A power battery pack and a cooling processing method thereof

Abstract

The application discloses a power battery pack and a cooling treatment method thereof, and sequentially comprises a tightly-fitted fireproof box, a cell module and a liquid cooling plate from top to bottom. A plurality of flow guide holes are formed in the bottom of the fireproof box. A plurality of exhaust valves are arranged on the top of the cell module. The number, position and profile of the exhaust valves are matched with the flow guide holes in the bottom of the fireproof box. The exhaust valves and the flow guide holes are in communication, forming a flow guide channel from the top of the cell to the exhaust pipe on the top of the fireproof box. The cell module comprises a cell array, fireproof cloth and an energy storage element. The cross section of the cell module has a plurality of first areas and second areas. The cells are arranged in the first areas. The energy storage element is arranged in the second areas. The first areas are arranged in a rectangular wave shape. Adjacent first areas are arranged in a staggered mode. The area ratio of the first areas to the second areas is 37:10. When a fire breaks out, the flow guide channel in the battery pack can directly discharge the flame and thermal runaway gas from the cells to the outside through the exhaust pipe.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power battery packs, and particularly relates to a power battery pack and a cooling treatment method thereof. BACKGROUND

[0002] With the wide popularization of new energy vehicles, the number of new energy vehicle fire accidents also increases year by year, attracting the attention of the industry and the whole society. The thermal runaway of power batteries is an important cause of new energy vehicle fire accidents. However, the triggering mechanism of the thermal runaway of power batteries is not clear, there are many causes, and the unanticipated thermal runaway is difficult to reproduce, which restricts the design of the power battery emergency management system and leads to problems such as new energy vehicle fire fighting difficulties. Researching the reproduction of new energy vehicle fire accidents, exploring the internal thermal spread and thermal diffusion process of the battery system, guiding the design of high-safety battery systems and post-fire emergency management, and finding out the causes of fire accidents are important research contents of new energy vehicle safety management.

[0003] The existing power battery pack is usually composed of battery cells connected into a module and placed inside the battery pack, or directly composed of battery cells. There is no other material to separate the battery cells, the battery pack and the module, which can improve the space utilization rate of the battery pack. However, this device does not consider the damage to other battery cells, the battery box and the electric vehicle caused by the fire of the thermal runaway battery cell. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a power battery pack and a cooling treatment method thereof. The battery cell array inside the power battery pack is not arranged in a conventional rectangular array, but in a staggered wave form to reduce heat transfer between two adjacent battery cells. Energy storage elements are arranged in the recessed place, which not only plays a role in cooling, but also improves the space utilization rate. When the power battery pack catches fire, the flow guide channel in the power battery pack can directly discharge the flame and thermal runaway gas from the battery cell to the outside through the exhaust pipe.

[0005] The first aspect of the present application provides a power battery pack, which comprises a control module and a battery module. The battery module comprises, from top to bottom, a fireproof box, a battery cell module and a liquid cooling plate. The bottom surface of the fireproof box and the top of the battery cell module are tightly attached. The bottom of the battery cell module and the top of the liquid cooling plate are tightly attached. A plurality of flow guide holes are formed in the bottom of the fireproof box. A plurality of exhaust valves are arranged on the top of the battery cell module. The number, position and profile of the exhaust valves are matched with the flow guide holes in the bottom of the fireproof box. The exhaust valves and the flow guide holes are connected to form a flow guide channel from the top of the battery cell to the exhaust pipe on the top of the fireproof box.

[0006] The fireproof box is a hollow box body used to contain thermal runaway gas and jet flames from the guide channel. It has holes on the top for installing multiple exhaust pipes. The ends of the exhaust pipes protrude from the top of the fireproof box for discharging smoke to the outside of the power battery pack after fire extinguishing. The inner wall of the fireproof box is coated with fire extinguishing agent.

[0007] The battery cell module includes a battery cell array, fireproof cloth, and energy storage elements. The cross-section of the battery cell module has multiple first regions and second regions. Battery cells are disposed in the first regions, and energy storage elements are disposed in the second regions. The first regions are arranged in a rectangular wave pattern, with adjacent first regions staggered, and the area ratio of the first region to the second region is 37:10.

[0008] The cell array consists of multiple cells arranged side by side, with adjacent cells staggered. A temperature sensor is installed at the center of the outer wall of one side of each cell. The temperature sensor communicates with the control module via a CAN bus, and each cell has an exhaust valve on its top.

[0009] The fireproof cloth is wrapped around the outer wall of the battery cell array for fire protection;

[0010] On the outside of the fireproof cloth, multiple energy storage elements are respectively filled in the recesses formed by the staggered battery cells, so that the cross-section of the battery cell module formed by the energy storage elements and the battery cell array wrapped in the fireproof cloth is rectangular. The energy storage elements are made of paraffin wax and are used for heat storage.

[0011] The liquid cooling plate is a hollow box with liquid cooling pipes inside. The liquid cooling pipes are laid in an S-shape inside the liquid cooling pipes, and the working fluid inside is water. A control valve is installed at the liquid inlet of the liquid cooling pipe. The control valve is electrically connected to the control module and is used to control the water flow rate according to the instructions of the control module.

[0012] The fireproof box has the same outer contour as the battery cell array, and the battery cell module has the same outer contour as the liquid cooling plate.

[0013] The control module is used to adjust the control valve at the liquid inlet of the liquid-cooled pipeline according to a pre-set threshold and the temperature detected by the temperature sensor, thereby controlling the flow rate of the working fluid.

[0014] Furthermore, a heat insulation plate is provided between two adjacent battery cells for heat insulation and fire prevention, and the heat insulation plate is located in the first area.

[0015] Furthermore, the top of the battery cell has two protruding tabs that form the positive and negative electrodes of the battery cell; the bottom of the fireproof box has a groove that matches the top contour of the battery cell module, so that the bottom of the fireproof box fits tightly with the battery cell module.

[0016] Further, a first fixing member is arranged on the outer wall of the fireproof cloth for fixing the fireproof cloth and the battery cell, the inner contour of the first fixing member is matched with the outer contour of the battery cell array surrounded by the fireproof cloth, and the first fixing member is bonded with the outer wall of the fireproof cloth.

[0017] Further, a second fixing member is arranged on the outer surface of the battery cell module for fixing the elements in the battery cell module, and the size of the second fixing member is matched with the outer surface of the battery cell module.

[0018] The second aspect of the application provides a cooling method of the power battery pack.

[0019] The temperature sensor of each battery cell monitors the temperature in real time and transmits the temperature to the control module, when the control module monitors that the highest battery cell temperature is 25-40 DEG C, the control valve at the liquid inlet of the liquid cooling pipe is adjusted, so that the flow rate of the working medium is 0.3 m / s;

[0020] When the highest battery cell temperature is monitored to be 40-60 DEG C, the control valve at the liquid inlet of the liquid cooling pipe is adjusted, so that the flow rate of the working medium is 0.8 m / s; when the temperature drops to 25-40 DEG C, return to the previous step, and adjust the control valve to reduce the flow rate of the working medium to 0.3 m / s;

[0021] When the battery cell temperature is monitored to be 60-90 DEG C, the control valve at the liquid inlet of the liquid cooling pipe is adjusted, so that the flow rate of the working medium in the liquid cooling pipe is 1.2 m / s; when the temperature drops to 40-60 DEG C, return to the previous step, and adjust the control valve to reduce the flow rate of the working medium to 0.8 m / s;

[0022] When the battery cell temperature is monitored to be more than 90 DEG C, the flow rate of the working medium in the liquid cooling pipe is kept at 1.2 m / s, and the BMS in the power battery pack is started.

[0023] Compared with the prior art, the technical scheme of the application has the beneficial effects that:

[0024] 1. The fireproof box body above the battery pack is in close contact with the battery, which guarantees that the flame does not spread to the surrounding module, and at the same time, the fastening requirement between the fireproof box and the battery is considered, and the overall stability of the battery pack is strengthened.

[0025] 2. The liquid cooling plate at the bottom of the battery pack is provided with a built-in serpentine flow channel, and the integrated cooling device improves the heat transfer efficiency and cooling efficiency, and ensures the fastening and stability between the components of the battery pack.

[0026] 3. The design that the battery cells are arranged staggered reduces the heat transfer between the adjacent battery cells, the phase change material paraffin is arranged at the staggered positions to absorb the heat generated by the battery cells, and the liquid cooling plate at the bottom can effectively take away the heat stored in the paraffin, so as to reduce the temperature of the battery cells and improve the safety performance of the overall battery pack.

[0027] 4. Add a layer of fireproof cloth material with the same shape as the cell arrangement structure to the outer wall of the cell module, and arrange module fixing parts with the same shape as the cell arrangement structure on the outside of the fireproof cloth material. This avoids secondary damage to other cells or modules by flames and greatly improves the thermal safety performance of the battery pack. Attached Figure Description

[0028] Figure 1 This is an exploded view of the power battery pack described in this invention;

[0029] Figure 2 This is a schematic cross-sectional view of the battery cell module.

[0030] In the picture:

[0031] 1: Fireproof box 2: Exhaust duct 3: Electrode tab

[0032] 4: Cell vent valve; 5: Cell; 6: Energy storage element

[0033] 7: Insulation board; 8: Fireproof cloth; 9: Liquid cooling pipes

[0034] 10: Liquid cooling plate; 11: First fastener; 12: Second fastener

[0035] 13: Area 1 14: Area 2 Detailed Implementation

[0036] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The specific embodiments described are only for explanation and illustration of the present invention and are not intended to limit the present invention.

[0037] like Figure 1 As shown, a power battery pack includes a control module and a battery module. The battery module includes an uppermost fireproof box 1, a middle cell module, and a lower liquid cooling plate 10. The bottom surface of the fireproof box and the top of the cell module are tightly fitted together, and the bottom surface of the cell module and the top of the liquid cooling plate are tightly fitted together.

[0038] The fireproof box 1 is a hollow box to contain thermal runaway gas and jet flames. It has openings at the top for three exhaust pipes 2, the ends of which protrude from the top of the fireproof box 1 to allow smoke to escape to the outside of the power battery pack after fire extinguishing. The bottom of the fireproof box 1 has guide holes that match the number, position, and outline of the exhaust valves 4 of the battery cell 5, used for spraying the thermal runaway jet flames from the battery cell 5. The bottom of the fireproof box 1 has grooves that fit the outline of the top of the battery cell module (i.e., fit the outer outline of the tabs), ensuring a tight fit between the bottom of the fireproof box and the top of the battery cell, thus forming a guide channel to prevent the spread of flames or thermal runaway smoke within the battery pack.

[0039] The inner wall of the fireproof box 1 is coated with NOVEC 1230 condensed bead extinguishing agent. When the thermal runaway gas is sprayed into the interior of the fireproof box 1 from the flow guide hole, the temperature of the thermal runaway gas will make the NOVEC 1230 condensed bead gasify rapidly, taking away a large amount of heat, thereby achieving the effect of cooling. If the flame is sprayed into the interior of the fireproof box, the strong heat absorption capacity of the NOVEC 1230 extinguishing agent will make the flame lose heat rapidly and interrupt the chain reaction of combustion.

[0040] The fireproof box 1 does not adopt the ordinary cuboid structure, but adopts a concave-convex structure adapted to the arrangement of the battery cells, that is, the transverse cross section of the fireproof box 1 is a rectangular wave shape having vertical concave-convex along the transverse direction.

[0041] The battery cell module comprises a battery cell array, fireproof cloth and energy storage elements 6. The battery cell array is composed of a plurality of battery cells 5 arranged side by side, and a heat insulation plate 7 is arranged between adjacent two battery cells 5 for heat insulation and fire prevention. The top of the battery cell 5 is provided with two tabs 3 protruding from the top, forming the positive and negative electrodes of the battery cell, and a temperature sensor is arranged at the center position of one side outer wall of each battery cell 5. The temperature sensor and the control module realize information communication by using CAN bus communication protocol, reducing wiring and improving anti-interference capability. The top of the battery cell 5 is also provided with an exhaust valve 4, the number, position and profile of which are adapted to the flow guide hole located at the bottom of the fireproof box 1, so that the exhaust valve 4 is in communication with the flow guide hole when the fireproof box and the battery cell array are attached. The arrangement of the battery cells is a rectangular wave shape having vertical concave-convex along the transverse direction of the battery cell array, that is, adjacent two battery cells are staggered. The size of the heat insulation plate 7 is adapted to the size of the side wall of the battery cell and is arranged along the side wall of the battery cell. The fireproof cloth 8 is wrapped around the outer side wall of the battery cell array for fire prevention. A first fixing member 11 is used to fix the fireproof cloth 8 and the battery cell 5. The first fixing member 11 is an aluminum alloy shell, the inner profile of which is adapted to the outer profile of the battery cell array wrapped with fireproof cloth. The inner wall of the first fixing member 11 is tightly attached to the outer side of the fireproof cloth 8, and the first fixing member 11 and the fireproof cloth are bonded by high-temperature resistant glue. On the outer side of the fireproof cloth 8, a plurality of energy storage elements 6 are arranged in the recess formed by the staggered battery cells and filled in the recess, so that the cross section of the battery cell module formed by the energy storage elements 6 and the battery cell array wrapped with fireproof cloth 8 is a rectangle. The energy storage elements 6 are made of paraffin for heat storage. In order to reinforce the device, a second fixing member 12 is sleeved on the outer wall of the battery cell module with a rectangular cross section. The second fixing member is used to fix the battery cell array and the energy storage elements in the battery cell module. The second fixing member 12 is also an aluminum alloy shell, the size of which is adapted to the outer surface of the battery cell module. The concave-convex arrangement of the battery cells can reduce the heat transfer between two adjacent battery cells, and the energy storage elements arranged in the recess not only play a role in cooling, but also improve the space utilization. In practical application, the form of the first fixing member is not limited as long as it can fix the fireproof cloth on the outer side of the battery cell array.

[0042] As shown in the figure, the cross section of the battery cell module has a plurality of first regions 13 and second regions 14, the battery cell 5 and the heat insulation plate 7 are arranged in the first region 13; the energy storage element 6 is arranged in the second region 14, the adjacent first region 13 and the second region 14 are arranged alternately, and the area ratio of the first region 13 to the second region 14 is 37:10. Figure 2 The cross section of the liquid cooling plate 10 is rectangular, and the outer contour is the same as the outer contour of the battery cell module provided with the energy storage element 6. The liquid cooling plate is a hollow box, which is provided with a liquid cooling pipe 9, the liquid cooling pipe 9 is arranged in an S shape in the liquid cooling pipe 9, the working medium in the liquid cooling pipe 9 is water, and a control valve is arranged at the liquid inlet of the liquid cooling pipe 9, the control valve is electrically connected with the control module, and is used for controlling the water flow rate according to the instruction of the control module.

[0043] The cross section of the fireproof box is the same as that of the battery cell array, and the cross section of the battery cell module is the same as that of the liquid cooling plate.

[0044] The working principle of the control module of the power battery pack is as follows:

[0045] The temperature sensor of each battery cell 5 monitors the temperature in real time and transmits it to the control module, when the control module monitors that the highest battery cell temperature is 25-40℃, the control valve at the liquid inlet of the liquid cooling pipe 9 is adjusted, so that the flow rate of the working medium is 0.3m / s;

[0046] When the highest battery cell temperature is monitored to be 40-60℃, the control valve at the liquid inlet of the liquid cooling pipe 9 is adjusted, so that the flow rate of the working medium is 0.8m / s; when the temperature drops to 25-40℃, return to the previous step, adjust the control valve to reduce the flow rate of the working medium to 0.3m / s;

[0047] When the battery cell temperature is monitored to be 60-90℃, the control valve at the liquid inlet of the liquid cooling pipe 9 is adjusted, so that the flow rate of the working medium in the liquid cooling pipe is 1.2m / s; when the temperature drops to 40-60℃, return to the previous step, adjust the control valve to reduce the flow rate of the working medium to 0.8m / s;

[0048] When the battery cell temperature is monitored to be more than 90℃, the flow rate of the working medium in the liquid cooling pipe is kept at 1.2m / s, and the BMS in the power battery pack is started. At this time, if the fire, the flame and the thermal runaway gas rise from the battery cell, pass through the exhaust valve 4 and the flow guide hole to the fireproof box 1, the NOVEC 1230 on the inner wall of the fireproof box will make the flame lose heat quickly, interrupt the chain reaction of combustion, and the smoke that has not been burned is discharged to the outside through the exhaust pipe 2.

[0049]

[0050] ​Although the preferred embodiments of the present application have been described above with reference to the accompanying drawings, the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are merely illustrative and not restrictive. A person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection scope of the present application.

Claims

1. A power battery pack comprising a control module and a battery module, characterized in that, The battery module sequentially comprises a fireproof box (1), a cell module and a liquid cooling plate (10) from top to bottom, the bottom surface of the fireproof box (1) and the top of the cell module are tightly attached, the bottom of the cell module and the top of the liquid cooling plate (10) are tightly attached, and a plurality of flow guide holes are formed in the bottom of the fireproof box (1), a plurality of exhaust valves (4) are arranged on the top of the cell module, the number, position and profile of the exhaust valves (4) are matched with the flow guide holes in the bottom of the fireproof box (1), the exhaust valves (4) are in communication with the flow guide holes to form a flow guide channel of the exhaust pipe (2) on the top of the fireproof box from the top of the cell; The fireproof box (1) is a hollow box body for containing thermal runaway gas and jet flame from the flow guide channel, a plurality of exhaust pipes (2) are arranged on the top of the fireproof box (1), the end of the exhaust pipe (2) protrudes from the top of the fireproof box (1) and is used for discharging smoke to the outside of the power battery pack after extinguishing the fire; and the inner wall of the fireproof box (1) is coated with a fire extinguishing agent; The cell module comprises a cell array, fireproof cloth and energy storage elements (6), the cross section of the cell module has a plurality of first areas (13) and second areas (14), the cell (5) is arranged in the first area; the energy storage element (6) is arranged in the second area (14), the first area (13) is arranged in a rectangular wave shape, and adjacent first areas (13) are arranged alternately, and the area ratio of the first area (13) to the second area (14) is 37:10; The cell array is composed of a plurality of cells (5) arranged side by side, and adjacent two cells are arranged alternately, a temperature sensor is arranged at the center position of one side outer wall of each cell (5), the temperature sensor and the control module realize information communication through CAN bus, and each cell (5) has an exhaust valve (4) on the top; The fireproof cloth (8) is wrapped around the outer side wall of the cell array for fire prevention; A plurality of energy storage elements (6) are respectively filled in the recesses formed by the staggered cells on the outer side of the fireproof cloth (8), so that the cross section of the cell module formed by the energy storage elements (6) and the cell array wrapped by the fireproof cloth (8) is rectangular, and the energy storage elements (6) are made of paraffin; The liquid cooling plate is a hollow box body, a liquid cooling pipeline (9) is arranged in the liquid cooling plate, the liquid cooling pipeline (9) is arranged in an S shape in the liquid cooling pipeline (9), and the working medium in the liquid cooling pipeline (9) is water, a control valve is arranged at the inlet of the liquid cooling pipeline (9), the control valve is electrically connected with the control module, and the control valve is used for controlling the water flow rate according to the instruction of the control module; The outer profile of the fireproof box (1) is the same as that of the cell array, and the outer profile of the cell module is the same as that of the liquid cooling plate (10); The control module is used for adjusting the control valve at the inlet of the liquid cooling pipeline (9) according to the preset threshold value and the temperature detected by the temperature sensor, so as to control the flow rate of the working medium; The temperature sensor of each cell (5) monitors the temperature in real time and transmits the temperature to the control module, when the control module monitors that the highest cell temperature is 25-40℃, the control valve at the inlet of the liquid cooling pipeline (9) is adjusted, and the flow rate of the working medium is 0.3m / s; When the highest cell temperature is monitored to be 40-60℃, the control valve at the inlet of the liquid cooling pipe (9) is adjusted to make the flow rate of the working medium 0.8 m / s; when the temperature drops to 25-40℃, return to the previous step, adjust the control valve to reduce the flow rate of the working medium to 0.3 m / s; When the cell temperature is monitored to be 60-90℃, the control valve at the inlet of the liquid cooling pipe (9) is adjusted to make the flow rate of the working medium inside the liquid cooling pipe 1.2 m / s; when the temperature drops to 40-60℃, return to the previous step, adjust the control valve to reduce the flow rate of the working medium to 0.8 m / s; When the cell temperature is monitored to be more than 90℃, keep the flow rate of the working medium inside the liquid cooling pipe (9) 1.2 m / s, and start the BMS inside the power battery pack.

2. The power battery pack of claim 1, wherein, Two adjacent said cells (5) are provided with a heat insulation plate (7) for heat insulation and fire prevention, and the heat insulation plate is located in the first area (13).

3. The power battery pack of claim 1, wherein, The top of the cell (5) is provided with two tabs (3) protruding from the top, forming the positive and negative electrodes of the cell; the bottom of the fireproof box (1) has a groove matching the top profile of the cell module, for tightly fitting the bottom of the fireproof box with the cell module.

4. The power battery pack of claim 1, wherein, A first fixing member (11) is provided on the outer wall of the fireproof cloth (8) for fixing the fireproof cloth (8) and the cell (5), and the inner contour of the first fixing member (11) is matched with the outer contour of the cell array surrounded by the fireproof cloth (8), and is bonded with the outer wall of the fireproof cloth.

5. The power battery pack of claim 1, wherein, A second fixing member (12) is provided on the outer surface of the cell module for fixing the elements in the cell module, and the size is matched with the outer surface of the cell module.

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