Heating circuit, battery module, flexible circuit board and battery pack

Abstract

The utility model discloses a heating circuit, a battery module, a flexible circuit board and a battery pack. The heating circuit is positioned on a circuit layer of a flexible circuit board of the battery module; the flexible circuit board is positioned on the lower layer of the plurality of chips of the battery module; the flexible circuit board further comprises a sampling circuit layer. The circuit layer where the heating circuit is located is separated from the sampling circuit layer through a film layer. The heating circuit comprises at least two first heating sub-circuits which are connected in series, and the at least two first heating sub-circuits are in one-to-one correspondence with the at least two chips; and the first heating sub-circuit is used for heating the corresponding chip. Therefore, the heating circuit is integrated on the flexible circuit board to form a multi-layer structure, so that the space for additionally arranging the heating circuit can be saved, and compared with the prior art that the heating film is arranged on the side surface or the bottom of the battery cell, the possibility of damage to the heating film can be reduced, so that the reliability and the safety of heating the battery cell are improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a heating circuit, a battery module, a flexible circuit board, and a battery pack. Background Technology

[0002] Battery modules or packs require cell heating at low temperatures to adjust cell temperature to the optimal operating temperature required by the system. Related technologies involve installing heating films on the sides or bottom of the module, with the heat from the film conducted to the cells to raise their temperature. However, current side or bottom heating films provide overall heating, failing to achieve localized heating control. Furthermore, problems such as broken or damaged metal wires in the heating film leading to ablation frequently occur during manufacturing. Utility Model Content

[0003] In view of this, embodiments of this application provide at least one heating circuit, a battery module, a flexible circuit board, and a battery pack.

[0004] The technical solution of this application embodiment is implemented as follows:

[0005] In a first aspect, embodiments of this application provide a heating circuit located on the circuit layer of a flexible circuit board of a battery module; the flexible circuit board is located on the lower layer of multiple pads of the battery module; the flexible circuit board further includes a sampling circuit layer; the circuit layer where the heating circuit is located and the sampling circuit layer are separated by a film layer; the heating circuit includes at least two first heating sub-circuits connected in series, and the at least two first heating sub-circuits correspond one-to-one with at least two pads; the first heating sub-circuits are used to heat the corresponding pads.

[0006] In this embodiment, the heating circuit is located on the circuit layer of the flexible circuit board of the battery module. The flexible circuit board is located below multiple battery cells in the battery module, and the circuit layer containing the heating circuit is separated from the sampling circuit layer in the flexible circuit board by a film layer. This multi-layer structure, integrating the heating circuit onto the flexible circuit board, not only saves space for additional heating circuitry but also reduces the possibility of heating film damage compared to related technologies that place the heating film on the side or bottom of the battery cell, thereby improving the reliability and safety of heating the battery cell. Furthermore, the heating circuit includes at least two first heating sub-circuits connected in series, with each of the at least two first heating sub-circuits corresponding one-to-one with at least two battery cells. These first heating sub-circuits heat the corresponding battery cells, enabling localized heating of the battery cells and improving the flexibility of battery cell heating.

[0007] In some embodiments, the first heating sub-circuit includes a first switching branch and a first heating branch connected in parallel; when the first switching branch is open, the first heating branch heats the corresponding plate.

[0008] In this embodiment, the first heating sub-circuit includes a first switching branch and a first heating branch connected in parallel. When the first switching branch is open, the first heating branch heats the corresponding electrode. Thus, the first switching branch can control whether the first heating branch heats the corresponding electrode, thereby improving the flexibility of cell heating.

[0009] In some embodiments, the first heating sub-circuit further includes a second heating branch connected in parallel with the first heating branch; the second heating branch is provided with a first switch; wherein, when the first switch branch is open and the first switch is open, the first heating branch is on; when the first switch branch is on and the first switch is on, the second heating branch is on; when the first switch branch is open and the first switch is on, the first heating branch and the second heating branch are on.

[0010] In this embodiment, the first heating sub-circuit further includes a second heating branch connected in parallel with the first heating branch; a first switch is provided on the second heating branch; when the first switch branch is open and the first switch is also open, the first heating branch is on; when the first switch branch is on and the first switch is on, the second heating branch is on; when the first switch branch is open and the first switch is on, both the first heating branch and the second heating branch are on. Thus, the first heating branch and / or the second heating branch can be selectively activated via the first switch branch and the first switch, thereby improving the flexibility of cell heating.

[0011] In some embodiments, the heating circuit further includes at least two second heating sub-circuits connected in series; each second heating sub-circuit is connected in series with the first heating sub-circuit; each second heating sub-circuit includes a second switching branch and a third heating branch connected in parallel; at least two second heating sub-circuits correspond one-to-one with at least two plates; wherein, when the second switching branch is open, the third heating branch is turned on to heat the corresponding plate.

[0012] In this embodiment, the heating circuit further includes at least two second heating sub-circuits connected in series; each second heating sub-circuit is connected in series with the first heating sub-circuit; each second heating sub-circuit includes a second switching branch and a third heating branch connected in parallel; at least two second heating sub-circuits correspond one-to-one with at least two battery pads; wherein, when the second switching branch is open, the third heating branch is closed to heat the corresponding battery pad. Thus, by opening and closing the second switching branch, the third heating branch can be opened and closed, thereby allowing selection of whether to heat the corresponding battery pad, thereby improving the flexibility of cell heating.

[0013] In some embodiments, the heating circuit further includes a second switch; the second switch is connected in series with the first heating sub-circuit.

[0014] In this embodiment, a second switch connected in series with the first heating sub-circuit can control whether the entire heating circuit is in a conducting state, thereby enabling the heating circuit to heat the battery module, which improves the flexibility of heating the battery module.

[0015] Secondly, embodiments of this application provide a flexible circuit board for a battery module, the flexible circuit board being located on the lower layer of multiple battery pads in the battery module; the flexible circuit board includes a heating circuit layer and a sampling circuit layer, the heating circuit layer and the sampling circuit layer being separated by a film layer; the heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, the at least two first heating sub-circuits being one-to-one with at least two battery pads; the first heating sub-circuits are used to heat the corresponding battery pads.

[0016] Thirdly, embodiments of this application provide a battery module, which includes a flexible circuit board and multiple battery cells; the multiple battery cells are connected in series through multiple battery pads; the flexible circuit board is located on the lower layer of the multiple battery pads; the flexible circuit board includes a heating circuit layer and a sampling circuit layer, the heating circuit layer and the sampling circuit layer are separated by a film layer; the heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, the at least two first heating sub-circuits correspond one-to-one with at least two battery pads; the first heating sub-circuits are used to heat the corresponding battery pads.

[0017] In some embodiments, the battery module further includes an interface integration unit; the interface integration unit includes a first pin of the sampling circuit layer and a second pin of the heating circuit; the second pin includes a first switch pin of the first switch branch, a second switch pin of the first switch and a third switch pin of the second switch branch; the interface integration unit is connected to the battery management unit through the first pin and the second pin.

[0018] In this embodiment, the sampling circuit layer and the port of the heating circuit are integrated on the interface integration unit. This allows for output through an integrated interface, eliminating the need for a separate connector interface for the heating interface and signal pins of the heating circuit.

[0019] In some embodiments, the interface integration unit further includes a positive pin of the sampling circuit layer, a negative pin of the sampling circuit layer, a positive pin of the heating circuit, and a negative pin of the heating circuit; the positive pin of the heating circuit is connected to the positive pin of the sampling circuit layer and the positive terminal of the battery module, respectively; the negative pin of the heating circuit is connected to the negative pin of the sampling circuit layer and the negative terminal of the battery module, respectively.

[0020] In this embodiment, the positive pin of the heating circuit is connected to the positive pin of the sampling circuit layer and the positive terminal of the battery module, respectively; the negative pin of the heating circuit is connected to the negative pin of the sampling circuit layer and the negative terminal of the battery module, respectively. This allows the battery module to supply power to the heating circuit via the interface integration unit, thereby improving the convenience of heating the battery cell.

[0021] Fourthly, embodiments of this application provide a battery pack, which includes multiple battery modules connected in series; each battery module includes a flexible circuit board and multiple battery cells; the multiple battery cells are connected in series through multiple batteries; the flexible circuit board is located on the lower layer of the multiple batteries; the flexible circuit board includes a heating circuit layer and a sampling circuit layer, the heating circuit layer and the sampling circuit layer are separated by a film layer; the heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, the at least two first heating sub-circuits correspond one-to-one with at least two batteries; the first heating sub-circuits are used to heat the corresponding batteries.

[0022] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of this application. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0024] Figure 1 This is a schematic diagram of the structure of a flexible circuit board provided in an embodiment of this application;

[0025] Figure 2 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 1 ;

[0026] Figure 3 A schematic diagram of the structure of a battery pack provided in an embodiment of this application. Figure 1 ;

[0027] Figure 4 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 2 ;

[0028] Figure 5 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 3 ;

[0029] Figure 6 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 4 ;

[0030] Figure 7A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 5 ;

[0031] Figure 8 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 6 ;

[0032] Figure 9 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 7 ;

[0033] Figure 10 A circuit diagram of the interface integration unit provided in an embodiment of this application;

[0034] Figure 11 A schematic diagram of the structure of a battery pack provided in an embodiment of this application. Figure 2 ;

[0035] Figure 12 This is a schematic diagram showing the location distribution of a heating circuit according to an embodiment of this application;

[0036] Figure 13 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 8 ;

[0037] Figure 14 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 9 ;

[0038] Figure 15 A circuit diagram of a heating circuit provided in an embodiment of this application. Figure 10 ;

[0039] Figure 16 A schematic diagram of the structure of a battery pack provided in an embodiment of this application. Figure 3 ;

[0040] Figure 17 A schematic diagram of the structure of a battery pack provided in an embodiment of this application. Figure 4 . Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application are further described in detail below with reference to the accompanying drawings and embodiments. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] In the following description, references to "some embodiments" refer to a subset of all possible embodiments. It is understood that "some embodiments" may be the same or different subsets of all possible embodiments and may be combined with each other without conflict. The terms "first / second / third" are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of this application.

[0044] Battery modules or packs require cell heating at low temperatures to adjust the cell temperature to the optimal operating temperature required by the system. Related technologies involve installing heating films on the sides or bottom of the module, with the heat from the film conducted to the cells to raise their temperature. However, current side or bottom heating films provide overall heating, failing to achieve localized heating control. Furthermore, problems such as broken or damaged metal wires in the heating film leading to ablation frequently occur during manufacturing.

[0045] To address the technical problems in related technologies, embodiments of this application provide a heating circuit, such as... Figure 1 As shown, the heating circuit is located on the heating circuit layer 100 of the flexible circuit board 10 of the battery module (not shown in the figure); the flexible circuit board 10 is located on the lower layer of multiple pads of the battery module; the flexible circuit board 10 also includes a sampling circuit layer 200, and the heating circuit layer 100 where the heating circuit is located is separated from the sampling circuit layer 200 by a film layer 300; as shown Figure 2 As shown, the heating circuit includes at least two first heating sub-circuits 101 connected in series, and the at least two first heating sub-circuits 101 correspond one-to-one with at least two bar pieces (e.g., Figure 2 As shown, the first heating sub-circuit 101 corresponds to the first plate 201.

[0046] The first heating sub-circuit 101 is used to heat the corresponding bar (i.e., Figure 2 The first tablet of the drug (201).

[0047] In this embodiment of the application, the number of heating circuit layers in the flexible circuit board is at least one ( Figure 1The number of heating circuit layers shown is 1, meaning that a flexible circuit board can have one heating circuit layer or multiple heating circuit layers. The heating circuit can be located on at least a portion of the heating circuit layer; that is, the entire heating circuit layer can be a heating circuit, or only a portion of the heating circuit layer can be a heating circuit.

[0048] In this embodiment, the heating circuit is integrated on a flexible printed circuit (FPC) with a sampling circuit layer, and the sampling circuit layer and the heating circuit are separated by a film layer. The sampling circuit can be the sampling circuit layer of a Cells Contact System (CCS). Because the flexible printed circuit with the sampling circuit layer is located below multiple battery cells in the battery module, the heating circuit on the flexible printed circuit is also located below the multiple battery cells. When the heating circuit is turned on, heat can be transferred to the battery cells through thermal conduction. The battery cells can then transfer heat to the cell terminals, and the cell terminals can transfer heat to the inside of the cell, thus forming a heat conduction path: heating circuit → battery cells → cell terminals → inside the cell.

[0049] For example, such as Figure 3 As shown, multiple battery cells are connected in series through different plates, for example... Figure 3 The two leftmost cells are connected in series via the first electrode plate 201, and the two rightmost cells are connected in series via the second electrode plate 202. When the heating circuit is turned on, heat can be transferred to the electrodes (first electrode plate 201 and second electrode plate 202), and then the heat is transferred sequentially to the cell terminals and the inside of the cell.

[0050] In this embodiment, the sampling circuit layer is used to collect the voltage and temperature of the battery cell. For example, Figure 2 As shown, the first sensor plate 201 can be a sensor plate equipped with a temperature acquisition unit, and the sampling circuit layer can acquire the temperature of the corresponding cell through the temperature acquisition unit set on the first sensor plate. For example, the temperature acquisition unit can be a negative temperature coefficient thermistor (NTC).

[0051] In this embodiment, the first heating sub-circuit corresponds to a first heating plate equipped with a temperature acquisition unit. That is, the first heating sub-circuit is used to heat the first heating plate equipped with the temperature acquisition unit. It is understood that because the first heating plate is equipped with a temperature acquisition unit, the battery control unit of the battery module or the battery management unit (BMU) of the battery pack can acquire the temperature of the corresponding battery cell through the temperature acquisition unit. When the temperature of the battery cell is low, the first heating sub-circuit heats the battery cell.

[0052] In some embodiments, the heating element corresponding to the first heating sub-circuit is a second heating element without a temperature acquisition unit. That is, the first heating sub-circuit is used to heat the second heating element without a temperature acquisition unit. In this embodiment, because the second heating element does not have a temperature acquisition unit, the first heating sub-circuit cannot be used to heat the battery cell by controlling the real-time temperature of the battery cell. In practical applications, the first heating sub-circuit can be controlled to heat the battery cell according to a preset heating cycle.

[0053] In some embodiments, the first heating sub-circuit includes a heating component that generates heat when current passes through it, thereby heating the battery cell. For example, the heating component may be a heating copper wire, which is folded into a coil shape, or wired in a U-shape with alternating directions, to achieve higher resistance and generate more heat during heating.

[0054] In this embodiment, the heating circuit is located on the circuit layer of the flexible circuit board of the battery module. The flexible circuit board is located below multiple battery cells in the battery module, and the circuit layer containing the heating circuit is separated from the sampling circuit layer in the flexible circuit board by a film layer. This multi-layer structure, integrating the heating circuit onto the flexible circuit board, not only saves space for additional heating circuitry but also reduces the possibility of heating film damage compared to related technologies that place the heating film on the side or bottom of the battery cell, thereby improving the reliability and safety of heating the battery cell. Furthermore, the heating circuit includes at least two first heating sub-circuits connected in series, with each of the at least two first heating sub-circuits corresponding one-to-one with at least two battery cells. These first heating sub-circuits heat the corresponding battery cells, enabling localized heating of the battery cells and improving the flexibility of battery cell heating.

[0055] In some embodiments, such as Figure 4 As shown, the first heating sub-circuit 101 includes a first switching branch 1012 and a first heating branch 1011 connected in parallel;

[0056] When the first switch branch 1012 is disconnected, the first heating branch 1011 heats the corresponding plate.

[0057] In this embodiment, a switch with a control terminal is provided on the first switch branch. The control terminal of the switch is connected to the battery management unit of the battery module or the battery management unit of the battery pack. The battery management unit can output a control voltage to the control terminal of the switch to turn the first switch branch on or off. For example, as shown... Figure 4 As shown, a metal-oxide-semiconductor field-effect transistor (MOS) is provided on the first switching branch.

[0058] In this embodiment, the first heating sub-circuit includes a first switching branch and a first heating branch connected in parallel. When the first switching branch is open, the first heating branch heats the corresponding electrode. Thus, the first switching branch can control whether the first heating branch heats the corresponding electrode, thereby improving the flexibility of cell heating.

[0059] In some embodiments, such as Figure 5 As shown, each first heating sub-circuit 101 further includes a second heating branch 1014 connected in parallel with the first heating branch 1011; the second heating branch 1014 is provided with a first switch 1013; wherein,

[0060] When the first switch branch 1012 is open and the first switch 1013 is open, the first heating branch 1011 is turned on.

[0061] When the first switch branch 1012 is turned on and the first switch 1013 is turned on, the second heating branch 1014 is turned on.

[0062] When the first switch branch 1012 is open and the first switch 1013 is closed, the first heating branch 1011 and the second heating branch 1014 are closed.

[0063] In this embodiment, both the first heating branch and the second heating branch are equipped with heating components. The resistance values ​​of the heating components on the two branches can be the same or different. When the resistance values ​​are different, the heating efficiency of the first heating branch and the second heating branch on the bar sheet is different; the higher the resistance value, the higher the heating efficiency. When both the first heating branch and the second heating branch are turned on, the heating efficiency of the first heating sub-circuit is the highest.

[0064] In this embodiment of the application, each first heating sub-circuit includes two parallel-connected first heating branches and second heating branches. The heating efficiency of the first heating branch on the cell plate is less than that of the second heating branch on the cell plate. Therefore, it is possible to determine which heating branch to activate based on the temperature of the corresponding cell.

[0065] For example, if the temperature of the corresponding battery cell is determined to be less than a first temperature threshold based on the temperature collected by the temperature acquisition unit on the first pad, the first switch branch can be disconnected and the first switch can be turned on. At this time, both the first heating branch and the second heating branch are turned on, and the first pad corresponding to the battery cell is heated by the first heating branch and the second heating branch together, thereby quickly increasing the temperature of the battery cell. If the temperature of the corresponding battery cell is determined to be greater than or equal to the first temperature threshold and less than the second temperature threshold based on the temperature collected by the temperature acquisition unit on the first pad, the first switch branch can be turned on and the first switch can be turned on. At this time, the second heating branch is turned on, and the first pad corresponding to the battery cell is heated by the second heating branch, which has a higher heating efficiency for the first pad. If the temperature of the corresponding battery cell is determined to be greater than or equal to the second temperature threshold and less than the third temperature threshold based on the temperature collected by the temperature acquisition unit on the first pad, the first switch branch can be disconnected and the first switch can be turned on. At this time, the first heating branch is turned on, and the first pad corresponding to the battery cell is heated by the first heating branch, which has a lower heating efficiency for the first pad.

[0066] In this embodiment, the first switch can be a MOSFET. When it is necessary to control the first switch to be on or off, the battery management unit can transmit a control voltage signal to the base of the MOSFET, thereby turning the MOSFET on or off.

[0067] In this embodiment, the first heating sub-circuit further includes a second heating branch connected in parallel with the first heating branch; a first switch is provided on the second heating branch; when the first switch branch is open and the first switch is also open, the first heating branch is on; when the first switch branch is on and the first switch is on, the second heating branch is on; when the first switch branch is open and the first switch is on, both the first heating branch and the second heating branch are on. Thus, the first heating branch and / or the second heating branch can be selectively activated via the first switch branch and the first switch, thereby improving the flexibility of cell heating.

[0068] In some embodiments, such as Figure 6 As shown, the heating circuit further includes at least two second heating sub-circuits 102 connected in series; each second heating sub-circuit 102 is connected in series with the first heating sub-circuit 101; each second heating sub-circuit 102 includes a second switching branch 1021 and a third heating branch 1022 connected in parallel; at least two second heating sub-circuits 102 correspond one-to-one with at least two plates; wherein,

[0069] When the second switch branch 1021 is disconnected, the third heating branch 1022 is turned on to heat the corresponding plate.

[0070] In this embodiment, because the second switch branch and the third heating branch are connected in parallel, when the second switch branch is turned on, the current in the heating circuit will flow through the second switch branch, thereby keeping the third heating branch in a non-conducting state. Similarly, when the second switch branch is turned off, the current in the heating circuit will flow through the third heating branch, thereby keeping the third heating branch in a conducting state.

[0071] In this embodiment, the second switch branch is equipped with a switch with a control terminal, such as a MOSFET. When it is necessary to control the second switch branch to be on or off, the battery management unit can transmit a voltage signal to the control terminal of the switch, thereby causing the switch to be on or off. That is to say, the control terminal of the switch on the second switch branch is also connected to the battery management unit.

[0072] In practical applications, the heating circuit operates in two modes: The first is a localized heating mode, where when a battery cell has a lower temperature, the corresponding first heating sub-circuit is activated to heat that cell, while the second heating sub-circuit remains off. The second is a comprehensive heating mode, where both the first and second heating sub-circuits operate to heat all battery cells. The activation of the first heating sub-circuit to heat a particular cell can be achieved by activating either the first heating branch or the second heating branch.

[0073] In some embodiments, such as Figure 6 As shown, the plate corresponding to the second heating sub-circuit can be a second plate 202 without a temperature acquisition unit.

[0074] In this embodiment, the heating circuit further includes at least two second heating sub-circuits connected in series; each second heating sub-circuit is connected in series with the first heating sub-circuit; each second heating sub-circuit includes a second switching branch and a third heating branch connected in parallel; at least two second heating sub-circuits correspond one-to-one with at least two battery pads; wherein, when the second switching branch is open, the third heating branch is closed to heat the corresponding battery pad. Thus, by opening and closing the second switching branch, the third heating branch can be opened and closed, thereby allowing selection of whether to heat the corresponding battery pad, thereby improving the flexibility of cell heating.

[0075] In some embodiments, such as Figure 7 As shown, the heating circuit also includes a second switch 103; the second switch 103 is connected in series with the first heating sub-circuit 101.

[0076] In this embodiment, the heating circuit is further provided with a second switch, which is connected in series with each of the first heating sub-circuits and each of the second heating sub-circuits. Thus, the second switch can control the on / off state of the entire heating circuit.

[0077] In this embodiment, the second switch can be a switch with a control terminal, such as a MOSFET. When it is necessary to control the second switch to be on or off, the battery management unit can transmit a voltage signal to the control terminal of the switch, thereby causing the switch to be on or off. That is, the control terminal of the switch is also connected to the battery management unit.

[0078] In this embodiment, a second switch connected in series with the first heating sub-circuit can control whether the entire heating circuit is in a conducting state, thereby enabling the heating circuit to heat the battery module, which improves the flexibility of heating the battery module.

[0079] This application embodiment also provides a flexible circuit board for a battery module, the flexible circuit board being located on the lower layer of multiple batteries in the battery module; the flexible circuit board includes a heating circuit layer and a sampling circuit layer, the heating circuit layer and the sampling circuit layer being separated by a film layer; the heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, the at least two first heating sub-circuits being one-to-one with at least two batteries; the first heating sub-circuits are used to heat the corresponding batteries.

[0080] In this embodiment, the heating circuit layer and the sampling circuit layer are integrated onto the flexible circuit board. This integration of the heating circuit onto the flexible circuit board to form a multi-layer structure not only saves space for additional heating circuitry, but also reduces the possibility of heating film damage compared to related technologies that place the heating film on the side or bottom of the battery cell, thereby improving the reliability and safety of heating the battery cell.

[0081] This application embodiment also provides a battery module, which includes a flexible circuit board and multiple battery cells; the multiple battery cells are connected in series through multiple batteries; the flexible circuit board is located on the lower layer of the multiple batteries; the flexible circuit board includes a heating circuit layer and a sampling circuit layer, the heating circuit layer and the sampling circuit layer are separated by a film layer; the heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, the at least two first heating sub-circuits correspond one-to-one with at least two batteries; the first heating sub-circuits are used to heat the corresponding batteries.

[0082] In this embodiment, the heating circuit is integrated on a flexible circuit board with a sampling circuit layer, and the sampling circuit layer and the circuit layer containing the heating circuit are separated by a film layer. Because the flexible circuit board with the sampling circuit layer is located on the lower layer of multiple battery cells in the battery module, the heating circuit on the flexible circuit board is also located on the lower layer of multiple battery cells. When the heating circuit is turned on, heat can be transferred to the battery cells through thermal conduction. The battery cells can transfer heat to the cell terminals, and the cell terminals can transfer heat to the inside of the cell, thus forming a heat conduction path of heating circuit → battery cells → cell terminals → inside the cell.

[0083] In some embodiments, the heating circuit further includes at least two second heating sub-circuits connected in series; the first heating sub-circuit includes a first switch branch and a first heating branch connected in parallel, a second heating branch connected in parallel with the first heating branch, and a first switch on the second heating branch; each second heating sub-circuit includes a second switch branch and a third heating branch connected in parallel.

[0084] In practical applications, the heating circuit operates in two heating modes. The first is a localized heating mode, where a battery cell with a lower temperature (whose heat exchanger is designated as the first heat exchanger) is heated by at least one branch of the first and second heating branches in the first heating sub-circuit. Simultaneously, for other battery cells with heat exchangers of normal temperature (whose heat exchangers are designated as the first heat exchanger), both the first and second heating branches in the corresponding first heating sub-circuit are disconnected. For other battery cells with heat exchangers designated as the second heat exchanger, the third heating branch is disconnected, meaning the second switching branch is conductive. The second heating mode is a global heating mode, where at least one branch of the first heating sub-circuit is conductive, and the third heating branch of the second heating sub-circuit is conductive, meaning the third switch is disconnected.

[0085] For example, such as Figure 7 and Figure 8 As shown, when the heating circuit is in overall heating mode, with the first switch branch 1012 open and the first switch 1013 open, current flows through the first heating branch 1011, heating the first electrode 201. The second switch branch 1021 is open, and the third heating branch 1022 is on, with current flowing through it, heating the second electrode 202. In other words, when the heating circuit is in overall heating mode, it heats all battery cells. In some embodiments, when the heating circuit is in overall heating mode, the second heating branch 1014 can also be on, and both the second heating branch 1014 and the first heating branch 1011 can also be on.

[0086] like Figure 7 and Figure 9As shown, when the heating circuit is in partial heating mode, the first switch branch 1012 is turned on, and the first switch 1013 is turned on. At this time, current flows through the second heating branch 1014, causing the second heating branch 1014 to heat the first pad 201. The second switch branch 1021 is turned on, and the third heating branch 1022 is turned off. Current flows through the second switch branch 1021, causing the third heating branch 1022 to stop heating the second pad 202. That is, when the heating circuit is in partial heating mode, the heating circuit heats the battery cell including the first pad equipped with a temperature acquisition unit. In some embodiments, when the heating circuit is in partial heating mode, the first heating branch 1011 may also be turned on, as may the second heating branch 1014 and the first heating branch 1011.

[0087] In some embodiments, such as Figure 10 As shown, the battery module also includes an interface integration unit 203; the interface integration unit includes the first pin of the sampling circuit layer (i.e., Figure 10 V0 to V_n in the circuit, and the second pin of the heating circuit; the second pin includes the first switch pin of the first switch branch ( Figure 10 Q1-1, Q2-1, and Qn-1 in the first switch, and the second switch pin of the first switch ( Figure 9 Q1-2, Q2-2, Qn-2 in the second switch branch and the third switch pin in the second switch branch (Q1-2, Q2-2, Qn-2 in the second switch branch) Figure 10 (not shown);

[0088] The interface integration unit is connected to the battery management unit of the battery module through the first pin and the second pin.

[0089] In some embodiments, the interface integration unit further includes a third pin of the temperature acquisition unit on the first pad ( Figure 10 NTC1+, NTC1-, NTC_n in .

[0090] In this embodiment, after setting the heating circuit on the flexible circuit board of the battery module, the control terminal of the heating circuit and the pins of the sampling circuit layer can be integrated together on the interface integration unit. This way, it can be output through one integrated interface, thus eliminating the need to make a separate connector interface for the heating interface and signal pin part of the heating circuit.

[0091] like Figure 10As shown, the interface integration unit 203 has a pin design with two rows. One row consists of the sampling circuit layer pin outputs in the flexible circuit board, which include the voltage of each cell, the total voltage of the module, and the pins of the cell NTC. The voltage pins include V0 to V_n, and the NTC pins include NTC1+, NTC1-, and NTC_n. The other row consists of the heating circuit pins in the flexible circuit board (i.e., the first pin, the second pin, and the third pin). The heating circuit pins are connected to the battery management unit of the battery module, so that the battery management unit can control the heating circuit to turn on and off.

[0092] In some embodiments, such as Figure 10 As shown, the interface integration unit 203 also includes a fourth pin Q, which is the switch pin of the second switch of the heating circuit. The second switch is connected to the battery management unit through the fourth pin. That is, the battery management unit can control the on and off of the second switch to control the operation of the heating circuit of the battery module.

[0093] In this embodiment, the sampling circuit layer and the port of the heating circuit are integrated on the interface integration unit. This allows for output through an integrated interface, eliminating the need for a separate connector interface for the heating interface and signal pins of the heating circuit.

[0094] In some embodiments, such as Figure 10 As shown, the interface integration unit also includes the positive pin of the sampling circuit layer (PWR+ in the figure), the negative pin of the sampling circuit layer (PWR- in the figure), the positive pin of the heating circuit (Heat+ in the figure), and the negative pin of the heating circuit (Heat- in the figure).

[0095] The positive pin of the heating circuit is connected to the positive pin of the sampling circuit layer and the positive terminal of the battery module, respectively.

[0096] The negative pin of the heating circuit is connected to the negative pin of the sampling circuit layer and the negative terminal of the battery module, respectively.

[0097] In this embodiment, the positive and negative pins of the heating circuit are connected in parallel with the positive and negative pins of the sampling circuit layer, and are also connected to the positive and negative terminals of the battery module, thereby enabling the heating circuit to be powered by the voltage of the battery module to heat the battery cell.

[0098] In this embodiment of the application, the positive and negative pins of the heating circuit are connected to the positive and negative pins of the sampling circuit layer and the positive and negative pins of the battery module through the interface integration unit, thereby realizing the power supply of the heating circuit through the voltage of the battery module to heat the battery cell.

[0099] In this embodiment, the positive pin of the heating circuit is connected to the positive pin of the sampling circuit layer and the positive terminal of the battery module, respectively; the negative pin of the heating circuit is connected to the negative pin of the sampling circuit layer and the negative terminal of the battery module, respectively. This allows the battery module to supply power to the heating circuit via the interface integration unit, thereby improving the convenience of heating the battery cell.

[0100] In some embodiments, this application provides a battery pack, which includes multiple battery modules connected in series; each battery module includes a flexible circuit board and multiple battery cells; the multiple battery cells are connected in series through multiple batteries; the flexible circuit board is located on the lower layer of the multiple batteries; the flexible circuit board includes a heating circuit layer and a sampling circuit layer, and the heating circuit layer and the sampling circuit layer are separated by a film layer;

[0101] The heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, and the at least two first heating sub-circuits correspond one-to-one with at least two bar pieces;

[0102] The first heating sub-circuit is used to heat the corresponding bar slices.

[0103] In some embodiments, such as Figure 11 As shown, the battery pack also includes a third switch 204; the third switch 204 is connected in series with each battery module 205.

[0104] like Figure 11 As shown, multiple battery modules 205 are connected in series, and the battery module 205 is connected in series with the third switch 204. The control terminal of the third switch 204 is also connected to the battery management unit 206.

[0105] In this embodiment, the third switch can be a heating relay, located in the safety-box (Sbox) of the battery pack. The battery management unit can control the on / off state of the third switch to activate and deactivate the heating circuit of the entire battery pack.

[0106] like Figure 11As shown, the battery pack also includes a data acquisition integration unit 207. Each battery module 205 in the battery pack is connected to the data acquisition integration unit 207 via the first pin of the interface integration unit 203. The data acquisition integration unit 207 is used to acquire the voltage of the battery module and transmit the acquired voltage to the battery management unit 206. Each battery module 205 in the battery pack is connected to the battery management unit 206 via the pin of the heating circuit of the interface integration unit 203. The battery management unit 206 will control the switching of the heating circuit of each battery module based on the temperature difference of the negative temperature coefficient thermistors (NTC) on different cells and according to the preset local heating control logic.

[0107] The following describes the application of the battery capacity determination method provided in the embodiments of this application in a real-world scenario.

[0108] Battery modules or packs require cell heating at low temperatures to adjust the cell temperature to the optimal operating temperature required by the system. Existing technology involves installing a heating film on the side or bottom of the module, with the heat from the film conducted to the cell to raise its temperature. However, current side or bottom heating films provide overall heating, failing to achieve localized heating control. Furthermore, problems such as broken or damaged heating film wires leading to ablation frequently occur during manufacturing. Therefore, this application provides a CCS integrated heating structure and circuit to achieve high safety, high reliability, and localized heating control in the product.

[0109] In this embodiment, the heating circuit is integrated onto the flexible printed circuit (FPC) circuit of the Cells Contact System (CCS) for sampling, thus realizing a multi-layer CCS structure design. Wherein:

[0110] The heating wire layer of the heating film on the FPC comes into contact with the cell electrode to achieve heat conduction (heat conduction path: heating copper wire → electrode → cell electrode → cell interior).

[0111] The heating wire structure (heating wire layer) can adopt different wiring methods, such as bending the heating wire into a coil shape, or using forward and reverse U-shaped wiring, to achieve greater heating wire resistance and generate more heat during heating.

[0112] The positive and negative connection lines of the heating circuit are integrated into the CCS low-voltage sampling connection port to realize the series and parallel connection of multiple CCS heating circuits, thereby realizing the heating circuit design of the Pack-level system.

[0113] In this embodiment, the heating film is integrated with the electrode or sampling nickel plate in contact to achieve heat conduction, reducing the reliability and safety issues caused by heating film damage. The heat conduction path is: heating resistance wire → electrode → cell electrode → inside the cell. The positive and negative pins of the heating circuit of a single module are directly integrated with the low-voltage sampling interface on the CCS, eliminating the need for a separate low-voltage connection port and improving manufacturing efficiency.

[0114] In some embodiments, a heating control method is adopted where the entire heating circuit is designed within the Pack, but on a single module:

[0115] The pack uses a series connection: the heating circuits on the CCS of multiple module units (i.e., battery modules) in the pack are connected in series and connected to the heating control circuit in the high voltage box. The heating relay is controlled by the BMU to control the heating function to turn on / off, so that the heating function of all units can be turned on and off at the same time.

[0116] Module-level local heating function: The heating film layer and metal wire layer have been enhanced with a transistor control circuit. Based on the maximum and minimum temperatures of the NTC on each module, the temperature difference value, and the temperature data combined with the BMU, the temperature regulation logic is added through software to control the opening and closing of the transistors on each unit module, thereby realizing the local heating control function of any module; the power supply for the heating wire of the local module is supplied through the power supply of the individual module.

[0117] Integrated design methods for heating switch control circuit: Method 1: The control circuit is designed in the heating layer of the multi-layer FPC and can be directly connected to the heating wire circuit to realize the integrated product structure and electrical circuit design scheme of multi-layer FPC + heating control circuit; Method 2: The control circuit can also be designed in the non-integrated FPC component of the battery system, which is an external control circuit scheme.

[0118] In this embodiment, with the heating circuit of each battery module connected in series, the heating circuits of all modules in the Pack are connected in series and powered by the Pack voltage; passive protection: the heating circuit is connected in series with a fuse to prevent abnormal high current; active control: the heating relay in the safety box is controlled by the BMU to control the heating circuit to close / open.

[0119] In this embodiment, with the heating circuits of each battery module connected in parallel, the voltage of each module supplies power to the heating circuit, generating current for heating; each heating circuit is connected in series with a fuse to prevent abnormally large currents and protect the circuit safety; each module heating circuit is connected in series with a metal-oxide-semiconductor field-effect transistor (MOS) switch, and the MOS transistor is integrated into the multilayer CCS film heating wire layer to achieve positive and negative connection with the low-voltage pin of the module. The signal control of the MOS transistor is connected to the BMU through the low-voltage connector interface.

[0120] In this embodiment, the BMU can set different temperature and temperature difference thresholds for heating activation and deactivation software control logic based on the NTC temperature of each module.

[0121] like Figure 12 As shown, the heating circuit in the flexible circuit board corresponding to the battery module is located on the top of the battery module and is in contact with the pad 40 of the battery cell of the battery module. The pad can be the first pad in the above embodiment or the second pad.

[0122] In some embodiments, such as Figure 13 As shown, the heating circuit corresponding to the battery module includes a first heating wire 1201, a second heating wire 1202 connected in parallel with the first heating wire 1201, and a third heating wire 1203. The heating wires contact the heat exchanger to achieve heating. A transistor control circuit is integrated to achieve partial heating of the heat exchanger with NTC. Specifically, the first heating wire 1201 and the second heating wire 1202 are in contact with the first heat exchanger 201 with NTC, and the third heating wire 1203 is in contact with the second heat exchanger 202 without NTC.

[0123] In this embodiment, when local heating control (i.e., overall heating) is not required, Q1-2, Q2-2, Qn_1-2, and Qn-2 are disconnected, and Q1-1, Q2-1, Qn_1-1, and Qn-1 are disconnected. At this time, the first heating wire 1201 is on, and the second heating wire 1202 is off. Simultaneously, K1, K2, and K3 are off, and the third heating wire 1203 is on. Thus, the heating circuit heats the battery cell's plates through the first heating wire 1201 and the third heating wire 1203. When local heating control is not required, the current flow direction of the heating circuit is as follows: Figure 14 .

[0124] In this embodiment, when local heating control is required, Q1-2, Q2-2, Qn_1-2, and Qn-2 are turned on, and Q1-1, Q2-1, Qn_1-1, and Qn-1 are turned on. At this time, the first heating wire 1201 is turned off, and the second heating wire 1202 is turned on. Simultaneously, K1, K2, and K3 are turned on, and the third heating wire 1203 is turned off. Thus, the heating circuit heats the electrode pads of the battery cell through the second heating wire 1202. The current flow direction of the heating circuit when local heating control is required is shown below. Figure 15 .

[0125] In the embodiments of this application, such as Figure 13 As shown, the heating circuit also includes a switch Q_total (the control terminal of Q_total is...). Figure 10 The fourth pin Q in the circuit controls the opening and closing of the heating circuit by controlling the switch Q.

[0126] In this embodiment, the heating circuit has a fuse, and the partially parallel MOS transistor heating control circuit also has a fuse, which serves to protect and cut off the circuit when the heating circuit current is too large.

[0127] In this embodiment, each battery module outputs an integrated low-voltage port, which includes a CCS sampling circuit and a heating control signal pin. The CCS sampling circuit is connected to the CSC, and the CSC then transmits the sampled voltage and temperature data to the BMU via Controller Area Network (CAN). The heating signal pins are all connected to the BMU. The BMU will control the switching of the local heating MOSFETs of each module based on the temperature difference of the NTC on different cells and according to the preset local heating control logic.

[0128] In this embodiment, the overall heating high pressure control is achieved by connecting the heating relay switch on the safety box via the BMU control circuit, and the MOS-Q master switch on the individual module in series.

[0129] In this embodiment, all lines of the multi-layer FPC on a single module are finally output through a single integrated interface; there is no need to make a separate connector interface for the heating interface and the signal pin part.

[0130] For example, such as Figure 10As shown, the integrated interface has two rows of pins. One row consists of the voltage and temperature sampling circuit layer pins in the multi-layer FPC structure. These pins output to the CCS sampling circuit, meaning they are only connected to the voltage and temperature sampling circuit of the CSC section. The pins include pins for each cell voltage, the total module voltage, and the cell NTC. The second row consists of the heating film layer circuit pins in the multi-layer FPC. These pins are connected to the BMU and include the Heat+ / - pins for the heating wire. These two pins are connected in parallel with the PWR+ / - pins of the FPC sampling circuit layer to provide the heating wire power supply voltage input. The pins also include the outputs of the MOSFETs Q, Q1-1, Q1-2, and Qn. Finally, an external adapter cable is connected to the BMU via this pin to connect to the heating signal control circuit.

[0131] In this embodiment, the heating copper wire in the heating film layer can be wired in different shapes, such as folding the heating wire into a coil shape or using a U-shaped wiring method, to achieve a higher resistance of the heating wire and generate more heat during heating.

[0132] 1. Increasing resistance increases heat generation, according to Joule's law. ;

[0133] 2. The heating wire circuit layer and the heat conduction part in contact with the battery cell need to be structurally extended and covered. The specific structural area can be flexibly designed according to the module structure space. If greater heating efficiency is required, the heating area can be increased to achieve a larger area of ​​heat conduction and improve heating efficiency. The reason for extending the heating wire circuit layer is that the size of the battery cell may be different in different modules. If the heating wire layer wants to increase the heat conduction contact area, the area of ​​the contact position of the heating wire layer in the FPC can be increased, thereby achieving a better heating temperature rise rate.

[0134] 3. To achieve local heating of the module, a MOS transistor circuit can be added to the heating wire circuit to realize the local heating control function of a single module.

[0135] In some embodiments, such as Figure 16 As shown, multiple battery modules 205 connected in series are connected to a heating relay 1501, which controls the opening and closing of the heating circuit in the battery pack.

[0136] In this embodiment, when the heating circuit in each battery module is connected in series, multiple modules are contained within the pack, and each module is equipped with a CCS. The top CCS integrates the heating film structure and connection lines, connecting the low-voltage interfaces of all modules in series to realize the connection of the heating circuit system. Through the pack, it is connected to the safety box. Passive protection: The heating circuit is connected in series with a fuse electronic component. When an abnormally large current occurs in the heating circuit, it is triggered to blow, protecting the product. Active control: The heating relay in the safety box is controlled by the BMU. When the heating start / stop conditions preset by the software are met, the heating circuit is actively controlled to turn on / off.

[0137] In some embodiments, where the heating circuits in each battery module are connected in parallel, such as Figure 17 As shown, the heating circuit corresponding to each battery module 205 is connected in parallel with the BMU via the fourth switch 1601. Each module's voltage supplies power to its heating module independently, enabling single-module heating. Each heating circuit is connected via a MOS transistor on the CCS (or the transistor circuit can be designed in an external unit of the module). The transistor's control signal pin is connected to the BMU via a low-voltage interface. The BMU controls the transistor's on / off state, thus enabling / disabling the heating circuit function of each module.

[0138] In this embodiment, the single-module heating trigger control logic is as follows: each module has N NTC temperature sensors. The NTCs are connected to the BMU through a low-voltage sampling circuit. The BMU can realize the independent heating control function of each module by setting the temperature control on and off logic in the software according to the maximum and minimum temperature values ​​and temperature difference of each module, thus realizing the flexible temperature adjustment function of the modules in the Pack.

[0139] In this embodiment, each heating circuit is designed with a fuse to prevent it from blowing when the heating current is abnormally high, thus achieving protection.

[0140] In some embodiments, this application also provides a local heating method, including the following steps:

[0141] Step S11: Module temperature data acquisition.

[0142] Step S12: The BMU parses the sequence number of each module and the corresponding Tmax, Tmin, and Tavg.

[0143] Among them, Tmax and Tmin are applicable to the heating control of a single module, or to the control of all modules connected in series into a system; Tavg is more often used when there are differences in Avg between different modules, and can realize the control logic of whether the heating function of a local single module is turned on or off.

[0144] In this embodiment of the application, after the battery system is powered on and connected to the communication, the battery temperature data of the CSC / BMU will be sampled and updated every 100ms; as long as the battery pack is working, this temperature value (Tmax, Tmin, Tavg) will change dynamically in real time every 100ms.

[0145] Step S13, temperature threshold determination.

[0146] If the system temperature difference is less than 5°C, the local heating function does not need to be activated; if the system temperature difference is greater than or equal to 5°C, proceed to step S14.

[0147] Step S14: Reverse analyze the module number where the temperature difference is greater than the preset value.

[0148] Step S15: Determine the transistor control branch that needs to activate the heating function based on the module serial number, and start local heating.

[0149] Step S16: Collect the temperature difference of the system / individual module after heating every 5 seconds.

[0150] Step S17, temperature threshold determination.

[0151] Step S18: If the system temperature difference is less than 5°C, stop the local heating function.

[0152] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above steps / processes do not imply a sequential order of execution; the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above embodiments of this application are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0153] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0154] The above are merely embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A heating circuit, characterized in that, The heating circuit is located on the circuit layer of the flexible circuit board of the battery module; The flexible circuit board is located on the lower layer of multiple battery cells in the battery module; the flexible circuit board also includes a sampling circuit layer; The circuit layer containing the heating circuit is separated from the sampling circuit layer by a film layer; The heating circuit includes at least two first heating sub-circuits connected in series, and the at least two first heating sub-circuits correspond one-to-one with at least two of the ba tablets; The first heating sub-circuit is used to heat the corresponding bar slice.

2. The heating circuit according to claim 1, characterized in that, The first heating sub-circuit includes a first switching branch and a first heating branch connected in parallel; When the first switch branch is disconnected, the first heating branch heats the corresponding plate.

3. The heating circuit according to claim 2, characterized in that, The first heating sub-circuit further includes a second heating branch connected in parallel with the first heating branch; the second heating branch is provided with a first switch; wherein, When the first switch branch is open and the first switch is off, the first heating branch is on. When the first switch branch is on and the first switch is on, the second heating branch is on. When the first switch branch is open and the first switch is closed, the first heating branch and the second heating branch are closed.

4. The heating circuit according to claim 1, characterized in that, The heating circuit further includes at least two second heating sub-circuits connected in series; each second heating sub-circuit is connected in series with the first heating sub-circuit; each second heating sub-circuit includes a second switching branch and a third heating branch connected in parallel; at least two second heating sub-circuits correspond one-to-one with at least two of the heat exchange plates; wherein... When the second switch branch is disconnected, the third heating branch is turned on to heat the corresponding plate.

5. The heating circuit according to any one of claims 1 to 4, characterized in that, The heating circuit also includes a second switch; the second switch is connected in series with the first heating sub-circuit.

6. A flexible circuit board for a battery module, characterized in that, The flexible circuit board is located on the lower layer of multiple battery cells in the battery module; The flexible circuit board includes a heating circuit layer and a sampling circuit layer, wherein the heating circuit layer and the sampling circuit layer are separated by a film layer; The heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, and the at least two first heating sub-circuits correspond one-to-one with at least two of the ba tablets; The first heating sub-circuit is used to heat the corresponding bar slice.

7. A battery module, characterized in that, The battery module includes a flexible circuit board and multiple battery cells; the multiple battery cells are connected in series through multiple battery pads; the flexible circuit board is located on the lower layer of the multiple battery pads; the flexible circuit board includes a heating circuit layer and a sampling circuit layer, the heating circuit layer and the sampling circuit layer are separated by a film layer; The heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, and the at least two first heating sub-circuits correspond one-to-one with at least two of the ba tablets; The first heating sub-circuit is used to heat the corresponding bar slice.

8. The battery module according to claim 7, characterized in that, The heating circuit further includes at least two second heating sub-circuits connected in series; the first heating sub-circuit includes a first switch branch and a first heating branch connected in parallel, a second heating branch connected in parallel with the first heating branch, and a first switch on the second heating branch; Each of the second heating sub-circuits includes a second switching branch and a third heating branch connected in parallel.

9. The battery module according to claim 8, characterized in that, The battery module further includes an interface integration unit; the interface integration unit includes a first pin of the sampling circuit layer and a second pin of the heating circuit; the second pin includes a first switch pin of the first switch branch, a second switch pin of the first switch, and a third switch pin of the second switch branch; The interface integration unit is connected to the battery management unit via the first pin and the second pin.

10. The battery module according to claim 9, characterized in that, The interface integration unit further includes the positive pin of the sampling circuit layer, the negative pin of the sampling circuit layer, the positive pin of the heating circuit, and the negative pin of the heating circuit; The positive pin of the heating circuit is connected to the positive pin of the sampling circuit layer and the positive terminal of the battery module, respectively. The negative pin of the heating circuit is connected to the negative pin of the sampling circuit layer and the negative terminal of the battery module, respectively.

11. A battery pack, characterized in that, The battery pack includes multiple battery modules connected in series; each battery module includes a flexible circuit board and multiple battery cells; the multiple battery cells are connected in series through multiple plates; the flexible circuit board is located on the lower layer of the multiple plates; the flexible circuit board includes a heating circuit layer and a sampling circuit layer, the heating circuit layer and the sampling circuit layer being separated by a film layer; The heating circuit of the heating circuit layer includes at least two first heating sub-circuits connected in series, and the at least two first heating sub-circuits correspond one-to-one with at least two of the ba tablets; The first heating sub-circuit is used to heat the corresponding bar slice.

12. The battery pack according to claim 11, characterized in that, The battery pack also includes a third switch; the third switch is connected in series with the heating circuit of each battery module.

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