Self-Heating Structure and Battery Pack Including the Same

Disclosed in the present application is a self-heating structure and a battery pack including the same. The self-heating structure includes a heating member, including a heating body and a connection lead molded on the heating body, the connection lead being used for electrically connecting a positive electrode tab of a core pack or a negative electrode tab of the core pack, so that a self-heating circuit is formed by the heating member and the core pack; and a control unit, controlling an on/off switching of the self-heating circuit according to temperature of the core pack, the control unit being provided on the connection lead to integrate the control unit and the connection lead.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority of Chinese Patent Application No. 202320253125.X filed on Feb. 16, 2023 before CNIPA. All the above are hereby incorporated by reference in their entirety.

FIELD

The present application relates to the technical field of self-heating batteries, in particular to a self-heating structure and a battery pack including the same.

BACKGROUND

As society develops and people pay more and more attention to environmental issues, new energy vehicle technology is recognized by more and more consumers, and it is expected that new energy vehicles may replace traditional vehicles gradually in the future. As the demand for new energy vehicles increases year by year, the limitations of climate for electric vehicles are becoming more and more obvious. It is well known that the performance of battery packs in low-temperature environments is limited, and the battery is even impossible to be charged. In order to address this problem and ensure the normal operation of the battery pack in a low-temperature environment, the current method adopted is: heating the battery by adopting the electrical energy of the battery pack itself to achieve self-heating of the battery.

However, the wiring of the self-heating circuit in the related technology is relatively complex, which requires a relatively large quantity of connecting wiring harnesses and electronic elements, and also requires a relatively high occupation of the internal space of the battery pack, which, on the one hand, reduces the energy density of the battery pack, and, on the other hand, increases the structural complexity and the production cost of the battery pack.

SUMMARY

In order to overcome at least one defect mentioned above in the prior art, provided in the present application is a self-heating structure and a battery pack including the same, which aims to address the problem that existing self-heating circuits reduce the energy density of battery packs as well as increase the structural complexity and production cost of battery packs.

The technical solutions adopted by the present application to solve the problems are as follows.

A self-heating structure includes a heating member, including a heating body and a connection lead molded on the heating body, the connection lead being used for electrically connecting a positive electrode tab of a core pack or a negative electrode tab of the core pack, so that a self-heating circuit is formed by the heating member and the core pack; and a control unit, provided on the connection lead, the control unit controlling an on/off switching of the self-heating circuit according to a temperature of the core pack.

In the self-heating structure provided in the present application, the connection lead is molded on the heating body, which increases the structural strength and the working stability of the heating member. Importantly, a self-heating circuit is formed by the heating member and the core pack through the connection lead. Also, the control unit and the connection lead are integrated to simplify the wiring, which also reduces the quantity and type of other connection structures and electrical elements. The structure is simple and the function is easy to realize, which improves the space utilization of the battery pack to increase the energy density of the battery pack, and also reduces the structural complexity and production cost of the battery pack.

Specifically, when the core pack is under a relatively lower temperature, the core pack is unable to be charged or the charging efficiency is extremely low. Then the control unit turns on the self-heating circuit, and the heating member is energized to produce a rapid thermal effect so as to achieve the self-heating inside the core pack. When an interior of the core pack reaches a temperature for normal charging, the control unit turns off the self-heating circuit, so that the heating member stops producing the thermal effect when power is off, and the self-heating inside the core pack ends subsequently, which avoids overheating of the core pack so as to achieve the purpose of protecting the core pack.

According to some implementations of the present application, the control unit includes a first inductive member, the first inductive member being used for detecting a first temperature signal inside the core pack, the control unit controlling an on/off switching of the self-heating circuit according to the first temperature signal.

According to some implementations of the present application, a surface of the heating member is provided with a passivation layer.

According to some implementations of the present application, the heating member is a metal foil, and the passivation layer is formed on a surface of the metal foil.

As another aspect, provided in the present application is a battery pack, including a core pack and the self-heating structure mentioned above.

According to some implementations of the present application, the connection lead is electrically connected to the positive electrode tab of the core pack.

According to some implementations of the present application, the connection lead is integrally connected to the positive electrode tab of the core pack.

According to some implementations of the present application, the heating member extends along a large surface of the core pack and is provided in contact with the large surface of the core pack.

According to some implementations of the present application, a projection of the heating member on the core pack does not extend beyond the large surface of the core pack.

According to some implementations of the present application, the battery pack also includes a housing; one or more of the core packs constitutes a battery module, the battery module being provided in the housing; and the heating member is clamped between the housing and the battery module.

According to some implementations of the present application, the battery pack also includes a second inductive member, the second inductive member being provided on a surface of the core pack; and the second inductive member is used for detecting a second temperature signal of the surface of the core pack, so that an on/off switching of the self-heating circuit is controlled according to the second temperature signal.

The meanings of the attached markings are as follows:

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the description of the present application, it is to be noted that the terms “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside” and other orientation or position relationships are based on the orientation or position relationships shown in the attached drawings. It is only intended to facilitate description and simplify operation, but not to indicate or imply that the referred device or element has a specific orientation, or is constructed and operated in a specific orientation. Therefore, they should not be construed as a limitation of the present application.

Referring toFIG.1toFIG.3, disclosed in the present application is a self-heating structure and a battery pack1including the self-heating structure. Specifically, the battery pack1also includes a core pack111and a housing12. The self-heating structure includes a heating member10, including a heating body101and a connection lead102molded on the heating body101, the connection lead102being used for electrically connecting a positive electrode tab1112of a core pack111or a negative electrode tab1114of the core pack111, so that a self-heating circuit is formed by the heating member10and the core pack111; and a control unit, the control unit being provided on the connection lead102, the control unit controlling an on/off switching of the self-heating circuit according to a temperature of the core pack111.

In such a setup, the connection lead102is molded on the heating body101, which increases the structural strength and the working stability of the heating member10. More importantly, a self-heating circuit is formed by the heating member10and the core pack111through the connection lead102. Also, the control unit and the connection lead102are integrated to simplify the wiring, which also reduces the quantity and type of other connection structures and electrical elements. The structure is simple and the function is easy to realize, which improves the space utilization of the battery pack1to increase the energy density of the battery pack1, and also reduces the structural complexity and production cost of the battery pack1.

It is to be noted that the connection lead102is molded on the heating body101, which may be, but is not limited to, such as integral injection molding, integral cut molding and integral press molding, which is not limited hereby.

Specifically, in the present embodiment, a width of the connection lead102is 3 m. Admittedly, in the other embodiments, the width of the connection lead102may also be, but is not limited to, such as 4 m, 5 m, 6 m and 7 m, which is not limited hereby.

Specifically, in the present embodiment, the control unit includes a first inductive member, the first inductive member being used for detecting a first temperature signal inside the core pack111, the control unit controlling an on/off switching of the self-heating circuit according to the first temperature signal. Admittedly, in the other embodiments, the control unit may also be, but is not limited to, a temperature relay, which is not limited hereby.

Further, in the present embodiment, the battery pack1also includes a second inductive member, the second inductive member being provided on a surface of the core pack111; and the second inductive member is used for detecting a second temperature signal of the surface of the core pack111, so that an on/off switching of the self-heating circuit is controlled according to the second temperature signal. In such a setup, the temperature of an interior of the core pack111and a surface of the core pack111is detected by the first inductive member and the second inductive member respectively, which achieves a double detection of the temperature of the core pack111, which ensures the detection accuracy of the temperature of the core pack111, so as to precisely control an on/off switching of the self-heating circuit, thereby improving the charging efficiency of the core pack111under a low-temperature environment.

It is to be noted that, in some embodiments, the first inductive member and the second inductive member are equivalent to inductive switches. When the detected temperature signal is lower than a preset value, the first sensing member and the second sensing member are turned on to energize the self-heating circuit; when the detected temperature signal is higher than the preset value, the second sensing member and the second sensing member are turned off to disconnect the self-heating circuit.

It is to be noted that, in some embodiments, the first inductive member and the second inductive member are equivalent to sensors. The control module receives a first temperature signal and a second temperature signal and controls an on/off switching of the self-heating circuit according to the first temperature signal and the second temperature signal. Specifically, the control module may be, but is not limited to, a battery management system (BMS) of the battery pack1.

Specifically, in the present embodiment, when the core pack111is under a relatively lower temperature, the core pack111is unable to be charged or the charging efficiency is extremely low. Then the first inductive member and the second inductive member turn on the self-heating circuit, and the heating member10is energized to produce a rapid thermal effect in order to achieve the self-heating inside the core pack111. When an interior of the core pack111reaches a temperature for normal charging, the first inductive member and the second inductive member turn off the self-heating circuit, so that the heating member10stops producing the thermal effect when power is off, and the self-heating inside the core pack111ends subsequently, which avoids overheating of the core pack111to achieve the purpose of protecting the core pack111.

It is to be noted that, in some other embodiment, it is also possible to provide only the first inductive member without the second inductive member to save production costs.

Further, in the present embodiment, a surface of the heating member10is provided with a passivation layer to prevent the heating member10from corroding by electrolyte, so as to prevent the heating member10from working abnormally. Exemplarily, it may avoid direct conductivity between the heating member10and the electrolyte, which may fail the self-heating circuit or cause the heating member10to produce heat excessively.

Preferably, in the present embodiment, the heating member10is a metal foil, and the passivation layer is formed on a surface of the metal foil. In such a setup, the passivation layer and the metal foil become an integral structure, which may prevent the passivation layer from shedding and failing due to long-term use, and greatly improve the security performance. Exemplarily, the metal foil may be processed by concentrated sulfuric acid (98% concentration), so that the passivation layer may be formed on the surface of the metal foil.

It is to be noted that, in some other embodiments, the heating member10may also be, but is not limited to, graphite. The passivation layer may be, but is not limited to, such as phenylethylammonium iodide and phenylmethylammonium iodide, which is not limited hereby.

Referring toFIG.3, it is to be understood that, the core pack111is formed by stacking or winding a plurality of positive electrode sheets1111and a plurality of negative electrode sheets1113, and a separator13is provided between two adjacent electrode sheets. A positive electrode tab1112is provided on the positive electrode sheet1111, and a negative electrode tab1114is provided on the negative electrode sheet1113, in which the quantity of the negative electrode sheets1113is generally greater than the quantity of positive electrode sheets1111to prevent short-circuiting within the core pack111. Specifically, in the present embodiment, the positive electrode sheet1111, the heating member10, and the negative electrode sheet1113are in decreasing order of chemical activity. More specifically, the positive electrode sheet1111may be, but is not limited to, an aluminum foil; the heating member10may be, but is not limited to, a nickel foil; and the negative electrode sheet1113may be, but is not limited to, a copper foil.

Preferably, in the present embodiment, the connection lead102is electrically connected to the positive electrode tab1112of the core pack111, so that a self-heating circuit is formed by the positive electrode sheet1111and the heating member10. In such a setup, the positive electrode sheet1111is equivalent to a positive electrode, and the heating member10is equivalent to a negative electrode. In such a setup, it avoids forming a loop between the heating member10and the negative electrode sheet1113and prevents the negative electrode sheet1113from being depleted resulting in an accident.

Preferably, in the present embodiment, in order to improve the connection strength and the working stability, the connection lead102is integrally connected to the positive electrode tab1112of the core pack111. Specifically, the connection may be, but is not limited to, such as welding connection and hot riveting connection, which is not limited hereby.

Admittedly, in some other embodiments, the connection lead102may be integrally connected to the negative electrode tab1114of the core pack111, so that a self-heating circuit is formed by the negative electrode sheet1113and the heating member10. In such a setup, the heating member10is equivalent to a positive electrode, and the negative electrode sheet1113is equivalent to a negative electrode.

Further, in the present embodiment, in order to increase the surface contact area with the core pack111, the heating member10is in the shape of a sheet, and the heating member10extends along and is provided in contact with a large surface of the core pack111to improve the heat transfer performance, which increases the rate of temperature increase of the core pack111.

Preferably, in the present embodiment, in order to avoid the problem that the dimension of the heating member10is oversize and occupies too much space of the battery pack1, the projection of the heating member10on the core pack111does not extend beyond a large surface of the core pack111, so as to ensure that the battery pack1is able to provide a high space utilization rate and energy density.

As shown inFIG.1andFIG.2, preferably, in the present embodiment, a plurality of core packs111constitutes a battery module11, the battery module11being provided in the housing12; and the heating member10is clamped between the housing12and the battery module11.

Compared to providing the heating member10between two core packs111, such a setup may improve the safety performance of the battery pack1and eliminate potential hazards.

Specifically, in the present embodiment, a thickness of a battery reinforcing sheet is close to that of an electrode sheet, which facilitates to control an overall dimension and assembly of the battery pack1. More specifically, a thickness of the reinforcing sheet may be, but is not limited to, such as 45 m, 50 m and 55 m, which is not limited hereby.

In summary, the self-heating structure and the battery pack1including the same disclosed in the present application may provide at least the following beneficial technical effects:1) The connection lead is molded on the heating body101, which improves the structural strength and the working stability of the heating member10.2) A self-heating circuit is formed by the heating member10and the core pack111through the connection lead102. Also, the control unit and the connection lead102are integrated to simplify the wiring, which also reduces the quantity and type of other connection structures and electrical elements. The structure is simple and the function is easy to realize, which improves the space utilization of the battery pack1to increase the energy density of the battery pack1, and also reduces the structural complexity and production cost of the battery pack1.3) A surface of the heating member10is provided with a passivation layer to prevent the heating member10from corroding by electrolyte, so as to prevent the heating member10from working abnormally, which may avoid direct conductivity between the heating member10and the electrolyte that may fail the self-heating circuit or cause the heating member10to produce heat excessively.4) The passivation layer is formed on a surface of the metal foil, so that the passivation layer and the metal foil become an integral structure, which may prevent the passivation layer from shedding and failing due to long-term use, and greatly improve the security performance.5) The temperature of an interior of the core pack111and a surface of the core pack111is detected by the first inductive member and the second inductive member respectively, which achieves a double detection of the temperature of the core pack111, which ensures the detection accuracy of the temperature of the core pack111, so as to precisely control an on/off switching of the self-heating circuit, thereby improving the charging efficiency of the core pack111under a low temperature environment.