Battery module and assembly method thereof

Abstract

A battery module and an assembly method thereof are disclosed. In one embodiment of the present application, the battery module may include: two or more batteries, a thermally conductive silicone sheet, and an optical fiber monitoring unit, wherein the thermally conductive silicone sheet is disposed between the two batteries and the two side surfaces of the thermally conductive silicone sheet are in contact with the surfaces of the two batteries respectively; the temperature monitoring unit includes: an optical fiber sensor, an optical fiber, and an optical fiber Bragg grating demodulator; wherein the optical fiber sensor and the optical fiber are both fixed inside the thermally conductive silicone sheet, one end of the optical fiber is connected to the optical fiber sensor, and the other end extends from the top of the thermally conductive silicone sheet and is connected to the optical fiber Bragg grating demodulator. The present application not only does not increase the volume of the battery pack, but also can accurately monitor the actual temperature of the battery in the battery module while ensuring the heat dissipation effect, thereby significantly reducing the risk of misjudgment and untimely response, and effectively preventing the occurrence of thermal runaway.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a battery module and an assembling method thereof. Background Art

[0002] At present, lithium-ion batteries are widely used in various energy storage fields due to their high energy density, long service life, and environmental protection. The ever-increasing battery energy density has put forward higher requirements for battery safety. However, lithium battery packs generate a lot of heat when working, and the heat generated by each battery is often different. The heat generated by the battery needs to be diffused in time, otherwise the battery life will drop rapidly and even cause explosion or combustion. In addition, the temperature of the battery must be kept consistent, otherwise the consistency error of the battery will gradually increase after running for a period of time, which will reduce the life of the battery pack, that is, the "short board effect".

[0003] At present, in the field of lithium battery modules or lithium battery packaging (pack), thermally conductive silicone has been widely used in the heat dissipation management of lithium battery packs. Thermally conductive silicone can timely transfer the waste heat generated by the lithium battery pack to ensure the consistency of the battery pack temperature. At the same time, it can also play a role in shock resistance and vibration reduction when the battery pack is impacted by external forces. When monitoring the temperature of the battery pack, temperature measuring elements such as thermistors are often used. Due to the limitation of the battery pack space, the gaps between the batteries are limited, and the thermally conductive silicone sheet has been filled, it is difficult to arrange temperature measuring elements on the battery surface. Therefore, the temperature probe is often bonded to the battery ear connector or placed in a fixed position where temperature measurement is required to detect the temperature of the battery pack, which leads to inaccurate temperature measurement of the battery pack. Summary of the invention

[0004] In order to partially or completely solve the above technical problems and other partial technical problems, the embodiments of the present application provide a battery module and an assembly method thereof.

[0005] According to one aspect of the present application, a battery module is provided, comprising:

[0006] Two or more batteries;

[0007] A thermally conductive silicone sheet is disposed between the two batteries and the two side surfaces of the thermally conductive silicone sheet are in contact with the surfaces of the two batteries respectively;

[0008] Temperature monitoring unit, including: fiber optic sensor, optical fiber and fiber grating demodulator;

[0009] The optical fiber sensor and the optical fiber are both fixed inside the thermally conductive silicone sheet, one end of the optical fiber is connected to the optical fiber sensor, and the other end extends from the top of the thermally conductive silicone sheet and is connected to the optical fiber Bragg grating demodulator.

[0010] According to another aspect of the present application, a method for assembling a battery module is provided, comprising:

[0011] Obtaining a thermally conductive silicone sheet of a predetermined thickness;

[0012] Punching holes in the thermally conductive silicone sheet;

[0013] Brazing a hollow pipe inside the thermally conductive silicone sheet;

[0014] Fixing the optical fiber sensor on the hole, and inserting one end of the optical fiber into the hollow pipe through the opening at the top of the thermal conductive silicone sheet and connecting to the optical fiber sensor;

[0015] Placing the thermally conductive silicone sheet between the two batteries, and making the two side surfaces of the thermally conductive silicone sheet contact with the surfaces of the two batteries respectively;

[0016] The other end of the optical fiber outside the heat-conducting silicone sheet is connected to a fiber grating demodulator.

[0017] In the embodiment of the present application, an optical fiber sensor that can be used to detect the battery temperature is integrated inside the thermal conductive silicone. The thermal conductive silicone sheet is used to dissipate the heat of the battery module while the optical fiber sensor can be used to monitor the battery temperature. Not only does it not increase the volume of the battery pack, but it can also accurately monitor the actual temperature of the battery in the battery module while ensuring the heat dissipation effect, thereby significantly reducing the risk of misjudgment and untimely response, and effectively preventing the occurrence of thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an example diagram of some structures in the battery module of the embodiment of the present application.

[0019] Figure 2 This is an example cross-sectional view of the thermally conductive silicone sheet of the battery module according to an embodiment of the present application.

[0020] Figure 3 This is an example diagram of an optical fiber sensor and an optical fiber being arranged on a thermally conductive silicone sheet according to an embodiment of the present application.

[0021] Figure 4 Schematic diagram of the process of assembling a battery module in an embodiment of the present application.

[0022] Description of reference numerals:

[0023] 10. Battery module; 11. Battery; 12. Thermal conductive silicone sheet; 13. Fiber optic sensor; 14. Fiber optic; 141. Fiber optic core; 142. Single-layer non-stick coating. DETAILED DESCRIPTION

[0024] The following will describe the embodiments of the present application in detail with reference to the accompanying drawings. It should be noted that, in the absence of conflict, the various embodiments and features therein in the present application can be combined with each other in any manner.

[0025] In the field of lithium-ion battery modules, in order to improve energy density, it is necessary to use battery materials with higher specific energy and make lighter and more compact designs. This requires the battery pack to have high heat dissipation and heat transfer performance, and a temperature measurement system with high measurement accuracy, short response time, and high anti-interference stability.

[0026] As mentioned above, in the related art, the heat dissipation performance and temperature consistency of the battery pack are improved by simply adding various types of thermally conductive films and heat dissipation devices, and the temperature of the battery pack needs to be monitored by components such as thermocouples. However, due to the limited volume of the battery pack and the limited gaps between the batteries, after the thermally conductive silicone film fills the gaps between the batteries, the position of components such as thermocouples is generally located on the tab connector. Since the temperature of the tab connector cannot accurately reflect the temperature of the battery itself, the temperature measurement using this method is often inaccurate, and there is a risk of misjudgment and untimely response. In other words, there is a contradiction between the volume of the battery pack and the accuracy of temperature measurement.

[0027] In order to solve the above technical problems, the basic concept of the embodiment of the present application is to provide a battery module and an assembly method thereof, in which an optical fiber sensor that can be used to detect the battery temperature is integrated into the thermal conductive silicone, and the battery temperature can be accurately measured without increasing the gap between the batteries, and the volume of the battery pack is not increased. The thermal conductive silicone sheet can still fill the gaps between the batteries and adhere to the battery surface, which does not affect the heat dissipation effect and has little effect on the energy density of the battery module. In addition, since the optical fiber has excellent anti-electromagnetic and atomic radiation performance, water-resistant, high-temperature-resistant, and corrosion-resistant chemical properties, and light weight and soft mechanical properties, it is very suitable for temperature monitoring of lithium-ion modules or assemblies. Therefore, while ensuring the heat dissipation performance of the battery module, it can accurately monitor the actual temperature of each battery in the battery module, which can significantly reduce the risk of misjudgment and untimely response, thereby effectively preventing the occurrence of thermal runaway.

[0028] The following is a detailed description of an exemplary implementation of the battery module and its assembly method in the embodiment of the present application.

[0029] Figure 1 The figure shows a partial structure of the battery module 10 in the embodiment of the present application. Figure 2 FIG. 1 shows a schematic diagram of a thermally conductive silicone sheet of a battery module 10 in an embodiment of the present application. Figure 1 As shown, the battery module 10 may include: two or more batteries 11, a thermally conductive silicone sheet 12 and a temperature monitoring unit, and the temperature monitoring unit may include: an optical fiber sensor 13, an optical fiber 14 and a fiber grating demodulator (not shown in the figure).

[0030] Figure 3 The figure shows an example of an optical fiber sensor 13 and an optical fiber 14 being arranged on a thermally conductive silicone sheet 12. The optical fiber sensor 13 and the optical fiber 14 are both fixed inside the thermally conductive silicone sheet 12, one end of the optical fiber 14 is connected to the optical fiber sensor 13, and the other end extends from the top of the thermally conductive silicone sheet 12 and is connected to a fiber Bragg grating demodulator (not shown in the figure).

[0031] In the embodiment of the present application, the thermally conductive silicone sheet 12 can be made of raw materials such as thermally conductive fillers, flame retardants, pigments, crosslinking agents, catalysts, etc. Figure 1 As shown, in order to improve the heat dissipation performance and temperature consistency of the battery module, the thermally conductive silicone sheet 12 can be tightly fitted between the two batteries 11 without any gaps. In some examples, the thickness of the thermally conductive silicone sheet 12 matches the size of the gap between adjacent batteries 11 in the battery module. For example, when the gap between adjacent batteries 11 in the battery module is 1 to 2 mm, the thickness of the thermally conductive silicone sheet 12 can be between 1 and 2 mm. For example, the thickness of the thermally conductive silicone sheet 12 is preferably about 1 mm. In addition, the size of the thermally conductive silicone sheet 12 can match the size of the surface of the battery 11. For example, the size of the thermally conductive silicone sheet 12 can be slightly smaller than the size of the surface of the battery 11 (i.e., the heating surface).

[0032] In the embodiment of the present application, the optical fiber sensor 13 can be fixed inside the thermal conductive silicone sheet 12 in various possible ways. In some examples, a hole can be provided at a predetermined position of the thermal conductive silicone sheet 12, and the optical fiber sensor is fixed in the hole. To facilitate processing and molding, the hole can be a hole of regular shape. Preferably, the size and shape of the hole can be adapted to the size and shape of the optical fiber sensor 13. For example, the optical fiber sensor 14 is generally a quadrilateral, and the hole can also be a quadrilateral, and the inner cavity of the hole can just accommodate the optical fiber sensor 13. In some examples, in order to avoid increasing the thickness, the thickness of the optical fiber sensor 13 can be slightly smaller than the thickness of the thermal conductive silicone sheet 12, and the optical fiber sensor 13 can be embedded in the hole of the thermal conductive silicone sheet 12 by inlaying or snapping. In this way, the optical fiber sensor 13 can not only contact the surface of the battery 11 on both sides of the thermal conductive silicone sheet 12 to monitor the optical signal related to its surface, but also will not increase the thickness of the thermal conductive silicone sheet 12 when embedded in the hole.

[0033] In practical applications, when the heat-conducting silicone sheet 12 is located between two batteries 11, the predetermined position on which the optical fiber sensor 13 is fixed can just contact the heating area on the surface of the battery 11. Figure 2 and Figure 3 For example, the predetermined position may be the center position of the surface of the thermally conductive silicone sheet 12. Figure 2 and Figure 3This is only an example. In actual applications, the predetermined position may also be any other position on the surface of the thermally conductive silicone sheet 12 , and the embodiment of the present application does not limit this.

[0034] In the embodiment of the present application, the optical fiber 14 can be disposed in the thermally conductive silicone sheet 12 in various applicable ways. Figure 2 and Figure 3 For example, a hollow pipe may be provided inside the thermally conductive silicone sheet 12, and one end of the optical fiber 14 passes through the opening at the top of the thermally conductive silicone sheet 12 and enters the hollow pipe and is connected to the optical fiber sensor 13, while the other end of the optical fiber 14 is located outside the thermally conductive silicone sheet 12 and is connected to the fiber optic Bragg grating demodulator (not shown in the figure). By setting the optical fiber 14 inside the thermally conductive silicone sheet 12 through a hollow pipe, the optical fiber 14 can be easily buried in the thermally conductive silicone sheet 12, which can not only protect the optical fiber 14 through the thermally conductive silicone sheet 12 to prevent the optical fiber 14 from breaking, but also does not increase the thickness of the thermally conductive silicone sheet 12, and does not need to increase the gap between the batteries 11 to accommodate the thermally conductive silicone sheet 12 containing the optical fiber 14, thereby not only ensuring the accuracy of the battery surface temperature monitoring, but also avoiding the additional increase in the volume of the battery module 10.

[0035] In the embodiment of the present application, since the optical fiber 14 is disposed in the thermally conductive silicone sheet 12, the thermally conductive silicone sheet 12 can protect the optical fiber 14. Therefore, the optical fiber 14 does not need to be protected by multiple layers like ordinary optical fibers, but only needs to add a layer of non-stick coating (for example, polytetrafluoroethylene (PTFE)) as a protective layer of the optical fiber. In other words, Figure 3 As shown, the optical fiber 14 of the embodiment of the present application may include a bare optical fiber core 141 and a single layer of non-stick coating 142 coated on its outer surface. The optical fiber 14 using the single layer of protective layer also helps to reduce the diameter of the optical fiber 14, thereby avoiding increasing the thickness of the thermal conductive silicone layer 12 due to the built-in optical fiber 14.

[0036] In the embodiment of the present application, the fiber Bragg grating demodulator can be arranged on the outer shell of the battery module 10, so as to facilitate the external battery management system. The fiber Bragg grating demodulator can be used to determine the surface temperature of the battery 11 according to the reflection center wavelength transmitted in real time by the optical fiber 14, and transmit the temperature value calculated in real time to the external battery management system, thereby realizing real-time monitoring of the battery surface temperature.

[0037] In actual applications, when the battery module 10 is working, the optical fiber 14 is connected to the fiber grating demodulator, that is, the reflection center wavelength of each fiber grating is measured, and then the temperature value of each measurement point is calculated based on the predetermined relationship between the reflection center wavelength and the temperature and transmitted to the battery management system, so that the temperature of the battery surface can be monitored in real time.

[0038] For example, the predetermined relationship between the reflection center wavelength and the temperature may be as shown in the following equation (1), wherein the coefficient α and the coefficient β may be obtained through statistical analysis through experiments.

[0039] λ=α+βt (1)

[0040] Wherein, λ represents the currently measured reflection center wavelength, and t represents the temperature at the location of the optical fiber sensor 13, that is, t is the temperature of the battery surface.

[0041] Figure 4 FIG. 1 shows an exemplary assembly method of the battery module 10 in an embodiment of the present application. Figure 4 As shown, the assembly method of the battery module 10 may include the following steps:

[0042] Step S410, obtaining a thermally conductive silicone sheet 12 of a predetermined thickness.

[0043] In some examples, this step may include: preparing a thermally conductive silicone sheet, and cutting the thermally conductive silicone sheet into a size that matches the side of the battery. Specifically, the raw materials such as silicone, thermally conductive filler, flame retardant, pigment, crosslinker, catalyst, etc. may first be heated to remove water, stirred, mixed, calendered, and vulcanized to obtain a 1mm thick thermally conductive silicone sheet, and then the prepared thermally conductive silicone sheet may be trimmed and cut into the required size according to the design requirements of the battery pack. The size of the thermally conductive silicone sheet after cutting may be slightly smaller than the maximum surface of the battery.

[0044] Step S420, punching holes in the thermally conductive silicone sheet 12;

[0045] A hole matching the size of the optical fiber sensor is punched out on the thermal conductive silicone sheet.

[0046] For example, this step can be performed by an automated punching device or an automated punching tool. First, after fixing the thermal conductive silicone sheet with a clamp, a regularly shaped hole is punched out at the corresponding temperature test position (i.e., the predetermined position mentioned above). For details of the hole, please refer to the above description and will not be repeated here.

[0047] Step S430, brazing a hollow pipe inside the thermally conductive silicone sheet 12.

[0048] For example, a hollow pipe can be drilled on one side of the thermally conductive silicone sheet using a stainless steel hollow tube whose diameter does not exceed the thickness of the thermally conductive silicone sheet (for example, the diameter is 0.75 times the thickness of the thermally conductive silicone sheet). One end of the hollow pipe can be connected to the above-mentioned hole, and the other end opening is located at the top of the thermally conductive silicone sheet.

[0049] In practical applications, this step can be performed using automated equipment.

[0050] Step S440 , fix the optical fiber sensor 13 on the hole of the thermal conductive silicone sheet 12 , and insert one end of the optical fiber 14 into the hollow pipe through the opening at the top of the thermal conductive silicone sheet 12 and connect to the optical fiber sensor 13 .

[0051] Specifically, the bare optical fiber core is coated with a layer of PTFE and then passed through the hollow pipe punched in step S430 to the other end of the hole on the thermal conductive silicone sheet 12. The optical fiber 14 is connected to the optical fiber sensor 13 at one end of the hole on the thermal conductive silicone sheet 12, and the thickness of the optical fiber 14, the end of the optical fiber connected to the optical fiber sensor 13, the connection between the optical fiber and the optical fiber sensor, and the optical fiber sensor are all equal to or slightly smaller than the thickness of the thermal conductive silicone sheet, so as to avoid an increase in the thickness of the thermal conductive silicone sheet 12, which increases the space it needs to occupy between the batteries, thereby affecting the volume of the battery module.

[0052] Step S450 , placing the thermally conductive silicone sheet 12 between the two batteries 11 , and making the two side surfaces of the thermally conductive silicone sheet 12 contact with the surfaces of the two batteries 11 respectively.

[0053] Specifically, when the module is made, the thermal conductive silicone sheet 12 containing the optical fiber 14 and the optical fiber sensor 13 is placed between two batteries 11. The battery 11, the thermal conductive silicone sheet 12 and the battery 11 are tightly attached without leaving any gaps between them. The optical fiber sensor 13 can be glued to the surface of one of the batteries.

[0054] Step S460: Connect the other end of the optical fiber 14 extending from the top of the thermally conductive silicone sheet 12 to the fiber grating demodulator.

[0055] Specifically, the other end of the optical fiber 14 passes through the upper portion of the thermally conductive silicone sheet 12 , and can be bundled together with a voltage measurement harness, etc., and connected to a fiber optic modem placed outside the battery module 10 .

[0056] In some examples, the assembly method of the battery module 10 may further include: before connecting the optical fiber to the fiber Bragg grating demodulator, the fiber Bragg grating demodulator may be first fixed to the housing of the battery module.

[0057] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A battery module, comprising: Two or more batteries; A thermally conductive silicone sheet is disposed between the two batteries and the two side surfaces of the thermally conductive silicone sheet are in contact with the surfaces of the two batteries respectively; Temperature monitoring unit, including: fiber optic sensor, optical fiber and fiber grating demodulator; Wherein, the optical fiber sensor and the optical fiber are both fixed inside the thermally conductive silicone sheet, one end of the optical fiber is connected to the optical fiber sensor, and the other end extends from the top of the thermally conductive silicone sheet and is connected to the optical fiber Bragg grating demodulator; The thickness of the thermally conductive silicone sheet matches the size of the gap between adjacent batteries in the battery module; A hole is provided at a predetermined position of the thermally conductive silicone sheet, and the optical fiber sensor is fixed in the hole; A hollow pipe is provided inside the thermally conductive silicone sheet, one end of the optical fiber passes through the opening of the hollow pipe at the top of the thermally conductive silicone sheet and enters the hollow pipe and is connected to the optical fiber sensor, and the other end of the optical fiber is located outside the thermally conductive silicone sheet and is connected to the optical fiber Bragg grating demodulator; The optical fiber comprises a bare optical fiber core and a single-layer non-stick coating coated on its outer surface.

2. The battery module according to claim 1, wherein: The thermally conductive silicone sheet is tightly fitted between the two batteries without any gap.

3. The battery module according to claim 1, wherein: The fiber grating demodulator is arranged outside the housing of the battery module.

4. A method for assembling a battery module, comprising: Obtaining a thermally conductive silicone sheet of a predetermined thickness; Punching holes in the thermally conductive silicone sheet; Brazing a hollow pipe inside the thermally conductive silicone sheet; Fixing the optical fiber sensor on the hole, and inserting one end of the optical fiber into the hollow pipe through the opening at the top of the thermal conductive silicone sheet and connecting to the optical fiber sensor; Placing the thermally conductive silicone sheet between the two batteries, and making the two side surfaces of the thermally conductive silicone sheet contact with the surfaces of the two batteries respectively; The other end of the optical fiber outside the heat-conducting silicone sheet is connected to a fiber grating demodulator.

5. The method of claim 4, wherein: Obtaining a thermally conductive silicone sheet comprises: preparing the thermally conductive silicone sheet, and cutting the thermally conductive silicone sheet into a size matching a side surface of a battery.

6. The method of claim 4, wherein: The hollow pipe is brazed out inside the thermally conductive silicone sheet, comprising: on one side of the thermally conductive silicone sheet, the hollow pipe is brazed out using a stainless steel hollow tube whose diameter does not exceed the thickness of the thermally conductive silicone sheet.

Images