Battery pack cooling structure

Abstract

The invention relates to a battery pack cooling structure, in particular to the field of batteries, and the battery pack cooling structure comprises a CCS assembly integrated on the top or the side surface of a battery cell group; the CCS assembly includes: a plastic cooling plate; the heat conductivity coefficient of the plastic cooling plate is greater than or equal to 1W (m.K); one surface of the plastic cooling plate is tightly attached to a battery cell spine of the battery cell group; and the battery core spine comprises a battery core pole, a current collector leading-out end and an area where connecting sheets are distributed. According to the battery pack cooling structure provided by the invention, the light-weight plastic cooling plate is directly embedded into the CCS part, and the characteristic that the light-weight plastic cooling plate is tightly attached to the battery cell spine is utilized, so that targeted precise cooling is realized, meanwhile, the original electrical function integrity of the CCS is maintained, the peak temperature of the battery cell spine can be reduced by 10 DEG C or above, and the overall temperature uniformity of the battery cell is improved by 30% or above; and the thermal runaway risk caused by local overheating is obviously inhibited.

Description

Technical Field

[0001] This invention relates to the field of batteries, and more specifically to a battery pack cooling structure. Background Technology

[0002] Currently, with the increasing demands for longer driving ranges and faster charging performance in new energy vehicles, the energy density of power battery packs continues to rise, leading to a significant increase in the heat generated by the battery cells during charging and discharging. In particular, the spine region of the battery cell (i.e., the sides or ends where the cell terminals, current collector leads, and connecting tabs are concentrated) has become a critical heat-sensitive area with the largest internal temperature gradient due to the high thermal conductivity of the metal conductive components (such as aluminum / copper terminals and nickel / copper connecting tabs) and the current concentration effect.

[0003] If the heat in this area cannot be dissipated in time, the local temperature will exceed 80°C or even 100°C, causing problems such as electrolyte decomposition, SEI film thickening, and active material structure decay, which will directly shorten the cycle life of the battery cell and threaten the overall safety performance of the package.

[0004] In current mainstream battery thermal management solutions, water-cooled plates are typically made of metal materials such as aluminum alloy and integrated with the bottom of the battery through welding or mechanical connection. For example, CN108987851A discloses a water-cooled plate and a water-cooled battery, including: a receiving cavity for containing coolant, the receiving cavity including a front region and a rear region, the front region including at least one first flow channel, and the rear region including at least one second flow channel, the first flow channel and the second flow channel are connected, the sum of the cross-sectional areas of all the first flow channels is greater than the sum of the cross-sectional areas of all the second flow channels, so that the coolant flow velocity in the first flow channel in the water inlet region is less than the coolant flow velocity in the second flow channel in the water outlet region, which improves the cooling effect of the cell in the water outlet region, makes the temperature difference between the cell in the water inlet region and the water outlet region smaller, and improves the battery performance.

[0005] However, metal water-cooled plates have the following limitations: First, although metal materials have high thermal conductivity, gaps are easily formed at the interface with the battery cell due to the difference in thermal expansion coefficients, which affects the heat transfer efficiency; second, metal water-cooled plates are relatively heavy, which is not conducive to the lightweight design of battery systems; third, traditional water-cooled plates and CCS (Cell Contacting System) components are usually independent parts, which need to be integrated through additional assembly processes, increasing system complexity and manufacturing costs.

[0006] In particular, existing solutions often lack specific design for cooling the cell spine (i.e., the cell electrode connection area). During charging and discharging, the cell spine generates local high temperatures due to the current collection effect. Since the space in this area is small, traditional water-cooling structures cannot achieve efficient cooling.

[0007] In summary, current battery cooling structures still suffer from poor cooling performance, necessitating the development of a lightweight, highly integrated thermal management solution that can precisely cool the core of the battery cell. Summary of the Invention

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide a battery pack cooling structure to solve the defect that the battery cooling structure still has poor cooling effect, so as to achieve lightweight, highly integrated thermal management that can accurately cool the spine of the battery cell.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] This invention provides a battery pack cooling structure, the battery pack cooling structure comprising:

[0011] CCS components integrated into the top or side of the battery cell assembly;

[0012] The CCS component includes: a plastic cooling plate;

[0013] The plastic cooling plate is made of plastic with a thermal conductivity ≥ 1 W / (m·K);

[0014] One side of the plastic cooling plate is in close contact with the cell spine of the cell assembly;

[0015] The cell spine includes: the cell electrode post, the current collector lead-out end, and the area where the connecting pieces are distributed.

[0016] The battery pack cooling structure provided by this invention achieves targeted and precise cooling by directly embedding a lightweight plastic cooling plate into the CCS components and utilizing its close fit with the cell spine, while maintaining the integrity of the original electrical functions of the CCS. This can reduce the peak temperature of the cell spine by more than 10°C, improve the overall temperature uniformity of the cell by more than 30%, and significantly suppress the risk of thermal runaway caused by local overheating.

[0017] As a preferred embodiment of the present invention, the battery cell assembly includes: battery cells connected in series and / or in parallel.

[0018] As a preferred embodiment of the present invention, the CCS component further includes: a sampling circuit board, a conductive connecting piece, and an insulating support.

[0019] As a preferred technical solution of the present invention, the plastic cooling plate is made of one of the following materials: polyimide composite material, boron nitride filled polypropylene, or graphene-reinforced polyamide.

[0020] As a preferred embodiment of the present invention, the thickness of the plastic cooling plate is 0.5-0.7 mm.

[0021] As a preferred technical solution of the present invention, the contact surface structure of the plastic cooling plate that is in close contact with the spine of the battery cell includes: a wavy structure and / or a sawtooth structure.

[0022] As a preferred embodiment of the present invention, the interior of the plastic cooling plate is provided with serpentine and / or spiral cooling channels.

[0023] As a preferred embodiment of the present invention, the cross-section of the cooling channel includes: a circle and / or a polygon.

[0024] Preferably, the depth of the cooling channel is 1-5 mm.

[0025] Preferably, the width of the cooling channel is 1-3 mm.

[0026] As a preferred embodiment of the present invention, the cooling channel extends to the edge of the CCS component and is connected to the external cooling pipeline.

[0027] As a preferred technical solution of the present invention, the connection method between the plastic cooling plate and the insulating bracket includes: one of the following: embedded injection molding process, snap-fit ​​connection or adhesive connection.

[0028] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0029] (1) High targeted cooling efficiency: The plastic cooling plate is directly attached to the spine area of ​​the cell (traditional solutions cannot accurately cover it). Through the synergistic effect of high thermal conductivity plastic (thermal conductivity 1-1.5-W / (m·K), which is much higher than ordinary plastic 0.2-0.5W / (m·K)) and coolant in the flow channel, the peak temperature of the spine area can be reduced by more than 10℃, and the overall temperature uniformity of the cell can be improved by more than 30%.

[0030] (2) Lightweight and low cost: The density of plastic cooling plates is only 1 / 4 to 1 / 3 of that of metals (such as aluminum) (for example, the density of PI composite material is about 1.4 g / cm³, while that of aluminum is 2.7 g / cm³), which significantly reduces weight while ensuring cooling performance (500-1000 g weight reduction per module); and the cost of plastic materials is low (about 1 / 2 of that of aluminum cooling plates), and the injection molding process is mature and suitable for large-scale production.

[0031] (3) High functional integration: The cooling function is integrated with the original electrical connection and sampling function of CCS into the same component, reducing the module space occupied by the independent cooling plate (saving 10-15% of the module height or width), simplifying the battery pack structure design and reducing the overall cost.

[0032] (4) High safety: The plastic cooling plate is made of non-conductive material, so even if the coolant leaks slightly, it will not cause a short circuit risk; the flow channel uses a coolant with low conductivity to further avoid electrical safety hazards; the flexible contact with the cell spine (through microstructure buffering) avoids mechanical stress damage.

[0033] (5) Functional integration: The plastic cooling plate is directly integrated into the CCS (cell connection system) components, combining the traditionally separate "electrical connection function" (such as voltage / temperature sampling, pole connection) with the "spine area cooling function" into one, solving the problem of space redundancy and structural complexity caused by the independent layout of thermal management components and electrical components in the prior art.

[0034] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0035] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0036] Currently, existing solutions often lack targeted designs for cooling the cell spine (i.e., the cell electrode connection area). During charging and discharging, the cell spine generates localized high temperatures due to the current-collecting effect. This area is confined, making it difficult for traditional water-cooling structures to achieve efficient cooling. Therefore, this invention optimizes the cooling structure, utilizing its close fit with the cell spine to achieve targeted and precise cooling, as detailed below:

[0037] This embodiment provides a battery pack cooling structure, which includes:

[0038] CCS components integrated into the top or side of the battery cell assembly;

[0039] The CCS component includes: a plastic cooling plate;

[0040] The plastic cooling plate is made of plastic with a thermal conductivity ≥ 1 W / (m·K);

[0041] One side of the plastic cooling plate is in close contact with the cell spine of the cell assembly;

[0042] The cell spine includes: the cell electrode post, the current collector lead-out end, and the area where the connecting pieces are distributed.

[0043] The battery cell assembly includes battery cells connected in series and / or in parallel.

[0044] In this invention, the arrangement of the battery cells can be selected as a commonly used arrangement of battery cells in the field, such as stacking, and is specifically carried out according to the conventional requirements in the field.

[0045] In this invention, the battery cell can be selected as a square battery cell, a cylindrical battery cell, a pouch battery cell, etc.

[0046] The CCS component further includes a sampling circuit board, a conductive connecting piece, and an insulating support.

[0047] The plastic cooling plate is made of one of the following materials: polyimide composite material, boron nitride-filled polypropylene, or graphene-reinforced polyamide. Specifically, it can be a commercially available product or prepared according to existing technology.

[0048] In this invention, the polyimide composite material can be selected from Torlon AI-10, etc.

[0049] The thickness of the plastic cooling plate is 0.5-0.7mm, for example, it can be 0.5mm, 0.52mm, 0.54mm, 0.56mm, 0.58mm, 0.6mm, 0.62mm, 0.64mm, 0.66mm, 0.68mm or 0.7mm, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0050] The contact surface structure of the plastic cooling plate that is in close contact with the spine of the battery cell includes: a wavy structure and / or a serrated structure.

[0051] In this invention, the design parameters of the wave-shaped structure can be selected as follows: amplitude of 30-200μm, wavelength of 100-500μm, and orientation angle of 10-35° with the incoming flow direction.

[0052] In this invention, the design parameters of the sawtooth structure can be selected as follows: tooth pitch of 20-100μm, tooth height of 10-50μm, tooth tip angle of 35-90°, and an asymmetrical structure can be selected.

[0053] The plastic cooling plate has serpentine and / or spiral cooling channels inside.

[0054] The cross-section of the cooling channel includes: a circle and / or a polygon.

[0055] In this invention, the polygon can be selected as a rectangle, square, triangle, pentagon, hexagon, etc.

[0056] The depth of the cooling channel is 1-5mm, for example, it can be 1mm, 1.4mm, 1.8mm, 2.2mm, 2.6mm, 3mm, 3.4mm, 3.8mm, 4.2mm, 4.6mm or 5mm, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0057] The width of the cooling channel is 1-3mm, for example, it can be 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm or 3mm, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0058] The cooling channel extends to the edge of the CCS assembly and connects to the external cooling pipeline.

[0059] The connection method between the plastic cooling plate and the insulating bracket includes one of the following: integral molding by embedded injection molding, snap-fit ​​connection, or adhesive connection.

[0060] In this invention, the cooling medium in the plastic cooling plate can be selected and designed according to conventional requirements in the field, such as a mixture of deionized water and ethylene glycol with a conductivity of <5μS / cm.

[0061] In this invention, the sampling circuit board and conductive connecting piece can be selectively arranged on the non-cooled side of the plastic cooling plate (the side away from the cell spine), and isolated by an insulating layer (such as PET film) to avoid the risk of coolant leakage.

[0062] In this invention, the inlet or outlet of the plastic cooling plate can be connected to the main cooling pipeline of the battery pack through a through hole (or integrated quick connector) reserved on the edge of the CCS component to achieve directional flow of coolant.

[0063] II. To illustrate the cooling effect achievable by the battery pack cooling structure provided by this invention, the following example is used for explanation:

[0064] Example 1

[0065] This embodiment provides a battery pack spine cooling structure with an integrated plastic cooling plate, including:

[0066] Cell assembly: It consists of multiple cylindrical cells stacked in series and parallel. Each cell has terminals (positive and negative), current collector leads, and a spine area (the area where the cell terminals, current collector leads, and connecting pieces are distributed).

[0067] CCS Components: Integrated on the top and sides of the cell assembly, including sampling circuit boards (for collecting cell voltage and temperature), conductive connecting pieces (such as Busbars), insulating supports, and plastic cooling plates;

[0068] Plastic cooling plate: Made of Torlon AI-10 material, it is manufactured using injection molding to form a thin-walled structure (0.6mm thick) that matches the contour of the cell spine. Its side surface has a contact surface that fits tightly against the outer wall of the cell spine (a wave-shaped microstructure to increase the contact area, with an amplitude of 100μm, a wavelength of 250μm, and an orientation angle of 35° to the incoming flow direction). The plastic cooling plate has a serpentine cooling channel inside (circular cross-section, 2mm wide, and 3mm deep). The channel inlet and outlet extend to the edge of the CCS module and connect to the external cooling pipes of the battery pack.

[0069] Cooling medium: Low conductivity coolant (a mixture of deionized water and ethylene glycol with a conductivity of 1 μS / cm) circulates through the flow channel. Driven by the pump, it flows through the plastic cooling plate channel, absorbs the heat conducted by the spinal region of the battery cell, and then transfers the heat to the main cooling system of the battery pack.

[0070] The integration method of the plastic cooling plate and the CCS component is as follows: the plastic cooling plate is integrally formed with the insulating bracket of the CCS through an embedded injection molding process, in which the cooling channel mold is pre-embedded in the injection molding process of the insulating bracket.

[0071] The sampling circuit board and conductive connecting piece are arranged on the non-cooled side of the plastic cooling plate, that is, the side away from the spine of the battery cell, and are isolated by an insulating PET film to avoid the risk of coolant leakage.

[0072] The inlet and outlet of the plastic cooling plate are connected to the main cooling pipeline of the battery pack through the through holes reserved on the edge of the CCS module to achieve directional flow of coolant.

[0073] Example 2

[0074] This embodiment provides a battery pack spine cooling structure with an integrated plastic cooling plate, including:

[0075] Cell assembly: It consists of multiple cylindrical cells stacked in series and parallel. Each cell has terminals (positive and negative), current collector leads, and a spine area (the area where the cell terminals, current collector leads, and connecting pieces are distributed).

[0076] CCS Components: Integrated on the top and sides of the cell assembly, including sampling circuit boards (for collecting cell voltage and temperature), conductive connecting pieces (such as Busbars), insulating supports, and plastic cooling plates;

[0077] Plastic cooling plate: Made of Torlon AI-10 material, it is manufactured using injection molding to form a thin-walled structure (0.5mm thick) that matches the contour of the cell spine. Its side surface has a contact surface that fits tightly against the outer wall of the cell spine (serrated microstructure to increase the contact area, tooth pitch 60μm, tooth height 30μm, tooth apex angle 60°); the plastic cooling plate has a serpentine cooling channel inside (circular cross-section, 1mm wide, 5mm deep), and the channel inlet and outlet extend to the edge of the CCS module and connect to the external cooling pipeline of the battery pack;

[0078] Cooling medium: Low conductivity coolant (a mixture of deionized water and ethylene glycol with a conductivity of 2 μS / cm) circulates through the flow channel. Driven by the pump, it flows through the plastic cooling plate channel, absorbs the heat conducted by the spinal region of the battery cell, and then transfers the heat to the main cooling system of the battery pack.

[0079] The integration method of the plastic cooling plate and the CCS component is as follows: the plastic cooling plate is integrally formed with the insulating bracket of the CCS through an embedded injection molding process, in which the cooling channel mold is pre-embedded in the injection molding process of the insulating bracket.

[0080] The sampling circuit board and conductive connecting piece are arranged on the non-cooled side of the plastic cooling plate, that is, the side away from the spine of the battery cell, and are isolated by an insulating PET film to avoid the risk of coolant leakage.

[0081] The inlet and outlet of the plastic cooling plate are connected to the main cooling pipeline of the battery pack through the through holes reserved on the edge of the CCS module to achieve directional flow of coolant.

[0082] Comparison Cases

[0083] In this case, no cooling structure is installed in the spine area of ​​the battery cell.

[0084] The cooling structure provided in the above embodiments and comparative cases was used to cool the battery cell assembly. During the process, charge and discharge tests were conducted and the temperature of the cell spine area was detected. The relevant results are shown in Table 1 below.

[0085] Table 1

[0086]

[0087] In summary, the cooling structure provided by this invention targets and cools the spinal region, which can reduce the peak temperature of the cell's spinal region by more than 10°C, improve the overall temperature uniformity of the cell by more than 30%, and significantly suppress the risk of thermal runaway caused by local overheating. The spinal temperature is efficiently cooled, which can simultaneously improve the high-rate charging and discharging of the cell, extend the charging and discharging time, reduce the charging time by about 16%-30%, extend the discharging time by 15%, and improve the electrical performance of the battery system.

[0088] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0089] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0090] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A battery pack cooling structure, characterized in that, The battery pack cooling structure includes: CCS components integrated into the top or side of the battery cell assembly; The CCS component includes: a plastic cooling plate; The plastic cooling plate is made of plastic with a thermal conductivity ≥ 1 W / (m·K); One side of the plastic cooling plate is in close contact with the cell spine of the cell assembly; The cell spine includes: the cell electrode post, the current collector lead-out end, and the area where the connecting pieces are distributed.

2. The battery pack cooling structure as described in claim 1, characterized in that, The cell assembly includes cells connected in series and / or in parallel.

3. The battery pack cooling structure as described in claim 1, characterized in that, The CCS assembly also includes: a sampling circuit board, a conductive connecting piece, and an insulating support.

4. The battery pack cooling structure as described in claim 1, characterized in that, The plastic cooling plate is made of one of the following materials: polyimide composite material, boron nitride-filled polypropylene, or graphene-reinforced polyamide.

5. The battery pack cooling structure as described in claim 1, characterized in that, The thickness of the plastic cooling plate is 0.5-0.7 mm.

6. The battery pack cooling structure as described in claim 1, characterized in that, The contact surface structure of the plastic cooling plate that is in close contact with the spine of the battery cell includes: a wavy structure and / or a serrated structure.

7. The battery pack cooling structure as described in claim 1, characterized in that, The plastic cooling plate has serpentine and / or spiral cooling channels inside.

8. The battery pack cooling structure as described in claim 7, characterized in that, The cross-section of the cooling channel includes: a circle and / or a polygon; Preferably, the depth of the cooling channel is 1-5 mm; Preferably, the width of the cooling channel is 1-3 mm.

9. The battery pack cooling structure as described in claim 7, characterized in that, The cooling channel extends to the edge of the CCS assembly and connects to the external cooling pipeline.

10. The battery pack cooling structure as described in claim 3, characterized in that, The connection method between the plastic cooling plate and the insulating bracket includes: one of the following: embedded injection molding process, snap-fit ​​connection or adhesive connection.

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