Battery grouping device

Abstract

The invention relates to the storage battery charging and discharging control technology, and discloses a battery grouping device which comprises a long-string battery pack, a short-string battery pack and a multi-choice switch, the multi-choice switch comprises a plurality of static contacts and a plurality of moving contacts, the static contacts are sequentially connected with nodes of the long-string battery pack, the moving contacts are sequentially connected with nodes of the short-string battery pack, and the static contacts are connected with the nodes of the short-string battery pack. Through relative movement of the moving contact and the static contact, parallel connection of each battery in the short-string battery pack and different batteries in the long-string battery pack is realized so as to realize natural equalization. Balanced management can be realized with low loss.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to battery charging and discharging control technology. Background Art

[0002] At present, with the development of electric vehicles, the management of power batteries has become increasingly prominent. Power batteries are generally composed of multiple batteries, and the series-parallel combination can achieve different output voltage and capacity requirements. However, during use, different batteries are prone to inconsistent power due to differences in manufacturing processes and usage environments. The voltage regulation of the battery pack and the balanced charging and discharging of each single cell have become the key technologies for power battery management.

[0003] To address this problem, traditional technologies usually use the following two methods: (1) energy-consuming passive balancing through resistor heating or special DC-DC circuits, but this reduces system efficiency; (2) setting up complex balancing circuits for active balancing, but this is costly and the balancing circuit itself consumes energy.

[0004] Therefore, designing a battery pack charging and discharging system that can flexibly achieve voltage regulation and achieve balanced management with low loss is a current technical challenge. Summary of the invention

[0005] The purpose of the present application is to provide a battery grouping device to solve the problems raised in the above background technology.

[0006] The present application discloses a battery grouping device, characterized in that it comprises:

[0007] A long battery string, comprising N first batteries connected in series, a positive electrode of the first first battery, a connection between the negative electrode of each first battery and the positive electrode of the next first battery, and a negative electrode of the last first battery, which sequentially form N+1 nodes;

[0008] A short string battery pack, comprising M second batteries connected in series, the positive electrode of the first second battery, the connection between the negative electrode of each second battery and the positive electrode of the next second battery, and the negative electrode of the last second battery, sequentially forming M+1 nodes, N>M>1;

[0009] A multiple-select switch, comprising a static contact group and a moving contact group, wherein the static contact group comprises N+1 static contacts with equal spacing, and the moving contact group comprises M+1 moving contacts with equal spacing, wherein the N+1 nodes of the long string battery group are electrically connected to the N+1 static contacts in sequence, and the M+1 nodes of the short string battery group are electrically connected to the M+1 static contacts in sequence, and the spacing between adjacent static contacts is equal to the spacing between adjacent moving contacts;

[0010] There are multiple connection positions in the multiple-selection switch. When the moving contact group moves to any of the connection positions, the M+1 moving contacts in the moving contact group are electrically connected to the continuous M+1 static contacts in the static contact group, so that the M second batteries in the short string battery group are connected in parallel with the continuous M first batteries in the long string battery group to achieve balance between the corresponding first batteries and the second batteries; when the moving contact group moves from one connection position to another connection position, the second batteries in the short string battery group can be connected in parallel with different first batteries in the long string battery group.

[0011] In a preferred embodiment, it also includes:

[0012] A total positive switch, used for selectively connecting the positive terminal of the long string battery group or the short string battery group to the positive output terminal of the device;

[0013] The total negative switch is used to selectively connect the negative terminal of the long string battery group or the short string battery group to the negative output terminal of the device.

[0014] In a preferred embodiment, in the static contact group, two extension directions at both ends of the N+1 static contacts arranged in a straight line further include M-1 suspended static contacts respectively;

[0015] The moving contact group slides between a total of N+2M-1 static contacts, so that any second battery in the short string battery group has the opportunity to be connected in parallel with any first battery in the long string battery group.

[0016] In a preferred example, the charging balance, discharging balance and voltage regulation of the battery are achieved by switching the multiple-selection switch, the total negative switch and the total positive switch.

[0017] In a preferred embodiment, the main positive switch connects the positive terminal of the long string battery pack to the positive output terminal of the device.

[0018] The total negative switch connects the negative terminal of the short string battery group to the negative output terminal of the device,

[0019] By adjusting the position of the moving contact group relative to the stationary contact group, the number of connections between the moving contacts in the moving contact group and the suspended stationary contacts in the stationary contact group changes, thereby adjusting the output voltage between the positive output terminal and the negative output terminal.

[0020] In a preferred embodiment, the main positive switch connects the positive terminal of the long string battery pack to the positive output terminal of the device.

[0021] The total negative switch connects the negative terminal of the short string battery group to the negative output terminal of the device,

[0022] The moving contact group is moved to the endmost connection position so that the negative electrode of the long string battery group is connected to the positive electrode of the short string battery group, thereby outputting a maximum voltage that can be provided between the positive output terminal and the negative output terminal.

[0023] In a preferred embodiment, the main positive switch connects the positive terminal of the long string battery pack to the positive output terminal of the device.

[0024] The main negative switch connects the negative terminal of the long string battery group to the negative output terminal of the device,

[0025] The moving contact group reciprocates within the range of the stationary contact group. Each time the moving contact group moves to a connection position, it stays for a predetermined time to achieve a balance between the corresponding first battery and the second battery, and then moves to the next connection position.

[0026] In a preferred embodiment, the main positive switch connects the positive terminal of the short string battery group to the positive output terminal of the device.

[0027] The total negative switch connects the negative terminal of the short string battery group to the negative output terminal of the device,

[0028] The moving contact group reciprocates within the range of the stationary contact group. Each time the moving contact group moves to a connection position, it stays for a predetermined period of time and then moves to the next connection position, thereby increasing the discharge time between the positive output terminal and the negative output terminal at the output voltage of the short string battery group.

[0029] In a preferred example, the rated capacity of a single battery cell in the long string battery pack is greater than the rated capacity of a single battery cell in the short string battery pack.

[0030] The present application also discloses an electric vehicle, characterized in that the battery group device described above is used as a power source.

[0031] In the embodiment of the present application, the moving contact group in the multi-select switch is electrically connected to the static contact group at different connection positions, so that each second battery in the short string battery group is connected in parallel with a different first battery in the long string battery group, and the first battery and the second battery are balanced by parallel connection for a certain period of time, and finally

[0032] The second battery in the short string battery group is connected in parallel with some of the first batteries in the long string battery group through a multiple-selection switch. The first battery and the second battery are balanced by parallel connection for a certain period of time. By moving the moving contact group between multiple connection positions in the multiple-selection switch, each second battery in the short string battery group is connected in parallel with different first batteries in the long string battery group, so that each first battery in the long string battery group is balanced. Because multiple batteries in two strings of batteries are connected in parallel, there are fewer contacts in the middle, the resistance is small, and the entire multiple-selection switch consumes very little electric energy. Because the number of second batteries in the short string of batteries is small, the relative voltage on the contacts does not meet the conditions for generating electric sparks, which reduces energy consumption and ensures safety.

[0033] Different voltages can be output through different connection methods of the total positive switch and the total negative switch, as well as different positions of the multi-select switch, and the output voltage can be adjusted within a certain range.

[0034] In general, the present application realizes the autonomous charging, discharging and voltage regulation function of the battery pack, and the output voltage has a wide variable range to adapt to different load requirements. The natural balancing effect between the series-connected battery packs is used to achieve lossless balanced charging and discharging. The rotation control strategy is adopted to balance all the batteries in the battery pack and improve the battery utilization rate. The ampere-second meter feedback and precise control are applied to improve the intelligent level of battery management. The overcharging and over-discharging of the single battery is avoided, and the service life of the battery is extended. The system does not require an additional balancing circuit, which simplifies the circuit structure and reduces the manufacturing cost. The scalability is good, and battery strings can be added as needed to change the voltage regulation range. The control strategy can be designed according to the number of battery packs to achieve personalized battery management. It is highly compatible with the existing battery management system. It can be widely used in electric vehicles and other occasions that require frequent speed and voltage regulation.

[0035] A large number of technical features are recorded in the specification of this application, which are distributed in various technical solutions. If all possible combinations of technical features of this application (i.e., technical solutions) are to be listed, the specification will be too long. In order to avoid this problem, the various technical features disclosed in the above-mentioned invention content of this application, the various technical features disclosed in the various embodiments and examples below, and the various technical features disclosed in the accompanying drawings can be freely combined with each other to form various new technical solutions (these technical solutions are all deemed to have been recorded in this specification), unless the combination of such technical features is technically infeasible. For example, in one example, feature A+B+C is disclosed, and in another example, feature A+B+D+E is disclosed, and features C and D are equivalent technical means that play the same role. Technically, only one can be used, and it is impossible to use them at the same time. Feature E can be combined with feature C technically. Then, the solution of A+B+C+D should not be deemed to have been recorded because it is technically infeasible, and the solution of A+B+C+E should be deemed to have been recorded. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic structural diagram of a battery grouping device according to a first embodiment of the present application;

[0037] Figure 2 is a schematic diagram of the working state of the battery grouping device according to the first embodiment of the present application;

[0038] Figure 3 It is a schematic diagram of battery parallel equalization analysis;

[0039] Figure 4 is a flow chart of charge equalization of a battery grouping device according to the first embodiment of the present application;

[0040] Figure 5 It is a discharge analysis diagram of the battery assembly device according to the first embodiment of the present application. DETAILED DESCRIPTION

[0041] In the following description, many technical details are provided to help readers better understand the present application. However, those skilled in the art can understand that the technical solution claimed in the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0042] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0043] The first embodiment of the present application relates to a battery assembly device, the structure of which is as follows: Figure 1 As shown, the battery grouping device includes: a long string battery group 10, a short string battery group 20, a multiple selection switch 30, a total negative switch 40, a total positive switch 50 and a control unit 60.

[0044] The long string battery pack 10 is composed of N battery cells connected in series, and the short string battery pack 20 is composed of M battery cells connected in series. Among them, M is less than N. The multiple-selection switch 30 includes N+2M+1 static contacts and M+1 moving contacts. The static contacts are sequentially connected to the nodes of the long string battery pack 10, and the moving contacts are sequentially connected to the nodes of the short string battery pack 20. The total negative switch 40 is used to selectively connect the negative terminal of the long string battery pack 10 or the short string battery pack 20 to the negative output terminal of the device. The total positive switch 50 is used to selectively connect the positive terminal of the long string battery pack 10 or the short string battery pack 20 to the positive output terminal of the device. Among the N+2M+1 static contacts, N+1 static contacts are electrically connected to the N battery cells in the long string battery pack 10, see Figure 1 SC0 to SC N , these N+1 static contacts that are actually connected are flanked by 2M suspended static contacts, M on each side, i.e. Figure 1 SC -1 To SC -M , SC N+1 To SC N+M .

[0045] The control unit 60 controls the charging balance, discharging balance and voltage regulation of the device by controlling the switching of the multiple-selection switch 30, the total negative switch 40 and the total positive switch 50. Specifically, the control unit 60 can adopt a rotation control method to regularly change the position of the multiple-selection switch 30 so that all batteries in the long-short string battery group 20 can achieve balanced charging and discharging.

[0046] Optionally, in another embodiment, the number of suspended static contacts in the multi-select switch 30 may not be 2M, and the number of suspended static contacts on each side may be any integer in the range of 0 to M-1, and the number of suspended static contacts on both sides may not be equal, so as to achieve the balance of the batteries in the long string battery pack 10. For example, the multi-select switch 30 may have only N+1 static contacts electrically connected to the N batteries in the long string battery pack 10, and no suspended static contacts. For another example, the multi-select switch 30 may have a total of N+2M-1 static contacts, of which there are M-1 suspended static contacts on each side.

[0047] To achieve accurate battery management, such as Figure 2 As shown, the device may also include an ampere-second meter 7. The output end of the ampere-second meter 7 is connected to the input end of the control unit 60. The ampere-second meter 7 detects the output current of the entire device, and the control unit 60 can calculate the remaining capacity of each battery pack according to the detected current, and control the action of the multiple-selection switch 30 accordingly, so as to monitor the battery status and perform equalization management.

[0048] The control unit 60 is used to control the switching of the multiple-selection switch 30, the total negative switch 40 and the total positive switch 50 to achieve balanced charging, balanced discharging and voltage regulation of the battery. Optionally, the control unit 60 adopts a rotation control method to regularly change the position of the multiple-selection switch 30 to achieve balanced charging and discharging of all batteries in the long string battery group 10 and the short string battery group 20.

[0049] The control unit 60 can calculate the remaining capacity of each battery pack according to the current value transmitted by the ampere-second meter. The control unit 60 can determine whether it is necessary to start the balancing function by comparing the difference in the remaining capacity of each battery pack. The control unit 60 can monitor the voltage of each battery pack to determine the charging and discharging state reached. The control unit 60 can determine the switching of the multi-select switch 30 according to the required power to achieve the adjustment of different output voltage gears.

[0050] Optionally, the rated capacity of a single battery in the long string battery group 10 is greater than the rated capacity of a single battery in the short string battery group 20. For example, the rated capacity of a single battery in the short string battery group 20 may be about half of the rated capacity of a single battery in the long string battery group 10.

[0051] Optionally, the batteries in the long string battery group 10 and the short string battery group 20 are various rechargeable batteries such as sodium ion batteries, lithium ion batteries, solid-state batteries, etc.

[0052] Optionally, in one embodiment, the ampere-second meter and the control unit 60 cooperate as follows:

[0053] Connection relationship: The output end of the ampere-second meter is connected to the input end of the control unit 60 to transmit the detected current information.

[0054] Working mode: The ampere-second meter detects the current flowing through the long and short string battery pack 20 in real time, and converts the current value into an output voltage or a digital quantity and outputs it to the control unit 60.

[0055] Working principle of the control unit 60: After receiving the output signal of the ampere-second meter, the control unit 60 performs the following calculations and controls:

[0056] (1) Calculate the remaining capacity of each battery pack based on the current;

[0057] (2) Compare the difference in remaining power of each battery pack;

[0058] (3) If the difference exceeds a preset threshold, the equalization function is activated to reduce the difference in the remaining power of each battery by controlling the position of the multiple-selection switch 30;

[0059] (4) Monitor the voltage of each battery pack, determine the charge and discharge status reached, and decide whether to switch the working mode;

[0060] (5) According to the power demand, the multiple-selection switch 30 is controlled to switch different output voltage gears.

[0061] Working together: The ampere-second meter continuously measures the current and provides accurate feedback to the control unit 60; the control unit 60 continuously adjusts the system based on the feedback to achieve accurate control of the entire device. The cooperation between the two realizes efficient battery management, balancing and voltage regulation functions.

[0062] Several working modes of the battery grouping device of the present application are described in detail below.

[0063] Charge balancing working mode:

[0064] In the charging balance mode, the total negative switch 40 connects to the negative pole of the long string battery group 10, and the total positive switch 50 connects to the positive pole of the long string battery group 10. At this time, the charging current is input to the input end of the device, that is, the long string battery group 10 is charged. At the same time, the control unit 60 realizes the parallel connection of the batteries in the short string battery group 20 with the different batteries in the long string battery group 10 in turn by controlling the different positions of the multi-selection switch 30. Relying on the natural balance effect during the charging process, all batteries in the long and short string battery groups 20 are charged evenly.

[0065] Specifically, when the device enters the charging balancing mode, the control unit 60 first controls the total negative switch 40 to connect the negative pole of the long string battery group 10, and controls the total positive switch 50 to connect the positive pole of the long string battery group 10. At this time, a positive charging current is input from the input end of the device, and the current flows through the long string battery group 10 for charging. At the same time, the control unit 60 begins to change the connection position of the multi-select switch 30 cyclically at a set time interval, that is, different alignments. Assuming that the short string battery group 20 has M batteries, and the multi-select switch 30 has M+1 moving contacts, each time the alignment is changed, a short string battery will be connected in parallel with different batteries in the long string battery group 10. After multiple cycles, all batteries in the short string battery group 20 have the opportunity to be connected in parallel with each battery in the long string battery group 10. Due to the natural balancing effect when the batteries are connected in series, the battery with a smaller capacity will be pulled by the battery with a larger capacity. When charged under the parallel condition, its power will be replenished until the power is consistent. Therefore, through the rotation control, balanced charging of all batteries in the long and short string battery groups 10 and 20 can be finally achieved.

[0066] This method avoids adding a complex equalization circuit, and the effect of equalization charging can be achieved only by arranging and combining the multiple-selection switches 30. The system is simple and reliable.

[0067] Discharge balance working mode:

[0068] In the discharge balance mode, the connection method is the same as the charging mode. The device outputs current from the long string battery group 10, and the short string battery group 20 is sequentially connected in parallel with different batteries in the long string battery group 10 to achieve balanced discharge.

[0069] Specifically, when the device enters the discharge balance mode, the control unit 60 still controls the total negative switch 40 to connect the negative pole of the long string battery group 10, and controls the total positive switch 50 to connect the positive pole of the long string battery group 10. The difference is that at this time, the device outputs current to the load, and the long string battery group 10 serves as the main power supply group. As in the charging mode, the control unit 60 changes the connection position of the multi-selection switch 30 in turn, so that the batteries in the short string battery group 20 are connected in parallel with different batteries in the long string battery group 10 in turn. During the discharge process, there is also a natural balance effect between the batteries, and the batteries with more power will provide current to the batteries with less power. After multiple working cycles, all the batteries in the short string battery group 20 will have the opportunity to be connected in parallel with different batteries in the long string battery group 10, thereby achieving balanced discharge of power. The device can ensure that all batteries participate in the balanced discharge process, effectively prevent over-discharge of the battery, and extend the service life.

[0070] This working mode does not require a complex balancing circuit, and balanced discharge management of the entire battery system can be achieved simply and efficiently by simply changing the connection combination of the multiple-selection switch 30.

[0071] Voltage regulation operating modes:

[0072] By changing the connection selection of the total positive and negative switches, it is possible to output only the long string voltage or the short string voltage, thereby adjusting the output voltage; or output the long and short string voltages at the same time to achieve a wider range of voltage regulation. Specifically, the total positive switch and the total negative switch in the device can be connected in different combinations to achieve the adjustment of the output voltage gear: when only the total positive and negative switches of the long string battery group are connected, the device outputs the voltage of the long string battery group, that is, the total voltage of N batteries; when only the total positive and negative switches of the short string battery group are connected, the device outputs the voltage of the short string battery group, that is, the total voltage of M batteries; when the total positive and negative switches of the long string battery group and the short string battery group are connected at the same time, the device outputs the superposition of the long and short string battery group voltages, which is the total voltage of N+M batteries. Through such a simple switch switching combination, the output voltage can be smoothly adjusted between M to N+M times the single battery voltage to meet the voltage requirements of different loads, such as the need for electric vehicles to adjust the power supply voltage of the drive motor at different speeds.

[0073] Compared with the method of using a DC-DC converter for voltage regulation, the device can achieve lossless DC voltage regulation, and the system efficiency is higher. At the same time, it has a simple structure, is easy to control, and reduces system complexity and cost.

[0074] Storage balance working mode:

[0075] During long-term storage, the positions of the multiple-selection switches 30 are changed regularly to establish a small current circulation between the batteries, balance the electricity, and improve the storage performance.

[0076] Specifically, when the device is in a long-term static storage state, the control unit 60 can start the storage balancing mode. In this mode, the control unit 60 regularly changes the connection combination of the multiple-selection switch 30, and different batteries are temporarily connected in parallel. Due to the difference in their own power, a small current will flow between the parallel batteries. The battery with more power will discharge slightly and provide some current to the battery with less power, thereby achieving a balanced effect. After several cycles, the power difference between all batteries can be gradually reduced. This regular small-scale discharge and recharge balancing process can avoid the self-discharge effect that occurs when the battery is in an absolutely static state, and maintain a healthy power level of the battery.

[0077] Compared with simple storage, the storage balancing mode can slow down the attenuation rate of battery power and ensure that the power of all batteries is in the optimal state when restarted, which greatly improves the storage performance of the battery.

[0078] Precise control: The control unit 60 receives the current information measured by the ampere-second meter, calculates the remaining power of each battery pack, controls the switching of the multiple-selection switch 30, monitors the battery status in real time, and ensures reliable operation of the device.

[0079] Specifically, the ampere-second meter detects the current value flowing through the long string battery pack 10 and the short string battery pack 20 in real time, and feeds back to the control unit 60 in digital or analog form. The control unit 60 has a built-in battery state algorithm model, which can calculate the remaining capacity value of each battery pack during the charging and discharging process according to the received current size and time parameters. The control unit 60 compares the remaining capacity of the two battery packs to determine whether the capacity difference exceeds the preset threshold. If it exceeds, the balancing mode is started, and the capacity deviation is corrected by changing the on state of the multiple-selection switch 30. At the same time, the control unit 60 can also monitor the voltage of each battery pack, determine the charging and discharging state, and set and switch the working mode in a targeted manner. According to the power demand, the control unit calculates the output voltage setting required by the load, determines the switching combination of the multiple-selection switch 30, and adjusts different output voltage gears in real time.

[0080] Through such precise management of closed-loop control, the device can be kept in the optimal working state at all times, avoiding battery overcharging, over-discharging, etc., and ensuring the reliable and safe operation of the system.

[0081] In summary, the device realizes the charging and discharging voltage regulation and intelligent balancing control of the battery by dynamically changing the series-parallel combination of the battery. It can be widely used in electric vehicles and other occasions.

[0082] The above embodiments have the following technical effects:

[0083] First, the battery pack's autonomous charging, discharging and voltage regulation function is realized, and the output voltage has a wide variable range to meet different load requirements. Specifically, the device can autonomously adjust the output voltage by controlling the combination of long and short string battery packs. It can output only long string voltage, or a combination of long and short strings to output a wider range of voltages, flexibly adapting to the different requirements of various loads that match it.

[0084] Furthermore, the device utilizes the natural balancing effect between the series-connected battery packs to achieve lossless balanced charging and discharging. Specifically, the device uses two battery packs of different capacities, long and short, in series. During the charging and discharging process, the battery pack with a smaller capacity can be affected by the voltage pull effect of the battery pack with a larger capacity, thereby achieving natural balance of power, without the need to use an energy-wasting balancing circuit like some technologies.

[0085] Furthermore, a rotation control strategy is adopted to balance all the batteries in the battery group and improve the battery utilization rate. Specifically, the device changes the alignment of the multiple-selection switch so that each battery in the short string battery group is connected in parallel with different batteries in the long string group in turn, thereby ensuring that all batteries participate in the balanced charging and discharging process, rather than only some batteries reaching balance, which greatly improves the comprehensive utilization rate of the battery.

[0086] Furthermore, the ampere-second meter feedback and precise control are applied to improve the intelligent level of battery management. Specifically, the device uses the ampere-second meter to feedback the current and power information in real time, and the control unit (microprocessor) makes precise control based on these data. This precise digital management method greatly improves the intelligent level of the entire system and is a more scientific battery management method.

[0087] Furthermore, the overcharge or over-discharge of a single cell can be avoided, thereby extending the service life of the battery. Specifically, the device can ensure that each battery participates in the balanced management, avoiding the overcharge or over-discharge of individual batteries, thereby maximizing the use of the capacity of each battery and extending the service life of the entire battery pack.

[0088] Furthermore, the system does not require an additional balancing circuit, which simplifies the circuit structure and reduces manufacturing costs. Specifically, the device can achieve balanced charging and discharging only through the series-parallel combination of batteries, and does not need to add complex and expensive balancing circuits like other technologies, thus greatly simplifying the structure of the entire system and reducing manufacturing and use costs.

[0089] Furthermore, the device has good scalability, and battery strings can be added as needed to change the voltage regulation range. Specifically, the device supports simply adding battery strings to expand the battery capacity and regulation range without changing its main topology, which provides great flexibility to meet different application requirements.

[0090] Furthermore, the control strategy can be designed according to the number of battery packs to achieve personalized battery management. Specifically, the microprocessor control unit in the device supports programmable design, and the user can customize the number of battery packs and connection mode, design a unique control strategy, and achieve personalized battery management.

[0091] Furthermore, it is highly compatible with existing battery management systems. Specifically, the voltage output regulation and balancing control implemented by the device are in line with standard battery management protocols, and can be seamlessly integrated into various existing battery management systems, replacing the battery modules therein and achieving better control effects.

[0092] Furthermore, it can also be widely used in electric vehicles and other occasions that require frequent speed and voltage regulation. The device can achieve flexible voltage output control while ensuring balanced management, which is very suitable for electric vehicles and other occasions that require frequent voltage regulation, and can effectively solve the technical pain points in this field.

[0093] In order to better understand the technical solution of the present application, a specific example is provided below for illustration. The details listed in the example are mainly for ease of understanding and are not intended to limit the scope of protection of the present application.

[0094] Overall composition:

[0095] Figure 1 There are two battery packs connected in series, the left side is a long string battery pack 10 composed of N batteries connected in series, and the right side is a short string battery pack 20 composed of M batteries connected in series. The two battery packs are combined together through a multiple-selection switch 30 to form a battery pack - an N-string + M-string mixed battery pack. The output ends of the two strings of batteries are respectively connected through the two-choice main switches K1 and K2 at the positive and negative ends to become the total output of the entire battery pack. The control unit 60 continuously reads the ampere-second meter to grasp the operating status of the battery pack, and controls the actions of the multiple-selection switch 30 and the main switch accordingly.

[0096] The specific details and working principle of this example are further explained below.

[0097] Multi-select switch 30

[0098] The multiple-select switch 30 is composed of N+2M+1 stationary contacts and M+1 moving contacts. -M To SC -1 , and static contact SC N+1 To SC N+M The floating pin is not brought out, and the static contact SC0 to SC N Connected to the two ends and the middle node of the long string battery group 10 (a total of N+1); moving contacts MC0 to MC MThey are sequentially connected to both ends and the middle node of the short string battery group 20 (a total of M+1).

[0099] The moving contact group can perform three actions according to the requirements of the control signal:

[0100] 1 disconnected, the moving contact is separated from the corresponding static contact, and the circuit connection is disconnected;

[0101] 2. Move. After disconnection, the moving contact can move up and down and locate to the position corresponding to the new static contact;

[0102] 3 is closed, the moving contact is closed with the corresponding static contact, and the circuit is connected.

[0103] Figure 2 The moving contact is shown in its uppermost and lowermost positions.

[0104] By changing the positional relationship of the multiple-selection switch 30 and coordinating the actions of the main switches K1 and K2, a variety of dynamic balancing and voltage regulation functions can be achieved.

[0105] Battery parallel balancing analysis:

[0106] In order to clearly analyze the situation of N strings and M strings of batteries moving and paralleling, we can start from the most basic analysis, that is, two batteries in parallel. Figure 3 As shown, two batteries E1 and E2 are connected in parallel and are in three states: storage (I), charging (II), and discharging (III):

[0107] Figure 3 In the example, r1 and r2 are the internal resistances of the two batteries, and the battery voltage E1>E2 is assumed.

[0108] Then I1=I2=(E1-E2) / (r1+r2)

[0109] That is to say, in the storage state, when two batteries with unequal voltages are connected in parallel, a current will be generated between them, and one battery (E1) will discharge and charge the other battery (E2). At this time, the currents flowing through the two batteries are equal in magnitude and opposite in direction. We may as well call this current the balancing current I 平 , that is: I 平 =(E1-E2) / (r1+r2), if we ignore the difference in battery internal resistance, we have: I 平 =ΔE / 2r

[0110] It should be noted that the battery has losses during charging and discharging. This loss usually exceeds 10%. Figure 3 In the (a) state, the energy transferred by the balance between the two batteries will be accompanied by balance loss.

[0111] Figure 3(2) Status: During charging,

[0112] E1 + I1r1 = E2 + I2r2 (1)

[0113] I = I1 + I2 (2)

[0114] Substituting I2 = I - I1 into equation (1) gives:

[0115] I1 = (Ir2 + E2 - E1) / (r1 + r2)

[0116] Similarly: I2 = (Ir1 + E1 - E2) / (r1 + r2)

[0117] If the difference in battery internal resistance is ignored, then: I1 = I / 2 - I 平 ; I2 = I / 2 + I 平

[0118] Furthermore, the inventors of the present application found that a battery with a low charge level will obtain a larger charging current due to its low voltage, while a battery with a high charge level will be charged less. That is to say, a battery with a low charge level will catch up through faster charging until the two batteries reach equilibrium. And this equilibrium is achieved automatically without special control. All that needs to be done is to connect the batteries in parallel.

[0119] In terms of loss, it is Figure 3 very different from (1). As long as both I1 and I2 are positive, it means that both batteries are in the charging state and there is no situation where one battery discharges to charge the other battery. Therefore, this form of equilibrium has no additional loss, whether it is electrical energy or battery life.

[0120] Thus, the inventors of the present application obtained an important conclusion: As long as the voltage difference between the two batteries is not too large and satisfies ΔE < rI, completely free battery equilibrium can be achieved during the charging process!

[0121] During discharging, that is Figure 3 (3) Status, actually only the current direction is opposite, and the rest is Figure 3 the same as (2). Therefore, similarly, when ΔE < rI is satisfied, battery equilibrium without additional loss can be achieved during the discharging process!

[0122] Charging equilibrium

[0123] How can two strings of batteries with different lengths be fully charged and balanced at the same time? In Figure 1In the figure, the total negative switch 40K1 is connected to the A terminal, and the total positive switch 50K2 is connected to the A terminal, that is, the total output P+ and P- of the battery pack are connected to the two ends of the long string battery. When the charging pile energizes the P+ and P- terminals, it starts to charge the long string battery. As mentioned above, while charging, as long as the two batteries are connected in parallel in time, the charging balance of the two batteries can be achieved, and the balanced batteries are in a state of equal power. Therefore, if the short string battery is connected in parallel to part of the long string battery through the multiple selection switch 30, it can share the charging current. The short string battery can be charged while balancing by constantly rotating the long string battery object corresponding to it in parallel. Due to the balancing effect of parallel charging, the difference of the batteries will be gradually leveled during the process of rotating parallel connection. For the entire battery pack, it is necessary to use the balancing medium of the short string and constantly change the parallel objects so that each battery in the long and short strings can be charged evenly and synchronously until it is full. In layman's terms, it is necessary to give each battery in the long string an equal opportunity to connect and connect in parallel with the battery in the short string one by one. In the process of continuously rotating the parallel objects, balanced charging of each battery is achieved without having to worry about the batteries being in an unbalanced power state at the beginning of charging, or having slight differences in the capacity of each battery.

[0124] In order to allow each battery to obtain an equal opportunity for parallel balancing and effectively improve the working efficiency of balancing, this example adopts a three-layer balancing cycle. The innermost layer is the long string coverage, that is, the moving contact of the multi-select switch 30 connects the long string batteries in parallel from the bottom (called single-step charging connection); after completing the single-step charging, it moves upward M positions and connects in parallel again; and the cycle continues until it reaches the top. The middle layer is the short string stepping, that is, after completing the innermost long string coverage, the moving contact of the multi-select switch 30 will return to the bottom, but it will be one static contact position higher than the starting position of the last long string coverage. Taking this as the starting point, another long string coverage is performed. After M cycles, each battery in the long string has achieved a parallel contact with any battery in the short string, that is, a complete coverage is completed. The outermost cycle is to continuously perform the middle layer cycle (complete coverage) until the charging is completed.

[0125] Figure 4 A flow chart of charge equalization is shown.

[0126] N series discharge balance

[0127] N-series discharge balancing is suitable for most power batteries and energy storage battery applications. This method is closest to the current usage on the market. As with charge balancing, the total negative switch 40K1 is connected to the A terminal, the total positive switch 50K2 is connected to the A terminal, and the total output P+ and P- of the battery pack are connected to the two ends of the long string of batteries. In this way, the N-series discharge balancing circuit is ready

[0128] This process is actually very similar to the aforementioned charge balancing, except that the direction of the current is opposite. During discharge, the M strings are still connected in parallel with the N strings in a continuous cycle, and the batteries are balanced while discharging. It is not difficult to see that the total energy of the battery pack is the sum of the energy of all batteries in the long string and the short string, and the output voltage is the superimposed voltage of the N string batteries. The N+M grouping method is very special: although it is asymmetric, all batteries can maintain the same charge and discharge progress and maintain consistency at all times. This is fundamentally different from some current redundant battery strategies.

[0129] It should be pointed out that battery inconsistency is ubiquitous, and new inconsistencies will continue to be generated during use. If there is no balancing strategy, assuming that there is a battery with a smaller capacity in a long string of batteries 10, then, due to the series operation, this battery will always be fully charged earlier than other batteries, and when discharging, this battery will always be the first to be discharged. Therefore, when other batteries still have a surplus, this battery has reached the limit state of charge and discharge. At this time, the protection circuit has to interrupt the operation of the entire battery pack. Therefore, the capacity of the entire string of batteries cannot be fully utilized. What is more serious is that the degradation of the battery always occurs more at the end of charging and discharging, so this poor battery will decay earlier than other batteries, and the capacity difference will become larger and larger, resulting in more and more serious inconsistency. Therefore, this is a vicious cycle.

[0130] After adopting this method, when the battery with small capacity is balanced in parallel, it will keep the same progress as other batteries by charging and discharging less, thus avoiding the impact on its own life and ensuring that the whole group of batteries can fully utilize all their capacity. Therefore, this is an excellent balancing method with a "health care" effect. In particular, there is no additional balancing loss in the whole process, which is a completely "free" good method.

[0131] It should be pointed out that in this balancing method, the working modes of long strings and short strings are different, which will lead to unbalanced working "intensity". Long string batteries work alone more often, while short string batteries always work in parallel with the corresponding batteries in the long string. Therefore, the working "intensity" of short string batteries is much smaller. This brings another problem. In order to distribute the workload more evenly, the capacity of a single short string battery should be smaller than that of a long string. This is also another important parameter of N+M string battery grouping: the configuration ratio of battery capacity.

[0132] Combine the following Figure 5 Perform calculations.

[0133] When discharging, most of the batteries in the long string work alone, while a few work in parallel with the short string. Therefore, the discharge speed of the long string battery will be greater than that of the short string battery.

[0134] For a long string of batteries, the time M / N is parallel discharge, and the time (NM) / N is single discharge. So the discharge amount is: I*M / N+I1*(NM) / N

[0135] The short string battery is always discharged in parallel. The discharge amount is I2

[0136] So the discharge ratio K of the two battery strings is I*M / N+I1*(NM) / N:I2

[0137] And I=I1+I2

[0138] If we assume that I1 = I2, then K = 2-M / N

[0139] It should be pointed out that the discharge speed of the short string is always slower than that of the long string. The two are just infinitely close, but the overall characteristic of the short string being slower in discharge is maintained. No matter how small the capacity of the short string is, it will still lag behind the long string. In fact, this is also very obvious. Even if the capacity of the short string is close to 0, it will not affect the operation of the long string. Therefore, the choice of the capacity of the short string is mainly based on the consideration of balance. Obviously, the higher the capacity of the short string, the larger the range of inconsistency that can be balanced.

[0140] Therefore, in this example, it is still appropriate to choose I1=I2. Therefore, the capacity of a single short string battery can be 1 / (2-M / N) of the long string, or directly 1 / 2. Of course, if the consistency of the long string is already very good, a smaller short string battery capacity can be configured.

[0141] Storage Balance

[0142] When the battery pack is stored for a long time, the capacity will slowly decrease due to the effect of self-discharge. In this process, inconsistencies may occur. In order to prevent individual batteries from discharging too early or too quickly, regular balancing is also required. This balancing is similar to the aforementioned discharge balancing, but because the energy information of self-discharge cannot be obtained, time needs to be used as a control variable. Generally speaking, a full cycle once a month can meet the requirements.

[0143] Voltage regulation and balance

[0144] With the emergence of sodium-ion batteries, the topic of wide discharge platform has gradually attracted attention. For such wide-platform batteries, the discharge voltage can gradually and linearly drop from 3.9V to 2.2V, or even wider, during the discharge process. This means that for 500V automotive applications, the total voltage will be below 300V in the later stage of discharge. This will seriously affect the application effect. Therefore, the battery pack needs to have a certain voltage regulation capability. This method just has good voltage regulation capability.

[0145] The N-string discharge method has been introduced above. If the total negative switch 40K1 is connected to the B terminal, and the total positive switch 50K2 is connected to the B terminal, the total output P+ and P- of the battery pack are connected to the two ends of the short string battery. At this time, it is the M-string discharge, and the discharge voltage is M*single-cell voltage. In this mode, a method similar to the aforementioned charge balancing can still be used to keep the moving contact of the multi-select switch 30 moving, and the M string is continuously connected in parallel with the N string in a cycle, and the battery is balanced while discharging. Unlike the N-string discharge, in this mode, all the short string batteries are put into operation, while on the long string battery side, only part of the batteries are involved in the work at the same time. Therefore, this time the short string battery discharges first, and the long string battery follows closely. The M-string discharge obtains a lower discharge voltage.

[0146] Optionally, if a higher voltage is required, N+M series discharge can be used. However, when discharging in this mode, balancing cannot be performed. Of course, balancing compensation can still be performed when returning to other modes. Move the multi-select switch 30 to the bottom, so that MC M Connected to SC0, the total negative switch 40K1 connects to the B terminal, and the total positive switch 50K2 connects to the A terminal, the battery pack realizes N+M series operation. Similarly, the multi-select switch 30 is moved to the top, so that MC0 and SC N When turned on, the total negative switch 40K1 connects to the A terminal, and the total positive switch 50K2 connects to the B terminal. The battery pack can also work in N+M series.

[0147] So far, three kinds of working voltages are obtained: M string, N string, and N+M string. This is enough for general inverter drive. If more abundant voltage regulation functions are needed, two groups of battery packs of this solution can be used in series, so that up to 9 voltage levels can be obtained. For example, the first battery pack is N1=2, M1=1, and the second battery pack is N2=3, M2=6. Then 9 voltage combinations of 4, 5, 6, 7, 8, 9, 10, 11, and 12 can be combined.

[0148] Optionally, if one is willing to sacrifice the consistency of discharge, in special cases, this solution can also implement any voltage combination from 1 to N+M strings.

[0149] In another embodiment of the present application, an electric vehicle is provided, which uses the above-mentioned battery group device as a power source.

[0150] It should be noted that in the application documents of this patent, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one" do not exclude the existence of other identical elements in the process, method, article or device including the elements. In the application documents of this patent, if it is mentioned that an action is performed according to an element, it means that the action is performed at least according to the element, which includes two situations: performing the action only according to the element, and performing the action according to the element and other elements. Expressions such as multiple, multiple, and multiple include 2, 2 times, 2 kinds, and more than 2, more than 2 times, and more than 2 kinds.

[0151] All documents mentioned in this application are considered to be included in the disclosure of this application as a whole, so that they can be used as the basis for modification when necessary. In addition, it should be understood that after reading the above disclosure of this application, those skilled in the art can make various changes or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A battery grouping device, characterized in that ,include: A long battery string, comprising N rechargeable first batteries connected in series, a positive electrode of the first first battery, a connection between the negative electrode of each first battery and the positive electrode of the next first battery, and a negative electrode of the last first battery, forming N+1 nodes in sequence; A short string battery pack, comprising M rechargeable second batteries connected in series, the positive electrode of the first second battery, the connection between the negative electrode of each second battery and the positive electrode of the next second battery, and the negative electrode of the last second battery, sequentially forming M+1 nodes, N>M>1; A multiple-select switch, comprising a static contact group and a moving contact group, wherein the static contact group comprises N+1 static contacts with equal spacing, and the moving contact group comprises M+1 moving contacts with equal spacing, wherein the N+1 nodes of the long string battery group are electrically connected to the N+1 static contacts in sequence, and the M+1 nodes of the short string battery group are electrically connected to the M+1 static contacts in sequence, and the spacing between adjacent static contacts is equal to the spacing between adjacent moving contacts; There are multiple connection positions in the multiple-selection switch. When the moving contact group moves to any of the connection positions, the M+1 moving contacts in the moving contact group are electrically connected to the continuous M+1 static contacts in the static contact group, so that the M second batteries in the short string battery group are connected in parallel with the continuous M first batteries in the long string battery group to achieve balance between the corresponding first batteries and the second batteries; when the moving contact group moves from one connection position to another connection position, the second batteries in the short string battery group can be connected in parallel with different first batteries in the long string battery group.

2. The battery assembly device according to claim 1, characterized in that: Also includes, A total positive switch, used for selectively connecting the positive terminal of the long string battery group or the short string battery group to the positive output terminal of the device; The total negative switch is used to selectively connect the negative terminal of the long string battery group or the short string battery group to the negative output terminal of the device.

3. The battery assembly device according to claim 2, characterized in that: In the static contact group, two extension directions at both ends of the N+1 static contacts arranged in a straight line also include M-1 suspended static contacts respectively; The moving contact group slides between a total of N+2M-1 static contacts, so that any second battery in the short string battery group has the opportunity to be connected in parallel with any first battery in the long string battery group.

4. The battery assembly device according to claim 3, characterized in that: By switching the multiple-selection switch, the total negative switch and the total positive switch, charging balance, discharging balance and voltage regulation of the battery are achieved.

5. The battery assembly device according to claim 4, characterized in that: The main positive switch connects the positive terminal of the long string of batteries to the positive output terminal of the device, The total negative switch connects the negative terminal of the short string battery group to the negative output terminal of the device, By adjusting the position of the moving contact group relative to the stationary contact group, the number of connections between the moving contacts in the moving contact group and the suspended stationary contacts in the stationary contact group changes, thereby adjusting the output voltage between the positive output terminal and the negative output terminal.

6. The battery assembly device according to claim 4, characterized in that: The main positive switch connects the positive terminal of the long string of batteries to the positive output terminal of the device, The total negative switch connects the negative terminal of the short string battery group to the negative output terminal of the device, The moving contact group is moved to the endmost connection position so that the negative electrode of the long string battery group is connected to the positive electrode of the short string battery group, thereby outputting a maximum voltage that can be provided between the positive output terminal and the negative output terminal.

7. The battery assembly device according to claim 4, characterized in that: The main positive switch connects the positive terminal of the long string of batteries to the positive output terminal of the device, The main negative switch connects the negative terminal of the long string battery group to the negative output terminal of the device, The moving contact group reciprocates within the range of the stationary contact group. Each time the moving contact group moves to a connection position, it stays for a predetermined time to achieve a balance between the corresponding first battery and the second battery, and then moves to the next connection position.

8. The battery assembly device according to claim 4, characterized in that: The main positive switch connects the positive terminal of the short string battery group to the positive output terminal of the device, The total negative switch connects the negative terminal of the short string battery group to the negative output terminal of the device, The moving contact group reciprocates within the range of the stationary contact group. Each time the moving contact group moves to a connection position, it stays for a predetermined period of time and then moves to the next connection position, thereby increasing the discharge time between the positive output terminal and the negative output terminal at the output voltage of the short string battery group.

9. The battery assembly device according to claim 1, characterized in that: The rated capacity of a single battery cell in the long string battery group is greater than the rated capacity of a single battery cell in the short string battery group.

10. An electric vehicle, characterized in that , using the battery group device as described in any one of claims 1-9 as the power source.

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