Specific heat capacity measuring device of energy storage battery

Abstract

A specific heat capacity measuring device for an energy storage battery belongs to the technical field of battery performance testing and comprises a constant-temperature box, a vacuum box, a suspension part, an aluminized reflecting film, the energy storage battery, an electric heating film, a heat preservation layer, a direct-current stabilized power supply, a thermocouple and a temperature acquisition instrument. The vacuum box is arranged inside the constant temperature box, the energy storage battery is suspended inside the vacuum box through a suspension piece, an aluminized reflecting film is attached to the inner wall of the vacuum box, thermocouples are distributed on the large face of the energy storage battery, an electric heating film is attached to the outer portion of the large face of the energy storage battery, and the whole energy storage battery is wrapped with a heat preservation layer. The electric heating film is connected with a direct-current stabilized power supply, and the thermocouple is connected with a temperature acquisition instrument. The device can fully meet the research on the influence of temperature on the specific heat capacity of the battery, and has the advantages of simple structure, low preparation cost, high measurement precision, flexible operation and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery performance testing, and relates to a device for measuring the performance of an energy storage battery, in particular to a device for measuring the specific heat capacity of a power and energy storage battery. Background Art

[0002] The specific heat capacity of energy storage batteries represents the battery's ability to handle heat. In addition, specific heat capacity is a key parameter for calculating the heat generation rate of batteries, and is also a necessary input parameter for thermal simulation research on energy storage batteries. The accuracy of specific heat capacity measurement is directly related to the accuracy of battery heat generation calculation and temperature field simulation. Therefore, accurately understanding the specific heat capacity of batteries is a prerequisite for thermal safety management of batteries.

[0003] Invention patent CN114113200A discloses a method for measuring the specific heat capacity of energy storage batteries based on heat flux density measurement. This method requires a heat flow meter, which is expensive and has a long measurement cycle. Invention patent CN108169679A discloses a method and system for detecting the specific heat capacity of batteries. This system requires an isothermal calorimeter, which is expensive and has no insulation in the test chamber. The measurement process is cumbersome, the accuracy is low, and the measurement device needs to be optimized.

[0004] At present, the measurement device of the specific heat capacity of energy storage batteries has problems such as expensive measurement equipment, cumbersome test steps, long cycle, and poor universality, which makes the measurement process of battery specific heat capacity expensive, time-consuming and labor-intensive. Therefore, it is particularly important to design a new measurement device to solve the common problems faced by battery specific heat capacity measurement. Utility Model Content

[0005] The utility model aims at the deficiencies existing in the existing energy storage battery specific heat capacity measuring device and the measuring process, and proposes a specific heat capacity measuring device for an energy storage battery, which can further reduce the measuring cost and improve the measuring accuracy while meeting the requirements of convenient operation.

[0006] The energy storage battery specific heat capacity measurement device provided in this application adopts the following technical solution:

[0007] A device for measuring the specific heat capacity of an energy storage battery comprises an energy storage battery, a DC regulated power supply and a temperature collector arranged outside the device; the characteristic is that the measuring device also comprises a constant temperature box and a vacuum box, the vacuum box is placed inside the constant temperature box, the energy storage battery is suspended inside the vacuum box through a suspension, an aluminum-plated reflective film is pasted on the inner wall of the vacuum box, a thermocouple is arranged on the large surface of the energy storage battery, an electric heating film is adhered to the outside of the large surface of the energy storage battery, an insulating layer is coated on the outside of the entire energy storage battery, the electric heating film is connected to the DC regulated power supply, and the thermocouple is connected to the temperature collector.

[0008] By adopting the above technical solution, the constant temperature box provides a wide temperature range test environment and is used for placing a vacuum box. The vacuum box is used to place the energy storage battery to be measured. The reflective film on the inner wall of the vacuum box has a smooth surface and strong reflective performance, which can weaken the radiation heat exchange capacity between the battery and the surrounding environment. The furnace temperature of the constant temperature box is adjusted to provide the battery with an initial temperature and a constant ambient temperature. Through the operation of the voltage-stabilized power supply and the temperature data acquisition instrument, the specific heat capacity of the energy storage battery can be conveniently calculated according to the temperature change of the energy storage battery.

[0009] Furthermore, a support tray is provided at the inner bottom of the constant temperature box, and ventilation holes are evenly distributed on the support tray.

[0010] By adopting the above technical solution, the support tray is used to support the vacuum box, and the air holes can ensure the stability of the airflow around the vacuum box.

[0011] Furthermore, a threading hole is provided on one side surface of the thermostatic box, and a plug is connected to the threading hole.

[0012] By adopting the above technical solution, the threading holes are arranged so as to allow the thermocouple wires, voltage wires and exhaust pipelines to pass through, and plugs are arranged on the threading holes to reduce the heat loss in the constant temperature box.

[0013] Furthermore, the vacuum box is composed of an upper cover and a vacuum box body, and the upper cover is respectively provided with an air extraction hole and a lead-in hole, and both holes are provided with rubber plugs.

[0014] By adopting the above technical solution, the vacuum box is made into a split structure to facilitate the removal and placement of the energy storage battery. The exhaust hole is used to connect an external vacuum pump to create a low-pressure environment. The lead hole is used to lead out the electric heating film voltage lead and the thermocouple lead. The rubber plug is used to effectively prevent the rapid escape of air.

[0015] Furthermore, support feet are provided at the four corners of the bottom of the vacuum box to form a gap between the vacuum box and the support tray.

[0016] By adopting the above technical solution, supporting feet are arranged at the bottom of the vacuum box, which can avoid large-area direct contact between the vacuum box and the supporting tray, thereby weakening the heat conduction between the vacuum box and the supporting tray.

[0017] Furthermore, the suspension member is composed of a suspension ring and filamentary wires, the suspension member is fixed at the center of the inner surface of the upper cover, and the energy storage battery is suspended by the wires and placed at the center of the vacuum box.

[0018] By adopting the above technical solution, the wire material uses thin filamentary wire material with poor thermal conductivity, such as thin cotton thread, to prevent the energy storage battery from being affected.

[0019] Furthermore, the thermal insulation layer is an aerogel felt layer with a thickness of 30 mm and a thermal conductivity not higher than 0.03 W / m°C.

[0020] By adopting the above technical solution, the thermal insulation layer completely covers the energy storage battery so that it is in close contact with the battery surface, preventing the heat loss after the electric heating film is heated, so as to improve the measurement accuracy.

[0021] In summary, the present invention includes at least one of the following beneficial technical effects:

[0022] (1) Low cost: The energy storage battery specific heat capacity measuring device proposed in the utility model adopts a conventional vacuum box, electric heating film and thermal insulation materials when conducting experiments. Compared with the use of accelerated adiabatic calorimeter, isothermal calorimeter or heat flow meter equipment to measure the specific heat capacity of the battery, the device has a simple structure and obvious advantages in manufacturing cost and measurement cost.

[0023] (2) High precision: The energy storage battery specific heat capacity measuring device proposed in the utility model can measure the specific heat capacity of the battery under a negative pressure (-80 to -100 kPa) environment, providing a nearly adiabatic measurement environment for the battery, and can also meet the heat loss calibration requirements of the battery, thereby ensuring a high measurement accuracy.

[0024] (3) Easy to operate: The energy storage battery specific heat capacity measurement device proposed in the utility model can provide specific heat capacity measurement in a wide temperature range of -60 to 80°C through a constant temperature box. It is easy to operate and can meet the needs of studying the effect of temperature on the specific heat capacity of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the specific heat capacity measuring device of the utility model.

[0026] Figure 2 It is a schematic diagram of the structure of the thermostat in the utility model.

[0027] Figure 3 This is a schematic diagram of the vacuum box structure in the utility model.

[0028] Figure 4 This is a schematic diagram of the external structure of the energy storage battery in the utility model.

[0029] In the figure: constant temperature box 1, vacuum box 2, suspension 3, aluminum-plated reflective film 4, energy storage battery 5, electric heating film 6, insulation layer 7, support tray 8, DC regulated power supply 9, thermocouple 10, temperature collector 11, threading hole 12, upper cover 13, exhaust hole 14, lead hole 15, vacuum box body 16. DETAILED DESCRIPTION

[0030] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications to various equivalent forms of the present invention by those skilled in the art fall within the scope defined by the claims attached to this application.

[0031] Real-time Example 1

[0032] like Figure 1-4 As shown, a device for measuring the specific heat capacity of an energy storage battery includes a thermostat 1, a vacuum box 2, a suspension 3, an aluminum-plated reflective film 4, an energy storage battery 5, an electric heating film 6, an insulation layer 7, a DC regulated power supply 9, a thermocouple 10, and a temperature collector 11. The thermostat 1 is placed in a well-ventilated area to timely evacuate the heat discharged from the furnace body. The thermostat 1 can provide a wide temperature range test environment of -60 to 80 °C, with a constant ambient temperature (± 0.5 °C), and a cavity volume not less than 10 times the volume of the vacuum box 2; the thermostat 1 has a built-in support tray 8, and there are air holes on the tray, which is located in the middle and lower position inside the thermostat 1 for supporting the vacuum box 2; the vacuum box 2 provides negative air pressure (-80 to -100 kPa) measurement environment, the suspension part 3 is located in the middle of the vacuum box cover and has an appropriate length. The energy storage battery 5 is suspended in the center of the vacuum box 2, and the aluminum-plated reflective film 4 is applied to the inner surface of the cavity of the vacuum box 2; the outside of the energy storage battery 5 is sequentially coated with an electric heating film 6 and a thermal insulation layer 7. For square and soft-pack batteries, both large surfaces are adhered, and for cylindrical batteries, the side surfaces can be adhered. In this embodiment, a square battery is selected, the electric heating film 6 covers the two large surfaces of the battery, and the thermal insulation layer 7 completely covers the energy storage battery 5; the electric heating film 6 is externally connected to a DC regulated power supply 9, and a thermocouple 10 is arranged at the center of the large surface or the inner center of the battery. An external temperature collector 11 is connected to collect the temperature change of the energy storage battery 5 in real time.

[0033] Example 2

[0034] like Figure 2 As shown, in order to facilitate the passage of thermocouple wires, voltage wires and exhaust pipes, a threading hole is provided on one side of the thermostat in this embodiment. Specifically, Figure 2 As shown, a threading hole 12 is provided on the right side surface of the thermostatic box 1, and a plug is connected to the threading hole 12 to reduce the heat loss in the thermostatic box.

[0035] In order to support the vacuum box and ensure stable airflow around the vacuum box, in this embodiment, a support tray 8 is provided at the middle and lower part of the constant temperature box 1, and air holes are opened on the tray.

[0036] In order to facilitate the placement and removal of the energy storage battery during the measurement process, the vacuum box 2 in this embodiment is made into a split structure consisting of an upper cover 13 and a vacuum box body 16. Specifically, Figure 3As shown, the upper cover 13 is provided with an air extraction hole 14 and a lead hole 15, and both holes are provided with rubber plugs. The air extraction hole is used to connect an external vacuum pump to create a low pressure environment, and the lead hole is used to lead out the voltage lead wire of the electric heating film and the thermocouple lead wire. The rubber plug can effectively prevent the rapid escape of air, and finally the edge of the gap is sealed tightly with vacuum sealant.

[0037] In order to avoid direct contact between the vacuum box and the support tray over a large area, so as to weaken the heat conduction between the vacuum box and the support tray. In this embodiment, support feet are provided at the bottom of the vacuum box 2. Specifically, as shown in FIG. Figure 3 As shown, support feet are provided at the four corners of the bottom of the vacuum box 2 to form a gap between the vacuum box 2 and the support tray 8.

[0038] like Figure 3 As shown, the inner surface of the vacuum box 2 is affixed with an aluminum-plated reflective film 4, which has a smooth surface and strong reflective performance, and mainly serves to reduce the radiation heat exchange capacity between the battery and the surrounding environment. The vacuum box 2 is made of acrylic, with a wall thickness of 20 mm and an internal volume of 400×400×400mm. The air extraction hole is externally connected to a vacuum pump to form a negative pressure environment. The pressure change inside the vacuum box is monitored in real time by the vacuum pump barometer. A suspension member 3 is set in the middle of the upper cover. The suspension member is composed of a ring and a thin wire. The thin wire is made of thin cotton thread or a thin filament with poor thermal conductivity. The energy storage battery 5 can be suspended in the center of the inner cavity of the vacuum box.

[0039] Real-time Example 3

[0040] like Figure 4 As shown, in order to increase the accuracy of the measurement, in this embodiment, the material of the electric heating film 6 is polyimide, with a nickel-chromium heating wire embedded in it, and a 0.05 mm thick thermal conductive adhesive is coated on the back of the heating film. The total thickness of the film is 0.20 mm, and the length and width are the same as the large surface size of the energy storage battery 5, and then it is completely adhered to the two large surfaces of the battery; the heating power of the electric heating film 6 is stable, and the influence of voltage and temperature is not more than 1%; the thermocouple 10 is located at the center of the two large surfaces of the energy storage battery 5, and an external temperature data acquisition instrument 11 monitors the temperature change of the battery; the insulation layer 7 is made of aerogel felt, pearl cotton, cotton, rock wool and glass wool board, etc., with a thermal conductivity of not more than 0.03 W / m°C. In this embodiment, white aerogel felt is used with a thickness of 30 mm to completely cover the energy storage battery 5, and then the aerogel felt is tied with fine cotton thread to make it in close contact with the battery surface.

[0041] like Figure 1-4 As shown, a method for using a specific heat capacity measuring device for an energy storage battery is as follows:

[0042] When in use, the electric heating film 6 is adhered to the two large surfaces of the energy storage battery 5, and then the lead wire is passed through the pores of the upper cover of the vacuum box 2; a thermocouple 10 is arranged in the center of the large surface of the battery, and its lead wire is passed through the lead wire hole 15 of the upper cover of the vacuum box 2, and sealed with vacuum mud; an aluminum-plated reflective film 4 is applied to the inner wall surface of the vacuum box 2, and then the upper cover is pressed down, and a vacuum is drawn by a vacuum pump; the voltage line, thermocouple line and exhaust pipe are passed through the threading hole 12 of the constant temperature box 1, and are respectively connected to the external stabilized power supply 9, the temperature acquisition instrument 11 and the vacuum pump; the vacuum box 2 is placed statically in the center of the support tray 8 of the constant temperature box 1; the furnace temperature of the constant temperature box 1 is adjusted to provide the battery with an initial temperature and a constant ambient temperature; the stabilized power supply 9 and the temperature data acquisition instrument 11 are turned on, and the specific heat capacity of the energy storage battery 5 is calculated according to the temperature change of the energy storage battery 5. After the test is completed, turn off the constant temperature box 1 and the vacuum pump, open the box door, take out the vacuum box 2 and the energy storage battery 5, peel off the insulation layer 7, the electric heating film 6 and the aluminum-plated reflective film 4, remove the thermocouple wire 9 and the electric heating film lead, etc., and place them in the original position to complete the battery specific heat capacity measurement.

Claims

1. A device for measuring the specific heat capacity of an energy storage battery, comprising an energy storage battery (5), a DC regulated power supply (9) and a temperature acquisition instrument (11) arranged outside the device; characterized in that: The measuring device further comprises a constant temperature box (1) and a vacuum box (2), wherein the vacuum box (2) is placed inside the constant temperature box (1), the energy storage battery (5) is suspended inside the vacuum box (2) via a suspension member (3), the inner wall of the vacuum box (2) is affixed with an aluminum-plated reflective film (4), a thermocouple (10) is arranged on the large surface of the energy storage battery (5), an electric heating film (6) is adhered to the outside of the large surface of the energy storage battery (5), the outside of the entire energy storage battery (5) is covered with a thermal insulation layer (7), the electric heating film (6) is connected to a DC regulated power supply (9), and the thermocouple (10) is connected to a temperature collector (11).

2. The specific heat capacity measuring device of an energy storage battery according to claim 1, characterized in that: The inner bottom of the thermostatic box (1) is provided with a support tray (8), and the support tray (8) is evenly provided with ventilation holes.

3. The specific heat capacity measuring device of an energy storage battery according to claim 2, characterized in that: A threading hole (12) is provided on one side surface of the thermostatic box (1), and a plug is connected to the threading hole (12).

4. The specific heat capacity measuring device of an energy storage battery according to claim 2, characterized in that: The vacuum box (2) is composed of an upper cover (13) and a vacuum box body (16). The upper cover (13) is provided with an air extraction hole (14) and a lead-in hole (15), and both holes are provided with rubber plugs.

5. The specific heat capacity measuring device of an energy storage battery according to claim 4, characterized in that: Support feet are provided at the four corners of the bottom of the vacuum box (2), so that a gap is formed between the vacuum box (2) and the support tray (8).

6. The specific heat capacity measuring device of an energy storage battery according to claim 1, characterized in that: The suspension member (3) is composed of a suspension ring and filamentary wires. The suspension member (3) is fixed at the center of the inner surface of the upper cover (13). The energy storage battery (5) is suspended by the wires and placed at the center of the vacuum box (16).

7. The device for measuring specific heat capacity of an energy storage battery according to claim 1, characterized in that: The thermal insulation layer (7) is made of a material with a thickness of 30 mm and a thermal conductivity coefficient not higher than 0.03 W / m°C.

Images