Intrinsic wide-temperature-range square-shell battery integrating self-heating and internal sensing

Abstract

The invention provides an intrinsic wide-temperature-range square-shell battery integrating self-heating and internal sensing, which comprises a battery cell, an integrated shell and a battery top cover, the battery cell is arranged in the integrated shell, the battery top cover is used for covering a top opening of the integrated shell, and the battery cell is arranged in the integrated shell. The integrated shell comprises a shell body, a heating piece and a sensor, the heating piece and the sensor are integrated on the inner wall of the shell body, the heating piece comprises a heating piece body, a first tab and a second tab, the first tab and the second tab are arranged at the head end and the tail end of the heating piece body, and the heating piece body is bent along the inner wall of the shell body to form a square cylinder. The sensor comprises a sensor main body, a connecting line and a connecting terminal. The heating piece is tightly attached to the inner wall of the shell and wraps the battery cell in a surrounding mode, the temperature regulation and control function under the conditions of low temperature or fast charging and the like is achieved, and compared with a traditional external heating method, the heat conduction heat resistance can be remarkably reduced, the low-temperature heating rate and the energy utilization efficiency of the battery are improved, and the service life is prolonged. And the problem of local dry burning and overheating caused by poor contact of the heating sheet is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to an intrinsic wide-temperature range square shell battery with integrated self-heating and internal sensing. Background Art

[0002] At present, lithium-ion batteries have become the preferred power battery for electric vehicles, but their performance is significantly affected by the ambient temperature. At low temperatures, the available capacity is reduced, the power output capacity is reduced, and there is a risk of lithium deposition during charging. Therefore, low-temperature heating of the battery is an important way to improve the battery's wide temperature range application capabilities.

[0003] Existing battery heating methods can be divided into external power heating method and self-heating method according to the energy source. The self-heating method does not require external power supply and is more suitable for mobile vehicle applications. The heating method can be divided into two categories according to the location of the heat source: external heating method and internal heating method. At present, the external heating method is adopted by most commercial electric vehicles because its heat source is located outside the battery and is easy to implement. However, due to the limitations of its heating principle, the external heating method has inherent problems such as slow heating rate, low energy utilization, and poor temperature uniformity. Especially for square shell batteries, the shell significantly increases the thermal resistance, resulting in the heat generated by the heating element arranged on the outside being difficult to conduct quickly and effectively to the internal battery, resulting in poor heating effect. At the same time, the provision of additional heating devices such as heating plates will also reduce the energy density of the battery system, increase the number of system components and the complexity of the structural layout, and increase the difficulty and cost of design, manufacturing, and assembly.

[0004] In addition, with the increasing requirements for high reliability and high safety of battery systems, the currently commonly used method of deploying a small number of external sensors cannot achieve full cell detection and internal state sensing, and the very limited information obtained is not enough to achieve the state estimation and safety warning of the higher-demand battery management system (BMS). Therefore, the "smart battery" that sets multi-sensors that can obtain information on multiple physical quantities inside the cell has been the focus of battery development in recent years, but it still faces many challenges in terms of cell design and manufacturing, signal acquisition and transmission, etc. before it can be industrialized.

[0005] Based on the above reasons, this case came into being. Summary of the invention

[0006] 1. Technical issues to be solved

[0007] In view of the shortcomings of the prior art, the present invention provides a square shell battery suitable for wide temperature range applications, integrating self-heating and internal sensing functions, and requiring no additional components.

[0008] (II) Technical solution

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions: an intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing, comprising a battery cell, an integrated shell and a battery top cover, wherein the battery cell is arranged in the integrated shell, and the battery top cover is used to cover the top opening of the integrated shell, the integrated shell comprises a shell and a heating plate and a sensor integrated on the inner wall of the shell, the heating plate comprises a heating plate body and a first pole ear and a second pole ear arranged at the front and rear ends of the heating plate body, the heating plate body is bent along the inner wall of the shell to form a square tube, the sensor comprises a sensor body, a connecting wire and a connecting terminal, the connecting terminal is arranged on the heating plate body, and the sensor is connected to the connecting terminal through a connecting wire.

[0010] Preferably, the heating sheet may be, but is not limited to, a copper metal wide line foil, a nickel metal wide line foil, a positive temperature coefficient thermistor heating element, and a carbon material heating film.

[0011] Preferably, the outer side of the heating plate is wrapped with a polyimide film.

[0012] Preferably, the sensor adopts a flexible circuit board and is integrated with a temperature sensor and a pressure sensor.

[0013] Preferably, the temperature sensor includes but is not limited to a thin film thermistor, a thin film thermocouple, and a thin film platinum thermal resistor, and the pressure sensor includes but is not limited to a resistive thin film pressure sensor and a piezoelectric thin film sensor.

[0014] Preferably, the heating plate and the sensor are integrated and packaged onto the inner wall of the shell through a UV curing process.

[0015] Preferably, the battery top cover includes a top cover body, a positive electrode post, a negative electrode post, a first heating electrode post, a second heating electrode post, a signal terminal, an explosion-proof valve, and an injection hole. The positive electrode tab and the negative electrode tab of the battery cell are connected to the positive electrode post and the negative electrode post, the first electrode tab and the second electrode tab of the heating plate body are connected to the first heating electrode post and the second heating electrode post, and the connecting terminal is connected to the signal terminal.

[0016] (III) Beneficial effects

[0017] The present invention provides an intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing. It has the following beneficial effects:

[0018] 1. The intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing can achieve temperature control under low temperature or fast charging conditions by fitting the heating plate tightly to the inner wall of the shell and surrounding the battery cell on all sides. Compared with the traditional external heating method, it can significantly reduce the thermal resistance, improve the low temperature heating rate and energy utilization efficiency of the battery, and effectively avoid the problem of local dry burning and overheating caused by poor contact of the heating plate. By fitting the integrated thin film sensor tightly to the surface of the battery cell inside the battery, the detection of multiple physical quantity signals and internal state sensing functions inside the battery can be realized, providing support for efficient state estimation and safety warning of BMS.

[0019] 2. The intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing uses UV light curing technology to integrate the heating plate and sensor on the inner wall of the battery shell. When the temperature is too low, the self-heating function is automatically activated to enable the battery cell to quickly reach the ideal operating temperature, ensure normal charging and discharging performance, and effectively improve the battery's intelligent sensing ability and wide temperature range adaptability. At the same time, the integrated shell structure design does not require the installation of additional heating devices and sensing devices, which can effectively improve the integration of battery cells and battery systems, reduce the number of components and structural complexity, and reduce the difficulty and cost of system design and assembly.

[0020] 3. The intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing integrates the heating plate and sensor into the shell structure through UV light curing process. The packaging layer is very thin and has good mechanical strength, insulation and corrosion resistance. It will not affect the normal working performance and safety of the battery cell, and realizes the non-destructive implantation of the heating plate and sensor. In addition, the structure also has the advantages of simple structure, mature technology, easy processing and manufacturing, and is suitable for practical industrial applications.

[0021] 4. The intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing has two additional heating poles and a signal terminal on the battery top cover compared to the traditional structure, which are welded together with the heating plate and sensor encapsulated inside the shell, integrating the battery electrical connection, heating plate electrical connection and internal sensor signal transmission functions. Each pole and terminal is independent of each other, suitable for various battery grouping methods, heating circuit structures and BMS topology architectures, and has strong flexibility and expansion capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the overall structure diagram of the present invention;

[0023] Figure 2 It is a schematic diagram of the combination of the heating plate, the sensor and the integrated housing of the present invention;

[0024] Figure 3 is a cross-sectional view of the side wall of the integrated housing of the present invention;

[0025] Figure 4 It is a structural diagram of the battery top cover of the present invention.

[0026] In the figure: 1 battery cell, 2 self-heating and internal sensor integrated shell, 3 battery top cover, 101 battery cell body, 102 positive pole ear, 103 negative pole ear, 201 heating plate, 202 sensor, 203 shell, 2011 heating plate body, 2012 first pole ear, 2013 second pole ear, 2021 sensor body, 2022 connecting wire, 2023 connecting terminal, 301 top cover body, 302 positive pole column, 303 negative pole column, 304 first heating pole column, 305 second heating pole column, 306 signal terminal, 307 explosion-proof valve, 308 injection hole, 3061 matrix, 3062 core column. DETAILED DESCRIPTION

[0027] The embodiment of the present invention provides an intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing, such as Figure 1-4 As shown, it includes a battery cell 1, an integrated shell 2 and a battery top cover 3. The battery cell 1 is arranged in the integrated shell 2, and the battery top cover 3 is used to cover the top opening of the integrated shell 2.

[0028] The battery cell 1 includes a battery cell body 101, a positive electrode tab 102 and a negative electrode tab 103. The battery cell 1 adopts a general manufacturing process, and is formed by stacking positive and negative electrode sheets and a separator, and the outside is completely wrapped by the separator. The positive electrode material can be but not limited to lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate and ternary materials, etc., and the negative electrode material can be but not limited to natural graphite, artificial graphite, silicon-carbon composite materials, etc. The manufacturing process of the battery cell includes but is not limited to stacking and winding.

[0029] like Figure 2 As shown, the integrated housing 2 includes a housing 203 and a heating plate 201 and a sensor 202 integrated on the inner wall of the housing 203 .

[0030] like Figure 2 As shown, the heating sheet 201 includes a heating sheet body 2011 and a first pole ear 2012 and a second pole ear 2013 arranged at both ends of the heating sheet body 2011. The heating sheet body 2011 is bent along the inner wall of the shell 203 to form a square tube. The heating sheet body 2011 is attached to the four side walls of the inner cavity of the shell 203, and the area is slightly smaller than the side walls of the inner cavity of the shell 203. When heating, the current flows into one pole ear of the heating sheet body 2011 and flows out from the other pole ear. The heating sheet body 2011 generates heat due to the thermal effect of the current. The heating sheet body 2011 surrounds the battery cell 1 on all four sides, and can heat the battery cell 1 from the front, back, left, and right directions.

[0031] The heating sheet 201 may be, but is not limited to, a copper metal wide line foil, a nickel metal wide line foil, a positive temperature coefficient thermistor (PTC) heating element, a carbon material heating film, and the like.

[0032] The outer side of the heating plate 201 is wrapped with a polyimide film, which plays the role of shaping, protection, corrosion resistance and insulation.

[0033] like Figure 2 As shown, the sensor 202 includes a sensor body 2021, a connecting line 2022 and a connecting terminal 2023. The connecting terminal 2023 is arranged on the heating plate body 2011. The sensor 202 plays the role of sensing multiple physical quantities and transmitting signals inside the battery.

[0034] The sensor 202 is manufactured using a flexible printed circuit (FPC) process, and a thin film temperature sensor and a pressure sensor are integrated and packaged together through a polyimide film. The sensor body 2021 is connected to the solder joints on the connection terminal 2023 through a connecting wire 2022 .

[0035] The temperature sensor includes but is not limited to thin film thermistors, thin film thermocouples, thin film platinum thermal resistors, etc. The pressure sensor includes but is not limited to resistive thin film pressure sensors, piezoelectric thin film sensors, etc.

[0036] The overall thickness of the sensor 202 is similar to that of the heating plate 201 (generally 0.2-2 mm), and is also attached to the side wall of the inner cavity of the housing 203. The heating plate 201 is designed with an appropriate gap to leave space for the arrangement and installation of the sensor 202, so as to avoid the stacking arrangement of the heating plate 201 and the sensor 202. The material of the housing 203 is generally aluminum alloy, and the outer side is wrapped with an insulating film.

[0037] The heating plate 201 and the sensor 202 are integrated and packaged on the inner wall of the housing 203 through an ultraviolet (UV) light curing process, thereby forming a self-heating and internal sensing integrated housing 2.

[0038] like Figure 3As shown, the specific method is: uniformly spraying UV light-curing adhesive in the inner cavity of the shell 203; tightly covering the side wall of the inner cavity of the shell 203 with the heating plate 201 and the sensor 202 according to the above arrangement method; spraying UV light-curing adhesive in the inner cavity of the shell 203 for the second time; after being irradiated with ultraviolet light, the adhesive is fully cured, and a uniform and dense adhesive curing layer 204 is formed between the side wall of the inner cavity of the shell 203 and the heating plate 201 and the sensor 202, as well as the outer surface of the heating plate 201 and the sensor 202. After curing, the UV light-curing adhesive has good insulation, high temperature resistance, low temperature resistance, electrolyte corrosion resistance, and good mechanical strength, thereby ensuring that the built-in heating plate 201 and the sensor 202 will not affect the performance and safety reliability of the battery 1, and will not cause problems such as internal short circuit, pole piece damage, and electrolyte leakage. The adhesive cured layer 204 is very thin (generally <0.2 mm) and has a low thermal resistance, thereby ensuring that the heating effect of the heating plate 201 is not affected and that the collection of temperature and stress signals by the sensor 202 is not affected.

[0039] like Figure 4 As shown, the battery top cover 3 includes a top cover body 301, a positive electrode post 302, a negative electrode post 303, a first heating electrode post 304, a second heating electrode post 305, a signal terminal 306, an explosion-proof valve 307, and a liquid injection hole 308. The positive electrode post 302, the negative electrode post 303, the first heating electrode post 304, and the second heating electrode post 305 are made of highly conductive metal materials and penetrate the top cover body 301. Good sealing is ensured by sealing rings, sealants, etc., and a welding area is provided at the bottom of the top cover body 301.

[0040] The signal terminal 306 includes an insulating, corrosion-resistant substrate 3061 and a highly conductive metal core column 3062. The number, size and arrangement of the core column 3062 correspond to the welding points on the connection terminal 2023 of the aforementioned sensor. The signal terminal 306 penetrates the top cover body 301, and good sealing is ensured by means of sealing rings, sealants, etc., and a welding area is provided at the bottom of the top cover body 301. The bottom edge of the top cover body 301 is grooved, and the width is consistent with the thickness of the shell 203, so that it can fit tightly to the top of the shell.

[0041] The height of the inner cavity of the shell 203 should be slightly higher than the height of the battery body 101, and the length and width of the inner cavity should be slightly larger than the battery body 101, to ensure that the battery can be smoothly placed in the cavity of the shell 203 and does not interfere with the battery top cover 3. During the operation of the battery, due to the internal electrochemical reaction, the battery body 101 expands, and the surface of the battery can be closely attached to the inner wall of the integrated shell 2, ensuring that the heating plate 201 and the sensor 202 are closely attached to the large surface of the battery 1, and can achieve uniform heat conduction and force, ensuring good heating effect and temperature and stress information sensing.

[0042] The first pole ear 2012 and the second pole ear 2013 of the heating plate 201, the connecting wire 2022 of the sensor, and the positive pole ear 102 and the negative pole ear 103 of the battery cell 1 should be flexible and designed to have an appropriate length; the arrangement positions of the positive pole column 302, the negative pole column 303, the first heating pole column 304, the second heating pole column 305, and the signal terminal 306 of the battery top cover 3 should correspond to the installation positions of the positive pole ear 102, the negative pole ear 103 of the battery cell 1, the first pole ear 2012, the second pole ear 2013 of the heating plate 201, and the connecting terminal 2023 of the sensor 202.

[0043] The positive electrode tab 102 of the battery cell 1 is welded to the positive electrode post 302 of the battery top cover 3, the negative electrode tab 103 of the battery cell 1 is welded to the negative electrode post 303 of the battery top cover 3, the first tab 2012 of the heating plate 201 is welded to the first heating pole 304 of the battery top cover 3, the second tab 2013 of the heating plate 201 is welded to the second heating pole 305 of the battery top cover 3, and the connecting terminal 2023 of the sensor 202 is welded to the core post 3062 of the signal terminal 306 of the battery top cover 3, and during the assembly and welding process and subsequent use, there is no interference between the components or contact between the conductors.

[0044] Specific application example: power battery for electric vehicles.

[0045] Due to the increasing demands for fast charging, low-temperature cold start, and low-temperature endurance of electric vehicles, the existing external heating solutions for square shell batteries have large thermal resistance, slow heating rate, and complex system structure, which cannot meet the wide temperature range thermal management and integration requirements of batteries. Therefore, the integrated square shell battery with integrated self-heating and internal sensing proposed in the present invention can be used as the power battery of electric vehicles, which can achieve rapid and uniform heating at low temperatures, accurate perception of the internal state of the battery cell, and improve the integration of the power battery system of electric vehicles. In addition to the normal series-parallel grouping of batteries, the heating circuit and control method can be designed according to demand.

[0046] For example, the second heating pole 305 of the battery is directly connected to the negative pole 303 through a bus, and the first heating pole 304 is connected to the positive pole 302 through a controllable switch. The controllable switch can be a relay, an insulated gate bipolar transistor (IGBT), a metal-oxide semiconductor field effect transistor (MOSFET), etc. The sensor signal of the battery is transmitted to the controller, and the controller sends a control instruction to the controllable switch according to the battery status information to control the start and stop of the heating process, thereby realizing the self-heating function of the battery cell powering the internal heating sheet.

[0047] For another example, the first heating pole 304 and the second heating pole 305 of each battery in the battery system are connected to each other, so that the internal heating plates 201 of each battery in the battery system are connected in series to form a heating plate loop, and the battery loop formed by connecting the positive and negative poles of the battery together constitutes a dual-circuit battery system. One end of the heating plate loop is directly connected to the total negative pole of the battery loop, and the other end is connected to the total positive pole of the battery loop through a controllable switch. The sensor signal of the battery is transmitted to the controller, and the controller issues a control instruction of the switch according to the battery status information to control the on and off of the heating circuit, thereby realizing the self-heating function of the battery circuit powering the heating plate loop.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing, comprising a battery cell (1), an integrated shell (2) and a battery top cover (3), wherein the battery cell (1) is arranged in the integrated shell (2), and the battery top cover (3) is used to cover the top opening of the integrated shell (2), characterized in that: The integrated shell (2) comprises a shell (203), a heating plate (201) and a sensor (202) integrated on the inner wall of the shell (203); the heating plate (201) comprises a heating plate body (2011) and a first pole ear (2012) and a second pole ear (2013) arranged at both ends of the heating plate body (2011); the heating plate body (2011) is bent along the inner wall of the shell (203) to form a square tube; the sensor (202) comprises a sensor body (2021), a connecting wire (2022) and a connecting terminal (2023); the connecting terminal (2023) is arranged on the heating plate body (2011); and the sensor (202) is connected to the connecting terminal (2023) via the connecting wire (2022).

2. According to claim 1, the intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing is characterized in that: The heating sheet (201) may be, but is not limited to, a copper metal wide line foil, a nickel metal wide line foil, a positive temperature coefficient thermistor heating element, and a carbon material heating film.

3. According to claim 1, the intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing is characterized in that: The outer side of the heating plate (201) is wrapped with a polyimide film.

4. According to claim 1, the intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing is characterized in that: The sensor (202) adopts a flexible circuit board and is integrated with a temperature sensor and a pressure sensor.

5. According to claim 4, the intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing is characterized in that: The temperature sensor includes but is not limited to a thin film thermistor, a thin film thermocouple, and a thin film platinum thermal resistor. The pressure sensor includes but is not limited to a resistive thin film pressure sensor and a piezoelectric thin film sensor.

6. The intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing according to claim 1, characterized in that: The heating plate (201) and the sensor (202) are integrated and packaged onto the inner wall of the housing (203) through an ultraviolet light curing process.

7. The intrinsic wide temperature range square shell battery with integrated self-heating and internal sensing according to claim 1, characterized in that: The battery top cover (3) comprises a top cover body (301), a positive pole (302), a negative pole (303), a first heating pole (304), a second heating pole (305), a signal terminal (306), an explosion-proof valve (307), and a liquid injection hole (308); the positive pole ear (102) and the negative pole ear (103) of the battery cell (1) are connected to the positive pole (302) and the negative pole (303); the first pole ear (2012) and the second pole ear (2013) of the heating plate body (2011) are connected to the first heating pole (304) and the second heating pole (305); and the connecting terminal (2023) is connected to the signal terminal (306).

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