Power battery liquid cooling system and heat exchange method

Abstract

The application discloses a power battery liquid cooling system, which comprises a plurality of array-distributed upper oil-immersed battery boxes and a plurality of array-distributed lower oil-immersed battery boxes; the lower side of each upper oil-immersed battery box is integrally connected with a lower oil-immersed battery box; the upper oil-immersed battery box and the lower oil-immersed battery box are respectively provided with airtight upper oil-immersed battery compartments and lower oil-immersed battery compartments; the system further comprises a heat pump heat exchanger, an a liquid guide pipe and a b liquid guide pipe; one end of the a liquid guide pipe is communicated with one end of the b liquid guide pipe through a heat exchange pipe in the heat pump heat exchanger; a bidirectional pump is arranged on the a liquid guide pipe; the upper oil-immersed battery compartments in the upper oil-immersed battery boxes are communicated with the a liquid guide pipe through upper communication nozzles; the lower oil-immersed battery compartments in the lower oil-immersed battery boxes are communicated with the b liquid guide pipe through lower communication nozzles; the power battery liquid cooling system improves the heat dissipation efficiency of single battery cells and effectively avoids the formation of local high-temperature zones in the oil-immersed battery module.

Description

Technical Field

[0001] This invention belongs to the field of battery cooling. Background Technology

[0002] Oil-immersed power batteries completely immerse the battery cells in cooling oil within the battery case. Because they are completely surrounded by cooling oil, the heat transfer contact area of ​​each individual cell is maximized, effectively improving the heat dissipation efficiency of any single cell. Using common cylindrical cells such as 18650, 18500, 14500, and 26650, when the cells are arranged in an oil-immersed battery case, a cooling oil cavity is formed within the area enclosed by any four adjacent cylindrical battery cells arranged in a rectangular pattern. Figure 5 As indicated by markings 16a and 16b, the cooling oil cavities are separated by the battery; heat tends to accumulate in each cooling oil cavity, which can easily lead to the formation of localized high-temperature zones inside the oil-immersed battery box. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the prior art, the present invention provides a liquid cooling system and heat exchange method for power batteries, which improves the heat dissipation efficiency of individual battery cells while effectively avoiding the formation of local high temperature zones in oil-immersed battery modules.

[0004] Technical Solution: To achieve the above objectives, the present invention provides a power battery liquid cooling system, comprising several arrayed upper oil-immersed battery boxes and several arrayed lower oil-immersed battery boxes; each upper oil-immersed battery box is integrally connected to a lower oil-immersed battery box on its lower side, and the upper and lower oil-immersed battery boxes contain sealed upper and lower oil-immersed battery compartments, respectively; it also includes a heat pump heat exchanger, an a-type liquid guide pipe, and a b-type liquid guide pipe, one end of the a-type liquid guide pipe and one end of the b-type liquid guide pipe being connected through a heat exchange pipe in the heat pump heat exchanger; a bidirectional pump is installed on the a-type liquid guide pipe; the upper oil-immersed battery compartments in each upper oil-immersed battery box are connected to the a-type liquid guide pipe through an upper connecting nozzle; the lower oil-immersed battery compartments in each lower oil-immersed battery box are connected to the b-type liquid guide pipe through a lower connecting nozzle.

[0005] Furthermore, the bidirectional pump is a gear pump.

[0006] Furthermore, several upper cylindrical battery cells are arranged in a rectangular array adjacent to each other in the upper oil-immersed battery compartment, and all of the upper cylindrical battery cells are immersed in the cooling oil in the upper oil-immersed battery compartment.

[0007] The lower oil-immersed battery compartment contains a rectangular array of adjacent lower cylindrical battery cells, all of which are immersed in the cooling oil within the compartment.

[0008] Furthermore, the upper oil-immersed battery compartment and the lower oil-immersed battery compartment are separated by a partition plate.

[0009] Furthermore, an upper cooling oil cavity is formed within the enclosure of any four adjacent upper columnar battery cells arranged in a rectangular shape within the upper oil-immersed battery compartment.

[0010] Within the lower oil-immersed battery compartment, a lower cooling oil cavity is formed within the enclosure of any four adjacent lower cylindrical battery cells arranged in a rectangular shape.

[0011] Each upper oil-immersed battery compartment has a corresponding lower cooling oil cavity directly below it.

[0012] Furthermore, each of the corresponding upper oil-immersed battery compartments and lower cooling oil cavities has a through-hole sleeve. Each sleeve is fitted with a rigid, vertically oriented gas exchange pipe, and the upper and lower ends of each gas exchange pipe are connected to an upper elastic airbag and a lower elastic airbag, respectively. The upper and lower elastic airbags are distributed along their length within the upper and lower cooling oil cavities. When the pressure in the upper oil-immersed battery compartment gradually increases and the pressure in the lower oil-immersed battery compartment gradually decreases, the upper elastic airbag gradually contracts under external pressure, while the lower elastic airbag gradually expands outward under internal pressure. Conversely, when the pressure in the upper oil-immersed battery compartment gradually decreases and the pressure in the lower oil-immersed battery compartment gradually increases, the upper elastic airbag gradually expands outward under internal pressure, while the lower elastic airbag gradually contracts under external pressure.

[0013] Furthermore, both the upper and lower elastic airbags are made of elastic silicone.

[0014] Furthermore, a heat exchange method for a power battery liquid cooling system:

[0015] The heat pump heat exchanger continuously cools the air, constantly absorbing heat from the heat exchange tubes; at the same time, it controls the bidirectional pump to operate in a periodic forward and reverse direction.

[0016] Beneficial effects: During the periodic forward and reverse operation of the bidirectional pump of the present invention, each upper elastic air bladder and each lower elastic air bladder alternately contracts and expands, so that each lower cooling oil cavity and each upper cooling oil cavity periodically exchange liquids through the heat exchange tubes that are continuously heated by the heat pump heat exchanger. Each exchange cycle of the liquid in each lower cooling oil cavity and each upper cooling oil cavity is heated by the heat exchange tubes at least twice. This invention effectively avoids the problem of no liquid exchange in local cavities, improves the uniformity of liquid exchange, and thus effectively avoids the accumulation of heat in each upper cooling oil cavity and each lower cooling oil cavity, and ultimately avoids the formation of local high temperature zones in the upper and lower oil-immersed battery boxes.

[0017] When the upper or lower cylindrical battery cell bulges, or when temperature changes cause expansion or contraction, the upper or lower elastic air bladders will automatically and adaptively contract and deform according to the external pressure, thus avoiding the problem of sudden internal pressure caused by the bulging of battery cells in the upper or lower oil-immersed battery compartment. Attached Figure Description

[0018] Figure 1 This is a front view of the overall cooling system.

[0019] Figure 2 This is a three-dimensional view of the overall cooling system;

[0020] Figure 3 This is a first cross-sectional view of the integrated connection between the lower and upper oil-immersed battery boxes.

[0021] Figure 4 This is a second cross-sectional view of the integrated connection between the lower and upper oil-immersed battery boxes.

[0022] Figure 5 This is a disassembly diagram of the lower and upper oil-immersed battery boxes. Detailed Implementation

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] As attached Figures 1 to 5 The power battery liquid cooling system shown is as follows: Figure 1 and 2 As shown, the system includes several arrayed upper oil-immersed battery boxes 1 and several arrayed lower oil-immersed battery boxes 2; each upper oil-immersed battery box 1 is integrally connected to a lower oil-immersed battery box 2 on its lower side, and the upper oil-immersed battery box 1 and the lower oil-immersed battery box 2 contain sealed upper oil-immersed battery compartments 20 and lower oil-immersed battery compartments 21, respectively; it also includes a heat pump heat exchanger 9, an a liquid guide pipe 11 and a b liquid guide pipe 12, one end of the a liquid guide pipe 11 and one end of the b liquid guide pipe 12 are connected through a heat exchange pipe 15 in the heat pump heat exchanger 9; a bidirectional pump 10 is installed on the a liquid guide pipe 11, and the bidirectional pump 10 is a gear pump; the upper oil-immersed battery compartments 20 in each upper oil-immersed battery box 1 are connected to the a liquid guide pipe 11 through an upper connecting nozzle 13; the lower oil-immersed battery compartments 21 in each lower oil-immersed battery box 2 are connected to the b liquid guide pipe 12 through a lower connecting nozzle 14.

[0025] like Figure 3 , 4As shown in Figure 5, several upper cylindrical battery units 7 are arranged in a rectangular array adjacent to each other in the upper oil-immersed battery compartment 20, and all of the upper cylindrical battery units 7 are immersed in the cooling oil in the upper oil-immersed battery compartment 20; several lower cylindrical battery units 8 are arranged in a rectangular array adjacent to each other in the lower oil-immersed battery compartment 21, and all of the lower cylindrical battery units 8 are immersed in the cooling oil in the lower oil-immersed battery compartment 21.

[0026] The upper oil-immersed battery compartment 20 and the lower oil-immersed battery compartment 21 are separated by a partition plate 3; the array arrangement of the upper columnar battery units 7 in the upper oil-immersed battery compartment 20 is the same as the array arrangement of the lower columnar battery units 8 in the lower oil-immersed battery compartment 21.

[0027] like Figure 5 As shown, an upper cooling oil cavity 16a is formed within the enclosure of four adjacent upper cylindrical battery cells 7 arranged in a rectangular shape within the upper oil-immersed battery compartment 20; a lower cooling oil cavity 16b is formed within the enclosure of four adjacent lower cylindrical battery cells 8 arranged in a rectangular shape within the lower oil-immersed battery compartment 20.

[0028] Each upper oil-immersed battery compartment 20 has a corresponding lower cooling oil cavity 16b directly below it. The partition plate 3 between any two corresponding upper oil-immersed battery compartments 20 and lower cooling oil cavities 16b is provided with a through-hole 16. Each through-hole 16 contains a rigid, vertically fitted gas exchange pipe 5. The upper and lower ends of each gas exchange pipe 5 are connected to an upper elastic airbag 4 and a lower elastic airbag 6. Both the upper and lower elastic airbags 4 and 6 are made of elastic silicone, and like a balloon structure, they can expand and contract adaptively according to the pressure difference between the inside and outside. The upper elastic airbags 4 and 6 are distributed along their length in the upper cooling oil cavity 16a and lower cooling oil cavity 16b, respectively. The upper elastic airbags 4 and 6 are pre-filled with inert gas.

[0029] When the pressure inside the upper oil-immersed battery compartment 20 gradually increases and the pressure inside the lower oil-immersed battery compartment 21 gradually decreases, the upper elastic airbag 4 gradually contracts and shrinks under external pressure, while the lower elastic airbag 6 gradually expands outward under internal pressure; when the pressure inside the upper oil-immersed battery compartment 20 gradually decreases and the pressure inside the lower oil-immersed battery compartment 21 gradually increases, the upper elastic airbag 4 gradually expands outward under internal pressure, while the lower elastic airbag 6 gradually contracts and shrinks under external pressure.

[0030] Working principle: The heat pump heat exchanger 9 continuously cools, thereby continuously absorbing heat from the heat exchange tube 15; at the same time, the bidirectional pump 10 is controlled to operate in a periodic forward and reverse direction.

[0031] When the bidirectional pump 10 is running in the forward direction, driven by the bidirectional pump 10, the cooling oil in the lower oil-immersed battery compartment 21 of each lower oil-immersed battery box 2 is gradually pumped into the upper oil-immersed battery compartment 20 of each upper oil-immersed battery box 1 through the b liquid guide pipe 12, heat exchange pipe 15 and a liquid guide pipe 11. This causes the pressure in the upper oil-immersed battery compartment 20 to gradually increase and the pressure in the lower oil-immersed battery compartment 21 to gradually decrease. Consequently, each upper elastic airbag 4 gradually contracts and shrinks under external pressure. After each upper elastic airbag 4 contracts and shrinks, each upper cooling... Cooling oil is gradually added to each oil cavity 16a. At the same time, the gas in each of the gradually shrinking upper elastic air bladders 4 is squeezed into the lower elastic air bladders 6 through the gas exchange pipe 5. The lower elastic air bladders 6 gradually expand outward under internal pressure. The gradually expanding lower elastic air bladders 6 squeeze out the coolant that was originally filling each of the lower cooling oil cavities 16b. After the coolant in each of the lower cooling oil cavities 16b is squeezed out, it is successively replenished to each of the upper cooling oil cavities 16a through the b liquid guide pipe 12, the heat exchange pipe 15 and the a liquid guide pipe 11.

[0032] When the bidirectional pump 10 operates in reverse, driven by the bidirectional pump 10, the cooling oil in the upper oil-immersed battery compartment 20 of each upper oil-immersed battery box 1 is gradually pumped into the lower oil-immersed battery compartment 21 of each lower oil-immersed battery box 2 through the a liquid guide pipe 11, heat exchange pipe 15 and b liquid guide pipe 12. This causes the pressure in the lower oil-immersed battery compartment 21 to gradually increase and the pressure in the upper oil-immersed battery compartment 20 to gradually decrease. Consequently, each lower elastic airbag 6 gradually contracts and shrinks under external pressure. After each lower elastic airbag 6 contracts and shrinks, each lower cooling... Cooling oil is gradually added to each oil cavity 16b. At the same time, the gas in each of the gradually shrinking lower elastic air bladders 6 is squeezed into the upper elastic air bladder 4 through the gas exchange pipe 5. The upper elastic air bladder 4 gradually expands outward under internal pressure. The gradually expanding upper elastic air bladders 4 squeeze out the coolant that was originally filled in each of the upper cooling oil cavities 16a. After the coolant in each of the upper cooling oil cavities 16a is squeezed out, it is successively replenished into each of the lower cooling oil cavities 16b through the a liquid guide pipe 11, the heat exchange pipe 15 and the b liquid guide pipe 12.

[0033] Based on the above analysis, during the periodic forward and reverse operation of the bidirectional pump 10, the upper elastic air bladders 4 and the lower elastic air bladders 6 alternately contract and expand, so that the lower cooling oil cavities 16b and the upper cooling oil cavities 16a periodically exchange liquid through the heat exchange tubes 15 that are continuously heated by the heat pump heat exchanger 9. In each exchange cycle, the liquid in the lower cooling oil cavities 16b and the upper cooling oil cavities 16a is heated by the heat exchange tubes 15 at least twice. This design effectively avoids the problem of no liquid exchange in local cavities, improves the uniformity of liquid exchange, and thus effectively avoids the accumulation of heat in the upper cooling oil cavities 16a and the lower cooling oil cavities 16b, and ultimately avoids the formation of local high temperature zones in the upper oil-immersed battery box 1 and the lower oil-immersed battery box 2.

[0034] Similarly, when heating occurs, if the upper cylindrical battery unit 7 or the lower cylindrical battery unit 8 bulges, or if temperature changes cause expansion or contraction, the upper elastic airbag 4 or the lower elastic airbag 6 will automatically and adaptively contract and deform according to the external pressure of the airbag, thus avoiding the problem of sudden internal pressure caused by the bulging of the battery units in the upper oil-immersed battery compartment 20 or the lower oil-immersed battery compartment 21.

[0035] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A liquid cooling system for a power battery, characterized in that: It includes several arrays of upper oil-immersed battery boxes (1) and several arrays of lower oil-immersed battery boxes (2); each upper oil-immersed battery box (1) is integrally connected to a lower oil-immersed battery box (2) on its lower side, and the upper oil-immersed battery box (1) and the lower oil-immersed battery box (2) contain sealed upper oil-immersed battery compartments (20) and lower oil-immersed battery compartments (21), respectively. It also includes a heat pump heat exchanger (9), a liquid guide pipe (11) and a liquid guide pipe (12), one end of the liquid guide pipe (11) and one end of the liquid guide pipe (12) are connected through the heat exchange tube (15) in the heat pump heat exchanger (9); A bidirectional pump (10) is installed on the liquid guide pipe (11); the upper oil-immersed battery compartments (20) in each upper oil-immersed battery box (1) are all connected to the liquid guide pipe (11) through the upper connecting nozzle (13); the lower oil-immersed battery compartments (21) in each lower oil-immersed battery box (2) are all connected to the liquid guide pipe (12) through the lower connecting nozzle (14). The upper oil-immersed battery compartment (20) contains a rectangular array of several upper cylindrical battery units (7) arranged close together, and the upper cylindrical battery units (7) are all immersed in the cooling oil in the upper oil-immersed battery compartment (20); The lower oil-immersed battery compartment (21) contains a rectangular array of several lower cylindrical battery units (8) arranged close together, and all of the lower cylindrical battery units (8) are immersed in the cooling oil in the lower oil-immersed battery compartment (21). The upper oil-immersed battery compartment (20) and the lower oil-immersed battery compartment (21) are separated by a partition plate (3); An upper cooling oil cavity (16a) is formed within the enclosure of any four adjacent upper columnar battery cells (7) arranged in a rectangular shape in the upper oil-immersed battery compartment (20). Within the lower oil-immersed battery compartment (20), a lower cooling oil cavity (16b) is formed within the enclosure of any four adjacent lower columnar battery cells (8) arranged in a rectangular shape. Each upper oil-immersed battery compartment (20) has a corresponding lower cooling oil cavity (16b) directly below it. Each of the upper oil-immersed battery compartment (20) and the lower cooling oil cavity (16b) is provided with a sleeve hole (16) that runs vertically through each other. Each sleeve hole (16) is fitted with a rigid and vertical gas exchange tube (5) that is press-fitted into it. The upper and lower ends of each gas exchange tube (5) are connected to an upper elastic airbag (4) and a lower elastic airbag (6). The upper elastic airbag (4) and the lower elastic airbag (6) are distributed along the length direction in the upper cooling oil cavity (16a) and the lower cooling oil cavity (16b), respectively; When the pressure inside the upper oil-immersed battery compartment (20) gradually increases and the pressure inside the lower oil-immersed battery compartment (21) gradually decreases, the upper elastic airbag (4) gradually contracts and shrinks under external pressure, and the lower elastic airbag (6) gradually expands outward under internal pressure. As the pressure inside the upper oil-immersed battery compartment (20) gradually decreases and the pressure inside the lower oil-immersed battery compartment (21) gradually increases, the upper elastic airbag (4) gradually expands outward under the internal pressure, and the lower elastic airbag (6) gradually contracts and shrinks under the external pressure.

2. The power battery liquid cooling system according to claim 1, characterized in that: The bidirectional pump (10) is a gear pump.

3. The power battery liquid cooling system according to claim 1, characterized in that: Both the upper elastic airbag (4) and the lower elastic airbag (6) are made of elastic silicone.

4. The heat exchange method of a power battery liquid cooling system according to claim 1, characterized in that: The heat pump heat exchanger (9) continuously cools and continuously absorbs heat from the heat exchange tube (15); at the same time, it controls the bidirectional pump (10) to run in a periodic forward and reverse direction.

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