A battery pack heating and feedback bleed integrated circuit

Abstract

This application discloses a battery pack heating and feedback discharge integrated circuit, relating to the technical field of battery thermal management. The integrated circuit includes: a battery pack having a battery pack body and electrode terminals, including a positive terminal and a negative terminal; a charging branch including a charging switch; a discharging branch including a discharging switch; the charging switch and the discharging switch are connected in series between the battery pack and the load port, and the charging switch and the discharging switch have a common connection point; a heating branch including a heating film and a connection switch, one end of the heating branch being connected to the common connection point, and the other end being connected to the load port; wherein the connection switch is configured to close when both the charging switch and the discharging switch are in the open state, forming a current loop for heating the heating film through the body diode of the charging switch or the discharging switch. This application can effectively improve the heating efficiency and safety of the heating circuit.

Description

Technical Field

[0001] This application relates to the technical field of battery thermal management, and in particular to an integrated circuit for battery pack heating and regenerative discharge. Background Technology

[0002] Currently, battery pack temperature management is one of the key technologies in electric vehicles and energy storage systems. In low-temperature environments, battery performance degrades or even fails to function properly, thus requiring heating to maintain its optimal operating temperature range. Currently, battery pack heating typically employs heating films and is controlled by a battery management system (BMS).

[0003] In related technologies, there are two main structures for battery pack heating circuits: one is where the heating film is connected to both the positive and negative terminals of the battery pack. In low-temperature environments, if charging and heating are required simultaneously, the charging current and heating current flow through the battery at the same time, causing additional stress on the battery (especially lithium iron phosphate batteries), reducing heating efficiency, and affecting battery life and safety. The other structure is where the heating film is connected to both the positive and negative terminals of the load port. In the discharge heating film type, this structure requires the charging switch and discharge switch to be closed simultaneously, causing the positive terminal of the load port to be directly connected to the positive terminal of the battery and become energized, posing a safety hazard of electric shock or sparking.

[0004] Therefore, a new type of battery pack heating and feedback discharge integrated circuit structure is proposed to solve the problems of low heating efficiency and poor safety of the above two structures. Summary of the Invention

[0005] The purpose of this application is to provide a battery pack heating and feedback discharge integrated circuit, which can effectively improve the heating efficiency and safety of the heating circuit.

[0006] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a battery pack heating and feedback discharge integrated circuit, comprising: a battery pack having a battery pack body and electrode terminals, the electrode terminals including a positive terminal and a negative terminal; a charging branch including a charging switch; a discharging branch including a discharging switch; the charging switch and the discharging switch being connected in series between the battery pack and a load port, and the charging switch and the discharging switch having a common connection point; and a heating branch including a heating film and a connection switch, one end of the heating branch being connected to the common connection point, and the other end of the heating branch being connected to the load port; wherein the connection switch is configured to close when both the charging switch and the discharging switch are in an open state, forming a current loop for heating the heating film through the body diode of the charging switch or the discharging switch.

[0007] For example, both the charging switch and the discharging switch are MOSFETs.

[0008] For example, the charging switch and the discharging switch are connected in series between the positive terminal of the battery pack and the positive terminal of the load port. The connection switch includes a first switch and a second switch electrically connected to both ends of the heating film. The first switch is connected to the common connection point, and the second switch is connected to the negative terminal of the load port.

[0009] For example, the body diode in the charging switch is configured to allow current to flow from the positive terminal of the battery pack to the common connection point when the charging switch is open; the body diode in the discharging switch is configured to allow current to flow from the positive terminal of the load port to the common connection point when the discharging switch is open.

[0010] For example, the heating branch includes a discharge heating film type and a charging heating film type. In the discharge heating film type, the battery pack supplies power to the heating film through the body diode of the charging switch. The current flows from the positive terminal of the battery pack through the body diode of the charging switch, the common connection point, the first switch, the heating film, the second switch, and the negative terminal of the battery pack in sequence. In the charging heating film type, the external charging power supply connected to the load port supplies power to the heating film through the body diode of the discharge switch. The current flows from the positive terminal of the load port through the body diode of the discharge switch, the common connection point, the first switch, the heating film, the second switch, and the negative terminal of the load port in sequence.

[0011] For example, the charging switch and the discharging switch are connected in series between the negative terminal of the battery pack and the negative terminal of the load port. The connection switch includes a first switch and a second switch electrically connected to both ends of the heating film. The second switch is connected to the common connection point, and the first switch is connected to the positive terminal of the load port.

[0012] For example, the body diode in the charging switch is configured to allow current to flow from the common connection point to the negative terminal of the battery pack when the charging switch is open; the body diode in the discharging switch is configured to allow current to flow from the common connection point to the negative terminal of the load port when the discharging switch is open.

[0013] For example, the heating branch includes a discharge heating film type and a charging heating film type. In the discharge heating film type, the battery pack supplies power to the heating film through the body diode of the charging switch. The current flows from the positive terminal of the battery pack through the first switch, the heating film, the second switch, the common connection point, the body diode of the charging switch, and the negative terminal of the battery pack in sequence. In the charging heating film type, the external charging power supply connected to the load port supplies power to the heating film through the body diode of the discharge switch. The current flows from the positive terminal of the load port through the first switch, the heating film, the second switch, the common connection point, the body diode of the discharge switch, and the negative terminal of the load port in sequence.

[0014] For example, it also includes a pre-charge branch, which includes a pre-charge resistor and a pre-charge switch connected in series. One end of the pre-charge branch is connected to the common connection point, and the other end is connected to the positive terminal of the load port. The pre-charge branch is connected in parallel with the discharge switch.

[0015] For example, the heating film is a PTC heating film or a metal heating film: According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a battery pack heating and feedback discharge integrated circuit. One end of the heating branch is connected to the common connection point of the charging switch and the discharging switch, and the other end is connected to the load port. A heating circuit is formed using a body diode when both the charging and discharging switches are open via a connection switch. By opening the charging and discharging switches and closing only the connection switch of the heating branch, pure charging heating or pure discharging heating can be achieved respectively. The heating process is completely decoupled from the charging and discharging process, avoiding the simultaneous flow of charging current and heating current through the battery, thereby eliminating the risk of battery damage caused by charging and heating at low temperatures. During heating, both the charging and discharging switches remain open, and the main circuit between the positive terminal of the battery and the positive terminal of the load port is cut off. Therefore, the positive terminal of the load port is not energized in the discharging heating state. In the charging heating film type, the current flows to the heating film through the body diode. This design also prevents the load port from being at a dangerous potential, ensuring that the load port remains energized during heating and effectively improving the safety of the heating process. Simultaneously, in discharge heating mode, disconnecting the charging switch allows for the discharge of feedback voltage or current through a pure discharge heating circuit via the discharge branch, achieving feedback discharge and ensuring system safety and reliability. This solves the safety problem of triggering alarms for excessively high feedback voltage or current when the battery pack is fully charged and the charging switch is closed (e.g., when braking downhill), which could affect circuit operation. By selecting the connection method between the heating branch and the load port (connecting to the negative or positive terminal of the load port), different application scenarios can be adapted, flexibly implementing both positive and negative control heating schemes, simplifying circuit design and improving system response speed and reliability. Based on this, this application can effectively improve heating efficiency and heating safety in the battery thermal management process. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the first circuit structure in the related technology.

[0018] Figure 2 This is a schematic diagram of the second circuit structure in the related technology.

[0019] Figure 3 This is a schematic diagram of the battery pack heating and feedback discharge integrated circuit in Embodiment 1 of this application.

[0020] Figure 4 This is a schematic diagram of the battery pack heating and feedback discharge integrated circuit in Embodiment 2 of this application.

[0021] Reference numerals in the attached diagram: 1. Battery pack; 2. Load port; 3. Heating film; 4. First switch; 5. Second switch; 6. Charging switch; 7. Discharging switch; 8. Pre-charge resistor; 9. Pre-charge switch. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 As shown, this is a heating circuit structure provided in related technologies. The heating film is connected between the positive and negative terminals of the battery pack, and is directly powered by the battery pack for heating during battery pack discharge. In the case of simultaneous charging and heating at low temperatures, both the charging current and the heating current pass through the battery pack, which can cause some damage to the battery pack, especially lithium iron phosphate batteries, and affect its lifespan. Figure 2 As shown, another heating circuit structure provided in related technologies is used. The heating film is connected between the positive and negative terminals of the load port. In the case of discharge heating, both the charging and discharging MOS need to be in the open state to successfully supply power to the heating film and achieve heating. In this case, the load port is in a energized state, which poses a safety hazard. Furthermore, pre-charging needs to be started before heating, and then the charging and discharging switches need to be turned off, which affects the heating efficiency.

[0025] To address the issues of low heating efficiency and safety hazards in the aforementioned related technologies, this application provides a novel integrated circuit for battery pack heating and feedback discharge.

[0026] Example 1 like Figure 3 As shown, a heating circuit for a battery pack 1 includes: a battery pack 1, a charging branch, a discharging branch, and a heating branch.

[0027] The device comprises a battery pack 1 body and electrode terminals, including a positive terminal (B+ in the figure) and a negative terminal (B- in the figure); a charging branch includes a charging switch 6; a discharging branch includes a discharging switch 7; the charging switch 6 and the discharging switch 7 are connected in series between the battery pack 1 and the load port 2, and the charging switch 6 and the discharging switch 7 have a common connection point; a heating branch includes a heating film 3 and a connection switch, one end of the heating branch is connected to the common connection point, and the other end of the heating branch is connected to the load port 2; the connection switch is configured to close when both the charging switch 6 and the discharging switch 7 are in the open state, forming a current loop for heating the heating film 3 through the body diode of the charging switch 6 or the discharging switch 7.

[0028] This application provides a heating circuit for a battery pack 1. One end of the heating branch is connected to the common connection point of the charging switch 6 and the discharging switch 7, and the other end is connected to the load port 2. A heating circuit is formed using a body diode when both the charging and discharging switches 7 are open via a connection switch. By opening the charging switch 6 and the discharging switch 7 and closing only the connection switch of the heating branch, pure charging heating or pure discharging heating can be achieved respectively. The heating process is completely decoupled from the charging and discharging process, avoiding the simultaneous flow of charging current and heating current through the battery, thereby eliminating the risk of battery damage caused by charging and heating at low temperatures. During heating, both the charging and discharging switches 7 remain open. When the battery is open, the main circuit between the positive terminal of the battery and the positive terminal of the load port 2 is cut off. Therefore, the positive terminal of the load port 2 will not be energized during the discharge heating state. Under the charging heating film 3, the current flows to the heating film 3 through the body diode, which will not cause the load port 2 to be at a dangerous potential. This ensures that the load port 2 will not be energized during heating, effectively improving the safety of the heating process. By selecting the connection method between the heating branch and the load port 2 (connected to the negative or positive terminal of the load port 2), different application scenarios can be adapted, flexibly realizing two heating schemes: positive control or negative control. This simplifies the circuit design and improves the system's response speed and reliability. Based on this, this application can effectively improve the heating efficiency and heating safety in the battery thermal management process.

[0029] For example, such as Figure 3 As shown, both the charging switch 6 and the discharging switch 7 are MOSFETs, and the connecting switches include a first switch 4 and a second switch 5 that are electrically connected to both ends of the heating film 3.

[0030] Charging switch 6 and discharging switch 7 are connected in series between the positive terminal of battery pack 1 and the positive terminal of load port 2 (P+ in the figure). First switch 4 is connected to the common connection point, and second switch 5 is connected to the negative terminal of load port 2 (P- in the figure). The body diode in charging switch 6 is configured to allow current to flow from the positive terminal of battery pack 1 to the common connection point when charging switch 6 is open; the body diode in discharging switch 7 is configured to allow current to flow from the positive terminal of load port 2 to the common connection point when discharging switch 7 is open.

[0031] Please refer to Figure 3 The charging switch 6 and the discharging switch 7 are connected in series back to back. Specifically: the source of the charging switch 6 is connected to the positive terminal of the battery pack 1, and the drain is connected to the common connection point. Its body diode is oriented from the source to the drain, which allows current to flow from the positive terminal of the battery pack 1 to the common connection point. The drain of the discharging switch 7 is connected to the common connection point, and the source is connected to the positive terminal of the load port 2. Its body diode is configured to allow current to flow from the positive terminal of the load port 2 to the common connection point.

[0032] One end of the heating film 3 is connected to a common connection point via a first switch 4, and the other end is connected to the negative terminal of the load port 2 via a second switch 5. The heating branch in this embodiment includes a discharge heating film 3 and a charging heating film 3.

[0033] When battery pack 1 requires pure discharge heating, both charging switch 6 and discharging switch 7 are kept in the open state, and only the first switch 4 and the second switch 5 of heating film 3 are closed. At this time, the current path is: positive terminal of battery pack 1, body diode of charging switch 6, common connection point, first switch 4, heating film 3, second switch 5 and negative terminal of battery pack 1, forming a complete heating circuit.

[0034] When battery pack 1 requires pure charging heating, the charge / discharge switch 7 remains open, with only the first switch 4 and the second switch 5 closed. An external charging power source (such as an external charger) is connected to load port 2. The current path is: positive terminal of the charger, positive terminal of load port 2, body diode of discharge switch 7, common connection point, first switch 4, heating film 3, second switch 5, and negative terminal of load port 2, ultimately flowing into the negative terminal of the external charger, forming a complete heating power supply circuit to achieve the heating function during charging. It should be noted that the charging heating film 3 here refers to heating achieved through an external charging power source, which can also achieve heating without turning on the charging switch 6 and the discharge switch 7. Similarly, the discharging heating film 3 refers to heating battery pack 1 by opening the charging switch 6 and the discharging switch 7. During charging heating, because the charging switch 6 and the discharging switch 7 are open, the heating current does not flow through battery pack 1, reducing the wear and tear on battery pack 1. During discharging heating, the opening of the discharging switch 7 blocks the current flow through load port 2, ensuring that load port 2 is not energized when the heating film 3 is working, effectively improving safety.

[0035] For example, the circuit also includes a pre-charge branch, which comprises a pre-charge resistor 8 and a pre-charge switch 9 connected in series. One end of the pre-charge branch is connected to a common connection, and the other end is connected to the positive terminal of the load port 2. The pre-charge branch is connected in parallel with the discharge switch 7. The function of the pre-charge branch is to prevent inrush current during power-on. When the battery pack 1 is first connected to a load or charger, to avoid inrush current, the pre-charge switch 9 is closed first. Current flows through the pre-charge resistor 8 to the positive terminal of the load port 2, performing current-limited charging on the load capacitor. When the voltage rises to near the voltage of the battery pack 1, the discharge switch 7 is closed, and then the pre-charge switch 9 is opened, switching to normal operating mode. This process effectively protects the circuit.

[0036] For example, the heating film 3 is a PTC (Positive Temperature Coefficient) self-regulating heating film. The heating film 3 is composed of a polymer PTC material and a conductive filler, and has a positive temperature coefficient characteristic. Its Curie temperature point is set to the upper limit of the battery's optimal operating temperature range (e.g., 45-55°C).

[0037] When the temperature of battery pack 1 is below the Curie temperature, the PTC heating film has low resistance, enabling efficient heating. As the temperature rises to near the Curie point, the resistance of the PTC heating film increases dramatically, automatically reducing the heating power and maintaining the temperature of battery pack 1 within a safe range. This further simplifies the temperature control system—no additional temperature sensors or control circuits are needed; the PTC material itself can achieve overheat protection and constant-temperature heating. Simultaneously, the self-limiting temperature characteristics of the PTC heating film effectively prevent localized overheating, improving the safety of battery pack 1.

[0038] In some embodiments, the heating film 3 is a metal electrothermal film. It includes a metal heating layer and an insulating encapsulation layer. The metal heating layer is copper foil, nickel-chromium alloy foil, or stainless steel foil etched with a preset circuit pattern, and the insulating encapsulation layer is a polyimide film or a silicone film. The circuit pattern of the metal electrothermal film can be customized according to the shape of the battery pack 1 and heating requirements. By adjusting the line width, spacing, and thickness, a zoned power density design can be achieved, optimizing heating uniformity. Using metal materials to prepare the heating film 3 results in high power density and fast heating response, making it suitable for scenarios requiring rapid temperature rise. Furthermore, the metal heating film 3 technology is mature and facilitates large-scale mass production applications.

[0039] Example 2 This application provides a heating circuit for a battery pack 1, including: a battery pack 1, a charging branch, a discharging branch, and a heating branch.

[0040] like Figure 4As shown, the difference from the above embodiment 1 is that the charging switch 6 and the discharging switch 7 are connected in series between the negative terminal of the battery pack 1 and the negative terminal of the load port 2, the second switch 5 is connected to the common connection point, and the first switch 4 is connected to the positive terminal of the load port 2.

[0041] The body diode in charging switch 6 is configured to allow current to flow from the common connection point to the negative terminal of battery pack 1 when charging switch 6 is open. The body diode in discharging switch 7 is configured to allow current to flow from the common connection point to the negative terminal of load port 2 when discharging switch 7 is open.

[0042] In this embodiment, the heating circuit also includes a discharge heating film 3 and a charging heating film 3. In the discharge heating film 3 mode, the battery pack 1 supplies power to the heating film 3 through the body diode of the charging switch 6. When the battery pack 1 requires pure discharge heating, both the charging switch 6 and the discharge switch 7 are kept in the open state, and only the first switch 4 and the second switch 5 of the heating film 3 are closed. Current flows sequentially from the positive terminal of the battery pack 1 through the first switch 4, the heating film 3, the second switch 5, the common connection point, the body diode of the charging switch 6, and the negative terminal of the battery pack 1, forming a complete heating circuit.

[0043] In the charging heating film 3 mode, the external charging power supply connected to the load port 2 supplies power to the heating film 3 through the body diode of the discharge switch 7. When the battery pack 1 needs pure charging heating, the charging switch 6 and the discharge switch 7 are kept open, and only the first switch 4 and the second switch 5 are closed. The current flows from the positive terminal of the load port 2 through the first switch 4, the heating film 3, the second switch 5, the common connection point, the body diode of the discharge switch 7, and the negative terminal of the load port 2 in sequence.

[0044] Combining Embodiments 1 and 2 above, regardless of whether the charging switch 6 and discharging switch 7 are used to control the positive or negative terminal of the circuit, by disconnecting the charging switch 6 and discharging switch 7 and only closing the connection switch of the heating branch, pure charging heating or pure discharging heating can be achieved. The heating process is completely decoupled from the charging and discharging process, avoiding the simultaneous flow of charging current and heating current through the battery, thereby eliminating the risk of battery damage caused by charging and heating at low temperatures. During heating, the charging and discharging switches 7 remain open, and the main circuit between the positive terminal of the battery and the positive terminal of the load port 2 is cut off. Therefore, the positive terminal of the load port 2 will not be energized during the discharging heating state. Under the charging heating film 3, the current flows to the heating film 3 through the body diode, and the load port 2 will not be at a dangerous potential, so that the load port 2 will not be energized during heating, effectively improving the safety of the heating process. By selecting the connection method between the heating branch and the load port 2 (connected to the negative or positive terminal of the load port 2), different application scenarios can be adapted, flexibly realizing two heating schemes of controlling the positive or negative, which simplifies the circuit design and improves the system's response speed and reliability. Based on this, this application can overcome the problems in related technologies and effectively improve the heating efficiency and heating safety in the battery thermal management process.

[0045] The technical features of the embodiments shown above can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A battery pack heating and feedback discharge integrated circuit, characterized in that, The battery pack heating and feedback discharge integrated circuit includes: A battery pack having a battery pack body and battery terminals, wherein the battery terminals include a positive terminal and a negative terminal; Charging circuit, including charging switch; The discharge branch includes a discharge switch; the charging switch and the discharge switch are connected in series between the battery pack and the load port, and the charging switch and the discharge switch have a common connection point; A heating branch includes a heating film and a connection switch, one end of the heating branch is connected to the common connection point, and the other end of the heating branch is connected to the load port; The connection switch is configured to close when both the charging switch and the discharging switch are in the open state, thereby forming a current loop for heating the heating film through the body diode of the charging switch or the discharging switch.

2. The battery pack heating and feedback discharge integrated circuit according to claim 1, characterized in that, Both the charging switch and the discharging switch are MOSFETs, and the connection switch includes a first switch and a second switch that are electrically connected to both ends of the heating film.

3. The battery pack heating and feedback discharge integrated circuit according to claim 2, characterized in that, The charging switch and the discharging switch are connected in series between the positive terminal of the battery pack and the positive terminal of the load port. The first switch is connected to the common connection point, and the second switch is connected to the negative terminal of the load port.

4. The battery pack heating and feedback discharge integrated circuit according to claim 3, characterized in that, The body diode in the charging switch is configured to allow current to flow from the positive terminal of the battery pack to the common connection point when the charging switch is open; the body diode in the discharging switch is configured to allow current to flow from the positive terminal of the load port to the common connection point when the discharging switch is open.

5. The battery pack heating and feedback discharge integrated circuit according to claim 4, characterized in that, The heating circuit includes a discharge heating film type and a charging heating film type. In the discharge heating film type, the battery pack supplies power to the heating film through the body diode of the charging switch. The current flows from the positive terminal of the battery pack through the body diode of the charging switch, the common connection point, the first switch, the heating film, the second switch, and the negative terminal of the battery pack in sequence. In the charging heating film type, the external charging power supply connected to the load port supplies power to the heating film through the body diode of the discharge switch. The current flows from the positive terminal of the load port through the body diode of the discharge switch, the common connection point, the first switch, the heating film, the second switch, and the negative terminal of the load port in sequence.

6. The battery pack heating and feedback discharge integrated circuit according to claim 2, characterized in that, The charging switch and the discharging switch are connected in series between the negative terminal of the battery pack and the negative terminal of the load port. The second switch is connected to the common connection point, and the first switch is connected to the positive terminal of the load port.

7. The battery pack heating and feedback discharge integrated circuit according to claim 6, characterized in that, The body diode in the charging switch is configured to allow current to flow from the common connection point to the negative terminal of the battery pack when the charging switch is open; the body diode in the discharging switch is configured to allow current to flow from the common connection point to the negative terminal of the load port when the discharging switch is open.

8. The battery pack heating and feedback discharge integrated circuit according to claim 7, characterized in that, The heating circuit includes a discharge heating film type and a charging heating film type. In the discharge heating film type, the battery pack supplies power to the heating film through the body diode of the charging switch. The current flows from the positive terminal of the battery pack through the first switch, the heating film, the second switch, the common connection point, the body diode of the charging switch, and the negative terminal of the battery pack in sequence. In the charging heating film type, the external charging power supply connected to the load port supplies power to the heating film through the body diode of the discharge switch. The current flows from the positive terminal of the load port through the first switch, the heating film, the second switch, the common connection point, the body diode of the discharge switch, and the negative terminal of the load port in sequence.

9. The battery pack heating and feedback discharge integrated circuit according to any one of claims 1-5, characterized in that, It also includes a pre-charge branch, which includes a pre-charge resistor and a pre-charge switch connected in series. One end of the pre-charge branch is connected to the common connection point, and the other end is connected to the positive terminal of the load port. The pre-charge branch is connected in parallel with the discharge switch.

10. The battery pack heating and feedback discharge integrated circuit according to any one of claims 1-8, characterized in that, The heating film is a PTC electric heating film or a metal electric heating film.

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