Immersed cooling power battery pack based on cross-flow runner

Abstract

The invention provides an immersed cooling power battery pack based on a cross-flow runner, which comprises a box body, batteries and a side cover, the batteries are arranged in groups in the box body; the flow guide partition plates are arranged between every two adjacent rows of batteries to form battery gap flow channels with cross flow on two adjacent sides, and a lower opening and an upper opening are formed in each of two sides of the box body; the side covers are tightly attached to the two sides of the box body, and a main inlet and a main outlet are formed in each side cover; the cooling liquid flows into the box body from the main inlet on one side, is discharged from the main outlet on the other side after passing through the battery gap flow channel, and is circulated to the main inlet again through an external water cooling machine; through the immersion cooling structure of the bidirectional cross-flow type flow channel, the temperature of the battery during charge-discharge circulation is effectively reduced, the temperature consistency of the battery is improved, and the probability of thermal runaway of the battery is reduced; and battery tabs are separated from the cooling liquid, and the battery is convenient to maintain and replace through liquid-electricity-gas separation design, so that early warning of thermal runaway of the battery is realized, and the electrical safety of the battery is ensured.

Description

Technical Field

[0001] The present invention relates to the field of energy and power technology, and in particular to an immersion-cooled power battery pack based on a cross-flow channel. Background Art

[0002] The development of new energy vehicles is the only way for my country to move from a large automobile country to a powerful automobile country. The "New Energy Vehicle Industry Development Plan (2021-2035)" proposes that the average energy consumption of new pure electric passenger vehicles will be reduced to 12 kWh / 100 km in 2025. Lithium batteries have become the mainstream choice of power batteries for new energy vehicles due to their high energy density and long cycle life. Research on lithium batteries has always been a hot topic in the new energy industry.

[0003] Current research shows that the optimal operating temperature of lithium batteries is around 20-40°C, and the maximum operating temperature difference between single cells should be less than 5°C. When the battery temperature is too high, it will easily cause thermal runaway of the battery, leading to fire and explosion of the vehicle. Effectively controlling the temperature of the lithium battery pack and performing reasonable heat dissipation have become the design focus of the battery management system.

[0004] At present, the mainstream battery pack heat dissipation methods include air cooling, liquid cooling and phase change cooling. Air cooling is favored by many companies in the early stage of new energy development because of its low price and simple design, but it is limited by the low thermal conductivity of air and cannot meet the current high-rate charging and discharging needs. Phase change cooling mainly uses the high latent heat of phase change materials to dissipate heat, but it will take up too much space and cannot meet the current requirements for highly integrated battery packs. Liquid cooling has become the main solution for companies to design new energy vehicles because of its good heat dissipation effect in high temperature environments, and has huge development potential and demand.

[0005] With the large-size of battery cells and the development of battery integration technology, the battery temperature rises rapidly during high-rate charging and discharging, and the battery temperature consistency is relatively poor. The traditional liquid cooling solution cannot meet the thermal management requirements of the battery under high-rate charging and discharging. Currently, most of the liquid cooling methods for power batteries on the market are cold plate heat dissipation structures, but are limited by the relatively single layout of the cold plate heat dissipation structure, the heat transfer path from the battery cell to the cold plate is long, and the overall heat transfer thermal resistance is relatively large. When the battery pack is large, the cold plate heat dissipation structure cannot ensure uniform battery temperature at all positions, thereby increasing the risk of thermal runaway of the battery pack. Summary of the invention

[0006] The object of the present invention is to provide a device that can effectively dissipate heat from a battery pack to ensure the consistency and safety of the internal temperature of the battery pack during operation.

[0007] To achieve the above object, the present invention proposes an immersion cooling power battery pack based on a cross-flow channel, comprising a box, a battery and a side cover:

[0008] The batteries are arranged in groups in the box, the batteries are arranged alternately with positive and negative on the same side, and the box is filled with coolant;

[0009] The box body is internally provided with a flow guide baffle, and the flow guide baffle is arranged between each two adjacent rows of batteries to form a battery gap flow channel, and the battery gap flow channel is a curved flow channel with cross-flow on the adjacent two sides;

[0010] Both sides of the box body are provided with a lower opening and an upper opening, and the lower opening and the upper opening are respectively the inlet and the outlet of the battery gap flow channel;

[0011] The side covers are closely attached to both sides of the box body, and a main inlet and a main outlet are provided on the side covers; so that the coolant flows into the box body from the main inlet on one side, passes through the battery gap flow channel, is discharged from the main outlet on the other side, and then passes through the external water cooler and circulates to the main inlet again;

[0012] The two sides of the tabs of the battery pack are sealed with coolant to form a tab cavity; a smoke guide device is arranged in the tab cavity to form a liquid-electricity-gas separation structure.

[0013] Furthermore, the battery gap flow channel is a curved flow channel with cross-flow on adjacent sides, the inlet and outlet positions of adjacent battery gap flow channels are oppositely distributed, the flow direction of the coolant in adjacent battery gap flow channels is opposite, and a separate coolant immersion space is formed between every two rows of batteries.

[0014] Furthermore, upper openings and lower openings are provided on both sides of the box body, and the upper openings and lower openings on the same side of the box body form two rows of staggered arrangement structures, so that adjacent battery gap flow channels are independent of each other, and the coolant enters the battery gap flow channels from the lower openings on both sides of the box body, and then flows out from the upper opening on the other side, forming a bidirectional cross-flow flow channel.

[0015] Furthermore, the side covers are closely attached to the two sides of the box body, so that a cavity is formed between the side covers and the two sides of the box body; each side cover is provided with a main inlet and a main outlet; the main inlet is close to the bottom end of the side cover, and the main outlet is close to the top end of the side cover; the cavity between the main inlet and the lower opening of the box body forms a confluence area, and the cavity between the main outlet and the upper opening forms a diversion area;

[0016] The coolant flows into the confluence area from the main inlet of the side cover, enters the interior of the box through the lower opening on one side of the box, flows into the diversion area from the upper opening on the other side of the box, and finally is discharged through the main outlet and circulated to the main inlet through the water cooler.

[0017] Furthermore, the coolant sealing cover is arranged at the upper and lower ends of the battery; the top opening and the bottom opening of the box body are respectively installed with an upper end cover and a lower end cover; so that the upper end cover and the lower end cover respectively form upper and lower end ear cavities with the coolant sealing covers at the ends of the battery ears, isolating the ears at both ends of the battery from the coolant.

[0018] The tab parts at the upper and lower ends of the battery and the tab connectors are not immersed in the coolant, and the part of the cylindrical battery between the upper and lower coolant sealing covers is immersed in the coolant.

[0019] Furthermore, the coolant sealing cover is provided with a plurality of openings, and the apertures of the openings are consistent with the diameters of the two ends of the battery.

[0020] Furthermore, the smoke guide device is arranged in the tab cavity, and the smoke guide device contains a gas detection sensor for early thermal runaway warning.

[0021] Furthermore, the tabs between adjacent batteries are connected by copper bars, so that a series circuit connection or a parallel circuit connection is formed between the adjacent batteries, and the copper bars are located between the battery tabs and the smoke guide device.

[0022] Furthermore, the battery is a cylindrical battery, the positive and negative poles of adjacent cylindrical batteries are facing opposite directions, and the battery pressure relief valve faces the side other than the coolant.

[0023] Furthermore, the coolant sealing cover is sealed with sealant at the gaps between the inner wall of the box and the surface of the cylindrical battery to isolate the coolant and electrical components; the gap between the smoke diversion device and the inner wall of the box is sealed with sealant so that when the battery is abnormal, the gas ejected from the battery pressure relief valve can all enter the smoke diversion device.

[0024] Furthermore, adjacent batteries in the battery pack are connected by sealant; and the guide baffle is attached between each two adjacent rows of batteries by sealant.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] 1. The present invention separates the coolant from the electrical components through the liquid-electricity-gas separation structural design, which effectively prevents the particles ejected from the pressure relief valve from generating arcs and aggravating the heat spread of the battery when the battery is under thermal runaway. At the same time, since the battery pressure relief valve will eject smoke before the battery is under thermal runaway, the smoke ejected from the battery pressure relief valve can be detected by the smoke diversion device in conjunction with the internal gas sensor, and the battery thermal runaway warning can be achieved in seconds in conjunction with the BMS.

[0027] 2. The present invention adopts the structure of the cross-flow channel and the external water cooler to circulate the coolant inside and outside, which effectively reduces the battery temperature, makes the cooling area larger, and improves the heat transfer efficiency. At the same time, the liquid-electric-gas separation design makes it unnecessary to immerse the battery box in the immersion liquid, making the entire cooling system lighter and saving the amount of coolant.

[0028] 3. The design of the total coolant inlet and outlet and multiple inlet and outlet branches of the present invention enables more uniform heat dissipation on both sides of the battery, improves the uniformity of battery temperature, effectively reduces the risk of thermal runaway, and improves the safety of the overall system.

[0029] 4. The liquid-electric-gas separation structure of the present invention can effectively detect the smoke ejected from the pressure relief valve before the battery thermal runaway, and cooperate with the BMS experiment to provide a thermal runaway warning in seconds; at the same time, since the electrical components such as the pole ear are separated from the coolant, it not only prevents the particles ejected from the pressure relief valve during the battery thermal runaway from generating a short-circuit arc and aggravating the phenomenon of battery heat spread, but is also more conducive to the later replacement and maintenance of the battery cells.

[0030] 5. The flow channel integrated box body and the flow channel integrated side cover structure of the present invention form two confluence areas and two divergence areas between the box body and the side cover; this area is not only used for the circulation of the coolant, but the cavity structure can also serve as a collision and collapse energy absorption structure for the battery pack when the vehicle is subjected to a side collision, thereby protecting the safety of the battery cells inside the battery pack.

[0031] 6. The design of the integrated flow channel box and the built-in flow channel partition of the present invention forms two cross-flow channels for every three rows of batteries, and the coolant cools the batteries from bottom to top, which not only improves the cooling effect of the batteries, but also reduces the shaking load of the liquid inside the battery pack on the inner wall of the battery box during the automobile forming process. This design scheme can be effectively used in actual vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of an immersion cooling power battery pack based on a cross-flow channel according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the flow direction of the cooling medium in the battery pack according to an embodiment of the present invention;

[0034] Figure 3 Schematic diagram of the flow channel between batteries in a battery pack according to an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of the coolant flow in a certain gap flow channel section in a battery pack according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described below.

[0037] This embodiment proposes an immersion cooling power battery pack based on a cross-flow channel, such as Figure 1 As shown, the battery pack includes a box body 6, cylindrical batteries 5 and a side cover 5, wherein the cylindrical batteries 5 are arranged in a honeycomb pattern and placed in a group in the box body 6, and the box body 6 is filled with coolant. The cylindrical batteries 5 are arranged in a staggered manner with positive and negative electrodes on the same side, and the positive and negative electrodes of adjacent cylindrical batteries 5 face opposite directions, and the battery pressure relief valve faces the side other than the coolant.

[0038] The box body 6 is built with a guide baffle, which is attached between each adjacent row of cylindrical batteries 5 through a sealant to separate the cylindrical surfaces of each row of cylindrical batteries 5, so that the coolant cools the battery 5 from bottom to top, forming a battery gap flow channel with a cross-flow channel structure, such as Figure 2 As shown, the battery gap flow channel is a curved flow channel with cross-flow on adjacent sides. Every three rows of batteries form two rows of cross-flow flow channels. The inlet and outlet positions of adjacent battery gap flow channels are oppositely distributed, and the flow direction of the coolant in the adjacent battery gap flow channels is opposite.

[0039] In this embodiment, both sides of the box body 6 are provided with upper openings and lower openings in two rows, which are staggered and distributed. Figure 3 As shown, the upper opening on each side is the inlet of the battery gap flow channel, and the lower opening is the outlet of the battery gap flow channel, that is, the coolant enters the battery gap flow channel from the lower openings on both sides of the box body and flows out from the upper opening, so that adjacent battery gap flow channels are independent of each other.

[0040] In addition, the two side covers 4 are respectively attached to the left and right sides of the box body 6, and the left and right side covers 4 are both provided with a total inlet and a total outlet. The total inlet is close to the bottom end of the side cover 4; the total outlet is close to the top end of the side cover 4, the total inlet is divided into a left lower total inlet and a right lower total inlet, and the total outlet is divided into a left upper total outlet and a right upper total outlet;

[0041] like Figure 1 As shown, four cavities are formed between the side cover 4 and the left and right sides of the box body 6, two on each side. The cavity between the lower left main inlet and the lower left opening of the box body forms the left confluence area, and the cavity between the upper right main outlet and the upper right opening of the box body forms the right diversion area; the cavity between the lower right main inlet and the lower right opening of the box body forms the right confluence area; the cavity between the upper left main outlet and the upper left opening of the box body forms the left diversion area.

[0042] Figure 3 and Figure 4It is an independent fluid domain flow direction. The coolant flows from the left lower total inlet of the side cover 4 into the left confluence area, enters the interior of the box body 6 through the lower opening on the left side of the box body, flows into the battery gap flow channel, and then flows from the upper opening on the right side of the box body into the right diversion area, and finally is discharged through the upper total outlet on the right side, completing a complete cycle. At the same time, through the adjacent gap flow channel, the flow direction of another fluid domain is completely opposite, that is, the coolant enters the right confluence area from the right lower total inlet of the side cover 4, enters the interior of the box body 6 through the lower opening on the right side of the box body, flows in the opposite direction into the battery gap flow channel, and then flows from the upper opening on the left side of the box body into the left diversion area, and finally is discharged through the upper total outlet on the left side, forming a two-way cross-flow flow channel, and circulates to the total inlet through the water cooler. The two opposite fluid domains jointly form cross-flow cooling for the battery pack, thereby achieving more uniform cooling of both sides of the cylindrical battery 5.

[0043] In addition, if Figure 1 As shown, the two ends of the cylindrical battery 2 are provided with pole ears, and the upper and lower pole ears of the cylindrical battery group 5 are installed with coolant sealing covers 3. The top opening and the bottom opening of the box 6 are respectively installed with box cover plates 1, that is, the upper end cover plate and the lower end cover plate. The upper end cover plate and the lower end cover plate respectively form a pole ear cavity with the coolant sealing covers 3 at the pole ears at both ends of the battery group. The battery pole ear is placed in the pole ear cavity, so as to isolate the battery pole ear from the coolant and realize liquid-electric separation. At the same time, a smoke diversion device, that is, a smoke exhaust groove, is provided in the pole ear cavity. The smoke exhaust groove can discharge the smoke from the pole ear position cavity in time when thermal runaway occurs. A gas detection sensor is contained in the smoke exhaust groove for early thermal runaway warning, thereby further forming a liquid-electric-gas separation structure. The liquid-electric-gas separation structure is located on the upper and lower sides of the cylindrical battery group 5, and the structures and components on the upper and lower sides are consistent.

[0044] In this embodiment, the tabs between adjacent cylindrical batteries 5 are connected by a bus bar 2, so that adjacent cylindrical batteries 5 form a series circuit connection or a parallel circuit connection. The bus bar 2 is located between the battery tabs and the smoke exhaust groove.

[0045] In this embodiment, an immersed cross-flow channel structure is formed by the cylindrical surface of the cylindrical battery 5, the flow channel partition, the upper and lower openings on both sides of the box body, and the total inlet and outlet of the side cover, forming an immersed cooling system. In this cooling system, the coolant flows in from the lower total inlet of the side cover 4, flows through the one side cavity (i.e., the confluence area) formed by the box body 6 and the side cover 4, flows into the inside of the box body 6 through the lower opening on one side of both sides of the box body 6, flows through the battery gap flow channel, and then flows into the other side cavity (i.e., the diversion area) formed by the box body 6 and the side cover 4 through the other side upper opening on both sides of the box body 6, and finally flows out through the upper total outlet of the side cover 4, and the coolant circulates through an external water cooler.

[0046] In this embodiment, adjacent cylindrical batteries 5 are connected by sealants; the coolant sealing cover 3 and the inner wall of the box body 6 and the gaps on the surface of the cylindrical batteries 5 are sealed with sealants; the gap between the smoke exhaust groove and the inner wall of the box body 6 is also sealed with sealants, so that when the battery is abnormal, the gas ejected from the battery pressure relief valve can all enter the channel of the smoke diversion device.

[0047] In this embodiment, the flow channel partitions and the box body 6 are an integrated structure and are staggered in length.

[0048] In this embodiment, a BMS protective cover 8 is also installed on the outer wall of the box body. The gas sensor arranged in the tab cavity inside the box body 6 can detect the characteristic gas before thermal runaway and send a signal to the BMS device 7 to realize the early warning function.

[0049] In this embodiment, Figure 4 As shown, the confluence area and the divergence area on both sides of the box body 6 can serve as collision collapse energy absorption structures when a collision occurs, and deform to absorb the impact to protect the battery cells.

[0050] The present invention has a simple structure and is easy to install, and can dissipate heat for the battery effectively and more evenly; at the same time, it can provide early warning of thermal runaway in conjunction with a gas sensor; the liquid-electric-gas separation structure can quickly discharge smoke even after thermal runaway occurs, and can effectively suppress heat spread in conjunction with a coolant; the cavity on the box body serves as a collision collapse energy absorption structure and can protect the battery cell to a certain extent during a collision.

[0051] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. An immersion cooling power battery pack based on a cross-flow channel, characterized in that: Including case, battery and side cover: The batteries are arranged in groups in the box, and the box is filled with cooling liquid; The box body is internally provided with a flow guide baffle, and the flow guide baffle is arranged between each two adjacent rows of batteries to form a battery gap flow channel, and the battery gap flow channel is a curved flow channel with cross-flow on the adjacent two sides; Both sides of the box body are provided with a lower opening and an upper opening, and the lower opening and the upper opening are respectively the inlet and the outlet of the battery gap flow channel; The side covers are closely attached to both sides of the box body, and a main inlet and a main outlet are provided on the side covers; so that the coolant flows into the box body from the main inlet on one side, passes through the battery gap flow channel, is discharged from the main outlet on the other side, and then passes through the external water cooler and circulates to the main inlet again; The two sides of the tabs of the battery pack are sealed with coolant to form a tab cavity; a smoke guide device is arranged in the tab cavity to form a liquid-electricity-gas separation structure.

2. The immersion cooling power battery pack based on the cross-flow channel according to claim 1 is characterized in that: The battery gap flow channel is a curved flow channel with cross-flow on adjacent two sides, the inlet and outlet positions of adjacent battery gap flow channels are oppositely distributed, and the flow directions of the coolant in the adjacent battery gap flow channels are opposite.

3. The immersion cooling power battery pack based on the cross-flow channel according to claim 2 is characterized in that: An upper opening and a lower opening are provided on both sides of the box body. The upper opening and the lower opening on the same side of the box body form an upper and lower row of staggered arrangement structures, so that adjacent battery gap flow channels are independent of each other. The coolant enters the battery gap flow channel from the lower openings on both sides of the box body, and then flows out from the upper opening on the other side, forming a bidirectional cross-flow flow channel.

4. The immersion cooling power battery pack based on the cross-flow channel according to claim 3 is characterized in that: The side covers are closely attached to the two sides of the box body, so that a cavity is formed between the side covers and the two sides of the box body; each side cover is provided with a main inlet and a main outlet; the main inlet is close to the bottom end of the side cover, and the main outlet is close to the top end of the side cover; the cavity between the main inlet and the lower opening of the box body forms a confluence area, and the cavity between the main outlet and the upper opening forms a diversion area; The coolant flows into the confluence area from the main inlet of the side cover, enters the interior of the box through the lower opening on one side of the box, flows into the diversion area from the upper opening on the other side of the box, and finally is discharged through the main outlet and circulated to the main inlet through the water cooler.

5. The immersion cooling power battery pack based on cross-flow channel according to claim 1, characterized in that: The coolant sealing cover is arranged at the upper and lower pole ears of the battery; the upper end cover and the lower end cover are respectively installed at the top opening and the bottom opening of the box body; the upper end cover and the lower end cover respectively form the pole ear cavities at the upper and lower ends with the coolant sealing cover at the pole ears at the two ends of the battery pack, isolating the pole ears at the two ends of the battery from the coolant.

6. The immersion cooling power battery pack based on the cross-flow channel according to claim 5, characterized in that: The coolant sealing cover is provided with a plurality of openings, and the apertures of the openings are consistent with the diameters of the two ends of the battery.

7. The immersion cooling power battery pack based on the cross-flow channel according to claim 1, characterized in that: The smoke guide device is arranged in the pole ear cavity, and the smoke guide device contains a gas detection sensor for early thermal runaway warning.

8. The immersion cooling power battery pack based on cross-flow channel according to claim 1, characterized in that: The tabs between adjacent batteries are connected by copper bars, so that the adjacent batteries form a series circuit connection or a parallel circuit connection. The copper bars are located between the battery tabs and the smoke guide device.

9. The immersion cooling power battery pack based on cross-flow channel according to claim 1, characterized in that: The battery is a cylindrical battery, the positive and negative poles of adjacent cylindrical batteries are facing opposite directions, and the battery pressure relief valve faces the side not facing the coolant.

10. The immersion cooling power battery pack based on cross-flow channel according to claim 1, characterized in that: The coolant sealing cover is sealed with sealant at the gaps between the inner wall of the box and the surface of the battery; the gap between the smoke diversion device and the inner wall of the box is sealed with sealant, so that when the battery is abnormal, the gas ejected from the battery pressure relief valve can all enter the smoke diversion device.

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