Liquid cooling assembly and power battery

Abstract

The invention belongs to the technical field of power batteries, and discloses a liquid cooling assembly and a power battery. The liquid cooling assembly is arranged between two adjacent rows of battery monomers so as to cool the battery monomers, the liquid cooling assembly comprises a cold plate, the cold plate comprises a plurality of heat exchange sections and communication sections, the heat exchange sections are used for being in heat conduction connection with the narrow surfaces of the battery monomers, the communication sections are connected between two adjacent heat exchange sections in a nested manner, and the communication sections are used for being in heat conduction connection with the narrow surfaces of the battery monomers. And each communicating section is used for communicating two adjacent heat exchange sections and can slide relative to the two adjacent heat exchange sections in the length direction of the cold plate. The cold plate is formed by splicing a heat exchange section and a communicating section, and the heat exchange section and the communicating section are arranged in a nested mode and can slide relative to each other. When the battery monomers are expanded, the heat exchange sections connected with the battery monomers can slide relative to the communication sections in a self-adaptive manner along with the expansion of the battery monomers, so that the overall length of the cold plate is adjusted, and the condition that the heat exchange sections and the battery monomers are adhered and cracked is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power batteries, and particularly relates to a liquid cooling assembly and a power battery. BACKGROUND

[0002] With the rapid expansion and development of the new energy market, the market share of new energy vehicles gradually increases, and the choice of consumers is increasingly inclined to new energy vehicles. As such, people pay more and more attention to and have higher requirements for the core components of new energy vehicles, i.e., power batteries. Not only should the power batteries provide good power performance, but also should the power batteries have extremely superior stability, so as to guarantee the personal safety of passengers even in the event of an emergency.

[0003] The liquid cooling scheme is a common battery cooling scheme. When the battery cells enter the tray, especially for the battery pack scheme without modules, due to the existence of the battery cell size tolerance, the battery cell stacking tolerance, the tray size tolerance, and the battery cell entering the tray process limitation, a certain gap is reserved between the battery cells, and the side surface of the outer battery cell is pasted with a cold plate to play the roles of protecting the battery cell, enhancing the module strength, and conducting heat exchange.

[0004] When the battery cells swell during charging, discharging and life attenuation, the side cold plate cannot limit the swelling of the battery cells, and there is a problem of adhesive separation between the battery cells and the cold plate, which affects heat exchange and overall structural strength. After experiencing long-term harsh working conditions, once the adhesive fails, the battery cells lack constraints, the internal structure of the battery pack may be damaged, and there is a safety risk. SUMMARY

[0005] The present application aims to provide a liquid cooling assembly and a power battery, which can reserve an expansion force release space, thereby reducing the risk of adhesive separation between the cold plate and the battery cell.

[0006] To achieve this purpose, in a first aspect, the present application adopts the following technical scheme:

[0007] A liquid cooling assembly is arranged between two adjacent rows of battery monomers to cool the battery monomers. The liquid cooling assembly comprises a cold plate, the cold plate comprises a plurality of heat exchange segments and a communication segment, the heat exchange segment is used for heat conduction connection with the narrow surface of the battery monomer, the communication segment is nested and connected between two adjacent heat exchange segments, the communication segment is used for communication between two adjacent heat exchange segments and can slide relative to two adjacent heat exchange segments in the length direction of the cold plate.

[0008] As an optional scheme of the above-mentioned liquid cooling assembly, a sealing element is arranged between the communication segment and each adjacent heat exchange segment. A sealing groove is arranged on the inner wall of the communication segment and the heat exchange segment or the outer wall of the communication segment and the heat exchange segment. The sealing element is embedded in the sealing groove to slide and seal the heat exchange segment and the communication segment.

[0009] As an optional solution of the liquid cooling assembly, the communication section is provided with a limiting part protruding towards the battery monomer, and the limiting part is used for limiting connection with two adjacent battery monomers.

[0010] As an optional solution of the liquid cooling assembly, the communication section is provided with a thinning area at one end along the height direction of the cold plate, and the thinning area can be broken when the battery monomer is in thermal runaway;

[0011] And / or, the communication section is made of hot melt material.

[0012] In a second aspect, the present application adopts the following technical solutions:

[0013] A power battery comprises:

[0014] A battery box;

[0015] Battery monomers arranged in multiple rows in the battery box; and

[0016] The liquid cooling assembly of the first aspect, wherein the cold plate is located between two adjacent rows of the battery monomers;

[0017] The heat exchange section is fixedly connected with the narrow surface of the battery monomer, the communication section corresponds to the middle position of two adjacent battery monomers, and the communication section can adjust the nesting area of the communication section and the heat exchange section when the distance between the two adjacent battery monomers changes.

[0018] As an optional solution of the power battery, the size L5 of the communication section along the length direction of the cold plate, the maximum size difference L2 of the battery monomer along the length direction of the cold plate before and after expansion, and the size L of the nesting area of the communication section and the heat exchange section along the length direction of the cold plate satisfy: 51 L2 < L 51 ≤ L5 / 2.

[0019] As an optional solution of the power battery, a heat-conducting adhesive layer is arranged between the heat exchange section and the battery monomer, and the heat-conducting adhesive layer is used for bonding and fixing the battery monomer and the heat exchange section.

[0020] The size L1 of the battery monomer along the length direction of the cold plate, and the size L6 of the heat-conducting adhesive layer along the length direction of the cold plate satisfy: L6 < L1-L5.

[0021] As an optional solution of the power battery, the limiting part is protruded from one side of the communication section away from the two adjacent heat exchange sections, and the avoiding surface matched with the outer surface of the battery monomer is arranged on the limiting part, and the avoiding surface is used for limiting and fixing the two adjacent battery monomers.

[0022] As an optional solution of the power battery, the buffer layer is arranged between the two adjacent battery monomers in each row of the battery monomers.

[0023] The side of the limiting part away from the two adjacent heat exchange sections corresponds to and abuts against the buffer layer.

[0024] As an optional solution of the power battery, the battery box is provided with the oppositely arranged positioning grooves, and the two ends of the cold plate are respectively located in the positioning grooves.

[0025] The battery box comprises a cross beam, one positioning groove is arranged on the cross beam, and the other positioning groove is arranged on the frame of the battery box.

[0026] The beneficial effects of the present application are as follows:

[0027] In the liquid cooling assembly, the cold plate adopts the structure that the heat exchange section and the communication section are nested, when the battery monomer expands, the heat exchange section can slide along the length direction of the cold plate relative to the communication section under the action of the expansion force, so that the nesting area of the communication section and the heat exchange section is adjusted according to the distance change between the two adjacent battery monomers, so as to avoid the heat exchange section and the battery monomer from being separated, thereby ensuring the heat exchange and the overall strength.

[0028] The power battery provided by the present application adopts the above-mentioned liquid cooling assembly, which can reduce the risk of cracking failure of the battery monomer and the cold plate, has good fixing effect on the battery monomer, and can reduce the safety hidden danger. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a schematic diagram of part of the structure of the power battery provided by the embodiment one of the present application;

[0030] Figure 2 is a top view of Figure 1 ;

[0031] Figure 3 is a structure schematic diagram of the cold plate provided by the embodiment one of the present application;

[0032] Figure 4 is a top view of Figure 2 ;

[0033] Figure 5 is a sectional view of the cold plate provided by the embodiment one of the present application;

[0034] Figure 6 is a sectional view of a partial structure of the power battery provided by the embodiment one of the present application;

[0035] Figure 7 is a sectional view of the cold plate and the heat-conducting glue layer provided by the embodiment one of the present application;

[0036] Figure 8 is a structural schematic view of the power battery when assembling single-row battery monomers provided by the embodiment one of the present application;

[0037] Figure 9 is a structural schematic view of the power battery when assembling double-row battery monomers provided by the embodiment one of the present application;

[0038] Figure 10 is a sectional view of the B-B direction in the figure; Figure 2

[0039] Figure 11 is an enlarged view of the part C in the figure; Figure 10

[0040] Figure 12 is a partial enlarged view of the power battery provided by the embodiment two of the present application;

[0041] Figure 13 is a partial structural schematic view of the cold plate provided by the embodiment three of the present application.

[0042] in the figure:

[0043] 10, battery box; 11, cross beam; 111, positioning groove; 12, fixing frame; 20, battery monomer; 30, cold plate; 31, heat exchange section; 311, flow channel; 312, sealing groove; 32, communication section; 32a, first communication section; 32b, second communication section; 321, thinning area; 321a, first thinning area; 321b, second thinning area; 322, limiting part; 3221, avoiding surface; 33, sealing element; 34, end current collector; 35, inlet and outlet pipe; 40, bottom liquid cooling assembly; 50, buffer layer; 60, heat-conducting glue layer. DETAILED DESCRIPTION

[0044] The present application will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0045] ​​In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0047] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0048] Example 1

[0049] like Figure 1 and Figure 2 As shown, this embodiment provides a power battery, including a battery housing 10 and multiple battery cells 20 disposed within the battery housing 10. Each battery cell 20 is the smallest unit in the battery where an electrochemical reaction takes place. Each battery cell 20 can be a secondary battery or a primary battery. Each battery cell 20 can be a lithium-sulfur battery, a sodium-ion battery, a lithium-ion battery, or a magnesium-ion battery, but is not limited to these. Each battery cell 20 can be cylindrical, flat, cuboid, prism, or other shapes.

[0050] In this embodiment, multiple battery cells 20 are arranged in multiple rows. Specifically, the multiple rows of battery cells 20 are arranged along the Y direction, and the multiple battery cells 20 in each row are arranged along the X direction, so that the multiple battery cells 20 are arranged in a matrix. Here, the X direction is the thickness direction of the battery cell 20, the Y direction is the length direction of the battery cell 20, and the Z direction is the height direction of the battery cell 20. This arrangement can increase the number of battery cells 20 that the battery housing 10 can accommodate, thereby improving energy density. In this embodiment, the multiple battery cells 20 are arranged in three rows. In other embodiments, the battery cells 20 may also be arranged in two, four, five, or more rows; there is no limitation on this.

[0051] To control the temperature of the battery cell 20 during operation and prevent thermal runaway, the power battery also includes a liquid cooling component. The liquid cooling component is located between two adjacent rows of battery cells 20 and cools the battery cells 20 through heat exchange with the adjacent rows of battery cells 20.

[0052] To ensure good contact between the liquid cooling assembly and the battery cell 20, the liquid cooling assembly is typically connected to the battery cell 20 via bonding or other methods to guarantee effective contact and thus ensure the cooling effect of the liquid cooling assembly on the battery cell 20. However, because the battery cell 20 expands during operation, adjacent battery cells 20 in the same row may press against each other, while the liquid cooling assembly does not expand. This can cause positional misalignment between the liquid cooling assembly and the battery cell 20, affecting the connection between them and potentially leading to detachment of the liquid cooling assembly from the battery cell 20, thus impacting heat exchange and overall strength.

[0053] To solve the above problems, such as Figure 3 As shown, the liquid cooling assembly includes a cold plate 30, which includes multiple heat exchange sections 31 and connecting sections 32. The heat exchange sections 31 are used for narrow-face thermal conductive connection with the battery cell 20. A connecting section 32 is nested between two adjacent heat exchange sections 31. The connecting section 32 is used to connect two adjacent heat exchange sections 31 and can slide relative to the two adjacent heat exchange sections 31 in the length direction of the cold plate 30.

[0054] It should be noted here that the length direction of the cold plate 30 is the X direction, which is the arrangement direction of multiple battery cells 20 in each row; the narrow surface of the battery cell 20 refers to the surface enclosed by the side length in the thickness direction and the side length in the height direction of the battery cell 20, that is, the surface parallel to the XZ plane.

[0055] In this embodiment, the cold plate 30 adopts a structure in which heat exchange section 31 and connecting section 32 are alternately nested. When the battery cell 20 expands, the heat exchange section 31 can adaptively slide relative to the connecting section 32 along the length direction of the cold plate 30 under the action of the expansion force. Thus, according to the change in the distance between two adjacent battery cells 20, the nesting area between the connecting section 32 and the heat exchange section 31 is adjusted to avoid the heat exchange section 31 from separating from the battery cell 20, thereby ensuring heat exchange and overall strength.

[0056] For example, when multiple battery cells 20 are installed, the battery cells 20 are compressed, and the distance between two adjacent battery cells 20 decreases. Correspondingly, the nesting area between the heat exchange section 31 and the connecting section 32 increases to shorten the distance between two adjacent heat exchange sections 31. When the battery cells 20 expand, the distance between two adjacent battery cells 20 increases, and correspondingly, the nesting area between the heat exchange section 31 and the connecting section 32 decreases to increase the distance between two adjacent heat exchange sections 31. Thus, the sliding nesting design of the heat exchange section 31 and the connecting section 32 ensures that the cold plate 30 maintains an effective seal throughout the entire life cycle of the battery cell 20 (assembly compression → cyclic expansion → life-degradation expansion).

[0057] In this embodiment, each row of battery cells 20 is divided into two cell groups spaced apart along the X direction. Correspondingly, the connecting segment 32 includes a first connecting segment 32a and a second connecting segment 32b. The connecting segment 32 between the heat exchange segments 31 of two adjacent battery cells 20 in each cell group is the first connecting segment 32a, and the connecting segment between the two cell groups is the second connecting segment 32b. The length of the second connecting segment 32b along the X direction is greater than the length of the first connecting segment 32a along the X direction, so that the two cell groups are spaced apart.

[0058] In other embodiments, the lengths of the multiple connected segments 32 along the X direction may all be the same, and this is not a limitation.

[0059] Optionally, the heat exchange section 31 and the narrow face of the battery cell 20 can be fixed by bonding. Bonding typically uses thermally conductive structural adhesive or double-sided adhesive pads, which not only ensures good contact between the heat exchange section 31 and the battery cell 20 but also improves the overall structural strength. Meanwhile, the heat exchange section 31 has a porous, thin-walled structure, formed by aluminum extrusion, and possesses excellent thermal conductivity, further enhancing the heat exchange effect with the battery cell 20.

[0060] like Figure 4As shown, a thermally conductive adhesive layer 60 is provided between the heat exchange section 31 and the narrow face of the battery cell 20. On the one hand, the thermally conductive adhesive layer 60 bonds and fixes the heat exchange section 31 and the narrow face of the battery cell 20 to improve the fixing effect and structural strength; on the other hand, the thermally conductive adhesive layer 60 helps to improve the heat exchange effect between the narrow face of the battery cell 20 and the heat exchange section 31, and helps to improve the cooling effect of the battery cell 20.

[0061] In this embodiment, the thermally conductive adhesive layer 60 is a silicone layer, which can both bond and fix the narrow surface of the battery cell 20 to the heat exchange section 31, and reduce the thermal resistance between the heat exchange section 31 and the battery cell 20, thus ensuring the heat exchange effect.

[0062] In some other embodiments, the thermally conductive adhesive layer 60 may be replaced with other materials, as long as they are capable of conducting heat.

[0063] To ensure the effective flow area at all points of the cold plate 30, such as Figure 4 As shown, the two ends of the connecting section 32 are respectively fitted outside the two adjacent heat exchange sections 31. This can guide the relative sliding of the heat exchange section 31 and the connecting section 32, while preventing the connecting section 32 from occupying the space inside the heat exchange section 31, ensuring the effective flow area inside the heat exchange section 31, increasing the effective flow area inside the connecting section 32, and utilizing the space between two adjacent battery cells 20 to accommodate the connecting section 32. This is beneficial to improving space utilization and making the structure more compact.

[0064] In some other embodiments, the nested arrangement of the connecting segment 32 and the heat exchange segment 31 can also allow the heat exchange segment 31 to be fitted outside the connecting segment 32.

[0065] To prevent damage from mutual compression when the battery cells 20 expand, such as Figure 4 As shown, a buffer layer 50 is provided between two adjacent battery cells 20 in the same row. By providing a buffer layer 50 between two adjacent battery cells 20, the compressive force exerted on each other when the battery cells 20 expand can be buffered, avoiding damage to the battery cells 20 due to excessive force; the buffer layer 50 is elastic and can be squeezed and deformed when the battery cells 20 expand, so as to provide space for the expansion of the battery cells 20.

[0066] Optionally, the buffer layer 50 can be 0.5-5mm in length along the cold plate 30 to ensure a certain buffer thickness.

[0067] Optionally, the buffer layer 50 can be buffer foam, which can be compressed as the battery cell 20 expands, providing good buffering effect.

[0068] In other embodiments, the buffer layer 50 can also be other elastic structures, such as a silicone layer, as long as it can buffer the expansion of the battery cell 20 and can adaptively compress as the battery cell 20 expands.

[0069] To ensure a seal at the connection between the connecting section 32 and the heat exchange section 31, such as Figure 5 As shown, a sealing element 33 is provided between the connecting section 32 and each adjacent heat exchange section 31. The sealing element 33 is sleeved on the end of the heat exchange section 31, so that after the connecting section 32 and the heat exchange section 31 are assembled, the sealing element 33 is clamped between the inner wall of the connecting section 32 and the outer wall of the heat exchange section 31. The gap between the connecting section 32 and the heat exchange section 31 is sealed by the deformation of the sealing element 33, thus achieving a seal.

[0070] Optionally, the seal 33 may be made of a rubber material to improve the sealing effect. For example, the seal 33 may be made of EPDM rubber.

[0071] To improve the stability of the seal 33 position, such as Figure 5 As shown, a sealing groove 312 is provided on the outer wall of the end of the heat exchange section 31, and the sealing element 33 is embedded in the sealing groove 312 to fix the position of the sealing element 33, so that the sealing element 33 can slide to seal the heat exchange section 31 and the connecting section 32, thereby achieving sliding sealing and preventing the medium in the cold plate 30 from leaking.

[0072] In some other embodiments, the heat exchange section 31 and the connecting section 32 may not be sealed with a seal 33, but instead are sealed by cold pressing. Specifically, the heat exchange section 31 and the connecting section 32 may be cold-pressed together using a cedar-shaped connector and a plastic pipe. The plastic pipe may be made of materials such as nylon, PA, or PP. Preferably, the cedar-shaped connector may be a multi-layered pipe.

[0073] In this embodiment, the heat exchange section 31 and the connecting section 32 are flat rectangular tube sections. The opposite two surfaces of the connecting section 32 along the Y direction are both planes. This plane can abut against the buffer layer 50 between two adjacent battery cells 20, which can prevent the buffer layer 50 from being over-compressed, so as to avoid over-squeezing the battery cells 20.

[0074] like Figure 6 As shown, during the assembly process, the battery cell 20 is inserted into the battery box 10 by extrusion. During this process, both the battery cell 20 and the buffer layer 50 are compressed. The dimension L1 of the battery cell 20 along the length of the cold plate 30 decreases, and the distance L4 between two adjacent battery cells 20 in each row decreases accordingly. Correspondingly, the distance L3 between two adjacent heat exchange sections 31 decreases, that is, the nesting area between the heat exchange section 31 and the connecting section 32 increases.

[0075] To ensure smooth assembly, after the battery cell 20 is extruded into the casing, adjacent heat exchange sections 31 are spaced apart, meaning the distance L3 between adjacent heat exchange sections 31 is greater than zero, thus reducing assembly difficulty. Specifically, during the extrusion process, the deformation of the module can be increased, causing adjacent heat exchange sections 31 to abut against each other, reducing L3 to zero, thereby decreasing the module's dimensions along the length of the cold plate 30 and facilitating assembly. After the module is inserted into the casing, the deformation decreases accordingly, and the distance L3 between adjacent heat exchange sections 31 returns to the set value.

[0076] As the power battery is installed and used in cycles, the dimension L1 of the battery cell 20 along the length of the cold plate 30 will gradually increase as the lifespan of the battery cell 20 decreases; correspondingly, the distance L4 between two adjacent battery cells 20 in each row will increase. Since the heat exchange section 31 is fixedly connected to the narrow surface of the battery cell 20, the heat exchange section 31 will be displaced with the battery cell 20, which will increase the distance L3 between two adjacent heat exchange sections 31.

[0077] To ensure that the size of the nested area between the heat exchange section 31 and the connecting section 32 meets the requirements during the assembly and expansion of the battery cell 20, the maximum dimensional difference of the battery cell 20 along the length of the cold plate 30 before and after expansion is L2; Figure 6 As shown, the dimension of the connecting section 32 along the length of the cold plate 30 is L5. Then, the dimension L of the nested region of the connecting section 32 and the heat exchange section 31 along the length of the cold plate 30 is... 51 Satisfy: L2 < L 51 ≤L5 / 2. In this way, the cold plate 30 can still maintain the sealing overlap area under the maximum expansion L2 of the battery cell 20, avoiding sealing failure. At the same time, it can avoid structural interference during assembly. This dynamic balance design links the expansion of the battery cell 20 and the structure of the cold plate 30 to form an adaptive adjustment range, which adapts to the size changes of the battery cell 20 and improves the reliability of heat exchange.

[0078] It is understandable that when the nested area between heat exchange section 31 and connecting section 32 has a dimension of L5 / 2 along the length of cold plate 30, correspondingly, the nested area between connecting section 32 and two adjacent heat exchange sections 31 has a dimension of L5 along the length of cold plate 30. That is, the ends of two adjacent heat exchange sections 31 within connecting section 32 abut against each other, and the distance L3 between two adjacent heat exchange sections 31 is zero. By abutting against each other, the buffer layer 50 is prevented from being over-compressed, thereby preventing the battery cell 20 from being over-compressed.

[0079] In extreme cases, if the dimension of the nested area between heat exchange section 31 and connecting section 32 along the length of cold plate 30 is zero, the seal between heat exchange section 31 and connecting section 32 will fail. To avoid seal failure, the minimum dimension of the nested area between heat exchange section 31 and connecting section 32 along the length of cold plate 30 must be greater than the maximum dimensional difference L2 of battery cell 20 along the length of cold plate 30 before and after expansion. This ensures that a nested area still exists between heat exchange section 31 and connecting section 32 during the expansion of battery cell 20, thus guaranteeing a sealing effect.

[0080] It should be noted here that the maximum dimensional difference L2 of the battery cell 20 along the length of the cold plate 30 before and after expansion refers to the difference between the size of the battery cell 20 along the length of the cold plate 30 when the battery cell 20 expands to its maximum extent and the size of the battery cell 20 along the length of the cold plate 30 in its original state (i.e., before expansion).

[0081] To avoid interference from the thermally conductive adhesive layer 60 and the extrusion of the battery cells 20 into the casing, such as... Figure 6 As shown, the dimension L6 of the thermally conductive adhesive layer 60 along the length of the cold plate 30 satisfies: L6 < L1 - L5. It can be understood that during the assembly and operation of the power battery, the maximum dimension of the nested area between the heat exchange section 31 and the connecting section 32 along the length of the cold plate 30 is L5 / 2. Therefore, the maximum dimension of the area of ​​each heat exchange section 31 covered by the connecting section 32 along the length of the cold plate 30 is L5. By setting L6 < L1 - L5, it can be ensured that the thermally conductive adhesive layer 60 is always spaced apart from the connecting section 32 along the length of the cold plate 30, avoiding contact between the thermally conductive adhesive layer 60 and the connecting section 32 and interference with the relative sliding between the connecting section 32 and the heat exchange section 31.

[0082] To avoid interference from the thermally conductive adhesive layer 60 during the extrusion of the battery cells 20 into the casing, such as Figure 7 As shown, when the battery cell 20 is pressed into the box without expansion, the distance between two adjacent heat exchange sections 31 along the length of the cold plate 30 is defined as L3, and the distance between the thermally conductive adhesive layer 60 and the adjacent connecting section 32 along the length of the cold plate 30 is defined as L9, then L9>L3. This arrangement ensures that during pressurized box insertion, as the distance between the two heat exchange sections 31 decreases, the thermally conductive adhesive layer 60 is always spaced apart from the adjacent connecting section 32, so as to avoid affecting the box insertion process due to the thermally conductive adhesive layer 60.

[0083] like Figure 7As shown, the distance L7 between the seal 33 and one end face of its adjacent connecting section 32 along the length of the cold plate 30 is defined. When the battery cell 20 is pressed into the box and the battery cell 20 does not expand, L7 should satisfy: L7 > L2. By setting L7 to be greater than the maximum deformation of the battery cell 20 along the length of the cold plate 30 throughout its entire life cycle, it can be ensured that the seal 33 is always located within the connecting section 32, thereby avoiding seal failure.

[0084] It should be noted that the seal 33 needs to have a certain width along the length of the cold plate 30 to ensure that the width of the seal 33 can ensure that the liquid cooling assembly does not leak when subjected to a certain internal pressure (≥200kpa) after the cold plate 30 is supplied with cooling medium.

[0085] Combination Figure 3 and Figure 8 As shown, the cold plate 30 also includes an end collector 34 and an inlet / outlet pipe 35. The two outermost heat exchange sections 31 along the length of the cold plate 30 are respectively connected to the end collector 34. Each end collector 34 is connected to an inlet / outlet pipe 35. The inlet / outlet pipe 35 communicates with the interior of the heat exchange section 31 through the end collector 34. One inlet / outlet pipe 35 is used for the inflow of cooling medium, and the other inlet / outlet pipe 35 is used for the outflow of cooling medium. Through the cooperation of the two inlet / outlet pipes 35, the flow of cooling medium in the cold plate 30 is realized, so as to improve the cooling effect on the battery cell 20.

[0086] Optionally, the surface of the cold plate 30 is covered with an insulating layer to ensure the insulating fit between the battery cell 20 and the cold plate 30, thereby improving safety in use.

[0087] Optionally, the thickness of the insulating varnish is greater than 150 μm to improve the voltage resistance of the cold plate 30.

[0088] In this embodiment, the insulating layer can be an insulating varnish applied to the surface of the cold plate 30 by spraying. In other embodiments, the insulating layer can also be made of other methods or materials, and the thickness of the insulating layer can be set according to actual needs.

[0089] like Figure 8 As shown, the battery housing 10 is provided with two opposing positioning grooves 111. The two positioning grooves 111 are arranged along the length of the cold plate 30. The two ends of the cold plate 30 are respectively locked in the positioning grooves 111 to fix the cold plate 30 and ensure the positional accuracy and heat exchange effect of the cold plate 30 and the battery cell 20.

[0090] like Figure 9As shown, in this embodiment, the battery box 10 includes a base plate, a frame, and a crossbeam 11. The frame is annular, and the bottom end of the frame is connected to the base plate. The base plate closes the bottom opening of the frame. The crossbeam 11 is perpendicular to the length direction of the cold plate 30 and is disposed inside the frame. The two ends of the crossbeam 11 are respectively connected to the two side walls of the frame. One positioning groove 111 is opened on the crossbeam 11, and the other positioning groove 111 is disposed on the frame.

[0091] Optionally, a fixing bracket 12 is provided on the side wall of the frame opposite to the crossbeam 11, and another positioning groove 111 is provided on the fixing bracket 12. By providing the fixing bracket 12, it is not necessary to drill holes in the frame, which helps to improve the strength and sealing of the frame.

[0092] To improve the cooling effect of the cold plate 30 on the battery cell 20, such as Figure 10 and Figure 11 As shown, the heat exchange section 31 is provided with multiple flow channels 311 arranged along the height direction of the battery cell 20. The multiple flow channels 311 can divert the cooling medium in the heat exchange section 31, improve the uniformity of the cooling medium flow, and thus improve the uniformity of cooling of the battery cell 20 along the height direction.

[0093] Optionally, the power battery also includes a bottom liquid cooling component 40, which is disposed on the bottom plate of the battery housing 10 and is used to form multiple battery cells 20 to increase the heat exchange area of ​​the battery cells 20 and improve the cooling effect of the battery cells 20.

[0094] In this embodiment, both the cold plate 30 and the bottom liquid cooling assembly 40 are made of aluminum extruded profiles or brazed plates, generally AL6061 or AL3003mod, which have good heat exchange effect.

[0095] Example 2

[0096] This embodiment provides a power battery, which is a further improvement on the first embodiment.

[0097] like Figure 12 As shown, the connecting section 32 has a protrusion on the side away from the two adjacent heat exchange sections 31 to form a limiting part 322. The limiting part 322 is used to limit the connection with the two adjacent battery cells 20. On the one hand, it can avoid excessive compression between the two adjacent battery cells 20 in the same row, and on the other hand, it can prevent the position of the connecting section 32 from shifting, which would cause the seal between the heat exchange sections 31 to fail.

[0098] Specifically, the limiting part 322 extends between two adjacent battery cells 20 and abuts against the adjacent battery cells 20 to prevent the relative position of the limiting part 322 and the battery cells 20 from changing, which helps to ensure the sealing effect of the heat exchange section 31 and the connecting section 32.

[0099] In this embodiment, limiting portions 322 are provided on both sides of the connecting segment 32 so that the connecting segment 32 and the two rows of battery cells 20 on both sides are limited by the limiting portions 322 to ensure the limiting effect of the connecting segment 32.

[0100] It should be noted that the side of the connecting segment 32 that is away from the two adjacent heat exchange segments 31 refers to the side of the connecting segment 32 along the length direction of the cold plate 30. Specifically, in this embodiment, limiting portions 322 are provided on both sides of the connecting segment 32 along the Y direction.

[0101] To prevent the battery cell 20 from being squeezed and damaged due to contact with the limiting part 322, the limiting part 322 is provided with a clearance surface 3221 that is adapted to the outer surface of the battery cell 20. The clearance surface 3221 is used to limit and fix the adjacent battery cell 20.

[0102] In this embodiment, the edges of the battery cell 20 are chamfered, and the limiting part 322 is positioned to match the chamfer of the battery cell 20. Correspondingly, the clearance surface 3221 is an arc surface adapted to the chamfer. By making the clearance surface 3221 an arc surface, the sharp edges on the clearance surface 3221 can be reduced, the contact area between the limiting part 322 and the battery cell 20 can be increased, and damage to the battery cell 20 can be avoided when it comes into contact with the clearance surface 3221.

[0103] In other embodiments, the clearance surface 3221 can be of other shapes, as long as it can be adapted to the surface shape of the corresponding position of the battery cell 20.

[0104] Optionally, the side of the limiting part 322 facing away from the two adjacent heat exchange sections 31 abuts against the buffer layer 50 to prevent the buffer layer 50 from being over-compressed. The limiting part 322 and the buffer layer 50 cooperate to limit the movement. The limiting part 322 can abut against the narrow surface of the battery cell 20, thereby limiting the compression of the buffer layer 50 to prevent the buffer layer 50 / battery cell 20 from being over-compressed and deformed. At the same time, the rebound force of the buffer layer 50 can offset part of the expansion stress and reduce the fatigue load of the cold plate 30.

[0105] Example 3

[0106] This embodiment provides a power battery that is further improved based on Embodiment 1 or Embodiment 2.

[0107] like Figure 13As shown, a thinning zone 321 is provided on the connecting section 32, and the wall thickness at the thinning zone 321 is less than the wall thickness at other locations on the connecting section 32. When the battery cell 20 experiences thermal runaway, the battery cell 20 will spray high-temperature and high-pressure thermal runaway fluid to the outside. When the thermal runaway fluid impacts the thinning zone 321, it can cause the thinning zone 321 to break under the impact, thereby allowing the cooling medium in the cold plate 30 to flow out through the opening formed at the thinning zone 321 to directly contact the battery cell 20. This not only enables rapid cooling of the battery cell 20 but also enables directional spraying for fire extinguishing, effectively suppressing the spread of heat after thermal runaway.

[0108] Optionally, the thinning region 321 can be set at one end of the connecting section 32 along the height direction of the cold plate 30 to avoid the thinning region 321 being blocked by the battery cell 20, the thermally conductive adhesive layer 60 or the buffer layer 50, so that the thinning region 321 can be broken through in time after the battery cell 20 experiences thermal runaway, and the heat spread can be controlled in time.

[0109] It should be noted that the height direction of the cold plate 30 refers to the Z direction, the length direction of the cold plate 30 is the X direction, and the thickness direction of the cold plate 30 is the Y direction. The X, Y, and Z directions are perpendicular to each other.

[0110] Optionally, the wall thickness of the connecting section 32 can be 0.5mm-3mm to ensure structural strength and heat exchange effect.

[0111] To facilitate the fracture of the thinned region 321 under the action of thermal runaway airflow, the minimum wall thickness of the thinned region 321 is 0.15mm-1mm. Within this thickness range, the pressure resistance of the connecting section 32 can be guaranteed while reducing the force required when the thinned region 321 is broken, so as to ensure that the thinned region 321 can fracture under the action of thermal runaway airflow.

[0112] like Figure 13 As shown, the thinning region 321 can be a first thinning region 321a, which is U-shaped. The first thinning region 321a extends from one end face of the connecting section 32 along the height direction of the cold plate 30 to the sides of the connecting section 32 facing the battery cells 20 on both sides. When the first thinning region 321a is broken through, it can be sprayed out from multiple directions to fully spray the thermally runaway battery cells 20, thereby improving the control effect of heat spread.

[0113] Specifically, the first thinning region 321a is connected in sequence to three strip-shaped regions. These three strip-shaped regions are located on three adjacent surfaces of the connecting section 32 and are connected in a U-shape. For ease of explanation, the three strip-shaped regions are referred to as the first strip-shaped region and two second strip-shaped regions. The first strip-shaped region is located on one end face of the connecting section 32 along the height direction of the cold plate 30, and both ends of the first strip-shaped region extend to the edge of the end face. The two sides of the connecting section 32 facing the battery cell 20 are respectively provided with second strip-shaped regions, which extend along the height direction of the cold plate 30 and are connected to the first strip-shaped region.

[0114] To facilitate the fracture of the thinning zone 321 under the action of thermal runaway airflow, the width of each strip zone gradually decreases from the opening towards the bottom, so that the opening of the strip zone expands outward, making it easier for the thermal runaway fluid to enter the strip zone, so as to cause the strip zone to fracture.

[0115] Optionally, the width of the opening of the strip area is greater than 0.5 mm, preferably 0.5 mm to 5 mm, which is conducive to the thermal runaway airflow entering the strip area.

[0116] Optionally, the thinning region 321 can be a second thinning region 321b, which is located on one end face of the connecting section 32 along the height direction of the cold plate 30 to avoid being obstructed. Optionally, the shape of the second thinning region 321b can be circular, polygonal, elliptical, or irregular, and is not specifically limited here.

[0117] Optionally, a secondary thinning zone can be provided within the thinning zone 321, and the thickness of the secondary thinning zone is further reduced to improve the breaking efficiency of the thinning zone 321.

[0118] Optionally, the secondary thinning zone can be set to various shapes such as a straight line, a cross, or a wave; there are no restrictions here.

[0119] In some other embodiments, the connecting segment 32 can be made of a hot-melt material so that it can melt under the action of a high-temperature thermal runaway fluid, thus achieving the same spraying effect and preventing the cold plate 30 from bursting.

[0120] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A liquid cooling assembly disposed between two adjacent rows of battery cells (20) for cooling the battery cells (20), characterized in that, The liquid cooling assembly includes a cold plate (30), which includes multiple heat exchange sections (31) and connecting sections (32). The heat exchange sections (31) are used for narrow-face thermal connection with the battery cell (20). The connecting sections (32) are nested between two adjacent heat exchange sections (31). The connecting sections (32) are used to connect two adjacent heat exchange sections (31) and can slide relative to the two adjacent heat exchange sections (31) in the length direction of the cold plate (30).

2. The liquid cooling assembly according to claim 1, characterized in that, A sealing element (33) is provided between the connecting section (32) and each adjacent heat exchange section (31); a sealing groove (311) is provided on the outer wall of the connecting section (32) or the inner wall of the heat exchange section (31), and the sealing element (33) is embedded in the sealing groove (311) to slide and seal the heat exchange section (31) and the connecting section (32).

3. The liquid cooling assembly according to claim 1, characterized in that, The connecting segment (32) has a limiting part (322) protruding towards the battery cell (20), and the limiting part (322) is used to limit the connection with two adjacent battery cells (20).

4. The liquid cooling assembly according to claim 1, characterized in that, The connecting section (32) is provided with a thinning region (321) at one end along the height direction of the cold plate (30), the thinning region (321) being able to break in the event of thermal runaway of the battery cell (20); and / or, the connecting section (32) is made of a hot-melt material.

5. A power battery, characterized in that, include: Battery housing (10); Battery cells (20), the battery cells (20) being arranged in multiple rows within the battery housing (10); and, The liquid cooling assembly as described in any one of claims 1-4, wherein the cold plate (30) is located between two adjacent rows of battery cells (20); The heat exchange section (31) is fixedly connected to the narrow face of the battery cell (20). The connecting section (32) corresponds to the middle position of two adjacent battery cells (20). The connecting section (32) can adjust the nesting area of ​​the connecting section (32) and the heat exchange section (31) when the distance between two adjacent battery cells (20) changes.

6. The power battery according to claim 5, characterized in that, The dimension L5 of the connecting segment (32) along the length direction of the cold plate (30), the maximum dimensional difference L2 of the battery cell (20) before and after expansion along the length direction of the cold plate (30), and the dimension L of the nested area of ​​the connecting segment (32) and the heat exchange segment (31) along the length direction of the cold plate (30) 51 Satisfy: L2 < L 51 ≤L5 / 2.

7. The power battery according to claim 6, characterized in that, A thermally conductive adhesive layer (60) is provided between the heat exchange section (31) and the battery cell (20), and the thermally conductive adhesive layer (60) bonds and fixes the battery cell (20) and the heat exchange section (31); The dimension L1 of the battery cell (20) along the length of the cold plate (30) and the dimension L6 of the thermally conductive adhesive layer (60) along the length of the cold plate (30) satisfy: L6 < L1 - L5.

8. The power battery according to claim 6, characterized in that, The connecting section (32) protrudes to form a limiting part (322) on one side away from the two adjacent heat exchange sections (31). The limiting part (322) is provided with a clearance surface (3221) that is adapted to the outer surface of the battery cell (20). The clearance surface (3221) is used to limit and fix the two adjacent battery cells (20).

9. The power battery according to claim 8, characterized in that, In each row of battery cells (20), a buffer layer (50) is provided between two adjacent battery cells (20); The limiting part (322) is opposite to the two adjacent heat exchange sections (31) and abuts against the buffer layer (50).

10. The power battery according to claim 9, characterized in that, The battery box (10) is provided with oppositely arranged positioning grooves (111), and the two ends of the cold plate (30) are respectively located in the positioning grooves (111); The battery box (10) includes a crossbeam (11), one positioning groove (111) is formed on the crossbeam (11), and another positioning groove (111) is provided on the side frame of the battery box (10).

Images