in a horizontal direction.

[0040] like Figures 2 to 4 As shown, specifically, the cooling plate assembly 200 includes a first cooling plate 210 and a second cooling plate 220, the first cooling plate 210 supports the bottom of the battery cell module 10 located above the two adjacent battery cell modules 10, and the second cooling plate 220 covers the top of the battery cell module 10 located below the two adjacent battery cell modules 10; the mechanical strength of the first cooling plate 210 is greater than the mechanical strength of the second cooling plate 220.

[0041] The battery pack in this embodiment is formed by stacking a number of battery cell modules 10 up and down, and a cooling plate assembly 200 is arranged between two adjacent battery cell modules 10, wherein the mechanical strength of the first cooling plate 210 in the cooling plate assembly 200 is greater than the mechanical strength of the second cooling plate 220, and the first cooling plate 210 is supported and arranged below the battery cell module 10, and plays a supporting role while cooling the battery cell module 10, thereby improving the mechanical strength of the battery pack, and the second cooling plate 220 is covered on the top of the battery cell module 10, and only plays a cooling role, thereby improving the heat dissipation capacity of the battery pack. The battery pack realizes good cooling of the multi-layer battery cell module 10, and the cooling effect is better, and the function of improving the carrying capacity and mechanical strength of the battery pack can be realized at a low cost, and the cooling and heat dissipation effect will not be affected.

[0042] It should be noted that the above-mentioned liquid cooling system specifically includes a connecting pipeline 100 and at least three cooling plate assemblies 200, wherein: along the above-mentioned first direction, the topmost cooling plate assembly 200 only includes the second cooling plate 220; along the above-mentioned first direction, the bottommost cooling plate assembly 200 includes the first cooling plate 210; the above-mentioned cooling plate assembly 200 between the topmost cooling plate assembly 200 and the bottommost cooling plate assembly 200 includes the above-mentioned second cooling plate 220 and the above-mentioned first cooling plate 210 stacked from top to bottom. In this embodiment, the liquid cooling system of the battery pack includes at least three cooling plate assemblies 200, and a receiving space for receiving the battery cell module 10 is formed between two adjacent cooling plate assemblies 200, that is, the liquid cooling system is used for liquid cooling and heat dissipation of a battery pack having at least two layers of battery cell modules 10, and a cooling plate assembly 200 is provided at both ends of each layer of battery cell modules 10 for heat dissipation of the battery cell modules 10, and the heat dissipation effect is better. The cooling plate assembly 200 is composed of a first cooling plate 210 and / or a second cooling plate 220. The top cooling plate assembly 200 is the second cooling plate 220, which is of low cost and is only used to cool the battery module 10. The bottom cooling plate assembly 200 is the first cooling plate 210, which is of high cost but has good mechanical properties and strong pressure bearing capacity. The remaining liquid cooling assembly in the middle is composed of the upper first cooling plate 210 and the lower second cooling plate 220 stacked together. The first cooling plate 210 is used to carry the battery module 10, and the second cooling plate 220 is used to cool the lower battery module 10. As a result, the liquid cooling system can achieve good cooling of the multi-layer battery module 10, and the cooling effect is better, and the function of improving the bearing capacity of the cooling system can be achieved at a low cost, and the cooling and heat dissipation effect will not be affected.

[0043] Specifically, the first cooling plate 210 includes an extruded plate, and the second cooling plate 220 includes a stamped plate. Specifically, the first cooling plate 210 in this embodiment is extruded from an aluminum profile labeled AL6061. This aluminum profile has higher mechanical strength, but higher cost, and a thickness of 6mm to 10mm, wherein the cavity height is 4mm, and 2mm aluminum plates are reserved above and below without cavity to provide support strength, to avoid the battery cell module 10 from pressing the first cooling plate 210, causing the surface of the first cooling plate 210 to be concave, and to improve the flatness of the first cooling plate 210; the second cooling plate 220 in this embodiment is stamped from an aluminum profile labeled AL3003mod. This aluminum profile has a lower cost, and the second cooling plate 220 does not need to bear weight, so the mechanical strength is lower, and the thickness of the second cooling plate 220 ranges from 4mm to 6mm.

[0044] In this embodiment, the wall thickness of the first cooling plate 210 is greater than that of the second cooling plate 220. On the one hand, this is due to the limitations of the extrusion and stamping processes. On the other hand, the larger wall thickness of the first cooling plate 210 can provide better supporting strength.

[0045] Specifically, the ratio of the thickness of the first cooling plate 210 to the thickness of the second cooling plate 220 is not greater than 5 / 2, which can ensure the cooling effect of the second cooling plate 220. If the second cooling plate 220 is too thin, there will not be enough internal space to open the flow channel. Specifically, in this embodiment, the thickness of the first cooling plate 210 is 8 mm, the thickness of the second cooling plate 220 is 6 mm, and the ratio of the thickness of the first cooling plate 210 to the second cooling plate 220 is 4 / 3, which will not be repeated here.

[0046] Optionally, the first cooling plate 210 and the second cooling plate 220 each include a water inlet 201 and a water outlet 202 connected thereto, the connecting pipeline 100 is connected to the water inlet 201 and the water outlet 202, the connecting pipeline 100 includes a water inlet pipeline 110 and a water outlet pipeline 120, the water inlet pipeline 110 is connected to the water inlet 201, and the water outlet pipeline 120 is connected to the water outlet pipe. The water inlet pipeline 110 is used for water inlet of the cooling plate assembly 200, and the water outlet pipeline 120 is used for water outlet of the cooling plate assembly 200, so as to realize the circulation of the coolant in the cooling plate assembly 200, and achieve a better heat dissipation and cooling effect.

[0047] It should be noted that, along the first direction, the first cooling plate 210 at the bottom includes a mounting structure 212, and the mounting structure 212 is in the same plane as the first cooling plate 210 at the bottom. The mounting structure 212 is specifically a pressed edge of the edge of the first cooling plate 210 at the bottom, so that the coverage area of ​​the first cooling plate 210 is larger than the coverage area of ​​other first cooling plates 210 or the coverage area of ​​the second cooling plate 220, so as to realize the installation of the first cooling plate 210 at the bottom and the battery box 11.

[0048] like Figure 3 and Figure 4 As shown, the water inlet pipeline 110 and the water outlet pipeline 120 both include a connecting main pipe 103 and a plurality of connecting branches 104. The connecting branch pipes 104 are arranged between any adjacent first cooling plate 210 and second cooling plate 220. The connecting main pipe 103 is connected to a plurality of connecting branches 104. The connecting main pipe 103 is provided with a water inlet main port 101 or a water outlet main port 102. The connecting branch pipes 104 are used to connect the water outlets 202 or water inlets 201 of the adjacent second cooling plate 220 and the first cooling plate 210, and then the connecting main pipe 103 is used to connect the connecting branches 104, so that the second cooling plate 220 and the first cooling plate 210 can be connected in parallel, and the flow of each second cooling plate 220 and each first cooling plate 210 is more uniform, which improves the heat dissipation and cooling capacity, and ensures that the heat dissipation capacity of each second cooling plate 220 or each first cooling plate 210 is the same, thereby ensuring the uniformity of heat dissipation.

[0049] Specifically, the middle parts of several of the above-mentioned connecting branch pipes 104 are connected in parallel to the same connecting main pipe 103, and a pipeline is led out from the middle part of the connecting branch pipe 104 and connected to the connecting main pipe 103. While realizing the parallel connection of several connecting branch pipes 104, the cooling medium in a single connecting branch pipe 104 is evenly diverted in the upper and lower directions, ensuring that the cooling effects of the first cooling plate 210 and the second cooling plate 220 are consistent, thereby improving the cooling performance of the LeCalcium battery pack.

[0050] Optionally, the water inlet 201 and the water outlet 202 are both provided with a water nozzle joint 204, and the connecting branch pipe 104 is fixedly connected to the water nozzle joint 204. The water nozzle joint 204 is made by machining, which is low in cost and can reduce the use of quick-insert joints, reducing the space occupied by the joints, which is conducive to improving the energy density of the battery pack.

[0051] Furthermore, in any adjacent first cooling plate 210 and second cooling plate 220, the water nozzle joint 204 of the first cooling plate 210 is arranged opposite to the water nozzle joint 204 of the second cooling plate 220. Through such an arrangement, the length of the connecting branch pipe 104 is reduced, the manufacturing cost of the connecting pipe 100 can be reduced, and the volume of the liquid cooling system of the battery pack is reduced.

[0052] like Figure 4 and Figure 5 As shown, in this embodiment, the first cooling plate 210 and the second cooling plate 220 both include a protrusion 203, the protrusion 203 extends out of the first cooling plate 210 or the second cooling plate 220 along the second direction, and the water inlet 201 and the water outlet 202 are arranged on the protrusion 203. The protrusion 203 is arranged so that the water inlet 201 and the water outlet 202 protrude outward from the main body of the first cooling plate 210 and the second cooling plate 220, so that the main body is accommodated in one space of the battery box 11, and the water inlet 201 and the water outlet 202 are in another space, so as to realize the separation of the connecting pipeline 100 and the cooling plate assembly 200, and improve the safety and reliability of use.

[0053] Specifically, if Figure 3 As shown, the raised portion 203 where the water inlet 201 is located and the raised portion 203 where the water outlet 202 is located can be divided into two raised portions 203; Figure 5 As shown, the raised portion 203 where the water inlet 201 is located and the raised portion 203 where the water outlet 202 is located can be integrally formed into one raised portion 203 , which is not limited in this embodiment.

[0054] Furthermore, a buffer gasket is sandwiched between the stacked first cooling plate 210 and the second cooling plate 220. The buffer gasket is used for buffering between the stacked first cooling plate 210 and the second cooling plate 220 to prevent the lower second cooling plate 220 from being squeezed and deformed, thereby improving the reliability and service life of the cooling system of the battery pack.

[0055] It should be noted that the ratio of the total thickness of the above-mentioned buffer gasket to the above-mentioned first cooling plate 210, or the ratio of the total thickness of the above-mentioned buffer gasket to the above-mentioned second cooling plate 220 is 0.05 to 0.5. A gap of preset thickness is left between the first cooling plate 210 and the second cooling plate 220 for installing the above-mentioned buffer gasket. The thickness range of the buffer gasket is 2mm to 3mm, and the material of the buffer gasket is specifically foam. If the buffer gasket is too thin, effective buffering between the upper and lower battery modules 10 cannot be achieved; if the buffer gasket is too thick, it will occupy the installation space of the first cooling plate 210 and the second cooling plate 220, affecting the cooling effect. In this embodiment, the thickness of the first cooling plate 210 in this embodiment is 8mm, the thickness of the second cooling plate 220 is 6mm, the thickness of the buffer gasket is 2mm, the ratio of the total thickness of the above-mentioned buffer gasket to the above-mentioned first cooling plate 210 is 0.25, and the ratio of the total thickness of the above-mentioned buffer gasket to the above-mentioned second cooling plate 220 is 0.33.

[0056] like Figure 5 As shown, Figure 5 A schematic diagram of a liquid cooling channel 205 of the first cooling plate 210 and the second cooling plate 220 in this embodiment is provided. The inner diameter of the connecting pipe 100 connected to the liquid cooling channel 205 is 14 mm, the height of the liquid cooling channel 205 is 4 mm, and the height of the first cooling plate 210 is 8 mm. The liquid cooling channel 205 includes a plurality of spiral inner channels to increase the heat exchange area between the liquid cooling channel 205 and the battery cell module 10 and improve the cooling capacity, which will not be described in detail here.

[0057] A battery pack manufacturing method is also provided in this embodiment. The battery pack manufacturing method is used to manufacture a battery pack as described in any of the above schemes, including the following steps: S1, preparing cooling plates: producing the required first cooling plates 210 and the second cooling plates 220; S2, assembling to form a cooling plate assembly 200: placing one of the first cooling plates 210 at the bottom to form the bottom cooling plate assembly 200; placing one of the second cooling plates 220 at the top to form the top cooling plate assembly 200; stacking one of the first cooling plates 210 and one of the second cooling plates 220 from top to bottom to form a middle cooling plate assembly 200; S3, assembling and forming: spacing a plurality of middle cooling plate assemblies 200 between the top cooling plate assembly 200 and the bottom cooling plate assembly 200, with a preset distance between two adjacent cooling plate assemblies 200, and sandwiching the battery cell module 10 between two adjacent cooling plate assemblies 200.

[0058] The battery pack manufactured by the battery pack manufacturing method can use the first cooling plate 210 to support the battery cell module 10, and use the second cooling plate 220 to cool the lower battery cell module 10. Therefore, the liquid cooling system of the battery pack can achieve good cooling of the multi-layer battery cell module 10, and the cooling effect is better, and the function of improving the carrying capacity and mechanical strength of the battery pack can be achieved at a low cost, and the cooling and heat dissipation effect will not be affected.

[0059] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A battery pack, characterized in that: It comprises a cooling plate assembly (200) and a plurality of battery cell modules (10) stacked from top to bottom, wherein the cooling plate assembly (200) is arranged between two adjacent battery cell modules (10), wherein: The cooling plate assembly (200) comprises a first cooling plate (210) and a second cooling plate (220), wherein the first cooling plate (210) supports the bottom of the battery cell module (10) located at the upper side of the two adjacent battery cell modules (10), and the second cooling plate (220) is arranged to cover the top of the battery cell module (10) located at the lower side of the two adjacent battery cell modules (10); The mechanical strength of the first cooling plate (210) is greater than the mechanical strength of the second cooling plate (220).

2. The battery pack according to claim 1, characterized in that: The battery pack further comprises a connecting pipeline (100), wherein the connecting pipeline (100) comprises a water inlet pipeline (110) and a water outlet pipeline (120), wherein the first cooling plate (210) and the second cooling plate (220) both comprise a water inlet (201) and a water outlet (202) which are arranged in communication with the interior thereof, wherein the water inlet pipeline (110) is connected to the water inlet (201), and the water outlet pipeline (120) is connected to the water outlet pipe.

3. The battery pack according to claim 2, characterized in that: The water inlet pipeline (110) and the water outlet pipeline (120) both comprise a connecting main pipe (103) and a plurality of connecting branch pipes (104); the connecting branch pipes (104) are arranged between the first cooling plate (210) below any one of the battery cell modules (10) and the second cooling plate (220) above the battery cell module (10); the connecting main pipe (103) is connected to the plurality of connecting branch pipes (104); and the connecting main pipe (103) is provided with a water inlet main port (101) or a water outlet main port (102).

4. The battery pack according to claim 3, characterized in that: The middle parts of a plurality of the connecting branch pipes (104) are connected in parallel to the same connecting main pipe (103).

5. The battery pack according to claim 3, characterized in that: The water inlet (201) and the water outlet (202) are both provided with a water nozzle joint (204), the connecting branch pipe (104) is fixedly connected to the water nozzle joint (204), and in any adjacent first cooling plate (210) and second cooling plate (220), the water nozzle joint (204) of the first cooling plate (210) and the water nozzle joint (204) of the second cooling plate (220) are arranged opposite to each other.

6. The battery pack according to claim 3, characterized in that: The first cooling plate (210) and the second cooling plate (220) both comprise a protrusion (203), wherein the protrusion (203) extends out of the first cooling plate (210) or the second cooling plate (220) along a second direction, and the water inlet (201) and the water outlet (202) are arranged on the protrusion (203).

7. The battery pack according to any one of claims 1 to 6, characterized in that: A buffer gasket is sandwiched between the first cooling plate (210) and the second cooling plate (220) which are stacked.

8. The battery pack according to claim 7, characterized in that: A ratio of the total thickness of the buffer gasket to the first cooling plate (210), or a ratio of the total thickness of the buffer gasket to the second cooling plate (220) is 0.05 to 0.

5.

9. The battery pack according to any one of claims 1 to 6, characterized in that: In the vertical direction, the first cooling plate (210) located at the bottom comprises a mounting structure (212), and the mounting structure (212) and the first cooling plate (210) located at the bottom are in the same plane.

10. The battery pack according to claim 9, characterized in that: The mounting structure (212) includes a pressed edge at the edge of the bottom first cooling plate (210) so that the coverage area of ​​the bottom first cooling plate (210) is larger than the coverage area of ​​other first cooling plates (210) or the coverage area of ​​the second cooling plate (220).

11. The battery pack according to any one of claims 1 to 6, characterized in that: The wall thickness of the first cooling plate (210) is greater than the wall thickness of the second cooling plate (220).

12. The battery pack according to claim 11, characterized in that: The ratio of the thickness of the first cooling plate (210) to the thickness of the second cooling plate (220) is no greater than 5 / 2.

13. The battery pack according to any one of claims 1 to 6, characterized in that: The first cooling plate (210) comprises an extruded plate, and the second cooling plate (220) comprises a stamped plate.

14. The battery pack according to any one of claims 1 to 6, characterized in that: The cooling plate assemblies (200) are provided with at least three, and along the vertical direction, the top cooling plate assembly (200) includes the second cooling plate (220), and the bottom cooling plate assembly (200) includes the first cooling plate (210); the cooling plate assembly (200) between the top cooling plate assembly (200) and the bottom cooling plate assembly (200) includes the first cooling plate (220) and the second cooling plate (210) stacked from top to bottom.

15. A method for manufacturing a battery pack, characterized in that: For making a battery pack as claimed in any one of claims 1 to 14, comprising the steps of: S1. Preparing cooling plates: producing the first cooling plate (210) and the second cooling plate (220) required; S2. Assembling to form a cooling plate assembly (200): placing one of the first cooling plates (210) at the bottom to form the cooling plate assembly (200) at the bottom; placing one of the second cooling plates (220) at the top to form the cooling plate assembly (200) at the top; stacking one of the first cooling plates (210) and one of the second cooling plates (220) from top to bottom to form a cooling plate assembly (200) in the middle; S3. Assembly and molding: a plurality of the middle cooling plate assemblies (200) are spaced between the top cooling plate assembly (200) and the bottom cooling plate assembly (200), a preset distance is provided between two adjacent cooling plate assemblies (200), and the battery cell module (10) is clamped between two adjacent cooling plate assemblies (200).

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