Parallel battery cell state difference detection device

Abstract

The utility model relates to the technical field of batteries, particularly provides a parallel battery cell state difference detection device, and aims to solve the problem of how to effectively measure the difference between parallel battery cells. In order to achieve the purpose, the parallel battery cell state difference detection device comprises a battery cell box and a control box, the battery cell box is used for placing parallel battery cells, and the control box is used for detecting the state difference of the parallel battery cells. A first interface, a plurality of second interfaces and a plurality of current sensors are arranged in the control box, the first interface is connected with one pole in the same polarity of the parallel battery cells, one end of each second interface is connected with one battery cell, and the other end of each second interface is connected with at least one current sensor in series; the second ends of the plurality of current sensors are connected in series or mutually connected. Through the above arrangement mode, the device can achieve the more accurate detection of the difference of the parallel cells, and is suitable for the cells of different specifications.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly provides a device for detecting the state difference of parallel-connected battery cells. Background Art

[0002] In a battery PACK, multiple battery cells are connected in parallel. The parallel connection is achieved through metal bars or wires for charging, discharging, or static placement. Under parallel connection, the voltages between the battery cells are the same, and the BMS detects this voltage and the total current. Usually, the states between the parallel-connected battery cells are considered to be the same. However, due to the incomplete identity of the properties such as capacity and internal resistance between the battery cells at the time of factory, and after a period of use, differences in the states of the battery cells will also occur. These factors will lead to inconsistent states between the parallel-connected battery cells. How to measure the differences between the parallel-connected battery cells is the problem to be solved by this patent. Summary of the Utility Model

[0003] In order to overcome the above defects, the present utility model is proposed to provide a solution to solve or at least partially solve the problem of how to effectively measure the differences between parallel-connected battery cells.

[0004] The present utility model provides a device for detecting the state difference of parallel-connected battery cells, and the device includes a battery cell box and a control box;

[0005] The battery cell box is used for placing the parallel-connected battery cells, and one pole of the same polarity of the parallel-connected battery cells is connected to the first interface of the control box;

[0006] The control box includes a plurality of second interfaces and a plurality of current sensors. One end of each second interface is respectively used for connecting to the other pole of the same polarity of the parallel-connected battery cells;

[0007] The other end of each second interface is connected to the first end of at least one of the current sensors;

[0008] The second ends of the plurality of current sensors are connected in series and interconnected with each other.

[0009] In a technical solution of the above device for detecting the state difference of parallel-connected battery cells, the first interface is further connected to the second end of the current sensor, and the current sensors are all connected in series with a switch, and the switch is used to control the current sensors to be connected to or cut out from the control box.

[0010] In a technical solution of the above device for detecting the state difference of parallel-connected battery cells, the current sensor includes a fluxgate current sensor and a wire passing through the fluxgate current sensor; one end of the wire is the first end of the current sensor, and the other end of the wire is the second end of the current sensor;

[0011] The second ends of the multiple current sensors are interconnected, and the first end of each current sensor is connected to one of the second interfaces.

[0012] In a technical solution of the above parallel battery cell state difference detection device, there are multiple first interfaces; each first interface is connected to one pole of one of the battery cells; the multiple first interfaces are interconnected within the control box.

[0013] In a technical solution of the above parallel battery cell state difference detection device, the control box further includes a discharge resistor, the first end of the discharge resistor is connected to the first interface, and the second end of the discharge resistor is connected to the second end of the current sensor.

[0014] In a technical solution of the above parallel battery cell state difference detection device, the control box further includes a discharge switch, the first end of the discharge switch is connected to the first interface, and the second end of the discharge switch is connected to the first end of the discharge resistor.

[0015] In a technical solution of the above parallel battery cell state difference detection device, there are multiple discharge resistors and multiple discharge switches, each discharge switch and a discharge resistor form a discharge branch, and the multiple discharge branches are connected in parallel.

[0016] In a technical solution of the above parallel battery cell state difference detection device, the control box further includes a voltmeter, the first end of the voltmeter is connected to the first interface, and the second end of the voltmeter is connected to the second end of the current sensor.

[0017] In a technical solution of the above parallel battery cell state difference detection device, the battery cell box further includes a fan, the fan is arranged at the top of the battery cell box; and / or,

[0018] The battery cell box includes multiple battery cell clamps for fixing the battery cells.

[0019] In a technical solution of the above parallel battery cell state difference detection device, the control box includes a temperature sensor, the temperature sensor is arranged on the surface of the current sensor or within a preset distance range; and / or,

[0020] The control box and the battery cell box adopt a back-to-back design.

[0021] One or more of the above technical solutions of the present utility model have at least one or more of the following beneficial effects:

[0022] In implementing the technical solution of the present utility model, the parallel battery cell state difference detection device of the present utility model includes a battery cell box and a control box. The battery cell box is used to place parallel battery cells, and the control box is used to detect the state differences of the parallel battery cells. One pole of the same polarity of the parallel battery cells is connected to the first interface of the control box. The control box includes a plurality of second interfaces and current sensors. One end of each second interface is respectively used to connect to the other pole of the same polarity of the parallel battery cells, and the other end of each second interface is connected to the first end of at least one current sensor. The second ends of the plurality of current sensors are connected in series or connected to each other. Through the above arrangement, the present utility model can more accurately detect the differences of parallel battery cells and adapt to various different specifications of battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Referring to the accompanying drawings, the disclosure of the present utility model will become more readily understood. It is readily understood by those skilled in the art that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present utility model. In addition, similar numbers in the figures are used to represent similar components, where:

[0024] Figure 1 is a schematic diagram of the main components of a parallel battery cell state difference detection device according to an embodiment of the present utility model.

[0025] Figure 2 is a schematic diagram of the main component circuit of a parallel battery cell state difference detection device according to an embodiment of the present utility model;

[0026] Figure 3 is a schematic diagram of the main component circuit of a parallel battery cell state difference detection device according to another embodiment of the present utility model;

[0027] Figure 4 is a schematic diagram of the main component circuit of a parallel battery cell state difference detection device according to a third embodiment of the present utility model;

[0028] Figure 5 is a schematic diagram of the main component circuit of a parallel battery cell state difference detection device according to a fourth embodiment of the present utility model.

[0029] List of Reference Numerals :

[0030] 1: Battery cell box; 11: Battery cell box door; 12: Battery cell clamp; 13: Battery cell; 2: Control box; 21: Current sensor; 22: Second interface; 23: Switch; 24: Discharge resistor; 25: Discharge switch; 26: Voltmeter; 27: First interface. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Some embodiments of the present utility model will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present utility model and are not intended to limit the protection scope of the present utility model.

[0032] It should be noted that in the description of the present utility model, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0033] In addition, it should also be noted that in the description of the present utility model, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0034] Refer to the attached Figure 1 , Figure 1 is a schematic diagram of the main components of a parallel battery cell state difference detection device according to an embodiment of the present utility model. As Figure 1 shown, in the embodiment of the present utility model, the parallel battery cell state difference detection device may include a battery cell box 1 and a control box 2; the battery cell box 1 is used to place parallel battery cells 13, and one pole of the same polarity of the parallel battery cells 13 is connected to the first interface 27 of the control box 2; the control box 2 includes a plurality of second interfaces 22 and a plurality of current sensors 21, and one end of each second interface 22 is respectively used to connect to the other pole of the same polarity of the parallel battery cells 13; the other end of each second interface 22 is connected to the first end of at least one current sensor 21; the second ends of the plurality of current sensors 21 are connected in series or connected to each other. Through the above setting method, the present utility model can more accurately detect the differences of parallel battery cells and adapt to various different specifications of battery cells 13. By measuring the current between the parallel battery cells 13, the differences between the parallel battery cells 13 can be obtained. For example, when discharging with an external resistor, the internal resistance of the battery cell 13 with a smaller output current is relatively larger.

[0035] In one embodiment, the battery cell box 1 can be replaced and can be replaced with different sizes to adapt to different sizes of battery cells 13.

[0036] In one example, the size of the battery cell box 1 can be 60×40×50 cm.

[0037] In one embodiment, the battery cell box 1 can be made of heat-insulating material to reduce the influence of external temperature changes on the test process.

[0038] In one embodiment, the battery cell box 1 can adopt temperature control, so that the temperature inside the battery cell box 1 can be kept constant, thereby improving the accuracy of the test.

[0039] In one embodiment, the control box 2 can also include a power supply, and the battery cell 13 can be charged through the power supply.

[0040] In one example, the size of the control box 2 can be 60×40×70 cm.

[0041] In one embodiment, a fan is provided on the top of the battery cell box 1, and air flow can be achieved by the rotation of the fan, so as to keep the temperature consistent among the battery cells 13, avoid different temperatures, and thus cause differences in the states of the battery cells 13.

[0042] In one embodiment, the battery cell box 1 can be provided with a battery cell box door 11, and the battery cell box door 11 remains closed during the test.

[0043] In one embodiment, there are multiple battery cell clamps 12 in the battery cell box 1, which are used to place, fix and connect the battery cells 13. Among them, the battery cell clamps 12 can be replaced and can be adapted to different types of battery cells 13, such as aluminum shell battery cells, cylindrical battery cells, soft package battery cells, etc. The battery cell clamps 12 can be placed at a position in the battery cell box 1 far from the box door, so as to shorten the wire length and reduce the resistance.

[0044] In one embodiment, the battery cell clamp 12 can be a four-probe clamp, that is, two voltage wires are added to each battery cell 13, and the voltage can be measured more accurately.

[0045] In one embodiment, the positive electrodes of the battery cells 13 are directly connected together through metal bars or wires, and each negative electrode of the battery cells 13 is respectively connected to a wire to connect to the first interface. Among them, the wire can adopt a low-resistance wire, such as a wire with a cross-sectional area greater than 4 square millimeters. The aforementioned positive electrodes and negative electrodes of the battery cells 13 can be interchanged.

[0046] In one embodiment, the first interface 27 is also connected to the second end of the current sensor 21, and the current sensors 21 are all connected in series with a switch 23, and the switch 23 is used to control the current sensor 21 to be connected to or cut out from the control box 2.

[0047] In one embodiment, the control box 2 can include a discharge resistor 24, the first end of the discharge resistor 24 is connected to the first interface 27, and the second end of the discharge resistor 24 is connected to the current sensor 21. The discharge resistor 24 can discharge the battery cell 13.

[0048] In one embodiment, the control box 2 can also include a discharge switch 25, the first end of the discharge switch 25 is connected to the first interface 27, and the second end of the discharge switch 25 is connected to the first end of the discharge resistor 24.

[0049] In one embodiment, both the discharge resistors 24 and the discharge switches 25 are multiple. Each discharge switch 25 and a discharge resistor 24 form a discharge branch, and multiple discharge branches are connected in parallel.

[0050] Reference can be made to the appendix Figure 2 , Figure 2 which is a schematic diagram of the main circuit components of a parallel battery cell state difference detection device according to an embodiment of the present invention. As Figure 2 shown, in this embodiment, there are two discharge branches, and each discharge branch includes a discharge resistor 24 and a discharge switch 25.

[0051] In one embodiment, as Figure 2 shown, the control box 2 may further include a voltmeter 26. The first end of the voltmeter 26 is connected to the first interface 27, and the second end of the voltmeter 26 is connected to the second end of the current sensor 21. The voltmeter 26 can measure the voltage of the battery cell 13.

[0052] In one embodiment, as Figure 2 shown, the switch 23 can be a low-resistance switch, and the resistance of the switch 23 is less than 5 mΩ. The current sensor 21 can be an ammeter. The ammeter can have two ranges. In one example, the two ranges can include ±10 A and ±0.1 A. The large-range ammeter can measure larger currents, and the small-range ammeter can have higher accuracy. Figure 2 Among them, 5 large-range ammeters respectively measure the currents at positions 1-5, and 5 small-range ammeters respectively measure the currents at positions 6-10.

[0053] In one embodiment, the control box 2 may further include a temperature sensor, which is arranged on the surface of the current sensor 21 or within a preset distance range. The temperature sensor can be one or more, and is used to measure the temperature of the current sensor 21, so as to compensate the current measurement result according to the temperature.

[0054] In one embodiment, the control box 2 may further include a data recorder, which is used to collect the signals of the current sensor 21 and the temperature sensor and record them.

[0055] In one embodiment, the control box 2 may further include a PLC (Programmable Logic Controller) system, which can realize operations such as starting and pausing the test, and can control the switching of the switch 23 in the circuit. The control process can be controlled by time, voltage, and current input signals, or can be manually controlled. Among them, the control system can also be implemented based on a PCB or an FPGA, etc.

[0056] In one embodiment, as Figure 1As shown, a back-to-back design can be adopted between the battery cell box 1 and the control box 2, which can shorten the wiring distance and reduce the circuit resistance. The control wire end is connected to the battery cell wire end as the interface of the control box 2, and the battery cell wire end can be led out from the battery cell box 1.

[0057] In one embodiment, reference can be made to the attached Figure 3 , Figure 3 which is a schematic diagram of the main component circuit of a parallel battery cell state difference detection device according to another embodiment of the present invention. As Figure 3 shown, the current sensor 21 can be arranged on the series branch of the battery cell 13.

[0058] In one embodiment, reference can be made to the attached Figure 4 , Figure 4 which is a schematic diagram of the main component circuit of a parallel battery cell state difference detection device according to the third embodiment of the present invention; as Figure 4 shown, the current sensor 21 can include a fluxgate current sensor and a wire passing through the fluxgate current sensor; one end of the wire is the first end of the current sensor, and the other end of the wire is the second end of the current sensor. The second ends of multiple current sensors are connected to each other, and the first end of each current sensor is connected to the second interface 22. As Figure 4 shown, there can be multiple first interfaces 27; each first interface 27 is connected to one pole of a battery cell 13; multiple first interfaces 27 are interconnected within the control box 2. It is powered by the power supply part, outputs a voltage in proportion to the measured current, the output voltage is collected and recorded, and the switch 23 is controlled based on the output voltage.

[0059] In one embodiment, reference can be made to the attached Figure 5 , Figure 5 which is a schematic diagram of the main component circuit of a parallel battery cell state difference detection device according to the fourth embodiment of the present invention. As Figure 5 shown, the current sensor 21 can include a fluxgate current sensor and a wire passing through the fluxgate current sensor. Figure 4 and Figure 5 the wires in can use thick wires with a cross-sectional area greater than 4 square millimeters, which can minimize the resistance of the parallel circuit. Among them, Figure 4 and Figure 5 the voltage acquisition, recording, and transmission parts in realize the function of a voltmeter.

[0060] Furthermore, it should be understood that since the setting of each module is only for explaining the functional units of the device of the present invention, the physical devices corresponding to these modules can be the processor itself, or a part of the software in the processor, a part of the hardware, or a part of the combination of software and hardware. Therefore, the number of each module in the figure is only illustrative.

[0061] Those skilled in the art can understand that the various modules in the device can be adaptively split or combined. Such splitting or combination of specific modules will not cause the technical solution to deviate from the principle of the present utility model. Therefore, the technical solutions after splitting or combination will all fall within the protection scope of the present utility model.

[0062] So far, the technical solution of the present utility model has been described in conjunction with the preferred embodiments shown in the drawings. However, those skilled in the art can easily understand that the protection scope of the present utility model is obviously not limited to these specific embodiments. Without departing from the principle of the present utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present utility model.

Claims

1. A parallel battery cell state difference detection device, characterized in that: The device comprises a battery box and a control box; The battery box is used to place the parallel battery cells, and one pole of the same polarity of the parallel battery cells is connected to the first interface of the control box; The control box comprises a plurality of second interfaces and a plurality of current sensors, one end of each of the second interfaces being respectively used to connect to the other pole of the same polarity of the parallel-connected battery cells; The other end of each of the second interfaces is connected to the first end of at least one of the current sensors; The second ends of the multiple current sensors are connected in series and to each other.

2. The parallel battery cell state difference detection device according to claim 1, characterized in that: The first interface is also connected to the second end of the current sensor. The current sensor is connected in series with a switch. The switch is used to control the current sensor to be connected to or disconnected from the control box.

3. The parallel battery cell state difference detection device according to claim 1, characterized in that: The current sensor comprises a fluxgate current sensor and a wire passing through the fluxgate current sensor; one end of the wire is a first end of the current sensor, and the other end of the wire is a second end of the current sensor; The second ends of the multiple current sensors are connected to each other, and the first end of each current sensor is connected to one of the second interfaces.

4. The parallel battery cell state difference detection device according to claim 3, characterized in that: There are multiple first interfaces; each of the first interfaces is connected to one pole of a battery cell; and multiple first interfaces are interconnected in the control box.

5. The parallel battery cell state difference detection device according to any one of claims 1 to 4, characterized in that: The control box further includes a discharge resistor, a first end of the discharge resistor is connected to the first interface, and a second end of the discharge resistor is connected to the second end of the current sensor.

6. The parallel battery cell state difference detection device according to claim 5, characterized in that: The control box further includes a discharge switch, a first end of the discharge switch is connected to the first interface, and a second end of the discharge switch is connected to the first end of the discharge resistor.

7. The parallel battery cell state difference detection device according to claim 6, characterized in that: There are multiple discharge resistors and multiple discharge switches, each discharge switch and a discharge resistor form a discharge branch, and the multiple discharge branches are connected in parallel.

8. The parallel battery cell state difference detection device according to any one of claims 1 to 4, characterized in that: The control box further includes a voltmeter, a first end of the voltmeter is connected to the first interface, and a second end of the voltmeter is connected to the second end of the current sensor.

9. The parallel battery cell state difference detection device according to claim 1, characterized in that: The battery box further comprises a fan, and the fan is arranged on the top of the battery box; and / or, The battery cell box includes a plurality of battery cell clamps, and the battery cell clamps are used to fix the battery cells.

10. The parallel battery cell state difference detection device according to claim 1, characterized in that: The control box comprises a temperature sensor, and the temperature sensor is arranged on the surface of the current sensor or within a preset distance range; and / or, The control box and the battery box are designed back to back.

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