Power battery and vehicle
The liquid-cooled battery system addresses thermal management challenges by directly contacting the battery components with a vaporizing coolant that condenses on a cold plate, enhancing performance and safety through efficient heat dissipation and existing cooling system integration.
Patent Information
- Application Number
- CN202510401558.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2025-07-15
AI Technical Summary
In the prior art, the cooling effect of the power battery is poor, especially during high-power fast charging and when the battery cell is thermally out of control, it is difficult to effectively dissipate heat, affecting battery performance and safety.
The liquid coolant is used to directly contact the elements in the shell for heat exchange, and heat is transferred to the outside through the cold plate. The coolant can be partially vaporized and condensed at the cold plate. The cooling flow rate is adjusted in combination with temperature and pressure sensors, and the existing automobile cooling system is used for cooling. The spacer design optimizes the cell gap to enhance the cooling effect.
It improves the heat dissipation performance of the power battery, especially when high-power fast charging and thermal runaway from the battery cell, can quickly take away heat, improve battery performance and safety, simplify the structure and reduce costs.
Smart Images
Figure CN120319932A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the cooling technology of power batteries and vehicles equipped with power batteries. Background Art
[0002] The power battery of an electric vehicle has a certain optimal operating temperature range. When the heat generation of the power battery is too large or the ambient temperature is too high, it is necessary to effectively cool the power battery. This application aims to study how to improve the cooling effect of the power battery.
[0003] The information provided in this part is for the purpose of generally presenting the background of this application, and thus may include information that does not constitute the prior art in this field. Summary of the Invention
[0004] The purpose of this application is to solve or at least alleviate one or more problems existing in the prior art.
[0005] One aspect of this application relates to a power battery, including:
[0006] Elements inside the shell, which are accommodated inside the shell of the power battery,
[0007] A cold plate, which is located above the elements inside the shell,
[0008] A coolant, which is accommodated inside the shell, and at least part of the coolant is in a liquid state to directly contact at least part of the outer surface of the elements inside the shell for heat exchange therewith.
[0009] In an embodiment of this application, optionally, the coolant absorbs heat to turn into a gaseous state and then is cooled to a liquid state by the cold plate.
[0010] In an embodiment of this application, optionally, the evaporation temperature of the coolant under standard atmospheric pressure is between 20°C and 45°C.
[0011] In an embodiment of this application, optionally, the cold plate has a cooling flow path for a heat exchange medium to flow through, so as to transfer the heat inside the shell.
[0012] In an embodiment of this application, optionally, a temperature sensor is provided inside the shell, and the flow rate of the heat exchange medium changes according to the parameters measured by the temperature sensor,
[0013] and / or, a pressure sensor is provided inside the shell, and the flow rate of the heat exchange medium changes according to the parameters measured by the pressure sensor.
[0014] In an embodiment of this application, optionally, the cold plate is the top part of the shell.
[0015] In an embodiment of the present application, optionally, the in-shell components include a plurality of battery cells, and a spacer is disposed between adjacent battery cells to form a gap between the adjacent battery cells.
[0016] In an embodiment of the present application, optionally, the spacer has a strip structure extending along the height direction of the battery cell.
[0017] In an embodiment of the present application, optionally, the coolant is a hydrofluoroolefin material.
[0018] In an embodiment of the present application, optionally, the filling amount of the coolant is as follows: when the coolant is all in a liquid state, the volume of the coolant is between 10% and 90% of the fillable volume, where the fillable volume is the total volume inside the housing of the power battery minus the volume of all solid components inside the housing.
[0019] Another aspect of the present application relates to a vehicle having the power battery according to any one of the foregoing. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Referring to the accompanying drawings, the disclosure of the present application will become more readily understood. It is readily understood by those skilled in the art that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. In addition, similar numbers in the figures are used to represent similar components, where:
[0021] Figure 1 shows a power battery according to an embodiment;
[0022] Figure 2 shows an exploded view of a power battery according to an embodiment;
[0023] Figure 3 shows a cold plate of a power battery according to an embodiment;
[0024] Figures 4a - 4b respectively show two different embodiments of the spacer of the power battery. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] First of all, it should be noted that the composition, characteristics, advantages, etc. of the power battery and the vehicle according to the present application will be described below by way of example. However, it should be understood that all the descriptions are only given for the purpose of illustration, and thus should not be construed as any limitation to the present application. In this article, the technical terms "first" and "second" are only used for the purpose of distinguishing expressions and are not intended to indicate their order and relative importance. The technical term "connection (or connected, etc.)" covers the direct connection of a specific component to another component and / or the indirect connection to another component. In addition, unless otherwise clearly specified and limited, the dimensions, directions or positional relationships indicated by technical terms such as "length", "width", "height", "upper", "top", "bottom", etc. are based on the dimensions, orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and should not be construed as a limitation to the present application.
[0026] In addition, for any single technical feature described or implied in the embodiments mentioned in this article, or any single technical feature shown or implied in the drawings, the present application still allows any combination or deletion to continue between these technical features (or their equivalents) without any technical obstacles, thereby obtaining more other embodiments of the present application that may not be directly mentioned in this article. In addition, general matters that are already well-known to those skilled in the art will not be elaborated in this article.
[0027] As Figure 1 shown, the power battery 100 generally includes a housing 10 and elements housed inside the housing 10. The elements inside the housing typically include a plurality of battery cells, high-voltage connectors, low-voltage connectors, as well as monitoring elements and control elements, etc. These elements inside the housing often generate heat during operation. Making the power battery operate in a comfortable temperature range is beneficial to the performance and lifespan of the power battery. During high-power fast charging, there are relatively high requirements for the heat dissipation performance of the power battery. In addition, to suppress the heat diffusion inside the power battery when a battery cell thermal runaway occurs, it is also necessary to be able to efficiently and quickly remove the heat of the runaway battery cell.
[0028] Figure 2 shows Figure 1 the exploded view of the power battery 100 in Figure 2 wherein the housing 10 includes a top plate 11 and a tray 12, and the top plate 11 and the tray 12 can be fastened via threaded parts or bonded via adhesives or joined together by other common joining methods in the art. The power battery 100 includes elements housed inside the housing 10. As shown in Figures 1 to 2In the illustrated embodiment, the cold plate 11 is a part of the housing 10 of the power battery. More specifically, the cold plate 11 constitutes the top portion of the housing 10 (or the top plate 11 ), that is, the cold plate 11 and the tray 12 can be joined together to form a sealed housing 10 .
[0029] The shell 10 also contains a coolant, and at least part of the coolant in the shell 10 is in a liquid state. The liquid coolant can directly contact the outer surface of the shell element and exchange heat with it. For example, the battery cell 20 can be immersed in the coolant to be cooled by the coolant. The coolant that absorbs heat can show a temperature rise to a certain extent, and can also be further (partially) converted into a gaseous state. The gaseous coolant rises to or near the cold plate 11 and is cooled by the cold plate 11, and further condensed to a liquid state. At this point, the heat in the battery cell 20 can be transferred to the outside of the power battery shell through the cold plate 11. In addition to the battery cell 20, other shell components inside the shell 10, such as the copper bus 31, the monitoring unit 32, the control unit 33, etc., can also be similarly cooled by the coolant and further transfer heat to the outside of the shell through the cold plate 11. The above-mentioned state changes of the coolant can continuously occur inside the shell 10 to cool the inside of the shell.
[0030] Preferably, each cell in the power battery 100 is immersed in the coolant, for example, the liquid level of the coolant can reach 1 / 4, 1 / 3, 1 / 2, 3 / 4 or even 100% of the cell height. In addition, other components in the shell such as copper busbars can also be immersed in the coolant.
[0031] In addition to controlling or transferring the heat of the power battery under normal operating conditions, the coolant in the power battery 100 can also quickly cool down and extinguish the runaway battery cell when a battery cell in the power battery experiences thermal runaway, thereby effectively preventing the spread of thermal runaway and improving the safety of the power battery.
[0032] These in-shell components can be at least partially immersed in the coolant to be cooled by the coolant, and can also be cooled by the condensed liquid (such as droplets) of the coolant falling from the cold plate 11. Accordingly, some in-shell components can be immersed in the coolant to be cooled by the coolant, and can also be not immersed in the coolant but cooled by the condensed liquid of the coolant falling from the cold plate 11. Those skilled in the art can comprehensively consider the cooling scheme of the in-shell components according to various factors such as the heating power of the in-shell components and the layout scheme inside the shell.
[0033] Inside the power battery, the arrangement of components such as the copper busbar and signal acquisition wire harness at the upper part of the battery cell needs to provide a channel for the vaporized coolant to flow out and rise, so as to condense the gaseous coolant. The condensed coolant can drip onto the copper busbar, battery cell, cell gap, control unit, etc. to play a role in cooling. Preferably, at least part of the volume of the battery cell 20 is immersed in the coolant.
[0034] Preferably, the evaporation temperature of the coolant under standard atmospheric pressure is between 20°C and 45°C, for example, between 25°C and 40°C, for example, between 30°C and 38°C, for example 35°C. The above evaporation temperature is conducive to the coolant absorbing heat through phase change at room temperature to better cool the components inside the shell. At the same time, the coolant needs to have properties such as insulation and non-flammability. Preferably, the coolant can also have characteristics such as low density and low viscosity. For example, the coolant can be hydrofluoroolefins.
[0035] As Figure 3 As can be seen, the cold plate 11 can be provided with a cooling flow path for the heat exchange medium to flow. The heat exchange medium can continuously flow into and out of the cooling flow path to achieve the cooling of the inside of the housing 10 by the cold plate 11. The heat exchange medium in the cooling flow path can use automotive coolant or refrigerant in the automotive air conditioning system. Connecting the cooling flow path on the cold plate 11 to the flow path of automotive coolant or the flow path of air conditioning refrigerant can achieve the cooling function of the cold plate 11. Borrowing the cooling capacity of existing devices can avoid adding new devices, simplify the structure of the power battery and reduce costs.
[0036] The heat generation of the housing interior of the power battery 100 or the components within the housing may vary under different operating conditions. Therefore, the flow rate of the heat transfer medium within the cold plate 11 can be further adjusted based on the state parameters inside the housing to more precisely control the internal state of the power battery. A temperature sensor can be provided inside the housing 10 to control the flow rate of the heat transfer medium within the cold plate 11 according to the temperature inside the housing 10. For example, one or more temperature sensors arranged at intervals can be provided on the side of the cold plate 11 facing the interior of the power battery, and the flow rate of the heat transfer medium within the cold plate can be controlled according to the value (average value) of the parameters measured by the temperature sensors. For example, the flow rate of the heat transfer medium within the cold plate can be controlled according to the rate of change of the value (average value) of the parameters measured by these temperature sensors. Alternatively, one or more temperature sensors can also be provided on the outer surfaces of one or more battery cells to control the flow rate of the heat transfer medium within the cold plate according to the parameters of these temperature sensors. In addition, a pressure sensor can also be provided inside the housing 10 to control the flow rate of the heat transfer medium according to the parameters it measures. When the temperature inside the housing is relatively high or the heat cannot be transferred out of the housing in a timely manner, the evaporation amount of the coolant is relatively large, and the proportion of the gaseous coolant is relatively high, and the pressure inside the housing will be correspondingly high. Controlling the flow rate of the heat transfer medium within the cold plate 11 according to the pressure parameters inside the housing can stabilize the internal pressure and temperature in a timely manner. One or more pressure sensors can be provided on the side of the cold plate 11 facing the interior of the power battery, and the flow rate of the heat transfer medium within the cold plate can be controlled according to the magnitude and / or rate of change of the average value of the pressure values measured by the one or more pressure sensors. Of course, the flow rate of the heat transfer medium within the cold plate 11 can also be controlled based on the parameters measured by both the temperature sensor and the pressure sensor simultaneously.
[0037] As Figure 2 shown, the interior of the housing includes a plurality of battery cells and also includes a spacer 40. The spacer 40 is disposed between adjacent battery cells, for example, between the large faces of two battery cells, to form a gap between adjacent battery cells. The gap between adjacent battery cells helps the coolant to enter between adjacent battery cells to fully contact the outer surface of the battery cells, thereby exchanging heat with the battery cells. Refer to Figure 4a and Figure 4b , which respectively show the first embodiment 40a and the second embodiment 40b of the spacer 40.
[0038] As Figure 4aAs shown, the spacer 40a includes a bar-shaped structure (cross bar 402) extending in the horizontal direction and three bar-shaped structures (longitudinal bars 401) extending in the longitudinal direction. The cross bar 402 is integrally formed with the three longitudinal bars 401 at the bottom of the longitudinal bars 401. The angle between the cross bar 402 and the longitudinal bars 401 is substantially 90°. And the tops of the longitudinal bars 401 are not connected to each other. There is a spacing between adjacent longitudinal bars 401 in the longitudinal direction (including the spacing between the tops of the longitudinal bars 401) to leave a path for the gaseous coolant to rise near the top plate or contact the top plate in the longitudinal direction, so that the gaseous coolant can be cooled by the top plate and then condensed. Optionally, the three longitudinal bars 401 are arranged at substantially equal intervals.
[0039] Reference Figure 4b , the spacer 40b includes three longitudinal bars 403 that are not connected to each other and extend parallel in the longitudinal direction. There is a certain spacing between the three longitudinal bars 403 to ensure the rising path after the coolant vaporizes and to be cooled and condensed near or on the cold plate 11. The three longitudinal bars 403 are arranged at substantially equal intervals. The spacer 40 (including 40a and 40b) has a certain thickness to ensure sufficient gaps between adjacent battery cells, and this thickness can be set according to factors such as the heat dissipation requirements of the battery cells and the space requirements of the power battery. Figure 4a The thicknesses of the three longitudinal bars 401 and the cross bar 402 in Figure 4b are substantially the same,
[0040] The spacer 40 in this article forms a gap between the battery cells and can also leave space for the battery cells to breathe and expand.
[0041] The filling amount of the coolant inside the housing of the power battery can be between 10% and 90% of the fillable volume of the power battery 100. Herein, the fillable volume is the difference between the total volume inside the housing 10 and the volume of all solid components inside the housing 10, that is, the sum of the internal void volumes of the power battery 100 when no coolant is filled. The filling amount of the coolant is the amount of the coolant converted to its fully liquid state. The specific filling amount of the coolant can be designed according to the heat generation, power, internal cavity volume, sealing performance, pressure resistance ability, etc. of the power battery and the properties of the coolant.
[0042] The specific embodiments described above for this application are only for more clearly describing the principle of this application, in which each component is clearly shown or described to make the principle of this application easier to understand. Without departing from the scope of this application, those skilled in the art can easily make various modifications or changes to this application. Therefore, it should be understood that these modifications or changes should all be included within the scope of patent protection of this application.
Claims
1. A power battery, comprising: Internal components within the housing, which are accommodated inside the housing of the power battery, A cold plate, which is located above the internal components within the housing, A coolant, which is accommodated inside the housing, and at least part of the coolant is in a liquid state to directly contact at least part of the outer surface of the internal components within the housing for heat exchange therewith.
2. The power battery according to claim 1, wherein, The coolant absorbs heat to transform into a gaseous state and is then cooled to a liquid state by the cold plate.
3. The power battery according to claim 1, wherein, The evaporation temperature of the coolant under standard atmospheric pressure is between 20°C and 45°C.
4. The power battery according to claim 1, wherein, The cold plate has a cooling flow path for a heat exchange medium to flow through, thereby transferring the heat inside the housing.
5. The power battery according to claim 4, wherein, A temperature sensor is provided inside the housing, and the flow rate of the heat exchange medium varies according to the parameters measured by the temperature sensor. And / or, a pressure sensor is provided inside the housing, and the flow rate of the heat exchange medium varies according to the parameters measured by the pressure sensor.
6. The power battery according to claim 1, wherein, The cold plate is the top part of the housing.
7. The power battery according to claim 1, wherein, The internal components within the housing include a plurality of battery cells, and a spacer is provided between adjacent battery cells to form a gap between the adjacent battery cells.
8. The power battery according to claim 7, wherein, The spacer has a strip-shaped structure extending along the height direction of the battery cell.
9. The power battery according to claim 1, wherein, The coolant is a hydrofluoroolefin material.
10. The power battery according to claim 1, wherein, The filling amount of the coolant is: when the coolant is all in a liquid state, the volume of the coolant is between 10% and 90% of the fillable volume, where the fillable volume is the total volume inside the housing of the power battery minus the volume of all solid components inside the housing.
11. A vehicle having the power battery according to any one of claims 1-10.