CN106058372A - Heat management system and method for power battery - Google Patents

Abstract

The invention relates to a thermal management method and system for a power battery. Firstly, find out the high-temperature heating area and the low-temperature heating area of the power battery; and then use different cooling devices for the high-temperature area and the low-temperature area. Different heat sinks include: arrange dense heat sinks in high-temperature areas and sparse heat sinks in low-temperature areas; or use metal heat sinks in high-temperature areas and plastic heat sinks in low-temperature areas; or use heat sinks in high-temperature areas Water-cooled or heat pipe-cooled heat sinks are used, and air-cooled or natural-cooled heat sinks are used in low-temperature areas. The battery thermal management system using the method includes a battery pack, the above heat dissipation device and a water pump, the battery pack includes a plurality of single batteries, and the heat dissipation device includes a plurality of heat dissipation water pipes distributed among the single batteries. The power battery thermal management method and system can make the power battery thermal management system targeted and improve efficiency.

Description

Power battery thermal management system and method

technical field

The invention relates to a power battery used in an electric vehicle, in particular to a heat management system and method for the power battery.

Background technique

In the prior art, power battery cooling solutions include air cooling, water cooling, phase change material cooling, and heat pipe cooling, among which the more mature solutions use air cooling and/or water cooling. The air cooling method is simple and easy to implement, but the effect is limited; in comparison, water has a high specific heat capacity, which is more conducive to taking out a large amount of heat inside the battery, so water cooling is more popular. The battery pack in the thermal management system of the power battery is generally composed of many single cells connected in series and parallel. Chemical power battery thermal management. For example, CN201110364978.2, announced on March 28, 2012, discloses a power battery in which a plurality of single batteries are combined through the connection of brackets, and there are arranged in the central gap of the rectangular area formed by four adjacent single batteries. Cooling pipes, multiple cooling pipes of the thermal management system of the entire power battery are evenly arranged in it.

However, we know that the heat of the battery pack is not evenly distributed, but there are high-temperature heating regions and low-temperature heating regions. The traditional power battery thermal management system disclosed in the above-mentioned CN201110364978.2 cannot control the high-temperature and low-temperature heating regions Different heat dissipation devices are treated differently, so better heat dissipation efficiency cannot be achieved.

Therefore, there is a need for an improved power battery thermal management system and method.

Contents of the invention

In order to overcome the above defects, the present invention provides a power battery thermal management system and method with higher heat dissipation efficiency.

The technical solution adopted by the present invention to solve the technical problem is: a power battery thermal management method, which is characterized in that: first find out the high-temperature heating area and the low-temperature heating area of the power battery; device.

Preferably, the different heat sinks include one or more of the following methods: arrange dense heat sinks in high-temperature areas, and arrange sparse heat sinks in low-temperature areas; use metal heat sinks in high-temperature areas, and arrange heat sinks in low-temperature areas. Use plastic cooling devices in the area; and water cooling or heat pipe cooling cooling devices in high temperature areas, and air cooling or natural cooling cooling devices in low temperature areas.

Another technical solution adopted by the present invention to solve the technical problem is: a power battery thermal management system, which adopts the above-mentioned power battery thermal management method, the power battery thermal management system includes a battery pack, the above-mentioned cooling device and a water pump, the battery The group includes a plurality of single batteries, and the heat dissipation device includes a plurality of heat dissipation water pipes distributed among the single batteries, and cooling liquid circulates in the heat dissipation water pipes.

Preferably, a battery case is provided on the outside of the battery pack, and a water curtain formed by other heat dissipation water pipes is installed on the surface of the battery case. So cycle.

Preferably, the thermal management system of the power battery further includes a heating device, the heating device is located between the heat dissipation water pipe and the water curtain, and the cooling liquid of each heat dissipation water pipe is heated by the heating device and then joins the water curtain.

Preferably, a battery case is provided on the outside of the battery pack, and a water curtain formed by other cooling water pipes is installed on the surface of the battery case. The water curtain then passes through the external cooling device, and then is pumped to the cooling water pipe by the water pump, so that it circulates.

Preferably, the thermal management system of the power battery further includes a cooling device, the cooling device is located between the water pump and the heat dissipation water pipe, and the cooling liquid from the water pump flows to the heat dissipation water pipe after being cooled by the cooling device.

Preferably, the power battery thermal management system also includes an external cooling device and a battery box arranged outside the battery pack, a water curtain is installed on the surface of the battery box, and a second water curtain is installed between the water curtain, the water pump and the external cooling device. Two solenoid valves, an internal temperature sensor is installed in the central area of the battery pack; when the internal temperature of the battery pack is lower than a certain temperature, the water curtain and the water pump are connected, and the cooling liquid of each heat dissipation water pipe merges into the water curtain, and then pumped to the heat dissipation water pipe by the water pump , so cycle; when the internal temperature of the battery pack exceeds the certain temperature, the water curtain is connected to the external cooling device, and the cooling liquid of each cooling water pipe merges into the water curtain, and then leads to the external cooling device, and then is pumped to the cooling water pipe by the water pump. So cycle.

Preferably, a heating device is installed between the heat dissipation water pipe and the water curtain, and a first electromagnetic valve is installed between the heat dissipation water pipe, the water curtain, and the heating device. When the external temperature of the battery pack is lower than 0 degrees, the heat dissipation water pipe and the heating device Connected, the water curtain is directly connected to the water pump, the coolant is heated by the heating device and then flows to the water curtain to heat and keep the battery pack warm, and finally pumped back by the water pump to flow to the heat dissipation water pipe; when the external temperature of the battery pack is higher than 0 degrees, the heat dissipation The water pipe is connected with the water curtain.

Preferably, a cooling device is installed between the water pump and the cooling water pipe, and a third electromagnetic valve is installed between the water pump, the cooling device and the cooling water pipe. , the coolant is cooled by the cooling device and then flows to the heat dissipation water pipe, then flows through the water curtain, the external heat dissipation device, and then is pumped back to the water pump, and so on; when the water temperature is lower than another specific temperature, the water pump is connected to the heat dissipation water pipe.

The invention can make the thermal management system of the power battery targeted, realize the heat dissipation and heat preservation of the power battery at the same time, and can also install different heat dissipation/heat preservation module devices according to different climate regions or working conditions.

Description of drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description in conjunction with the accompanying drawings and embodiments, in which the same reference numerals represent the same features throughout, wherein:

Fig. 1 is a schematic diagram of the distribution of cooling water pipes in the power battery thermal management system of the present invention.

Fig. 2 is a schematic cross-sectional view of the cooling water pipe of the power battery thermal management system of the present invention.

Fig. 3 is a schematic diagram of the water curtain of the power battery thermal management system of the present invention.

Fig. 4 is a schematic diagram of a small cycle of the power battery thermal management system of the present invention.

Fig. 5 is a schematic diagram of a large cycle of the power battery thermal management system of the present invention.

Fig. 6 is a schematic diagram of a small heating cycle of the power battery thermal management system of the present invention.

Fig. 7 is a schematic diagram of a large cooling cycle of the power battery thermal management system of the present invention.

Explanation of reference symbols:

Single battery 1; cooling water pipe 2; water curtain 3.

detailed description

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same numbers will be used throughout the drawings to refer to the same or like parts. In addition, although the terms used in the present invention are selected from well-known and commonly used terms, some terms mentioned in the description of the present invention may be selected by the applicant according to his or her judgment, and the detailed meanings are set out in this article described in the relevant section of the description. Furthermore, it is required that the present invention be understood not only by the actual terms used, but also by the meaning implied by each term.

The invention relates to a thermal management method for a power battery, which is a heat dissipation method based on finite element analysis: conduct thermal simulation on a power battery pack through finite element analysis and perform experimental verification to find out high-temperature heating regions and low-temperature heating regions. Usually, the concentrated area of heat is located in the central area of the power battery pack. The closer to the central area, the higher the temperature, and the worse the heat dissipation. The farther away from the center, the lower the temperature, and the better the heat dissipation. Therefore, different heat dissipation methods can be adopted for different temperature regions, such as arranging dense heat dissipation water pipes or heat pipes in high temperature regions, and sparse heat dissipation devices in low temperature regions; Use plastic materials with average heat conduction effects; or use water cooling or heat pipe cooling for high temperature areas, and air cooling or natural cooling for low temperature areas. That is to say, compared with the low-temperature region, more heat-dissipating devices or heat-dissipating methods with better heat dissipation effects are used in the high-temperature region, so that it can be targeted and improve the heat dissipation efficiency of the heat-dissipating device.

In the thermal management system of the power battery in the specific embodiment of the present invention, water cooling is selected as the heat dissipation method, because water cooling is easier to collect heat in a concentrated manner. Through finite element analysis and experimental verification, it is found that the concentrated heating area of the battery pack (also called a high temperature area) and the good heat dissipation area (also called a low temperature area), and then install densely distributed heat dissipation water pipes in the concentrated heating area of the battery pack. Sparsely distributed heat dissipation water pipes are installed in areas with good heat dissipation. At the same time, the water pipes in the concentrated heat area are made of aluminum alloy, and the water pipes in the low temperature area are made of plastic.

The power battery thermal management system in the specific embodiment of the present invention includes a battery pack and a heat dissipation device, the battery pack includes a plurality of single batteries 1, and the heat dissipation device may be a plurality of heat dissipation water pipes distributed between the single batteries 2. When the single battery is cylindrical, taking the 18650 battery as an example, the cooling water pipe shown in Figure 1 can be used, and the installation diagram is shown in Figure 2. The single cells 1 are arranged in a matrix to form a cuboid shape, and gaps are formed between four adjacent single cells 1 . The cross-section of the heat dissipation water pipe 2 is the same as the contour of the gap, so as to fit the side wall of the single battery 1 and enhance the heat dissipation effect. The width and length of the cooling water pipe 2 are both 18mm, and the center is provided with a through hole with a diameter of 5mm for the circulation of cooling liquid. The coolant cooling device adopts a partitioned wall heat exchanger. Pay attention to the size parameters of the pipes passing through the refrigerant to meet the evaporation requirements of the refrigerant.

The power battery thermal management system of the present invention can have various types according to the specific use environment, and the following will introduce them respectively:

1. Basic type

The basic power battery thermal management system also includes an external heat sink (also called an external heat sink, equipped with a cooling fan) and a water pump. Pump back to each cooling water pipe, and so on.

2. Improved type 1 is suitable for use in normal temperature areas

The improved type 1 is based on the above-mentioned basic type, and there is a battery box on the outside of the battery pack. The surface of the battery box is equipped with a water curtain 3 formed by arranging cooling water pipes. The arrangement of the water curtain is determined by finite element analysis. , because the water curtain has the function of heat preservation, so the water curtain lays more pipes in the area with good heat dissipation, and the area with poor heat dissipation is more sparse. The schematic diagram of the water curtain is shown in Figure 3.

The cooling liquid of each heat dissipation water pipe flowing through the heating area of the battery pack is combined to the water curtain 3, and then leads to the external heat sink (also can be called an external heat dissipation device), and then is pumped to the internal heat absorption pipe of each battery by a water pump (also can be called cooling pipes), and so on. Install a second solenoid valve between the water curtain on the surface of the battery box, the water pump, and the external heat sink, and install an internal temperature sensor (hereinafter referred to as the internal temperature sensor) in the central area of the battery pack. According to the internal temperature of the battery pack, there are two circulation modes. When the internal temperature of the battery pack is lower than 40 degrees, it is controlled by the second solenoid valve, the water curtain and the water pump are connected, and the coolant does not pass through the external heat sink, but only in the battery box. Internal circulation realizes small circulation; when the internal temperature of the battery pack exceeds 40, through the control of the second solenoid valve, the water curtain is connected to the external heat sink to realize large circulation. Because the internal heat of the battery pack is brought to the surface of the battery box with good heat dissipation, the small circulation can not only reduce the heat dissipation pressure of the external heat sink and the flow supply pressure of the water pump, but also keep the battery pack warm through the high-temperature coolant in the water curtain at low temperatures. Serves multiple purposes.

Improved type 2 is suitable for low temperature use areas

When the temperature is extremely low in winter, the heat generated by the battery pack itself is not enough to keep the battery pack warm. Therefore, on the basis of the improved type 1, a heating device is installed between the heat-absorbing pipe and the water curtain, and an external temperature sensor (called an external temperature sensor) is installed on the outermost layer of the battery pack. Install the first electromagnetic valve between the heating devices. Controlled by the first solenoid valve, when the external temperature of the battery pack is lower than 0 degrees, the heat absorbing pipe is connected to the heating device, and the water curtain is directly connected to the water pump. After heating, the coolant flows to the water curtain to heat and keep the battery pack warm, and finally is pumped back by the water pump to flow to the hot water pipe to realize a small heating cycle. When the external temperature of the battery pack is higher than 0 degrees, the heat-absorbing pipe is connected to the water curtain, and then the same as described in the improved type 1, controlled by the second solenoid valve, when the internal temperature of the battery pack is lower than 40 degrees, a small cycle is realized; when the battery pack When the internal temperature of the group is higher than 40 degrees, a large cycle is implemented.

In some areas where the perennial temperature is lower than 0 degrees, because a small heating cycle is used, no external radiator is required.

The improved type 2 is not suitable for areas where the annual minimum temperature is higher than minus 5 degrees, that is, there is no need to install a coolant heating device in the system.

Improved type 3 is suitable for high temperature areas

In hot summer, the temperature often reaches above 35 degrees, and the surface temperature is even higher. If an electric vehicle is exposed to high temperature for a long time, the internal coolant temperature may rise to above 40 degrees, and neither water cooling nor air cooling will have much effect. At this time, the air conditioning system is needed to meet the heat dissipation requirements of the battery pack. Improved type 3 is based on improved type 1, and a cooling device is installed between the water pump and the heat absorption pipe inside the battery. The refrigerant of the cooling device comes from the air conditioning system. Install a water temperature sensor at the water outlet of the water pump, and install a third solenoid valve between the water pump, the coolant cooling device, and the heat-absorbing pipe inside the battery. Controlled by the third solenoid valve, when the outlet water temperature is higher than 40 degrees, the water pump is connected to the cooling device, and the cooling liquid flows to the heat-absorbing pipe after being cooled by the refrigerant. When the water temperature is lower than 40 degrees, the water pump is connected to the heat absorption pipe inside the battery, and the coolant flows in the same direction as the improved type 1, controlled by the second solenoid valve. When the internal temperature of the battery pack is lower than 40 degrees, the same as the improved type 1 The small cycle described in the above; when the internal temperature of the battery pack is higher than 40 degrees, the same as the large cycle described in the improved type 1 is implemented.

All-round type suitable for various temperature regions

When electric vehicles use a wide range of ambient temperature, in order to cope with extreme high temperature and extreme low temperature, the above types are integrated, so that the thermal management system can not only heat and keep the battery pack at low temperature, but also protect it at high temperature. For good thermal cooling. The comprehensive power battery thermal management system includes: internal heat-absorbing pipe of the battery ((also called heat dissipation water pipe)), coolant heating device, battery box water curtain, external heat sink (also called external heat sink), water pump , coolant cooling device, first solenoid valve, second solenoid valve, third solenoid valve, internal temperature sensor, external temperature sensor and outlet water temperature sensor. The whole system is controlled by ECU water cooling control unit.

Because multiple types are involved, the omnipotent type is a synthesis of other types in addition, including all the contents of the invention. Therefore, the omnipotent type is explained in conjunction with FIG. 4 to FIG. 7 , so as to further describe the invention. For different climate regions, different heat dissipation/insulation components can be adopted to realize the modularization of the thermal management system.

When the external temperature of the battery is lower than 0 degrees, start the small heating cycle, as shown in Figure 1, the coolant flow direction: water pump—the third solenoid valve—heat absorption pipe inside the battery—the first solenoid valve—coolant heating device—water on the surface of the battery box Curtain—second solenoid valve—water pump.

When the external temperature of the battery is higher than 0 degrees and the internal temperature is lower than 40 degrees, start a small cycle, as shown in Figure 2, the coolant flows: water pump—third solenoid valve—heat absorption pipe inside the battery—first solenoid valve—surface of the battery box Water curtain—second solenoid valve—water pump.

When the external temperature of the battery is higher than 0 degrees and the internal temperature is higher than 40 degrees, it can be divided into the following two modes depending on the water temperature:

When the outlet water temperature of the water pump is lower than 40 degrees, open the large cycle, as shown in Figure 3, the coolant flow direction: water pump—the third solenoid valve—heat absorption pipe inside the battery—the first solenoid valve—water curtain on the surface of the battery box—the second solenoid valve— External cooling fins - water pump.

When the outlet water temperature of the water pump is higher than 40 degrees, turn on the large cooling cycle, as shown in Figure 4, the coolant flow direction: water pump—third solenoid valve—coolant cooling device—heat absorption pipe inside the battery—first solenoid valve—water curtain on the surface of the battery box -Second solenoid valve -External cooling fin -Water pump.

A brief summary of the above flows can be:

Normal temperature, when the temperature is low (outside temperature is greater than 0 degrees, internal temperature is lower than 40 degrees), implement small circulation; normal temperature, when the temperature is high (outside temperature is greater than 0 degrees, internal temperature is higher than 40 degrees, water temperature lower than 40 degrees), a large cycle is implemented, which corresponds to the thermal management system mode of the power battery of the improved type 1;

Under low temperature conditions (external temperature is lower than 0 degrees), it is necessary to implement a small cycle after heating, that is, a small heating cycle, which corresponds to the power battery thermal management system mode of the improved type 2;

In case of high temperature (external temperature is greater than 0 degrees, internal temperature is higher than 40 degrees, and water temperature is higher than 40 degrees), it needs to be cooled and then perform a large cycle, that is, a large cooling cycle, which corresponds to the power battery thermal management system mode of the improved type 3.

The invention proposes a power battery thermal system management method to find out the heating temperature distribution of the battery box through finite element analysis and experimental verification, implement different heat dissipation methods for different temperature regions, and propose a method for different climate regions on this basis Finite element all-round modular battery thermal management system.

The invention can make the thermal management device targeted, realize the heat dissipation and heat preservation of the power battery at the same time, and can also install different heat dissipation/heat preservation module devices according to the temperature of different climate regions or working conditions.

Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims (10)

1. a power battery thermal management method, it is characterised in that: heating high-temperature area and the heating of first finding out electrokinetic cell are low Temperature area；Then different heat abstractors is used for high-temperature area and low-temperature region.

2. power battery thermal management method as claimed in claim 1, it is characterised in that: described different heat abstractor include with One or more under type: arrange intensive heat abstractor at high-temperature area, arrange sparse heat radiation dress at low-temperature region Put；Use the heat abstractor of metal material at high-temperature area, use the heat abstractor of plastic material at low-temperature region；And at high temperature Region carries out water-cooled or heat pipe cooling heat radiator, takes the air-cooled or heat abstractor of natural cooling at low-temperature region.

3. a power battery thermal management system, it is characterised in that: use electrokinetic cell heat management side as claimed in claim 2 Method, this power battery thermal management system includes set of cells, above-mentioned heat abstractor and water pump, and this set of cells includes many monomer electricity Pond, this heat abstractor includes the multiple heat dissipation pipes being distributed between described cell, and in heat dissipation pipe, circulation has coolant.

4. power battery thermal management system as claimed in claim 3, it is characterised in that: it is provided with battery case outside this set of cells Body, this Battery case surface installs the cascade arranged by other heat dissipation pipes and formed additional, and each heat dissipation pipe's coolant is collaborated Cascade, is then extracted into each heat dissipation pipe by water pump, so circulates.

5. power battery thermal management system as claimed in claim 4, it is characterised in that: this power battery thermal management system also wraps Including heater, this heater is between heat dissipation pipe and cascade, and each heated device of heat dissipation pipe's coolant is heated Rear interflow is to cascade.

6. power battery thermal management system as claimed in claim 3, it is characterised in that: it is provided with battery case outside this set of cells Body, this Battery case surface installs the cascade arranged by other heat dissipation pipes and formed additional, and this power battery thermal management system also wraps Including external radiating device, each heat dissipation pipe's coolant collaborates cascade, then by this external radiating device, then is taken out by water pump To heat dissipation pipe, so circulate.

7. power battery thermal management system as claimed in claim 6, it is characterised in that: this power battery thermal management system also wraps Including chiller, this chiller is between water pump and heat dissipation pipe, after the cooling of water pump coolant out cooled device Flow to heat dissipation pipe.

8. power battery thermal management system as claimed in claim 3, it is characterised in that: this power battery thermal management system also wraps Including external radiating device and be located at the Battery case outside set of cells, this Battery case surface adds cascade, at cascade and water Install the second electromagnetic valve between pump, external radiating device additional, install internal temperature sensor additional in set of cells central area；Work as set of cells When interior temperature is less than uniform temperature, cascade is connected with water pump, and each heat dissipation pipe's coolant collaborates cascade, then is extracted into by water pump Heat dissipation pipe, so circulates；When in set of cells, temperature exceedes this uniform temperature, cascade is connected with external radiating device, and each dissipates Hot-water line coolant collaborates cascade, leads to external radiating device the most again, then is extracted into heat dissipation pipe by water pump, so follows Ring.

9. power battery thermal management system as claimed in claim 8, it is characterised in that: install additional between heat dissipation pipe and cascade Heater, installs the first electromagnetic valve between heat dissipation pipe and cascade, heater additional, when the outer temperature of set of cells is less than 0 degree, dissipates Hot-water line is connected with heater, and cascade is directly connected with water pump, flows to cascade again, to electricity after the heating of coolant heated device Pond group carries out heating and thermal insulation, is finally drawn back by water pump and flows to heat dissipation pipe；When the outer temperature of set of cells is higher than 0 degree, heat dissipation pipe and water Curtain is connected.

10. power battery thermal management system as claimed in claim 8 or 9, it is characterised in that: between water pump and heat dissipation pipe Install chiller additional, between water pump and chiller, heat dissipation pipe, install the 3rd electromagnetic valve additional, when water pump water outlet temperature is higher than another During one specified temp, water pump is connected with chiller, flows to heat dissipation pipe again, then flow through after the cooling of coolant cooled device Cascade, external radiating device, then it is drawn back into water pump, so circulate；When water temperature is less than another specified temp, water pump and water of radiation Pipe is connected.