Battery pack and submerged energy storage battery system

Abstract

The present application relates to the field of battery cooling and heat dissipation, and particularly relates to a battery pack and an immersed energy storage battery system. The battery pack comprises: a frame arranged in an immersion space filled with immersion coolant; phase change liquid cooling plates and batteries arranged at intervals along a first direction and fixed in the frame; a surface of the phase change liquid cooling plate facing the adjacent battery is formed with a boss array protruding towards the battery and closely attached to the battery, each boss in the boss array has a sealed cavity inside, the sealed cavity is filled with a phase change material; adjacent bosses have a gap space; the phase change liquid cooling plate has an inner cavity channel for circulating coolant to flow; a spraying system is arranged on the top of the frame, is connected to a coolant supply port of the immersion coolant or the circulating coolant, and is used for spraying the closely attached boss side of the battery. The present application can effectively suppress the temperature rise of the battery in the full operating condition range, and realize efficient and stable battery thermal management.

Description

Technical Field

[0001] This invention relates to the field of battery cooling and heat dissipation, and specifically to a battery pack and an immersed energy storage battery system. Background Technology

[0002] With the rapid development of new energy vehicles and the energy storage industry, the thermal management of power batteries has received increasing attention. Batteries generate a large amount of heat during charging and discharging. If heat dissipation is not timely or the temperature distribution is uneven, it will lead to battery performance degradation, shortened cycle life, and in severe cases, even thermal runaway accidents.

[0003] Currently, immersion liquid cooling technology is increasingly being applied in battery thermal management due to its high heat exchange efficiency and good temperature uniformity. Existing immersion energy storage battery systems typically use an insulating liquid medium to fill the battery casing, immersing the internal battery modules for heat dissipation. However, this approach has the following shortcomings in actual operation: First, vertical temperature stratification of the immersion liquid leads to uneven heat exchange between batteries at different heights; second, relying solely on natural convection and boiling heat exchange results in a lagging thermal response and insufficient suppression of peak temperature rise under high-rate charge and discharge conditions.

[0004] While existing technologies combine immersion cooling with internal flow channel liquid cooling, the liquid cooling plate and battery surface are mostly in planar contact, reducing the contact area between the immersion coolant and the battery and weakening the heat exchange effect of the immersion medium. The overall solution still suffers from slow thermal response and an inability to effectively suppress temperature fluctuations. More critically, existing solutions generally lack the ability to quickly and precisely intervene in localized thermal runaway within the battery module. Once a single cell experiences a thermal anomaly, only full-pack flooding cooling is often the only option, resulting in low cooling efficiency and potentially causing unnecessary thermal shock to normal batteries.

[0005] Therefore, it is urgent to solve the above-mentioned technical problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a battery pack that can effectively suppress battery temperature rise and achieve efficient and stable battery thermal management across the entire operating range.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is: a battery pack, comprising: A frame for placement in an immersion space filled with immersion coolant; A phase change liquid cooling plate and a battery are arranged at intervals along a first direction and fixed within the frame; the surface of the phase change liquid cooling plate facing the adjacent battery has an array of protrusions that protrude towards and are in close contact with the battery, each protrusion in the array has a sealed cavity inside, and the sealed cavity is filled with phase change material; there is a gap space between adjacent protrusions; the phase change liquid cooling plate has an internal flow channel for circulating coolant. The spray system 4 is located on the top of the frame 1 and is connected to the supply port of the immersion coolant or circulating coolant. It is used to spray the side of the battery 3 that is attached to the boss 21.

[0008] Furthermore, the cross-sectional area of ​​the protrusion decreases from the root to the top, with the top closely attached to the battery surface.

[0009] Furthermore, the melting point of the phase change material is lower than the boiling point of the circulating coolant.

[0010] Furthermore, the boiling point of the circulating coolant is between 40°C and 60°C.

[0011] Furthermore, the frame is provided with a straight groove for alternating insertion of batteries and phase change liquid cooling plates; and inlet manifolds and outlet manifolds are respectively provided on both sides, the inlet manifolds connecting to the inlets of each inner cavity flow channel, and the outlet manifolds connecting to the outlets of each inner cavity flow channel.

[0012] Furthermore, the frame is also configured with temperature measuring points for measuring the temperature of each battery.

[0013] Furthermore, the volume of the protrusions in the protrusion array is designed non-uniformly based on the historical heat density of the corresponding contact battery region.

[0014] The present invention also relates to a cooling method for a battery pack, characterized in that, include: The battery pack is placed in an immersion space filled with immersion coolant, so that the battery is at least partially immersed in the immersion coolant; circulating coolant is continuously introduced into the inner cavity flow channel of the phase change liquid cooling plate; each boss in the boss array of the phase change liquid cooling plate is in close contact with the battery. The phase change material in the sealed cavity absorbs the heat of the battery to suppress the instantaneous temperature rise of the battery, and the circulating coolant in the inner cavity channel carries away the basic heat of the phase change material and the battery; the immersion coolant that submerges the battery absorbs the heat of the battery and the surface of the phase change liquid cooling plate, and at least part of the immersion coolant undergoes phase change to become gaseous coolant to absorb heat. Simultaneously, monitoring signals characterizing the temperature status of each region of the battery are acquired in real time or at intervals, and the heating rate of each region is calculated based on the monitoring signals. When the heating rate of any region exceeds the preset safety threshold, the spray system is controlled to extract coolant and spray coolant onto the region at a fixed point to perform emergency cooling of the region.

[0015] The present invention also relates to an immersion energy storage battery system, comprising: The battery casing is filled with submerged coolant. At least one battery pack is placed inside the battery housing.

[0016] Furthermore, the battery box has a direct cooling channel inside the cover, and fins are provided on the inner side of the cover.

[0017] By adopting the above technical solution, this invention constructs a gradient heat transfer path: phase change material (primary buffer) → circulating coolant (secondary continuous heat dissipation) → immersion coolant evaporation + spraying (tertiary auxiliary + emergency). The three-stage heat dissipation methods work in tandem, ensuring the battery receives a cooling response matching the heat load under different operating conditions. This effectively suppresses battery temperature rise, reduces peak temperature, and narrows temperature difference distribution across the entire operating range, achieving efficient and stable battery thermal management. Furthermore, the physical isolation of the three-phase media ensures that leaks do not propagate, while the low-cost coolant handles the main heat dissipation, and the modular structure facilitates maintenance, combining efficient heat dissipation with high reliability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the battery pack structure of the present invention; Figure 2 This is a schematic diagram of the phase change liquid cooling plate of the present invention; Figure 3 This is a schematic diagram of the frame and spray system of the present invention; Figure 4 This is a cross-sectional view of the submersible energy storage battery system of the present invention; In the diagram, 1 is the frame; 11 is the straight channel; 12 is the inlet manifold; 13 is the outlet manifold; 2 is the phase change liquid cooling plate; 21 is the boss; 22 is the inner cavity flow channel; 3 is the battery; 4 is the spray system; 5 is the battery box; 51 is the box cover; 511 is the direct cooling channel; and 512 is the fin. Detailed Implementation

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Example 1: As Figures 1 to 4 As shown, a battery pack includes: Frame 1, for placement in an immersion space filled with immersion coolant; The phase change liquid cooling plate 2 and the battery 3 are arranged at intervals along the first direction and fixed in the frame 1; the surface of the phase change liquid cooling plate 2 facing the adjacent battery 3 is formed with an array of protrusions that protrude towards the battery 3 and are in close contact with the battery 3, and each protrusion 21 in the protrusion array has a sealed cavity inside, which is filled with phase change material; there is a gap space between adjacent protrusions 21; the phase change liquid cooling plate 2 has an inner cavity flow channel 22 for circulating coolant to flow; The spray system 4, located on the top of the frame 1, is used to draw in or circulate coolant to spray the side of the protrusion 21 of the battery 3.

[0021] It should be noted that the submerged coolant and the circulating coolant each establish a separate circulation with the external refrigerant. The submerged coolant and the circulating coolant can be the same refrigerant, such as fluorinated liquid, or they can be different refrigerants. When using the same refrigerant, the inlet of the spray system 4 can be connected to either the submerged coolant supply port or the circulating coolant supply port. When using different refrigerants, the inlet of the spray system 4 is connected to the submerged coolant supply port. Preferably, the same refrigerant is used.

[0022] The cooling method for this type of battery pack is as follows: The battery pack is placed in an immersion space filled with immersion coolant, so that the battery 3 is at least partially immersed in the immersion coolant; circulating coolant is continuously introduced into the inner cavity flow channel 22 of the phase change liquid cooling plate 2; each protrusion 21 in the protrusion array of the phase change liquid cooling plate 2 is in close contact with the battery 3. The phase change material in the sealed cavity absorbs the heat of the battery 3 to suppress the instantaneous temperature rise of the battery 3, and the circulating coolant in the inner cavity flow channel 22 carries away the basic heat of the phase change material and the battery 3; the immersion coolant immersed in the battery 3 absorbs the heat of the battery 3 and the surface of the phase change liquid cooling plate 2, and at least part of the immersion coolant undergoes phase change to become gaseous coolant to absorb heat. Simultaneously, monitoring signals characterizing the temperature status of each region of battery 3 are acquired in real time or at intervals (temperature sensors and controllers are configured, and the spray system 4 is linked). The heating rate of each region is calculated based on the monitoring signals. When the heating rate of any region exceeds the preset safety threshold, the spray system 4 is controlled to extract coolant and spray it at a fixed point to that region (mainly the gap space of the protrusion array 21 corresponding to that region) to perform emergency cooling of that region.

[0023] Specifically, the protruding surface of the protrusion 21 is in close contact with the battery 3. The latent heat of phase change material within the enclosed cavity of the protrusion rapidly absorbs the instantaneous heat peak generated by the battery, effectively suppressing the temperature rise slope and preventing heat from accumulating locally on the battery surface to form hot spots. Simultaneously, the circulating coolant within the phase change liquid cooling plate 2 continuously flows, carrying away the latent heat stored in the phase change material and the basic heat generated by the battery 3 through the large-area metal wall at the base of the protrusion 21, preventing the phase change material from prematurely saturating and failing due to continuous heat absorption. Furthermore, the gaps between adjacent protrusions 21 form a natural convection path for the coolant, increasing the contact area between the coolant and the battery 3 within the immersion space. The immersion coolant in the battery 3 absorbs residual heat through natural convection and boiling evaporation. Under abnormal thermal conditions, the spray system 4 provides forced convection cooling to localized high-temperature areas, utilizing the latent heat of vaporization of the immersion coolant to achieve efficient and rapid cooling. Therefore, this embodiment constructs a gradient heat transfer path of phase change material (primary buffer) → circulating coolant (secondary continuous heat dissipation) → immersion coolant evaporation + spraying (tertiary auxiliary + emergency). The three-stage heat dissipation methods are successively supported and coordinated, so that battery 3 can obtain a cooling response that matches the heat load under different operating conditions: the phase change material quickly absorbs the instantaneous thermal shock in the form of latent heat, the circulating coolant continuously removes the main body heat to maintain the reversible circulation of the phase change material, and the immersion coolant provides auxiliary heat dissipation under normal operating conditions and achieves rapid cooling through fixed-point spraying under abnormal thermal conditions. Thus, the battery temperature rise is effectively suppressed, the peak temperature is reduced, and the temperature difference distribution is narrowed in the entire operating range, so as to achieve efficient and stable battery thermal management.

[0024] Furthermore, during spraying, the coolant flows down the sidewall of the protrusion 21, forming a thin liquid film evaporation effect, which further expands the effective heat transfer area. At the same time, the uneven structure of the protrusion array disrupts the liquid film boundary layer, enhances local turbulence, and improves the convective heat transfer coefficient.

[0025] In summary, the phase change material in this embodiment effectively buffers temperature fluctuations, and the combination of heating rate criterion enables early warning of thermal runaway. The fixed-point spraying only acts on abnormal areas to avoid overcooling of normal battery 3. The phase change material, circulating coolant and immersion coolant are physically isolated, and single-loop leakage does not contaminate other systems. The modular design facilitates single-board replacement, and the closed-loop liquid cooling cycle has high energy efficiency and low maintenance cost.

[0026] In this embodiment, preferably, as follows: Figure 2 As shown, the cross-sectional area of ​​the boss 21 decreases from the root to the top, with its top edge in close contact with the surface of the battery 3. The cross-section can be rectangular, oriented, circular, trapezoidal, etc., with the oriented shape being the best.

[0027] This structure concentrates the heat generated by battery 3 into the small-area end, which is then transferred to the protrusion 21. This increases the local heat flux density, allowing heat to penetrate the wall more quickly and shortening the response delay of the phase change material in sensing the temperature rise and initiating phase change heat absorption. The large-area end expands the heat dissipation area on the side of the phase change liquid cooling plate 2, reducing the thermal resistance of the coolant side. Simultaneously, the inclined sidewalls of adjacent protrusions 21 cause the horizontal gap between them to gradually widen from the phase change liquid cooling plate 2 side towards the battery 3 side. As the fluid flows through, the cross-section continuously changes, generating velocity disturbances and disrupting the thermal boundary layer, thus enhancing convective heat transfer of the immersed coolant. Furthermore, this ensures that both liquid cooling and phase change cooling are present on the battery 3 side. In addition, this conical structure facilitates stamping and demolding and helps disperse the stress generated by the volume expansion of the phase change material.

[0028] In this embodiment, preferably, the melting point of the phase change material is lower than the boiling point of the circulating coolant. The boiling point of the circulating coolant is between 40°C and 60°C.

[0029] In this way, the phase change material is ensured to melt and absorb latent heat preferentially when the battery 3 heats up, delaying the time for the coolant to reach the boiling point, avoiding premature boiling of the coolant which would lead to deterioration of heat transfer or increase in system pressure, and suppressing system pressure fluctuations. At the same time, the boiling point range of 40°C to 60°C matches the optimal operating temperature range of the battery 3, so that the coolant remains in a liquid state and circulates efficiently under normal operating conditions, and only boils when the battery 3 is abnormally overheated to assist in heat dissipation.

[0030] In this embodiment, preferably, the frame 1 is provided with a straight groove 11 for alternating insertion of the battery 3 and the phase change liquid cooling plate 2; and an inlet manifold 12 and an outlet manifold 13 are respectively provided on both sides, the inlet manifold 12 is connected to the inlet of each inner cavity flow channel 22, and the outlet manifold 13 is connected to the outlet of each inner cavity flow channel 22.

[0031] This design facilitates the installation and fixation of the battery 3 and the phase change liquid cooling plate 2, and also promotes the circulation of coolant in the inner cavity flow channel 22 of each phase change liquid cooling plate 2.

[0032] In this embodiment, preferably, the frame 1 is also configured with temperature measuring points for measuring the temperature of each battery 3. The temperature measuring points have temperature sensors, such as thermocouples. This facilitates monitoring the temperature of each battery 3.

[0033] In this embodiment, preferably, the volume of the protrusions in the protrusion array is non-uniformly designed based on the historical heat density of the corresponding contact battery region 3. This design allows for a larger volume of phase change material in high heat flux density regions (such as near the battery tabs), enhancing local heat buffering capacity and effectively suppressing the formation of local hot spots; while in low heat flux density regions, the protrusion volume is appropriately reduced to avoid redundant waste of phase change material and excessive cooling. By allocating the amount of phase change material as needed, the overall temperature uniformity of the battery pack is improved while also achieving lightweighting and cost control.

[0034] In this embodiment, preferably, the spray system 4 includes a spray manifold and multiple nozzles connected to the spray manifold. The nozzle types include a first flow nozzle corresponding to the high heat flux density area of ​​the battery and a second flow nozzle corresponding to the ordinary area. The first flow nozzle corresponds to a larger spray flow rate. The control system matches and starts nozzles with different flow rates to spray according to the area type where the temperature measuring point is located and the heating rate threshold.

[0035] The spray system 4 is equipped with nozzles of different flow rates based on the differences in heat load in the battery areas, and is controlled in conjunction with the temperature rise rate threshold. This design enables high heat flux density areas to achieve rapid cooling with a large flow rate during abnormal conditions, while ordinary areas are precisely controlled with a small flow rate, avoiding waste of cooling resources and thermal shock to normal batteries 3 caused by excessive cooling. By spraying in stages as needed, the system improves the efficiency of suppressing local thermal runaway while effectively saving the amount of immersion coolant and maintaining the overall temperature uniformity of the system.

[0036] Example 2: Figure 4 As shown, an immersion energy storage battery system includes: Battery housing 5 is filled with submerged coolant; At least one battery pack, as in Embodiment 1, is placed inside the battery housing 5.

[0037] In this embodiment, preferably, the battery box 5 has a direct cooling channel 511 inside the box cover 51, and fins 512 are provided on the inner side of the box cover 51.

[0038] After the gaseous coolant floats to the surface, it is condensed by the fins 512. The heat is carried away by the medium in the direct cooling channel 511, realizing efficient condensation and recycling of the submerged coolant, maintaining a stable level of submerged coolant in the tank and reducing the frequency of replenishment. At the same time, the tank is sealed and does not require external condensation pipes, resulting in a high degree of system integration.

[0039] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A battery pack, characterized in that, include: A frame (1) is used to be placed in an immersion space filled with immersion coolant; The phase change liquid cooling plate (2) and the battery (3) are arranged at intervals along the first direction and fixed in the frame (1); the surface of the phase change liquid cooling plate (2) facing the adjacent battery (3) is formed with an array of protrusions that protrude towards the battery (3) and are in close contact with the battery (3), each protrusion (21) in the protrusion array has a sealed cavity inside, and the sealed cavity is filled with phase change material; there is a gap space between adjacent protrusions (21); the phase change liquid cooling plate (2) has an inner cavity flow channel (22) for circulating coolant to flow inside. A spray system (4) is configured on the top of the frame (1) and connected to the supply port of the immersion coolant or circulating coolant, for spraying the side of the battery (3) that is attached to the boss (21).

2. The battery pack according to claim 1, characterized in that, The cross-sectional area of ​​the boss (21) decreases from the root to the top, and its top is in close contact with the surface of the battery (3).

3. The battery pack according to claim 1, characterized in that, The melting point of the phase change material is lower than the boiling point of the circulating coolant.

4. The battery pack according to claim 3, characterized in that, The boiling point of the circulating coolant is between 40°C and 60°C.

5. The battery pack according to claim 1, characterized in that, The frame (1) is provided with a straight groove (11) for alternating insertion of the battery (3) and the phase change liquid cooling plate (2); and an inlet manifold (12) and an outlet manifold (13) are provided on both sides respectively. The inlet manifold (12) is connected to the inlet of each inner cavity flow channel (22), and the outlet manifold (13) is connected to the outlet of each inner cavity flow channel (22).

6. The battery pack according to claim 1, characterized in that, The frame (1) is also equipped with temperature measuring points for measuring the temperature of each battery (3).

7. The battery pack according to claim 1, characterized in that, The volume of the protrusions in the protrusion array is designed non-uniformly based on the historical heat density of the corresponding contact battery (3) region.

8. A cooling method for a battery pack according to any one of claims 1-7, characterized in that, include: The battery pack is placed in an immersion space filled with immersion coolant, so that the battery (3) is at least partially immersed in the immersion coolant; circulating coolant is continuously introduced into the inner cavity flow channel (22) of the phase change liquid cooling plate (2); each boss (21) in the boss array of the phase change liquid cooling plate (2) is in close contact with the battery (3). The phase change material in the sealed cavity absorbs the heat of the battery (3) to suppress the instantaneous temperature rise of the battery (3), and the circulating coolant in the inner cavity flow channel (22) carries away the basic heat of the phase change material and the battery (3); the immersion coolant immersed in the battery (3) absorbs the heat of the surface of the battery (3) and the phase change liquid cooling plate (2), and at least part of the immersion coolant undergoes phase change to gaseous coolant to absorb heat; Meanwhile, monitoring signals characterizing the temperature status of each region of the battery (3) are acquired in real time or at intervals, and the heating rate of each region is calculated based on the monitoring signals. When the heating rate of any region exceeds the preset safety threshold, the spray system (4) is controlled to extract coolant and spray it onto the region at a fixed point to cool the region in an emergency.

9. An immersion-type energy storage battery system, characterized in that, include: The battery housing (5) is filled with submerged coolant; At least one battery pack as described in any one of claims 1-7 is placed inside the battery housing (5).

10. The submersible energy storage battery system according to claim 9, characterized in that, The battery box (5) has a direct cooling channel (511) inside the box cover (51), and fins (512) are provided on the inner side of the box cover (51).

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