Battery pack and connection structure detection method and device thereof, BMS (Battery Management System) and electric equipment

Abstract

The invention provides a battery pack and a connection structure detection method and device thereof, a BMS and electric equipment, and the method comprises the steps: obtaining the detection voltage between a structural member and the other end of a battery cell, and the detection current flowing through the battery cell at the moment of the switching state of the battery pack, thereby determining whether the connection structure corresponding to the structural member is abnormal or not; therefore, the impedance change of the connection structure of the battery cells can be determined more directly and accurately, the impedance change caused by the abnormity of the connection structure between the battery cells can be determined more effectively, and the accuracy and effectiveness of detection of the connection structure are improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular to a battery pack, a method and device for detecting its connection structure, a BMS, and an electrical device. Background Art

[0002] With the continuous development of battery technology, the capacity of battery packs is getting larger and larger, which will bring more reasons for battery failure. Among them, the connection problem between different battery cells in the battery pack is the main reason for the overall failure of the battery pack.

[0003] In the prior art, some battery pack suppliers use an impedance detection device to detect the impedance of each battery cell in the battery pack, so as to determine whether the impedance of each battery cell is normal. However, the impedance of the battery cells determined by this detection method cannot directly determine the connection problem between the battery cells, resulting in the connection problem between the battery cells not being detected, and further affecting the safety performance of the battery pack.

[0004] Therefore, how to more effectively detect the impedance of battery cells in a battery pack is a technical problem to be solved in this field. Summary of the Invention

[0005] The present application provides a battery pack, a method and device for detecting its connection structure, a BMS, and an electrical device to more effectively detect the impedance of battery cells in the battery pack.

[0006] In a first aspect of the present application, a method for detecting the connection structure of a battery pack is provided. The battery pack includes at least one battery cell connected in series. At least two structural members are provided at one end of the battery cell, and there is a connection structure between adjacent structural members. The method includes: obtaining a detection voltage between the structural member and the other end of the battery cell, and a detection current flowing through the battery cell at the moment when the battery pack switches states; determining whether the connection structure corresponding to the structural member is abnormal according to the detection voltage and the detection current.

[0007] In a second aspect of the present application, a device for detecting the connection structure of a battery pack is provided. The battery pack includes at least one battery cell connected in series. At least two structural members are provided at one end of the battery cell, and there is a connection structure between adjacent structural members. The device includes: a voltage acquisition module, which is respectively connected to the at least two structural members and to the other end of the battery cell, and is used to obtain a detection voltage between the structural member and the other end of the battery cell; a current acquisition module, which is used to collect a detection current flowing through the battery cell at the moment when the battery pack switches states; a calculation and analysis module, which is used to execute the method for detecting the connection structure of the battery pack provided in the first aspect of the present application.

[0008] In a third aspect of the present application, a BMS is provided, which is used to execute the method described in the first aspect of the present application.

[0009] In a fourth aspect of the present application, a battery pack is provided, including at least one battery cell connected in series. At least two structural members are provided at one end of the battery cell, and there is a connection structure between adjacent structural members; a BMS for performing the method described in the first aspect of the present application.

[0010] In a fifth aspect of the present application, an electrical device is provided, including the battery pack provided in the fourth aspect of the present application.

[0011] The battery pack, the connection structure detection method, device, BMS and electrical device provided by the present application determine whether the connection structure corresponding to the structural member is abnormal by obtaining the detection voltage between the structural member and the other end of the battery cell, and the detection current flowing through the battery cell at the moment when the battery pack switches states. Therefore, it is more direct and accurate to determine the impedance change of the connection structure of the battery cell, and further more effectively determine the impedance change caused by the abnormality of the connection structure between the battery cells, improving the accuracy and effectiveness of detecting the connection structure. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0013] Figure 1 Schematic diagram of an embodiment of a connection structure detection device for a battery pack;

[0014] Figure 2 Schematic diagram of the structure of a battery cell in a battery pack;

[0015] Figure 3 Schematic diagram of the structure of a connection structure detection device for a battery pack provided by the present application;

[0016] Figure 4 Schematic diagram of the structure of a voltage acquisition module provided by the present application;

[0017] Figure 5 Schematic diagram of the flowchart of an embodiment of a connection structure detection method for a battery pack provided by the present application;

[0018] Figure 6 Schematic diagram of another embodiment of a connection structure detection device for a battery pack;

[0019] Figure 7 Schematic diagram of the change of the detection voltage in the simulation experiment;

[0020] Figure 8 is the impedance detection value of the connection area in the simulation experiment;

[0021] Figure 9 is a schematic structural diagram of an electronic device provided by the present application. Specific embodiments

[0022] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0023] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0024] Figure 1 is a schematic diagram of an embodiment of a connection structure detection device for a battery pack. As Figure 1 shown, the battery pack 10 includes at least one battery cell connected in series. In Figure 1 , taking n battery cells 101 as an example, they are respectively denoted as battery cell 101-1, battery cell 101-2... battery cell 101-n. The battery pack 10, the switch circuit 11 and the input / output circuit 12 form a power consumption loop. When the input / output circuit 12 is connected to a load and the switch circuit 11 is turned on, the battery pack 10 supplies power to the load through the input / output circuit 12; when the input / output circuit 12 is connected to a charging device and the switch circuit 11 is turned on, the charging device charges the battery pack 10 through the input / output circuit 12.

[0025] With the continuous development of battery technology, the capacity of the battery pack 10 is getting larger and larger, and the number of battery cells 101 connected in series in the battery pack 10 is also increasing, which will bring more causes of battery failure problems. Among them, the connection problem between different battery cells 101 in the battery pack 10 is the main cause of the overall failure of the battery pack 10.

[0026] Specifically,Figure 2 It is a schematic structural diagram of a battery cell in a battery pack. As Figure 2 shown Figure 1 in the connection method of any battery cell 101 in the battery pack 10 shown. Figure 2 Taking the left side of the battery cell 101 as the positive electrode and the right side as the negative electrode as an example, the following structural components are arranged on the negative electrode on the right side of the battery cell 101, in sequence: tab 102, lead-out sheet 103, and sampling lead-out sheet 104. Among them, there is a connection structure L1 between the tab 102 and the lead-out sheet 103, and there is a connection structure L2 between the lead-out sheet 103 and the sampling lead-out sheet 104. The connection structure can specifically be a welding point. The lead-out sheet 103 is also connected to the lead-out sheet 103 of another battery cell 101 on the right side, that is, the sampling lead-out sheet 104 is simultaneously connected to the lead-out sheets 103 of two battery cells 101. It can be understood that, as Figure 2 shown in the structural components arranged at the negative electrode end of the battery cell 101, the structural components arranged at the positive electrode end of the battery cell 101 are, in sequence, tab 102, lead-out sheet 103, and sampling lead-out sheet 105, and the structure of each battery cell 101 is the same as that Figure 2 shown.

[0027] Combined with Figure 2 the structure of the battery cell 101 shown, it can be seen that there are multiple structural components between different battery cells 101, and there are connection structures such as tabs and lead-out sheets between adjacent structural components. These connection structures pose a risk of high-voltage arcing in the battery due to problems such as tab breakage, lead-out sheet damage, and poor soldering in the connection structure. When there are problems in the connection structure between the battery cells 101, it will first be manifested in the impedance of the battery cell 101. The increase in impedance mainly comes from the abnormal connection structure between the structural components, resulting in an increase in impedance.

[0028] Therefore, some suppliers of the battery pack 10 use a connection structure detection device 20 to detect the impedance of the battery cells 101 in the battery pack 10, so as to determine whether the connection structure between the battery cells is normal according to the change in impedance. For example, combined with Figure 1 the example shown, the connection structure detection device 20 can be used to detect the impedance of the battery cells 101 in the battery pack 10. Among them, combined with Figure 2 the example shown, the voltage acquisition module 201 in the connection structure detection device 20 can be used to collect the voltage between one side of the battery cell 101 and the sampling lead-out sheet 104 through the sampling nickel sheet 105. The connection structure detection device 20 can calculate the impedance of the battery cell 101 based on the collected voltage and the current flowing through the battery cell 101, so as to determine whether the connection structure of the battery cell 101 is abnormal according to the impedance of the battery cell 101.

[0029] However, although this detection method can determine that the impedance of the battery cell 101 has changed, it cannot directly determine that the impedance change is caused by the connection problem between the battery cells 101. Moreover, since there are generally multiple connection structures between the battery cells 101, it is also impossible to specifically determine which connection structure between the battery cells 101 is abnormal and causes the impedance change. Even in some cases where the overall impedance of the battery cell 101 does not change, it is impossible to accurately detect the abnormality of the connection structure, thereby affecting the safety performance of the battery cell 101 and the battery pack 101 where it is located.

[0030] Based on the above technical problems, the present application provides a method and device for detecting the connection structure of a battery pack to more effectively and accurately detect the impedance of the connection structure between the battery cells 101 in the battery pack 10. The technical solution of the present application will be described in detail below with specific embodiments. These specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0031] Figure 3 FIG. is a schematic structural diagram of a connection structure detection device provided by the present application, as Figure 3 shown. The connection structure detection device 20 can be applied to Figure 1 the scenario shown and is used to detect whether the connection structure between the battery cells 101 in the battery pack 10 is abnormal. Specifically, as Figure 3 shown, the connection structure detection device 20 includes a voltage acquisition module 201, a current acquisition module 202, a calculation and analysis module 203, and a low-voltage module.

[0032] Figure 4 FIG. is a schematic structural diagram of the voltage acquisition module provided by the present application. In Figure 4 the example shown, taking at least two structural members provided at the negative electrode end of the battery cell 101 as an example, the at least two structural members are, in sequence: the tab 102, the lead-out piece 103, and the sampling lead-out piece 104. Among them, there is a connection structure L1 between the tab 102 and the lead-out piece 103, and there is a connection structure L2 between the lead-out piece 103 and the sampling lead-out piece 104. The connection structure can specifically be a welding point. As Figure 4 shown, the voltage acquisition module 201 is respectively connected to each of the at least two structural members provided at the negative electrode end of the battery cell 101, and is also connected to the other end of the battery cell 101.

[0033] In one embodiment, the voltage detection module 201 specifically includes at least two sampling structures, and the at least two sampling structures correspond one-to-one to the at least two structural members. Each sampling structure is respectively provided on the corresponding structural member. The sampling structure can specifically be a sampling nickel sheet. For example, in Figure 4In the illustrated example, a sampling nickel sheet 107 is provided on the tab 102, a sampling nickel sheet 106 is provided on the lead-out sheet 103, and a sampling nickel sheet 105 is provided on the sampling lead-out sheet 104.

[0034] The voltage detection module 201 can be used to obtain the detection voltage between each structural member at one end of the battery cell 101 and the other end of the battery cell 101. For example, the voltage detection module 201 can be used to obtain the voltage U between the tab 102 at one end of the battery cell 101 and the other end of the battery cell 101. C1 and the voltage U between the lead-out sheet 103 and the other end of the battery cell 101. C2 and the voltage U between the sampling lead-out sheet 104 and the other end of the battery cell 101. C3 .

[0035] The current acquisition module 202 is used to acquire the detection current ΔI flowing through the battery cell 101 at the moment when the battery pack 10 switches states. Combining Figure 1 the illustrated example, the battery cells included in the battery pack 10 are in a series structure. Therefore, the specific implementation manner of the current acquisition module 202 in the embodiments of the present application is not limited, and the position where the current acquisition module acquires the detection current is not limited, but it is necessary to ensure that the acquired detection current is equal to the current flowing through the battery cell 101.

[0036] More specifically, the moment when the battery pack 10 switches states described in this embodiment includes: at least one of the moment when the battery pack 10 switches from the charging state to the standby state, the moment when the battery pack 10 switches from the discharging state to the standby state, the moment when the battery pack 10 switches from the standby state to the charging state, or the moment when the battery pack 10 switches from the standby state to the discharging state.

[0037] In one embodiment, as Figure 3 shown, the connection structure detection device 20 of the battery pack further includes a power supply module 204, and this power supply module 204 can be used to supply power to the voltage acquisition module 201, the current acquisition module 202, and the calculation and analysis module 203. The power supply module 204 can also be referred to as a low-voltage module, etc.

[0038] Next, in combination with the attached Figure 5 , the specific processing logic of the calculation and analysis module 103 in the connection structure detection device of the battery pack will be described. Among them, Figure 5 This is a schematic flowchart of a method for detecting the connection structure of a battery pack according to an embodiment of the present application. As Figure 5 shown, the method can be applied to Figure 3 the connection structure detection device 20 of the battery pack shown, and is specifically executed by the calculation and analysis module 203. Specifically, as Figure 5 shown, the method for detecting the connection structure of the battery pack includes:

[0039] S101: Obtain the detection voltage between the structural member and the other end of the battery cell, and the detection current flowing through the battery cell at the moment when the battery pack switches states. Among them, after the voltage acquisition module 201 obtains the detection voltage, it sends the obtained detection voltage to the calculation and analysis module 203. After the current acquisition module 202 obtains the detection current, it sends the obtained detection current to the calculation and analysis module 203. Then, the calculation and analysis module 203 can receive the detection voltage and the detection current.

[0040] S102: Determine whether the connection structure corresponding to the structural member is abnormal according to the detection voltage and detection current obtained in S101. Among them, the calculation and analysis module 203 calculates according to the received detection voltage and detection current, and thus determines whether the connection structure corresponding to the structural member is abnormal according to the calculated impedance detection value.

[0041] In a specific implementation manner, the calculation and analysis module 203 specifically determines whether the connection structure corresponding to the structural member is abnormal based on the detection voltage, the detection current, and the initial detection voltage between the structural member and the other end of the battery cell when the battery pack is in a standby state.

[0042] Specifically, the calculation and analysis module 203 specifically calculates the absolute value of the difference between the detection voltage on the structural member side and the initial detection voltage, and calculates the ratio of the absolute value to the detection current to obtain an intermediate impedance detection value. Subsequently, based on the intermediate impedance detection value and the positional relationship between the structural member and the battery cell 101, the impedance detection value of the connection structure corresponding to the structural member is determined, and then whether the connection structure corresponding to the structural member is abnormal is determined according to the impedance detection value.

[0043] Refer to Figure 4 As shown in the battery cell 101, according to the principle of circuit impedance voltage division, when the battery pack 10 is in a standby state and not charging or discharging externally, no current passes through the connection structure on one side of the battery cell 101, and the connection structure at this time is equivalent to a pure resistor. Then, according to the formula U = I * R, it can be seen that no voltage division occurs when there is no current passing through the connection structure at this time. Therefore, the detection voltage U between the sampling lead-out piece 104 collected by the sampling nickel piece 105 and the other end of the battery cell 101 C3 is equal to the voltage across the battery cell 101.

[0044] When the battery pack 10 is in a non-standby state and charging or discharging externally, current passes through the connection structure on one side of the battery cell 101, and voltage division occurs when there is current passing through the connection structure. Therefore, the detection voltage U between the sampling lead-out piece 104 collected by the sampling nickel piece 105 and the other end of the battery cell 101 C3 includes the vector sum of the voltage across the battery cell 101 and the voltage generated by the impedance of the connection structure.

[0045] Meanwhile, since the voltage of the battery cell 101 depends on its own capacity and is relatively stable under non-large current charging and discharging conditions, no sudden change will occur. The connection structure on one side of the battery cell 101 can be equivalently regarded as a simple resistor, and its voltage division will change suddenly with the generation of the current value.

[0046] Based on the above principle, the overall impedance value of all structural components on one side of the battery cell 101 can be calculated by the following formula (1):

[0047] Formula (1)

[0048] Wherein, R is the overall impedance value of all structural components and the connection structure on one side of the battery cell 101, U C is the detected voltage between the sampling lead-out piece 104 and the other end of the battery cell 101 collected by the sampling nickel piece 105 when the battery pack 10 is in a non-idle state, U 0 is the detected voltage between the sampling lead-out piece 104 and the other end of the battery cell 101 collected by the sampling nickel piece 105 when the battery pack 10 is in an idle state, and ΔI is the current value flowing through the battery cell 101 when the battery pack 10 switches states.

[0049] Therefore, after the calculation and analysis module 203 calculates the overall impedance value R of all structural components on one side according to the above formula (1), it can determine whether the overall connection area corresponding to the structural components is abnormal according to the overall impedance value R.

[0050] Furthermore, referring to Figure 4 the structural components and the connection structure on one side of the battery cell 101 shown in the figure, the calculation and analysis module 203 can also perform a detailed calculation of the impedance of each connection structure in the overall connection area according to the detected voltage of each structural component, so as to determine the specific connection structure with an abnormality on one side of the battery cell 101.

[0051] Specifically, the calculation and analysis module 203 calculates the intermediate impedance detection value L corresponding to the tab 102 according to the following formula (2) 1 :

[0052] Formula (2)

[0053] Wherein, U C1 is the detected voltage between the tab 102 and the other end of the battery cell 101 collected by the sampling nickel piece 107 when the battery pack 10 is in a non-idle state, U 0 is the detected voltage between the tab 102 and the other end of the battery cell 101 collected by the sampling nickel piece 107 when the battery pack 10 is in an idle state, and ΔI is the current value flowing through the battery cell 101 when the battery pack 10 switches states.

[0054] And, the intermediate impedance value L corresponding to the lead-out piece 103 is calculated according to the following formula (3) 2 :

[0055] Formula Three

[0056] wherein, U C2 is the detected voltage of the lead-out piece 103 and the other end of the battery cell 101 collected by the sampling nickel piece 106 when the battery pack 10 is in a non-shelf state, and U 0 is the detected voltage of the lead-out piece 103 and the other end of the battery cell 101 collected by the sampling nickel piece 106 when the battery pack 10 is in a shelf state, and ΔI is the current value flowing through the battery cell 101 when the battery pack 10 switches states.

[0057] The intermediate impedance value L corresponding to the sampling lead-out piece 105 is calculated according to the following Formula Four 3 :

[0058] Formula Four

[0059] wherein, U C3 is the detected voltage of the sampling lead-out piece 105 and the other end of the battery cell 101 collected by the sampling nickel piece 105 when the battery pack 10 is in a non-shelf state, and U 0 is the detected voltage of the sampling lead-out piece 105 and the other end of the battery cell 101 collected by the sampling nickel piece 105 when the battery pack 10 is in a shelf state, and ΔI is the current value flowing through the battery cell 101 when the battery pack 10 switches states.

[0060] Subsequently, the calculation and analysis module 203 determines the impedance detection value of the connection structure corresponding to each structural member based on the positional relationship between each structural member and other structural members and the battery cell.

[0061] Among them, the tab 102 is directly connected to the battery cell 101, and there is no other structural member between the tab 102 and the battery cell 101. Therefore, the impedance detection value R corresponding to the tab 102 1 =L 1 .

[0062] There is a tab 102 between the lead-out piece 103 and the battery cell 101. Therefore, the impedance detection value corresponding to the lead-out piece 103 is the difference between the intermediate impedance detection L 2 value and the impedance detection value R 1 of the tab 102, and is expressed by the formula as R 2 =L 2 -R 1 .

[0063] There are a tab 102 and a lead-out piece 103 between the sampling lead-out piece 105 and the battery cell 101. Therefore, the impedance detection value corresponding to the sampling lead-out piece 105 is the intermediate impedance value L 3 and the impedance detection value R 1 of the tab 102, the impedance detection value R2 The difference is represented by the formula as R 3 =L 3 -R 2 -R 1 .

[0064] Finally, the calculation and analysis module 203 can determine whether the connection structure L1 on one side of the battery cell 101 is abnormal based on the impedance detection value R corresponding to the lead-out piece 103, and determine whether the connection structure L2 on one side of the battery cell 101 is abnormal based on the impedance detection value R corresponding to the sampling lead-out piece 105 2 3 .

[0065] In one embodiment, the calculation and analysis module 203 can specifically determine whether the impedance detection value R 2 and the impedance detection value R 3 are greater than a preset value. When the impedance detection value R 2 is greater than the preset value, it is determined that the connection structure L1 is abnormal. When the impedance detection value R 3 is greater than the preset value, it is determined that the connection structure L2 is abnormal. Alternatively, in another embodiment, the calculation and analysis module 203 can also perform numerical analysis. When the calculated value of the impedance detection value R 2 is outlier, it is determined that the connection structure L1 is abnormal. When the impedance detection value R 3 is outlier, it is determined that the connection structure L2 is abnormal

[0066] In summary, in the connection structure detection method of the battery pack provided in this application, by obtaining the detection voltage between the structural member and the other end of the battery cell, and the detection current flowing through the battery cell at the moment when the battery pack switches states, it is determined whether the connection structure corresponding to the structural member is abnormal. This application can more directly and accurately determine the impedance change of the connection structure of the battery cells, and further more effectively determine the impedance change caused by the abnormality of the connection structure between the battery cells. Therefore, the accuracy and effectiveness of detecting the connection structure are improved. Even when there are many connection structures between the battery cells, it is possible to more specifically determine the specific abnormal connection structure. Therefore, the granularity of detecting the connection structure is also improved, ensuring the safe and stable operation of the battery cell and the battery pack where it is located

[0067] In one embodiment, when the calculation and analysis module 203 of the connection detection device 20 of the battery pack is based on as Figure 5 ​When the method shown determines that the connection structure corresponding to the structural member is abnormal, the calculation and analysis module 203 can also send an indication message, which is used to indicate the determined abnormal connection structure, so as to more effectively identify the abnormal connection structure and then give a warning indication in time. For example, the calculation and analysis module 203 can send an indication message to the server of the supplier of the battery pack 10, so that the maintenance personnel of the supplier can detect and repair the battery pack 10 according to the indication message, so as to improve the efficiency of detection and repair, resolve the high-voltage risk in time, reduce the abnormality caused by the abnormal connection structure, improve the overall safety performance of the battery pack 10, and improve the user satisfaction of the battery pack 10, etc.

[0068] Further, in the above embodiment, the present application provides a method for determining whether the connection structure corresponding to the structural member is abnormal based on the detected voltage and the detected current. Referring to the above formulas one to four, different circuit parameters need to be collected in different states, especially at the moment when the battery pack 10 switches states, so as to complete the collection of the detected current ΔI flowing through the battery cell 101.

[0069] Refer to Figure 1 Shown in the circuit structure, the state switching of the battery pack 10 is controlled by the relay 11, and the relay 11 is independent of the connection structure detection device 20 of the battery pack. Therefore, in some cases, the connection structure detection device 20 of the battery pack needs to "passively" obtain the detected current ΔI flowing through the battery cell 101 when the battery pack 10 switches states at the moment when the relay 11 closes or disconnects, and determine whether the connection structure is abnormal based on the method shown in Figure 5 Shown. This method can be called a passive detection scheme, which has the advantage of not requiring additional electronic devices and circuit connections, and can effectively reduce the hardware implementation cost.

[0070] In one embodiment, when the battery pack 10 switches states, the current acquisition module 202 in the connection structure detection device 20 of the battery pack acquires the detected current ΔI flowing through the battery cell 101 at the moment of state switching and sends it to the calculation and analysis module 203. After the circuit is stable, the voltage acquisition module 201 acquires the detected voltage between the structural member and the other end of the battery cell and sends it to the calculation and analysis module 203. The calculation and analysis module 203 determines whether the connection structure is abnormal according to the method shown in Figure 5 Shown.

[0071] Alternatively, in another embodiment, the current acquisition module 202 in the connection structure detection device 20 of the battery pack continuously acquires the detection current at a preset acquisition frequency and sends it to the calculation and analysis module 203, and the voltage acquisition module 201 continuously acquires the detection voltage at a preset acquisition frequency and sends it to the calculation and analysis module 203. Only when the battery pack 10 switches states, will the calculation and analysis module 203, according to the detection current ΔI flowing through the battery cell 101 at the moment of the state switch collected by the current acquisition module 202 currently received, and the detection voltage between the structural member and the other end of the battery cell acquired by the voltage acquisition module 201 after the circuit stabilizes, determine whether the connection structure is abnormal according to the method as Figure 5 shown.

[0072] In addition, the initial detection voltage between the structural member and the other end of the battery cell 101 when the battery pack 10 is in the idle state can be the one collected by the voltage acquisition module 201 before the battery pack 10 switches states and sent to the calculation and analysis module 203.

[0073] Specifically, referring to Figure 3 , during the state switch of the battery pack 10, when the battery pack 10 switches from the non-idle state to the idle state, the power supply module 204 of some connection structure detection devices 20 of the battery pack stops supplying power to other modules, which may cause the calculation and analysis module 203 to be unable to execute the method as Figure 5 shown, so as to determine whether the connection structure is abnormal.

[0074] Therefore, in an embodiment of the present application, when the battery pack 10 switches from the non-idle state to the idle state, the power supply module 204 of the connection structure detection device 20 of the battery pack does not immediately stop supplying power, but continuously supplies power to the voltage acquisition module 201, the current acquisition module 202, and the calculation and analysis module 203, enabling the current acquisition module 202 to acquire the detection current ΔI flowing through the battery cell 101 at the moment of the state switch and send it to the calculation and analysis module 203, and enabling the voltage acquisition module 201 to acquire the detection voltage between the structural member and the other end of the battery cell after the circuit stabilizes and send it to the calculation and analysis module 203. Finally, after the calculation and analysis module 203 determines whether the connection structure is abnormal according to the method as Figure 5 shown, the power supply module 204 stops supplying power to the voltage acquisition module 201, the current acquisition module 202, and the calculation and analysis module 203, thereby improving the completeness of the connection structure detection method provided by the present application and ensuring the effective execution of this detection method.

[0075] In another embodiment of the present application, the connection structure detection device 20 of the battery pack can "actively" obtain the detection voltage and the detection current, and based on the method as Figure 5The method shown determines whether the connection structure is abnormal. This method can be called an active detection scheme, which has the advantages of not affecting the high-voltage circuit of the battery pack 10, strong initiative, not being affected by the charge and discharge of the battery pack 10, and high accuracy of the detection result.

[0076] Specifically, Figure 6 FIG. is a schematic diagram of another embodiment of a connection structure detection device for a battery pack, as Figure 6 shown, the connection structure detection device of the battery pack in Figure 1 Based on the shown embodiment, it further includes a detection circuit 205 and a control module 206. Among them, the detection circuit 205 is connected in parallel on both sides of the battery pack 10, and the control module 206 can be used to control the detection circuit 205 so that the battery pack 10 can also achieve a state change through the detection circuit 205 when the relay 11 is disconnected.

[0077] In one embodiment, the detection circuit 205 can be a discharge circuit. Then, when the control module 206 controls the detection circuit 205 to conduct, a loop is formed between the battery pack 10 and the detection circuit 205, and the battery pack 10 discharges through the detection circuit 205, so that the battery pack 10 switches from the standby state to the discharge state.

[0078] Alternatively, in another embodiment, the detection circuit 205 can also be other battery packs to be detected. Then, when performing sub-module detection on the battery pack, the battery packs of other modules can be connected in parallel with the currently detected battery pack and provide an excitation current to the currently detected battery pack. The positive and negative directions of the excitation current determine whether the battery pack 10 switches from the standby state to the discharge state or from the standby state to the charge state.

[0079] Then, when the control module 206 controls the detection circuit 205 to cause the battery pack 10 to change its state through the detection circuit 205, the calculation and analysis module 203 of the connection structure detection device 20 of the battery pack can execute the method as Figure 5 shown to determine whether the connection structure corresponding to the structural member is abnormal.

[0080] In one embodiment, the control module 206 can be an independent control unit and can control other modules in the connection structure detection device 20 of the battery pack. Alternatively, the control module 206 can also be integrated in the BMS.

[0081] In addition, the present application also provides experimental data to reflect the relationship between the impedance of the connection structure and the impedance detection value to verify the effectiveness of determining whether the connection structure is abnormal based on the impedance detection value.

[0082] Specifically, Figure 7 FIG. is a schematic diagram of the change in the detected voltage in the simulation experiment. Among them, in order to achieve as Figure 7In the simulation experiment shown, a 1Ω resistor is connected in series at the battery cell's tab to replace the abnormal impedance connection structure caused by poor connection. Then, a simulated external power supply is used to apply excitation currents in different directions to the battery cell, with excitation currents of 1A and 2A. The final experimental results are Figure 7 It can be seen that when no current is applied, the detection voltage between the resistor and the other side of the battery cell is the voltage of the battery cell itself, 3V. When a positive current of 1A is applied, the detection voltage is about 4V. When a positive current of 2A is applied, the detection voltage is about 5V. When a negative current of 2A is applied, the detection voltage is about 1V. When a negative current of 1A is applied, the detection voltage is about 2V. The detection voltage is the vector sum of the resistor voltage and the battery cell voltage.

[0083] Then, Figure 7 The detection voltage shown is used to calculate the impedance detection value by the method provided in this application, and the following is obtained: Figure 8 The impedance detection value shown. Specifically, Figure 8 is the impedance detection value of the connection area in the simulation experiment, from Figure 8 In the illustrated embodiment, it can be seen that the calculated impedance detection value is approximately 1Ω, which is consistent with the resistance value added in the simulation experiment.

[0084] at the same time, Figure 8 The impedance detection values ​​when the battery pack 10 is switched from the charging state to the rest state, from the discharging state to the rest state, from the rest state to the discharging state, and from the rest state to the non-discharging state in the simulation experiment are also given. It can be seen that the calculation results under different states also have certain differences. Therefore, the calculation analysis module 203 of the battery pack connection structure detection device 20 can also perform the following according to the best switching state in the simulation experiment. Figure 5 The method shown.

[0085] In the foregoing embodiments of the present application, the connection structure detection method of the battery pack provided in the embodiments of the present application is introduced. In order to realize the functions of the connection structure detection method of the battery pack provided in the embodiments of the present application, the connection structure detection device of the battery pack as the execution subject can be implemented by hardware structure and / or software module, for example, as follows Figure 2 The above functions are implemented in the form of hardware structure, software module, or hardware structure plus software module. Whether a function of the above functions is implemented in the form of hardware structure, software module, or hardware structure plus software module depends on the specific application and design constraints of the technical solution.

[0086] It should be understood that the division of each module of the above device is only a division of logical functions. In actual implementation, it can be fully or partially integrated into a physical entity, or physically separated. And these modules can all be implemented in the form of software called by processing elements; they can also all be implemented in the form of hardware; or some modules can be implemented in the form of software called by processing elements, and some modules can be implemented in the form of hardware. For example, the processing module can be a separately established processing element, or can be integrated in a certain chip of the above device. In addition, it can also be stored in the memory of the above device in the form of program code, and the function of the above determined module can be called and executed by a certain processing element of the above device. The implementation of other modules is similar. In addition, all or part of these modules can be integrated together or can be independently implemented. The processing element mentioned here can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above modules can be completed by the integrated logic circuit in the processor element or the instruction in the form of software.

[0087] For example, the above modules can be one or more integrated circuits configured to implement the above method, such as: one or more application specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs), etc. Again, when a certain module above is implemented in the form of a processing element scheduling program code, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processors that can call program code. Again, these modules can be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0088] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wirelessly (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD)), etc.

[0089] For example, Figure 9 FIG. is a schematic structural diagram of an electronic device provided by the present application. As Figure 9 shown, the device can be used to execute the connection structure detection method provided in any embodiment of the present application. In one embodiment, as Figure 9 shown, the electronic device 1000 includes one or more processors 1001 and a memory 1002. Among them, the memory 1002 is used to store computer-executable instructions, and the processor 1001 can execute the computer-executable instructions stored in the memory 1002. When the computer-executable instructions are executed by the processor 1001, the processor 1001 is caused to implement the connection structure detection method of any battery pack in the foregoing embodiments of the present application.

[0090] In one embodiment, as Figure 9 shown, the electronic device 1000 further includes a communication interface 1003. Among them, the processor 1001 can communicate with other devices through the communication interface 1003. For example, the processor 1001 obtains the detection voltage, detection current, etc. through the communication interface 1003.

[0091] The present application also provides a battery management system (Battery Management System, abbreviated as: BMS), which can be used to execute the connection structure detection method of any battery pack in the foregoing embodiments of the present application. In a specific implementation manner, the BMS can specifically include asFigure 3 The connection structure detection device shown

[0092] This application also provides a battery pack, including at least one series-connected battery cell and a BMS. Among them, the BMS can be used to execute the connection structure detection method of any battery pack in the foregoing embodiments of this application.

[0093] This application also provides an electrical device, including the battery pack provided in the embodiments of this application. The specific implementation of the electrical device in the embodiments of this application is not limited. In a specific implementation manner, the electrical device can specifically be an electric vehicle.

[0094] This application also provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed, they can be used to implement the connection structure detection method of any battery pack in the foregoing embodiments of this application.

[0095] The embodiments of this application also provide a chip for executing instructions. The chip is used to execute the connection structure detection method of any battery pack in the foregoing embodiments of this application.

[0096] The embodiments of this application also provide a computer program product, including a computer program. When the computer program is executed, it implements the connection structure detection method of any battery pack in the foregoing embodiments of this application.

[0097] Those of ordinary skill in the art can understand that all or part of the steps to implement the foregoing method embodiments can be completed by hardware related to program instructions. The foregoing program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps including the foregoing method embodiments; and the foregoing storage medium includes: various media such as ROM, RAM, magnetic disk, or optical disc that can store program codes.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, rather than to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for detecting a connection structure of a battery pack, characterized in that: The battery pack includes at least one battery cell connected in series, one end of the battery cell is provided with at least two structural members, and there are connection structures between adjacent structural members, and the method includes: Acquire a detection voltage between the structural member and the other end of the battery cell, and a detection current flowing through the battery cell at the moment when the battery pack is switched; Whether a connection structure corresponding to the structural component is abnormal is determined according to the detection voltage and the detection current.

2. The method according to claim 1, characterized in that The determining whether the connection structure corresponding to the structural component is abnormal according to the detection voltage and the detection current includes: Whether the connection structure corresponding to the structural member is abnormal is determined according to the detection voltage, the detection current, and an initial detection voltage between the structural member and the other end of the battery cell when the battery pack is in a shelf state.

3. The method according to claim 2, characterized in that The determining whether the connection structure corresponding to the structural member is abnormal according to the detection voltage, the detection current, and the initial detection voltage between the structural member and the other end of the battery cell when the battery pack is in a standby state includes: calculating an absolute value of a difference between a detection voltage of the structural component and the initial detection voltage, and obtaining an intermediate impedance detection value according to a ratio of the absolute value to the detection current; Determine an impedance detection value of a connection structure corresponding to the structural member based on the intermediate impedance detection value and a difference between impedance detection values ​​of the structural member and other structural members between the battery cell; According to the impedance detection value, it is determined whether the connection structure corresponding to the structural component is abnormal.

4. The method according to claim 3, characterized in that The determining, based on the impedance detection value, whether the connection structure corresponding to the structural component is abnormal includes: When the impedance detection value meets a preset condition, it is determined that the connection structure of the structural component on the side of the battery cell is abnormal.

5. The method according to claim 4, characterized in that After determining that the connection structure of the structural component on one side of the battery cell is abnormal, the method further includes: Sending indication information, where the indication information is used to indicate that the connection structure is abnormal.

6. The method according to any one of claims 1 to 5, characterized in that: The obtaining of the detection voltage between the structural member and the other end of the battery cell, and the detection current flowing through the battery cell at the moment of switching the battery pack state, includes: When the battery pack switches states, a detection voltage between the structural member and the other end of the battery cell is obtained, as well as a detection current flowing through the battery cell at the moment of switching states of the battery pack.

7. The method according to any one of claims 1 to 5, characterized in that: The determining the impedance of the connection structure corresponding to the structural component according to the detection voltage and the detection current includes: When the battery pack switches states, it is determined whether the connection structure corresponding to the structural component is abnormal according to the detection voltage and the detection current.

8. The method according to any one of claims 1 to 5, characterized in that: The obtaining of the detection voltage between the structural member and the other end of the battery cell, and the detection current flowing through the battery cell at the moment of switching the battery pack state, includes: When the battery pack switches state through the detection circuit, a detection voltage between the structural member and the other end of the battery cell is obtained, as well as a detection current flowing through the battery cell at the moment of switching state of the battery pack.

9. A battery pack connection structure detection device, characterized in that: The battery pack includes at least one battery cell connected in series, one end of the battery cell is provided with at least two structural members, and there are connection structures between adjacent structural members, and the device includes: A voltage acquisition module, connected to the at least two structural members, and connected to the other end of the battery cell, for acquiring a detection voltage between the structural member and the other end of the battery cell; A current acquisition module, used to acquire the detection current flowing through the battery cell at the moment when the battery pack switches state; A calculation and analysis module, used to execute the battery pack connection structure detection method as described in any one of claims 1-7.

10. The device according to claim 9, characterized in that Also includes: A power supply module is used to supply power to the voltage acquisition module, the current acquisition module and the calculation and analysis module.

11. The device according to claim 10, characterized in that The power supply module is also used for: When the battery pack is switched from a non-shelf state to a shelf state, power is continuously supplied to the voltage acquisition module, the current acquisition module and the calculation and analysis module until the calculation and analysis module determines the impedance of the connection structure corresponding to the structural member, and then power is stopped to the voltage acquisition module, the current acquisition module and the calculation and analysis module.

12. The device according to claim 9 or 10, characterized in that Also includes: A detection circuit connected in parallel on both sides of the battery pack; A control module is connected to the detection circuit and is used to control the detection circuit so that the battery pack switches state through the detection circuit.

13. The device according to claim 12, characterized in that The detection circuit includes other battery packs to be detected.

14. The device according to any one of claims 9 to 13, characterized in that: The voltage acquisition module specifically includes at least two sampling structures, and the at least two sampling structures are respectively arranged on the at least two structural members.

15. The device according to any one of claims 9 to 14, characterized in that: The at least two sampling structures include: a tab, a tab lead-out piece and a sampling lead-out piece in sequence.

16. A BMS, characterized in that: Used to perform the method according to any one of claims 1 to 8.

17. A battery pack, characterized in that: include: At least one battery cell connected in series, one end of the battery cell being provided with at least two structural members, and there being a connection structure between adjacent structural members; A BMS, used for executing the method according to any one of claims 1-8.

18. An electrical equipment, characterized in that: Comprising the battery pack as claimed in claim 17.

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