Double-cell sampling control circuit, battery management system and energy storage device

Abstract

The utility model provides a double-cell sampling control circuit, a battery management system and an energy storage device. The circuit comprises a voltage sampling sub-circuit and / or an equalization and impedance measurement sub-circuit. After the voltage sampling sub-circuit receives a sampling action signal of the first control pin, a sampling path between the two battery cells or between one battery cell and the sampling pin is switched on; after the equalization and impedance measurement sub-circuit receives a switch selection signal of the second control pin and an equalization action signal of the third control pin, an equalization path of a target battery cell in the two battery cells is switched on; or after the equalization and impedance measurement sub-circuit receives the switch selection signal of the second control pin and the excitation action signal of the fourth control pin, the measurement access of the two battery cells or one of the battery cells is switched on. According to the scheme provided by the utility model, one sampling chip can manage two battery cells, the battery cell sampling cost is reduced, and the function completeness of the battery cell sampling link is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery management, and in particular to a dual-cell sampling control circuit, a battery management system and an energy storage device. Background Art

[0002] At present, in order to monitor the working status of the battery cells in the battery pack, sampling chips are usually used to collect key information such as the battery cell voltage and temperature, thereby providing an effective data basis for battery management.

[0003] In the related art, usually a sampling chip can only realize the sampling function of one battery cell, that is, there is a one-to-one relationship between the battery cell and the sampling chip. The cost of battery cell sampling is high, and the sampling link function is not perfect, which makes it difficult to meet the high-precision battery management needs. Utility Model Content

[0004] The utility model provides a dual-cell sampling control circuit, a battery management system and an energy storage device, which are used to solve the defects of traditional cell sampling solutions, such as high cost and imperfect functions.

[0005] On the one hand, the utility model provides a dual-cell sampling control circuit, which is arranged between two cells and a sampling chip, and the circuit includes: a voltage sampling subcircuit and / or an equalization and impedance measurement subcircuit;

[0006] The voltage sampling subcircuit is connected to the first control pin and the sampling pin of the sampling chip and the two battery cells respectively. After receiving the sampling action signal of the first control pin, the voltage sampling subcircuit connects the sampling path between the two battery cells or one of the battery cells and the sampling pin;

[0007] The balancing and impedance measurement subcircuit is respectively connected to the second control pin, the third control pin, the fourth control pin and the two battery cells of the sampling chip. After receiving the switch selection signal of the second control pin and the balancing action signal of the third control pin, the balancing and impedance measurement subcircuit connects the balancing path of the target battery cell among the two battery cells; or, after receiving the switch selection signal of the second control pin and the excitation action signal of the fourth control pin, the balancing and impedance measurement subcircuit connects the measurement path of the two battery cells or one of the battery cells.

[0008] According to the dual-cell sampling control circuit provided by the utility model, the voltage sampling subcircuit includes: a first switch and an operational amplifier;

[0009] The first switch is connected to the two battery cells, the first control pin and the operational amplifier respectively, and the operational amplifier is connected to the sampling pin.

[0010] According to the dual-cell sampling control circuit provided by the utility model, the equalization and impedance measurement subcircuit includes: a channel selection module, a second switch and a third switch;

[0011] The channel selection module is respectively connected to the two battery cells, the second control pin, the second switch and the third switch, the second switch is connected to the third control pin, and the third switch is connected to the fourth control pin.

[0012] According to the dual-cell sampling control circuit provided by the utility model, the two cells include: a first cell and a second cell;

[0013] The channel selection module includes: a first selection branch and a second selection branch;

[0014] The first selection branch is connected to the positive electrode of the second battery cell, the second selection branch is connected to the positive electrode of the first battery cell, and both the first selection branch and the second selection branch are connected to the second control pin.

[0015] According to the dual-cell sampling control circuit provided by the utility model, the first selection branch includes: a first resistor and a fourth switch;

[0016] The first resistor is connected to the positive electrode of the second battery cell and the fourth switch respectively, and the fourth switch is connected to the second control pin.

[0017] According to the dual-cell sampling control circuit provided by the utility model, the second selection branch includes: a second resistor and a fifth switch;

[0018] The second resistor is connected to the positive electrode of the first battery cell and the fifth switch respectively, and the fifth switch is connected to the second control pin.

[0019] According to the dual-cell sampling control circuit provided by the utility model, the second switch includes: an upper terminal switch and a lower terminal switch;

[0020] The upper terminal switch is connected to the first selection branch and the negative electrode of the second battery cell respectively, and the lower terminal switch is connected to the second selection branch and the negative electrode of the first battery cell respectively.

[0021] According to the dual-cell sampling control circuit provided by the utility model, the circuit further includes: a fuse;

[0022] One end of the fuse is connected to the middle connecting line of the two battery cells, and the other end of the fuse is connected to the balancing and impedance measurement sub-circuit.

[0023] On the other hand, the utility model also provides a battery management system, comprising any one of the dual-cell sampling control circuits described above.

[0024] On the other hand, the utility model also provides an energy storage device, comprising any one of the above-mentioned dual-cell sampling control circuits or the above-mentioned battery management system.

[0025] The dual-cell sampling control circuit, battery management system and energy storage device provided by the utility model can realize the management of two cells by one sampling chip by setting a voltage sampling subcircuit and / or a balancing and impedance measurement subcircuit, and the cell sampling cost is effectively reduced. At the same time, after receiving the sampling action signal of the first control pin, the voltage sampling subcircuit connects the sampling path between the two cells or one of the cells and the sampling pin, thereby realizing the cell voltage sampling function; after receiving the switch selection signal of the second control pin and the balancing action signal of the third control pin, the balancing and impedance measurement subcircuit connects the balancing path of the target cell in the two cells, thereby realizing the balancing function for the target cell; or, after receiving the switch selection signal of the second control pin and the excitation action signal of the fourth control pin, the balancing and impedance measurement subcircuit connects the measurement path of the two cells or one of the cells, thereby realizing the impedance measurement function. Therefore, the solution provided by the utility model can not only realize the management of two battery cells by one sampling chip, but also realize at least part of the functions of battery cell voltage sampling, battery cell balancing and impedance measurement, thereby reducing the battery cell sampling cost and improving the functional completeness of the battery cell sampling link. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the sampling principle of a sampling chip on a battery cell;

[0028] Figure 2 It is a structural schematic diagram of a dual-cell sampling control circuit provided by an embodiment of the utility model;

[0029] Figure 3 This is a schematic diagram of the pin structure of the sampling chip. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] The utility model relates to the field of battery management, and can be specifically applied to the battery cell sampling link. At present, the battery cell sampling function is usually implemented by a sampling chip, and usually one sampling chip is responsible for data collection of one battery cell, such as Figure 1 The diagram shows a sampling process of a sampling chip U1 for a cell CELL. The sampling chip U1 can be connected to both ends of the cell CELL through a peripheral circuit connected to relevant pins on the chip.

[0032] In actual applications, since a battery pack is usually equipped with multiple battery cells, sampling chips also need to be configured one-to-one. The cost of battery cell sampling is high, and the sampling link usually only has basic data sampling functions such as battery cell voltage and temperature. The functions are relatively simple and not perfect.

[0033] Based on this, this embodiment provides a solution to the above technical problem. Figures 2 to 3 The detailed scheme of the dual-cell sampling control circuit, battery management system and energy storage device provided by the embodiments of the utility model is described.

[0034] Figure 2 It is a structural schematic diagram of a dual-cell sampling control circuit provided in an embodiment of the utility model.

[0035] like Figure 2 As shown, the dual-cell sampling control circuit provided by the embodiment of the utility model is arranged between two cells and the sampling chip. The circuit specifically includes: a voltage sampling subcircuit 110 and / or a balancing and impedance measurement subcircuit 120.

[0036] The voltage sampling subcircuit 110 is connected to the first control pin and sampling pin P of the sampling chip and two cells respectively. After receiving the sampling action signal from the first control pin, the voltage sampling subcircuit 110 connects the sampling path between the two cells or one of the cells and the sampling pin P.

[0037] The balancing and impedance measurement sub-circuit 120 is respectively connected to the second control pin, the third control pin, the fourth control pin and the two battery cells of the sampling chip. After receiving the switch selection signal of the second control pin and the balancing action signal of the third control pin, the balancing and impedance measurement sub-circuit 120 connects the balancing path of the target battery cell in the two battery cells; or, after receiving the switch selection signal of the second control pin and the excitation action signal of the fourth control pin, the balancing and impedance measurement sub-circuit 120 connects the measurement path of the two battery cells or one of the battery cells.

[0038] In this embodiment, the voltage sampling subcircuit 110 can realize the cell voltage collection function of the two battery cells or one of the battery cells, and the balancing and impedance measurement subcircuit 120 can realize the balancing function of the target battery cell in the two battery cells, or can realize the impedance measurement function of the two battery cells or one of the battery cells.

[0039] In practical applications, the sampling chip can control the corresponding switching actions in the voltage sampling subcircuit 110 and the equalization and impedance measurement subcircuit 120 through the relevant control pins connected to the voltage sampling subcircuit 110 and the equalization and impedance measurement subcircuit 120, thereby realizing the connection of the sampling path, the equalization path or the measurement path, thereby performing the corresponding sampling function.

[0040] It is not difficult to find that the solution provided in this embodiment can realize the management of two battery cells by one sampling chip, thereby reducing the use of sampling chips and reducing the battery cell sampling cost. At the same time, it can also realize at least part of the functions of voltage acquisition, battery cell balancing, and impedance measurement, and the functions are more complete.

[0041] In one embodiment, see Figure 2 The voltage sampling sub-circuit 110 specifically includes: a first switch K1 and an operational amplifier U;

[0042] The first switch K1 is connected to the two battery cells, the first control pin and the operational amplifier U respectively. The operational amplifier U is connected to the sampling pin P.

[0043] In this embodiment, the first switch K1 can be controlled by a sampling action signal sent by the first control pin. The sampling action signal can control the upper end or the lower end of the first switch K1 to be closed. When the upper end is closed, the sampling pin can collect the total voltage of the two battery cells in series, and then the cell voltage of each of the two battery cells can be converted according to the principle of resistance voltage division. When the lower end is closed, the sampling pin can collect the cell voltage of the first battery cell CELL1.

[0044] It can be understood that in order to ensure the sampling accuracy, the collected cell voltage needs to be amplified by an operational amplifier before being given to the sampling pin P. In addition, considering the accuracy of the voltage divider resistor, the voltage sampling accuracy can be compensated according to the measurement results.

[0045] In one embodiment, see Figure 2 The equalization and impedance measurement sub-circuit 120 specifically includes: a channel selection module 1201, a second switch K5 and a third switch K4.

[0046] The channel selection module 1201 is respectively connected to the two battery cells, the second control pin, the second switch K5 and the third switch K4. The second switch K5 is connected to the third control pin, and the third switch K4 is connected to the fourth control pin.

[0047] In this embodiment, the second switch K5 is mainly used to cooperate with the channel selection module 1201 to achieve balanced control of the battery cells, and the third switch K4 is mainly used to cooperate with the channel selection module 1201 to achieve impedance measurement of the battery cells.

[0048] In one embodiment, see Figure 2 The two battery cells specifically include: a first battery cell CELL1 and a second battery cell CELL2.

[0049] The channel selection module 1201 specifically includes: a first selection branch and a second selection branch.

[0050] The first selection branch is connected to the positive electrode of the second battery cell CELL2, the second selection branch is connected to the positive electrode of the first battery cell CELL1, and both the first selection branch and the second selection branch are connected to the second control pin.

[0051] In one embodiment, see Figure 2 The first selection branch specifically includes: a first resistor R1 and a fourth switch K2.

[0052] The first resistor R1 is connected to the positive electrode of the second battery cell CELL2 and the fourth switch K2 respectively, and the fourth switch K2 is connected to the second control pin.

[0053] In one embodiment, see Figure 2 The second selection branch specifically includes: a second resistor R2 and a fifth switch K3.

[0054] The second resistor R2 is connected to the positive electrode of the first battery cell CELL1 and the fifth switch K3 respectively, and the fifth switch K3 is connected to the second control pin.

[0055] In one embodiment, see Figure 2 , the second switch K5 specifically includes: an upper terminal switch and a lower terminal switch;

[0056] The upper terminal switch is connected to the first selection branch and the negative electrode of the second battery cell CELL2 respectively, and the lower terminal switch is connected to the second selection branch and the negative electrode of the first battery cell CELL1 respectively.

[0057] In this embodiment, when realizing the cell balancing function, the first resistor R1 and the second resistor R2 in the channel selection module 1201 are two balancing resistors. In practical applications, the resistance values ​​and rated powers of the two balancing resistors can be determined according to the internal resistance of the cell. For example, the resistance values ​​of the two balancing resistors can be set to 5 ohms according to the internal resistance of the cell, the rated power of the first resistor R1 is not less than 11W, and the rated power of the second resistor R2 is not less than 2.7W.

[0058] When realizing the battery cell balancing function, the fourth switch K2 or the fifth switch K3 can be controlled to be closed according to the switch selection signal of the second control pin, and the upper terminal switch or the lower terminal switch of the second switch K5 can be controlled to be closed according to the balancing action signal of the third control pin, thereby connecting the balancing path of the target battery cell in the two battery cells.

[0059] Specifically, when the upper terminal switch of the second switch K5 is closed and the fourth switch K2 is closed, the second battery cell CELL2 starts to balance, and the balance current is V2 / R1×50%; when the lower terminal switch of the second switch K5 is closed and the fifth switch K3 is closed, the first battery cell CELL1 starts to balance, and the balance current is V1 / R2×50%.

[0060] Wherein, V1 is the cell voltage of the first cell CELL1 , V2 is the cell voltage of the second cell CELL2 , and 50% is the duty cycle of the effective signal in the balancing action signal.

[0061] It should be noted that the fourth switch K2 and the fifth switch K3 are controlled by the second control pin GPIO2 of the sampling chip. As selection switches for selecting the equalization channels, only one of the equalization channels can be turned on at a time, and two equalization channels cannot be turned on at the same time.

[0062] The second switch K5 is a balancing control switch, which is controlled by a balancing action signal with a 4MHZ clock and a duty cycle of about 50% output by the third control pin MISO of the sampling chip. The termination of balancing requires the management of the battery management system. For example, when the voltage difference is less than 50mV, the battery management system sends a control instruction to the sampling chip, and the sampling chip controls the second switch K5 to turn off, thereby achieving the termination of balancing.

[0063] In this embodiment, when the impedance measurement function is realized, the third switch K4 can cooperate with at least part of the selection branch in the channel selection module 1201 to realize the impedance measurement function of two battery cells or one battery cell. The third switch K4 can be controlled by the excitation action signal sent by the fourth control pin VSW of the acquisition chip. In practical applications, the excitation source is introduced by the fourth control pin VSW. When the impedance of two battery cells is measured at the same time, the fourth switch K2 and the third switch K4 are closed, and the excitation is applied to the two battery cells at the same time.

[0064] Since the impedance measurement function and the cell balancing function share the channel selection module 1201 , the impedance measurement function and the cell balancing function cannot be turned on at the same time.

[0065] In order to synchronously perform impedance measurement on two battery cells in this embodiment, the two battery cells need to be stimulated at the same time, so that the power consumption will be relatively large. At this time, the impedance test mean current is I=(V1+V2) / 2R1; wherein I is the impedance test mean current, V1 is the battery cell voltage of the first battery cell CELL1, V2 is the battery cell voltage of the second battery cell CELL2, and R1 is the resistance value of the first resistor.

[0066] In practical applications, the impedance of the first cell CELL1 may be measured alone without measuring the impedance of the second cell CELL2, thereby reducing the test power consumption. At this time, the impedance test mean current size I=V1 / 2R2, where R2 is the resistance value of the second resistor.

[0067] When the impedance of the first battery cell CELL1 is measured alone, the fifth switch K3 and the third switch K4 need to be controlled to be closed, and at the same time, the upper end and the lower end of the second switch K5 are selected to be closed alternately.

[0068] In one embodiment, see Figure 2 The above-mentioned dual-cell sampling control circuit may further include: a fuse F.

[0069] One end of the fuse F is connected to the middle connection line of the two battery cells, and the other end of the fuse F is connected to the balancing and impedance measurement sub-circuit 120 .

[0070] It can be understood that if the two battery cells are blade cells, for the blade cells with poles at both ends, the aluminum bar connected in the middle is on the opposite side. In order to simplify the design and reduce costs, it is chosen to transmit the midpoint voltage signal from the battery cell shell to the chip placement side. In order to prevent the battery cell shell from short-circuiting due to being charged when the insulation fails, the present embodiment adds a fuse shell with a fuse F. The electrical signal can only carry a small current. When a short circuit occurs between the shells, fuse protection can be performed to protect the working safety of the battery cell.

[0071] It should be noted that the pin structure of the sampling chip in this embodiment can be found in Figure 3, combined with Figure 3 The functions of each pin in the sampling chip can be seen in Table 1 below:

[0072] Table 1 Sampling chip pin function description

[0073]

[0074]

[0075] It should be noted that the above-mentioned control pins can be reasonably set according to control requirements. In this embodiment, the first control pin is GPIO1 pin, the second control pin is GPIO2 pin, the third control pin is MISO pin, the fourth control pin is VSW pin, and the sampling pins are VCHm pin and VCHg pin.

[0076] In summary, the dual-cell sampling control circuit provided in this embodiment has at least the following advantages compared with the traditional sampling scheme:

[0077] The cell sampling function is more comprehensive, which improves the safety of the battery pack, reduces the sampling cost, and makes the promotion and application of the chip collection solution simpler. In addition, since the number of sampling chips used is halved, the probability of sampling chip failure is reduced by 50%, and the reliability of the entire battery management system is effectively improved.

[0078] In addition, an embodiment of the utility model further provides a battery management system, including the dual-cell sampling control circuit provided by the above embodiments.

[0079] In addition, an embodiment of the utility model further provides an energy storage device, including the dual-cell sampling control circuit provided in the above embodiments or the above battery management system.

[0080] It is understandable that the energy storage device may be a vehicle, a working machine, etc.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A dual-cell sampling control circuit, characterized in that: It is arranged between two battery cells and the sampling chip, and the circuit includes: a voltage sampling subcircuit and / or an equalization and impedance measurement subcircuit; The voltage sampling subcircuit is connected to the first control pin and the sampling pin of the sampling chip and the two battery cells respectively. After receiving the sampling action signal of the first control pin, the voltage sampling subcircuit connects the sampling path between the two battery cells or one of the battery cells and the sampling pin; The balancing and impedance measurement subcircuit is respectively connected to the second control pin, the third control pin, the fourth control pin and the two battery cells of the sampling chip. After receiving the switch selection signal of the second control pin and the balancing action signal of the third control pin, the balancing and impedance measurement subcircuit connects the balancing path of the target battery cell among the two battery cells; or, after receiving the switch selection signal of the second control pin and the excitation action signal of the fourth control pin, the balancing and impedance measurement subcircuit connects the measurement path of the two battery cells or one of the battery cells.

2. The dual-cell sampling control circuit according to claim 1, characterized in that: The voltage sampling subcircuit includes: a first switch and an operational amplifier; The first switch is connected to the two battery cells, the first control pin and the operational amplifier respectively, and the operational amplifier is connected to the sampling pin.

3. The dual-cell sampling control circuit according to claim 1, characterized in that: The equalization and impedance measurement subcircuit includes: a channel selection module, a second switch and a third switch; The channel selection module is respectively connected to the two battery cells, the second control pin, the second switch and the third switch, the second switch is connected to the third control pin, and the third switch is connected to the fourth control pin.

4. The dual-cell sampling control circuit according to claim 3, characterized in that: The two battery cells include: a first battery cell and a second battery cell; The channel selection module includes: a first selection branch and a second selection branch; The first selection branch is connected to the positive electrode of the second battery cell, the second selection branch is connected to the positive electrode of the first battery cell, and both the first selection branch and the second selection branch are connected to the second control pin.

5. The dual-cell sampling control circuit according to claim 4, characterized in that: The first selection branch includes: a first resistor and a fourth switch; The first resistor is connected to the positive electrode of the second battery cell and the fourth switch respectively, and the fourth switch is connected to the second control pin.

6. The dual-cell sampling control circuit according to claim 4, characterized in that: The second selection branch includes: a second resistor and a fifth switch; The second resistor is connected to the positive electrode of the first battery cell and the fifth switch respectively, and the fifth switch is connected to the second control pin.

7. The dual-cell sampling control circuit according to claim 4, characterized in that: The second switch includes: an upper terminal switch and a lower terminal switch; The upper terminal switch is connected to the first selection branch and the negative electrode of the second battery cell respectively, and the lower terminal switch is connected to the second selection branch and the negative electrode of the first battery cell respectively.

8. The dual-cell sampling control circuit according to any one of claims 1 to 7, characterized in that: The circuit further comprises: a fuse; One end of the fuse is connected to the middle connecting line of the two battery cells, and the other end of the fuse is connected to the balancing and impedance measurement sub-circuit.

9. A battery management system, characterized in that: Comprising the dual-cell sampling control circuit as described in any one of claims 1 to 8.

10. An energy storage device, characterized in that: It comprises the dual-cell sampling control circuit as claimed in any one of claims 1 to 8 or the battery management system as claimed in claim 9.

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