Thermal insulation system of power battery and control method

Abstract

The invention belongs to the field of power battery heat preservation, and particularly relates to a heat preservation system of a power battery and a control method. Comprising a battery box; the battery box comprises a non-metal shell used for covering the top area and the peripheral area of the power battery, and a bottom plate used for covering the opening area of the shell; the bottom plate and the shell form a sealed cavity in the battery box, and the sealed cavity can be vacuumized; the bottom plate comprises a liquid cooling layer comprising a liquid cooling plate made of a metal material and a heat preservation layer comprising a vacuum closed cavity box body made of a non-metal material; the upper surface of the liquid cooling plate is in contact with the bottom of the power battery, and the lower surface is in contact with the upper surface of the closed cavity box body; and the liquid cooling plate is fixedly connected with the closed cavity box body. After the system cools or heats the battery, heat preservation is realized through vacuumizing; the mode can achieve a good heat preservation effect, does not need to add a large number of heat preservation materials on the surface of the battery box, does not need to occupy redundant space to achieve the heat preservation function, and is suitable for miniaturization design of the power battery.

Description

Technical Field

[0001] The present invention belongs to the field of power battery insulation, and particularly relates to a power battery insulation system and a control method. Background Art

[0002] In recent years, new energy vehicles have been playing an increasingly important role as a substitute for traditional energy vehicles. Power batteries are an important energy component of new energy vehicles.

[0003] With the development of the new energy vehicle industry, sales of pure electric vehicles in Northeast China have increased annually. However, due to the generally low temperatures in Northeast China (for example, the lowest ambient temperature in Mohe County reaches -40°C; in other parts of Northeast China, the ambient temperature ranges from -30°C to -20°C during winter), power batteries in low-temperature environments experience rapid capacity decay, increased power consumption, and reduced driving range. Consequently, there is growing interest in power battery insulation technologies. These technologies aim to improve the battery's thermal insulation properties to raise the battery's temperature before departure in the morning, shortening the heating time and reducing heating energy consumption, thereby increasing driving range.

[0004] However, in order to improve the thermal insulation performance of the battery, it is usually necessary to ensure that the thickness of the thermal insulation material on the surface of the battery box is as thick as possible. The battery box itself has extremely high requirements for energy density and size space. It is impossible to meet the thermal insulation performance of the battery by increasing the thickness of the thermal insulation material indefinitely. This method will seriously occupy the battery box space. If good thermal insulation performance is to be ensured, the volume of the battery box will increase, and a large amount of redundant space will be occupied just for the purpose of battery insulation, thereby affecting the miniaturization design of the power battery. Summary of the Invention

[0005] The object of the present invention is to provide a thermal insulation system and control method for a power battery, which is used to solve the problem in the prior art that a large amount of redundant space is occupied to meet the thermal insulation performance of the battery, affecting the miniaturization design of the power battery.

[0006] In order to achieve the above-mentioned object, the present invention provides a power battery insulation system, which includes a battery box; The battery box includes: a non-metallic shell for covering the top area and surrounding areas of the power battery, and a bottom plate for covering the opening area of the shell; the bottom plate and the shell form a sealed cavity in the battery box, and the sealed cavity can be vacuumed; The bottom plate includes: a liquid cooling layer including a metal liquid cooling plate and a heat preservation layer including a non-metal vacuum sealed cavity box body; The upper surface of the liquid cooling plate is used to contact the bottom of the power battery, and the lower surface is used to contact the upper surface of the closed cavity box body; the liquid cooling plate and the closed cavity box body are fixedly connected.

[0007] Beneficial Effects: The present invention provides a novel thermal insulation system for power batteries, comprising a battery case. The battery case primarily comprises a shell and a base plate. The shell and base plate are connected together to completely seal and cover the power batteries. The space formed by the seal between the shell and base plate (i.e., the sealed cavity within the battery case) is evacuated. A higher vacuum level reduces the amount of heat transfer medium (gas) within the space, improving the thermal insulation of the power batteries. Conversely, a lower vacuum level results in poor thermal insulation and improved heat dissipation. The base plate primarily consists of two components: a liquid cooling layer (which includes a metal liquid cooling plate) and an insulation layer (which includes a non-metallic vacuum-enclosed cavity). In the base plate's dual-layer structure, the liquid cooling layer is located on the upper layer, with the upper surface of the liquid cooling plate in contact with the bottom of the power batteries. This layer cools or heats the power batteries. Because the metal liquid cooling plate in this layer is made of metal, the power batteries can be cooled or heated through rapid heat conduction and convection after coolant is introduced. The insulation layer is located in the lower layer, that is, the lower surface of the liquid cooling plate is used to contact the upper surface of the vacuum-sealed cavity box body, which is equivalent to the liquid cooling layer fixedly covering the insulation layer. The specific principle of battery insulation is as follows: Since the above-mentioned sealed cavity can be evacuated, the sealed cavity can be evacuated when insulation is required, and the vacuum is used to achieve an insulating environment in the sealed cavity in the battery box, thereby minimizing or slowing down the heat loss of the power battery through the gas medium, and achieving the effect of heat preservation of the power battery; at the same time, the liquid cooling layer in the above-mentioned double-layer structure (that is, the structure composed of the liquid cooling layer and the insulation layer) can realize the function of actively cooling or heating the power battery, and the insulation function of the insulation layer can be used to maintain the cooling or heating effect of the liquid cooling layer as much as possible; when the power battery has When higher temperature insulation is required, it can be met by combining active heating of the liquid cooling layer and increasing the vacuum degree of the sealed cavity; when the power battery has a lower temperature insulation requirement, it can be met by combining active cooling of the liquid cooling layer and increasing the vacuum degree of the sealed cavity; when the power battery has a higher temperature heat dissipation requirement, it can be met by combining active cooling of the liquid cooling layer and decreasing the vacuum degree of the sealed cavity; this method can achieve good and flexible insulation effect, and does not require adding a large amount of insulation material to the surface of the battery box, and does not require occupying redundant space to achieve the insulation function, and is suitable for the miniaturized design of power batteries.

[0008] Furthermore, the battery box further comprises: a regulating valve for adjusting the vacuum degree of the sealed cavity in the battery box and a pressure sensor for obtaining the pressure corresponding to the vacuum degree of the sealed cavity in the battery box; The method of adjusting the vacuum degree of the sealed cavity in the battery box includes: When the vehicle is in a driving state, if the driving speed is greater than or equal to a set speed, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a first reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the first reference value; if the driving speed is less than the set speed, it is determined whether the ambient temperature is within a set temperature range including an upper limit and a lower limit; If the ambient temperature is not within the set temperature range, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a second reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the second reference value; otherwise, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a third reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the third reference value; the second reference value is greater than the third reference value; and the first reference value is less than the second reference value; The lower limit value of the set temperature range is less than or equal to the minimum heating temperature of the power battery; the upper limit value of the set temperature range is less than the liquid cooling start-up temperature of the power battery and the difference between the upper limit value and the liquid cooling start-up temperature is less than the set temperature difference value, or is greater than or equal to the liquid cooling start-up temperature of the power battery.

[0009] Furthermore, the method of adjusting the vacuum degree of the sealed cavity in the battery box also includes: When the vehicle is in a parked state or a parked state, if the ambient temperature is less than a first temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a fourth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fourth reference value; If the ambient temperature is greater than the first temperature threshold and less than the second temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a fifth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fifth reference value; the fifth reference value is less than the fourth reference value; If the ambient temperature is greater than or equal to the second temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a sixth reference value according to the received instruction, so that the battery box has the thermal insulation performance corresponding to the vacuum degree of the sixth reference value; the sixth reference value is less than the fifth reference value.

[0010] Furthermore, a metal mounting point is provided on the edge of the liquid cooling plate; the metal mounting point is integrally formed with the liquid cooling plate and is used for fixed connection with the bottom crossbeam of the vehicle through fasteners.

[0011] Furthermore, it also includes an external vacuum subsystem; The external vacuum pumping subsystem includes a controller; the controller is used to determine a reference value corresponding to the current adjustment of the vacuum degree of the sealed cavity in the battery box based on the pressure and ambient temperature corresponding to the vacuum degree of the sealed cavity in the battery box, or based on the pressure, ambient temperature and driving speed corresponding to the vacuum degree of the sealed cavity in the battery box, and determine the difference between the actual vacuum degree of the sealed cavity in the battery box and the corresponding reference value, so as to generate a corresponding control instruction and send it to the regulating valve to control the regulating valve.

[0012] Furthermore, the method of fixedly connecting the liquid cooling plate and the vacuum sealed cavity box body includes: fixedly connecting the lower surface of the liquid cooling plate to the four sides of the upper surface of the vacuum sealed cavity box body.

[0013] Furthermore, the metal liquid cooling plate is an aluminum alloy liquid cooling plate.

[0014] The present invention also provides a new power battery heat preservation control method, according to which the heat preservation system of the power battery is controlled; the heat preservation system of the power battery includes a battery box; The battery box includes: a non-metallic shell for covering the top area and surrounding areas of the power battery, and a bottom plate for covering the opening area of the shell; the bottom plate and the shell form a sealed cavity in the battery box, and the sealed cavity can be vacuumed; The bottom plate includes: a liquid cooling layer including a metal liquid cooling plate and a heat preservation layer including a non-metal vacuum sealed cavity box body; The upper surface of the liquid cooling plate is used to contact the bottom of the power battery, and the lower surface is used to contact the upper surface of the vacuum closed cavity box body; the liquid cooling plate and the closed cavity box body are fixedly connected; Methods for controlling the thermal insulation system of the power battery include: adjusting the vacuum degree of the sealed cavity in the battery box according to the thermal insulation or heat dissipation requirements of the power battery.

[0015] The control method can achieve the same beneficial effects as the above-mentioned power battery insulation system on the basis of controlling the power battery insulation system through automation.

[0016] Furthermore, the battery box further comprises: a regulating valve for adjusting the vacuum degree inside the sealed cavity of the battery box and a pressure sensor for obtaining the pressure corresponding to the vacuum degree of the sealed cavity of the battery box; The method of adjusting the vacuum degree of the sealed cavity in the battery box includes: When the vehicle is in a driving state, if the driving speed is greater than or equal to a set speed, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a first reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the first reference value; if the driving speed is less than the set speed, it is determined whether the ambient temperature is within a set temperature range including an upper limit and a lower limit; If the ambient temperature is not within the set temperature range, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a second reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the second reference value; otherwise, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a third reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the third reference value; the second reference value is greater than the third reference value; and the first reference value is less than the second reference value; The lower limit value of the set temperature range is less than or equal to the minimum heating temperature of the power battery; the upper limit value of the set temperature range is less than the liquid cooling start-up temperature of the power battery and the difference between the upper limit value and the liquid cooling start-up temperature is less than the set temperature difference value, or is greater than or equal to the liquid cooling start-up temperature of the power battery.

[0017] Furthermore, the method of adjusting the vacuum degree of the sealed cavity in the battery box also includes: When the vehicle is in a parked state or a parked state, if the ambient temperature is less than a first temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a fourth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fourth reference value; If the ambient temperature is greater than the first temperature threshold and less than the second temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a fifth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fifth reference value; the fifth reference value is less than the fourth reference value; If the ambient temperature is greater than or equal to the second temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a sixth reference value according to the received instruction, so that the battery box has the thermal insulation performance corresponding to the vacuum degree of the sixth reference value; the sixth reference value is less than the fifth reference value.

[0018] Furthermore, a metal mounting point is provided on the edge of the liquid cooling plate; the metal mounting point is integrally formed with the liquid cooling plate and is used for fixed connection with the bottom crossbeam of the vehicle through fasteners.

[0019] Furthermore, it also includes an external vacuum subsystem; The external vacuum pumping subsystem includes a controller; the controller is used to determine a reference value corresponding to the current adjustment of the vacuum degree of the sealed cavity in the battery box based on the pressure and ambient temperature corresponding to the vacuum degree of the sealed cavity in the battery box, or based on the pressure, ambient temperature and driving speed corresponding to the vacuum degree of the sealed cavity in the battery box, and determine the difference between the actual vacuum degree of the sealed cavity in the battery box and the corresponding reference value, so as to generate a corresponding control instruction and send it to the regulating valve to control the regulating valve.

[0020] Furthermore, the method of fixedly connecting the liquid cooling plate and the vacuum sealed cavity box body includes: fixedly connecting the lower surface of the liquid cooling plate to the four sides of the upper surface of the vacuum sealed cavity box body.

[0021] Furthermore, the metal liquid cooling plate is an aluminum alloy liquid cooling plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a physical structural diagram of a power battery heat preservation system in an embodiment of the power battery heat preservation system of the present invention; Figure 2 This is a cross-sectional view of a bottom plate in an embodiment of a thermal insulation system for a power battery according to the present invention; Figure 3 This is a physical structural diagram of the metal mounting point in the embodiment of the power battery insulation system of the present invention; Figure 4 This is an architectural diagram of a power battery thermal insulation system in an embodiment of the power battery thermal insulation system of the present invention; Figure 5 This is a flow chart of a method for adjusting the vacuum degree of a sealed cavity in a battery box in an embodiment of a thermal insulation system for a power battery of the present invention; Among them, 100 is a double-layer composite material vacuum cold plate; 101 is a double-layer composite material vacuum-sealed cavity box; 102 is an aluminum alloy upper liquid cooling plate; 1021 is a flow channel; 1022 is a metal mounting point; 200 is a composite material vacuum upper box; 300 is a vacuum regulating valve; 400 is a pressure sensor; and 500 is a power battery module. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and implementation methods.

[0024] Implementation method of power battery insulation system This embodiment provides a technical solution for a power battery insulation system. The main concept of this solution is: the system includes a specially designed battery box, which can not only heat or cool the power battery through the liquid cooling layer in its bottom plate (this layer is mainly composed of a metal liquid cooling plate), but also use the vacuum insulation layer in the bottom plate for insulation. It can also achieve the effect of power battery insulation by vacuuming the sealed cavity formed by the shell and the insulation layer in its bottom plate (this layer is mainly composed of a non-metallic vacuum-sealed cavity box).

[0025] In this embodiment, the system includes a battery box; The battery box includes: a non-metallic shell for covering the top area and surrounding areas of the power battery, and a bottom plate for covering the opening area of the shell; the bottom plate and the shell form a sealed cavity in the battery box, and the sealed cavity can be vacuumed; The bottom plate includes: a liquid cooling layer including a metal liquid cooling plate (the metal liquid cooling plate is an aluminum alloy liquid cooling plate) and a heat preservation layer including a non-metal vacuum sealed cavity box body.

[0026] The upper surface of the liquid cooling plate is used to contact the bottom of the power battery, and the lower surface is used to contact the upper surface of the closed cavity box body; the liquid cooling plate and the closed cavity box body are fixedly connected (the fixed connection method includes: fixing the lower surface of the liquid cooling plate to the upper surface of the vacuum closed cavity box body on all sides).

[0027] In a preferred embodiment of this embodiment, the main components of the system are: a vacuum battery box (i.e., a battery box) and an external vacuum pumping subsystem; the vacuum battery box assumes the main function of heat preservation of the power battery.

[0028] The structure of the vacuum battery box is referenced Figure 1 and Figure 2 The bottom plate of the battery box utilizes a double-layer composite vacuum cold plate design. This double-layer composite vacuum cold plate 100 (i.e., the bottom plate) primarily consists of a double-layer composite vacuum-enclosed cavity box 101 (i.e., a non-metallic vacuum-enclosed cavity box) and an aluminum alloy upper liquid cold plate 102 (i.e., a metallic liquid cold plate). In addition to the bottom plate, the battery box also includes a composite vacuum upper box 200 (i.e., a non-metallic shell, in this embodiment, the non-metallic material is a composite material), a vacuum regulating valve 300 (i.e., a regulating valve), and a pressure sensor 400. The sealed chamber (which can be evacuated) formed by the vacuum-enclosed cavity box 101 and the shell 200 houses the power battery module 500 (i.e., the power battery).

[0029] like Figure 2As shown, the double-layer composite vacuum cold plate 100 has a two-layer structure. The upper layer is a liquid cooling layer made of a metal liquid cooling plate. This liquid cooling layer comprises an aluminum alloy liquid cooling plate 102 (102 also includes a flow channel 1021). The upper surface of the aluminum alloy liquid cooling plate 102 is designed to contact the bottom of the power battery, meaning that the liquid cooling layer is in direct contact with the power battery. The lower layer is a thermal insulation layer made of a non-metallic vacuum-enclosed cavity box. This insulation layer comprises a double-layer composite vacuum-enclosed cavity box 101. The non-metallic materials used in this embodiment are all composite materials, meaning that both 101 and 200 are composite materials. The sealed cavity they form is also equivalent to a composite cavity, capable of being evacuated. This composite material (i.e., composite RTM, PCM, etc.) is commonly used in power batteries. It primarily uses glass fiber, is relatively low in cost, has a high density, and a thermal conductivity of 0.2 W / (°C*K), providing good thermal insulation properties. Therefore, evacuating this sealed cavity can improve the thermal insulation of the power battery.

[0030] In addition, the lower surface of the aluminum alloy liquid cooling plate 102 is used to contact the upper surface of the vacuum sealed cavity box 101, which is equivalent to fixing 102 and 101 together through the lower surface of 102 and the upper surface of 101. Figure 2 In this embodiment, the fixed connection method is: high-performance adhesive is used to bond the four sides of the vacuum-sealed cavity box body 101 and the aluminum alloy liquid cooling plate 102 to each other.

[0031] In summary, the liquid cooling layer provided by this system can achieve cooling (lowering the temperature) or heating (increasing the temperature) of the power battery. Specifically, the upper surface of the liquid cooling plate 102 in the liquid cooling layer uses aluminum alloy to quickly transfer heat to the battery cells (i.e., the power battery). (The heat transfer path of the module 500 dissipates heat externally through contact with the aluminum alloy liquid cooling plate 102 at the bottom, and dissipates heat externally through convection around the module and the top.) The thermal insulation layer provided by this system can also achieve the effect of insulating the power battery. Specifically, the sealed cavity is vacuumed, which can effectively reduce the heat transfer capacity and enhance the thermal insulation performance.

[0032] In this embodiment, a metal mounting point is provided at the edge of the liquid cooling plate; the metal mounting point is integrally formed with the liquid cooling plate and is used to be fixedly connected to the bottom crossbeam of the vehicle through fasteners. Figure 3As shown, in one embodiment of this embodiment, metal mounting point 1022 and the upper aluminum alloy liquid cooling plate and its flow channel (i.e., flow channel 1021) are integrally formed. Metal locking bolts are used as fasteners to secure mounting point 1022 to the vehicle's bottom cross member. This secures the integrated liquid cooling plate to the vehicle via these metal locking bolts, thereby ensuring the structural strength of the entire battery compartment. The hollowed-out bottom portion of the metal mounting point is enclosed in a non-metallic housing, which can be made of plastic, ceramic, or a composite material such as fiberglass.

[0033] In this embodiment, the battery box further includes: a regulating valve for adjusting the vacuum degree of the sealed cavity in the battery box and a pressure sensor for obtaining the pressure corresponding to the vacuum degree of the sealed cavity in the battery box.

[0034] refer to Figure 1 In one embodiment of this embodiment, the vacuum regulating valve 300 and the pressure sensor 400 are both disposed on the upper case 200. The vacuum regulating valve 300 is disposed on the outer wall of the upper case 200 to facilitate gas exchange between the interior and exterior of the battery case; the pressure sensor 400 is disposed on the inner wall of the upper case 200 to detect the vacuum level of the sealed cavity within the battery case.

[0035] In this embodiment, the function of the pressure sensor 400 is to obtain the pressure corresponding to the vacuum degree of the sealed cavity in the battery box; that is, through the pressure sensor 400, the actual pressure in the battery box can be known before the vacuum degree is adjusted, and whether the vacuum degree is adjusted to the reference value can be known after the vacuum degree is adjusted. In this embodiment, the pressure sensor 400 is a capacitive sensor, and its range can cover the entire target vacuum range (0~100kPa). In other embodiments of this embodiment, other forms of pressure sensors can also be used according to actual needs. It should be noted that the pressure sensor 400 only obtains the pressure corresponding to the vacuum degree of the sealed cavity in the battery box, not the actual vacuum degree. The vacuum degree can be calculated based on its corresponding pressure.

[0036] In this embodiment, the function of the vacuum regulating valve 300 is: according to the control signal received (the control signal is Figure 4 (generated by the controller in the external vacuum subsystem shown) to regulate the vacuum level within the sealed chamber of the battery compartment. In this embodiment, the vacuum control valve 300 is a bidirectional electric proportional valve that can be opened and closed or adjusted to control the flow of gas into and out of the compartment. Gas can flow into and out of the battery compartment based on the required vacuum level. In other embodiments of this embodiment, other control valves (such as high-speed solenoid valves) can be used based on actual needs.

[0037] In this embodiment, the system further includes an external vacuum pumping subsystem.

[0038] The external vacuum pumping subsystem includes a controller; the controller is used to determine a reference value corresponding to the current adjustment of the vacuum degree of the sealed cavity in the battery box based on the pressure and ambient temperature corresponding to the vacuum degree of the sealed cavity in the battery box, or based on the pressure, ambient temperature and driving speed corresponding to the vacuum degree of the sealed cavity in the battery box, and determine the difference between the actual vacuum degree of the sealed cavity in the battery box and the corresponding reference value, so as to generate a corresponding control instruction and send it to the regulating valve to control the regulating valve.

[0039] refer to Figure 4 In one embodiment of the present embodiment, the dynamic adjustment process of the vacuum degree is realized by a controller, and its main functions are: receiving the pressure corresponding to the vacuum degree of the sealed cavity in the battery box obtained by the pressure sensor 400; receiving the ambient temperature obtained by the temperature sensor; obtaining the current driving speed, and then calculating the deviation between the target vacuum degree and the actual vacuum in the box under the corresponding ambient temperature / vehicle speed based on the above data, and outputting a control signal through a PID or other control algorithm, and transmitting it to the vacuum regulating valve 300, so as to dynamically adjust the vacuum degree inside the battery box through the vacuum regulating valve 300, thereby adjusting the internal pressure of the battery box to ensure the vacuum degree target control requirements of the vehicle under different ambient temperatures.

[0040] In this embodiment, the method of adjusting the vacuum degree of the sealed cavity in the battery box includes: When the vehicle is in driving state, if the driving speed is greater than or equal to the set speed, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a first reference value; so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the first reference value; if the driving speed is less than the set speed, it is determined whether the ambient temperature is within the set temperature range including the upper limit value and the lower limit value. If the ambient temperature is not within the set temperature range, the control regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a second reference value so that the battery box has thermal insulation performance corresponding to the vacuum degree of the second reference value; otherwise, the control regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a third reference value so that the battery box has thermal insulation performance corresponding to the vacuum degree of the third reference value; the second reference value is greater than the third reference value; the first reference value is less than the second reference value.

[0041] The lower limit of the above-mentioned set temperature range is less than or equal to the minimum heating temperature of the power battery; the upper limit of the set temperature range is less than the liquid cooling start-up temperature of the power battery and the difference between it and the liquid cooling start-up temperature is less than the set temperature difference, or is greater than or equal to the liquid cooling start-up temperature of the power battery.

[0042] refer to Figure 5In a preferred embodiment of this embodiment, the controller first determines the online status of the vehicle (the status includes the parking status, the shelving status or the driving status). When it is determined that the vehicle status is the driving status, the driving speed is then determined (that is, the influence of different vehicle speeds needs to be considered), that is, the average vehicle speed is determined every 30 minutes, and re-determined according to the speed limit value requirements.

[0043] Specifically, when the vehicle speed is ≥ V0 km / h (i.e., the set speed), i.e., at a high speed, the power battery output power is high, the battery operating rate is high, and the battery heat generation is high. At this time, the battery temperature rises rapidly, eliminating the need for insulation and requiring heat dissipation to delay reaching the liquid cooling threshold, thereby saving heating and cooling energy. Therefore, the vacuum level can be controlled at a low level or normal atmospheric pressure. In this embodiment, the vacuum level of the sealed cavity within the battery box is adjusted to p (i.e., the first reference value). When the vehicle speed is < V0 km / h, i.e., at a low speed, the power battery output power is low, the operating rate is low, the battery heat generation is low, and the temperature rise is slow. In this embodiment, the ambient temperature is obtained by a temperature sensor included in the external vacuum pumping subsystem, which is located near the box.

[0044] In the above judgment logic, the ambient temperature T needs to be divided into three intervals for discussion: 1) When T<T1 (the set temperature range is [T1, T2], where T1 is the lower limit of the set temperature range), it indicates that the ambient temperature is very low. It can be considered that the ambient temperature is far below the minimum heating temperature of the battery (T1 is less than or equal to the minimum heating temperature of the power battery). At this time, the battery temperature continues to drop during driving. At this time, it is necessary to increase the vacuum degree and improve the thermal insulation performance to reduce the battery cooling rate, increase the battery operating temperature, and extend the vehicle's range.

[0045] Specifically, the regulating operation adopted in this embodiment is: the vacuum regulating valve 300 adjusts the vacuum degree in the battery box to q1 (ie, the second reference value, which is a larger vacuum degree value, and p<q1) according to the received instruction.

[0046] 2) When T>T2 (T2 is the upper limit of the set temperature range), it means that the ambient temperature is very high. Since T2 is lower than the liquid cooling start-up temperature of the power battery and the difference between T2 and the liquid cooling start-up temperature is less than the set temperature difference △T (this value is an extremely small value), it can be considered that the ambient temperature has approached or exceeded the liquid cooling start-up temperature of the battery. At this time, it is still necessary to increase the vacuum degree to improve the thermal insulation performance, block the heat exchange between the external hot air and the battery liquid cooling system, improve the liquid cooling efficiency, and save energy.

[0047] Specifically, the regulating operation adopted in this embodiment is: the vacuum regulating valve 300 adjusts the vacuum degree in the battery box to q1 (ie, the second reference value, which is a larger vacuum degree value) according to the received instruction.

[0048] 3) When T1≤T<T2, the vacuum degree can be controlled at a low value (i.e., the vacuum degree can be controlled at a lower value). If the vacuum degree is adjusted too high, the battery heat dissipation performance will be poor, the liquid cooling start-up temperature will be reached faster, and energy consumption will increase.

[0049] Specifically, the regulating operation adopted in this embodiment is: the vacuum regulating valve 300 adjusts the vacuum degree in the battery box to q2 (ie, the third reference value, which is a smaller vacuum degree value, and q1>q2) according to the received instruction.

[0050] In fact, in this embodiment, as long as the ambient temperature T is not within the set temperature range of T1~T2, that is, regardless of whether the ambient temperature is too high or too low, the vacuum degree needs to be increased to improve the thermal insulation performance; only when T is within T1~T2, the vacuum degree needs to be controlled at a lower value, which is conducive to battery heat dissipation.

[0051] In this embodiment, when the controller determines that the vehicle is in a parked state or a resting state, and if the ambient temperature is less than a first temperature threshold, the regulating valve adjusts the vacuum degree of the battery box to a fourth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fourth reference value; If the ambient temperature is greater than the first temperature threshold and less than the second temperature threshold, the regulating valve adjusts the vacuum degree of the battery box to the fifth reference value according to the received instruction, so that the battery box has the thermal insulation performance corresponding to the vacuum degree of the fifth reference value; the fifth reference value is less than the fourth reference value.

[0052] If the ambient temperature is greater than or equal to the second temperature threshold, the regulating valve adjusts the vacuum degree of the battery box to the sixth reference value according to the received instruction, so that the battery box has the thermal insulation performance corresponding to the vacuum degree of the sixth reference value; the sixth reference value is less than the fifth reference value.

[0053] In one embodiment of the present embodiment, Tb and Ta represent the first temperature threshold and the second temperature threshold, respectively, and Tb<Ta, wherein when setting Tb, it is usually set to a lower temperature. If the temperature is lower than this value, it means that the external environment temperature is extremely low and extremely cold at this time; and when setting Ta, it is usually set to a higher temperature. If the temperature is higher than this value, it means that the external environment temperature is too high and relatively hot at this time; that is, by setting the above two thresholds, extreme working conditions can be distinguished at the temperature level.

[0054] like Figure 5As shown, if the vehicle is parked or parked, the temperature sensor near the box will be used to automatically wake up the vehicle and record the initial ambient temperature. If the ambient temperature changes by ≤±3°C within 2 hours, the original ambient temperature is maintained. If the ambient temperature changes by >±3°C, the value is read again. In this judgment logic, the ambient temperature T still needs to be divided into three intervals for discussion: a) If the ambient temperature T is less than the first temperature threshold Tb (i.e., T < Tb), this indicates an extremely cold operating condition. In this case, the battery compartment cooling rate needs to be as slow as possible to lower the initial departure temperature of the battery after storage. This improves the battery's initial feedback capability, discharge capacity, and charging speed to ensure the battery's low-temperature endurance. At this time, the vacuum level in the battery compartment needs to be increased to improve the thermal insulation performance of the battery compartment.

[0055] Specifically, the regulating operation adopted in this embodiment is: the vacuum regulating valve 300 adjusts the vacuum degree of the battery box to A0 (ie, the fourth reference value) according to the received instruction.

[0056] b) If the ambient temperature T is greater than the first temperature threshold Tb and less than the second temperature threshold Ta (i.e., Tb < T < Ta), it indicates that the system is operating at a relatively low temperature. However, high vacuum is not required to meet the minimum temperature requirement for the battery after standing. Therefore, it is sufficient to control the vacuum level in the battery compartment to an appropriate value without maintaining a high vacuum level inside the battery pack.

[0057] Specifically, the regulating operation adopted in this embodiment is: the vacuum regulating valve 300 adjusts the vacuum degree of the battery box to B0 (ie, the fifth reference value, and B0<A0) according to the received instruction.

[0058] c) If the ambient temperature is greater than or equal to the second temperature threshold Ta (i.e., T≥Ta), it means that the ambient temperature is relatively high at this time. Even under low vacuum conditions or normal atmospheric pressure conditions, the battery temperature can meet the usage requirements and does not need to be insulated. In some operating conditions, the battery may even need to be cooled. Therefore, in this case, it is only necessary to adjust the vacuum degree to a lower value.

[0059] Specifically, the regulating operation adopted in this embodiment is: the vacuum regulating valve 300 adjusts the vacuum degree of the battery box to C0 (ie, the sixth reference value, and C0<B0<A0) according to the received instruction.

[0060] In one embodiment of this embodiment, in addition to the controller and temperature sensor, the external vacuum pump subsystem also includes an external vacuum pump. In this embodiment, the external vacuum pump is a vortex pump, selected based on the actual air volume within the box and the vacuum target requirement. Its primary function is to extract air from the battery box to reduce the pressure within the box and increase the vacuum level. The vacuum pump can vacuum the battery box using an external 24V power supply or directly using power from the battery.

[0061] Implementation method for thermal insulation control of power battery This embodiment provides a technical solution for a power battery thermal insulation control method. The main concept of this solution is to control the power battery thermal insulation system in the power battery thermal insulation system embodiment, thereby utilizing the specially designed battery box included in the system to achieve thermal insulation of the power battery. The battery box can heat or cool the power battery through the liquid cooling layer in its bottom plate (this layer is mainly composed of a metal liquid cooling plate). It also achieves thermal insulation by evacuating the sealed cavity formed by the shell and the thermal insulation layer in its bottom plate (this layer is mainly composed of a non-metallic vacuum-sealed cavity box).

[0062] Since the specific working mode and working principle of the heat preservation control method of the power battery of this embodiment have been described in detail in the above-mentioned heat preservation system embodiment of the power battery, they will not be repeated here.

[0063] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention.

Claims

1. A power battery insulation system, characterized in that: Including battery box; The battery box includes: a non-metallic shell for covering the top area and surrounding areas of the power battery, and a bottom plate for covering the opening area of the shell; the bottom plate and the shell form a sealed cavity in the battery box, and the sealed cavity can be vacuumed; The bottom plate includes: a liquid cooling layer including a metal liquid cooling plate and a heat preservation layer including a non-metal vacuum sealed cavity box body; The upper surface of the liquid cooling plate is used to contact the bottom of the power battery, and the lower surface is used to contact the upper surface of the vacuum closed cavity box body; the liquid cooling plate and the closed cavity box body are fixedly connected.

2. The power battery insulation system according to claim 1, characterized in that: The battery box further comprises: a regulating valve for adjusting the vacuum degree of the sealed cavity in the battery box and a pressure sensor for obtaining the pressure corresponding to the vacuum degree of the sealed cavity in the battery box; The method of adjusting the vacuum degree of the sealed cavity in the battery box includes: When the vehicle is in a driving state, if the driving speed is greater than or equal to a set speed, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a first reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the first reference value; if the driving speed is less than the set speed, it is determined whether the ambient temperature is within a set temperature range including an upper limit and a lower limit; If the ambient temperature is not within the set temperature range, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a second reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the second reference value; otherwise, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a third reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the third reference value; the second reference value is greater than the third reference value; and the first reference value is less than the second reference value; The lower limit value of the set temperature range is less than or equal to the minimum heating temperature of the power battery; the upper limit value of the set temperature range is less than the liquid cooling start-up temperature of the power battery and the difference between the upper limit value and the liquid cooling start-up temperature is less than the set temperature difference value, or is greater than or equal to the liquid cooling start-up temperature of the power battery.

3. The power battery insulation system according to claim 2, characterized in that: The method of adjusting the vacuum degree of the sealed cavity in the battery box also includes: When the vehicle is in a parked state or a parked state, if the ambient temperature is less than a first temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a fourth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fourth reference value; If the ambient temperature is greater than the first temperature threshold and less than the second temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a fifth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fifth reference value; the fifth reference value is less than the fourth reference value; If the ambient temperature is greater than or equal to the second temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a sixth reference value according to the received instruction, so that the battery box has the thermal insulation performance corresponding to the vacuum degree of the sixth reference value; the sixth reference value is less than the fifth reference value.

4. The power battery insulation system according to claim 1 or 2, characterized in that: A metal mounting point is provided at the edge of the liquid cooling plate; the metal mounting point is integrally formed with the liquid cooling plate and is used for fixed connection with the bottom crossbeam of the vehicle through fasteners.

5. The power battery insulation system according to claim 2, characterized in that: Also included is an external vacuum subsystem; The external vacuum pumping subsystem includes a controller; the controller is used to determine a reference value corresponding to the current adjustment of the vacuum degree of the sealed cavity in the battery box based on the pressure and ambient temperature corresponding to the vacuum degree of the sealed cavity in the battery box, or based on the pressure, ambient temperature and driving speed corresponding to the vacuum degree of the sealed cavity in the battery box, and determine the difference between the actual vacuum degree of the sealed cavity in the battery box and the corresponding reference value, so as to generate a corresponding control instruction and send it to the regulating valve to control the regulating valve.

6. The power battery insulation system according to claim 1 or 2, characterized in that: The method of fixedly connecting the liquid cooling plate and the vacuum sealed cavity box body includes: fixedly connecting the lower surface of the liquid cooling plate and the upper surface of the vacuum sealed cavity box body around.

7. The power battery insulation system according to claim 1 or 2, characterized in that: The metal liquid cooling plate is an aluminum alloy liquid cooling plate.

8. A method for controlling thermal insulation of a power battery, characterized in that: Control the thermal insulation system of the power battery; the thermal insulation system of the power battery includes the battery box; The battery box includes: a non-metallic shell for covering the top area and surrounding areas of the power battery, and a bottom plate for covering the opening area of the shell; the bottom plate and the shell form a sealed cavity in the battery box, and the sealed cavity can be vacuumed; The bottom plate includes: a liquid cooling layer including a metal liquid cooling plate and a heat preservation layer including a non-metal vacuum sealed cavity box body; The upper surface of the liquid cooling plate is used to contact the bottom of the power battery, and the lower surface is used to contact the upper surface of the vacuum closed cavity box body; the liquid cooling plate and the closed cavity box body are fixedly connected; Methods for controlling the thermal insulation system of the power battery include: adjusting the vacuum degree of the sealed cavity in the battery box according to the thermal insulation or heat dissipation requirements of the power battery.

9. The power battery heat preservation control method according to claim 8, characterized in that: The battery box further includes: a regulating valve for adjusting the vacuum degree inside the sealed cavity of the battery box and a pressure sensor for obtaining the pressure corresponding to the vacuum degree of the sealed cavity of the battery box; The method of adjusting the vacuum degree of the sealed cavity in the battery box includes: When the vehicle is in a driving state, if the driving speed is greater than or equal to a set speed, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a first reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the first reference value; if the driving speed is less than the set speed, it is determined whether the ambient temperature is within a set temperature range including an upper limit and a lower limit; If the ambient temperature is not within the set temperature range, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a second reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the second reference value; otherwise, the regulating valve is controlled to adjust the vacuum degree of the sealed cavity in the battery box to a third reference value, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the third reference value; the second reference value is greater than the third reference value; and the first reference value is less than the second reference value; The lower limit value of the set temperature range is less than or equal to the minimum heating temperature of the power battery; the upper limit value of the set temperature range is less than the liquid cooling start-up temperature of the power battery and the difference between the upper limit value and the liquid cooling start-up temperature is less than the set temperature difference value, or is greater than or equal to the liquid cooling start-up temperature of the power battery.

10. The power battery heat preservation control method according to claim 9, characterized in that: The method of adjusting the vacuum degree of the sealed cavity in the battery box also includes: When the vehicle is in a parked state or a parked state, if the ambient temperature is less than a first temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a fourth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fourth reference value; If the ambient temperature is greater than the first temperature threshold and less than the second temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a fifth reference value according to the received instruction, so that the battery box has a thermal insulation performance corresponding to the vacuum degree of the fifth reference value; the fifth reference value is less than the fourth reference value; If the ambient temperature is greater than or equal to the second temperature threshold, the regulating valve adjusts the vacuum degree of the sealed cavity in the battery box to a sixth reference value according to the received instruction, so that the battery box has the thermal insulation performance corresponding to the vacuum degree of the sixth reference value; the sixth reference value is less than the fifth reference value.

11. The power battery heat preservation control method according to claim 8 or 9, characterized in that: A metal mounting point is provided at the edge of the liquid cooling plate; the metal mounting point is integrally formed with the liquid cooling plate and is used for fixed connection with the bottom crossbeam of the vehicle through fasteners.

12. The power battery heat preservation control method according to claim 9, characterized in that: Also included is an external vacuum subsystem; The external vacuum pumping subsystem includes a controller; the controller is used to determine a reference value corresponding to the current adjustment of the vacuum degree of the sealed cavity in the battery box based on the pressure and ambient temperature corresponding to the vacuum degree of the sealed cavity in the battery box, or based on the pressure, ambient temperature and driving speed corresponding to the vacuum degree of the sealed cavity in the battery box, and determine the difference between the actual vacuum degree of the sealed cavity in the battery box and the corresponding reference value, so as to generate a corresponding control instruction and send it to the regulating valve to control the regulating valve.

13. The power battery heat preservation control method according to claim 8 or 9, characterized in that: The method of fixedly connecting the liquid cooling plate and the vacuum sealed cavity box body includes: fixedly connecting the lower surface of the liquid cooling plate and the upper surface of the vacuum sealed cavity box body around.

14. The power battery heat preservation control method according to claim 8 or 9, characterized in that: The metal liquid cooling plate is an aluminum alloy liquid cooling plate.

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