Hybrid battery system

Abstract

The invention relates to the technical field of storage batteries, in particular to a hybrid battery system. According to the hybrid battery system provided by the invention, the technical problem that a storage battery in the prior art is poor in environmental adaptability or low in energy density is solved. A hybrid battery system includes a first battery pack; the first battery pack and the second battery pack respectively adapt to different working environments; the working states of the first battery pack and the second battery pack are controlled by the control unit; according to the hybrid battery system, the first battery pack, the second battery pack and the control unit are arranged, the control unit controls the first battery pack and the second battery pack to work, and the first battery pack and the second battery pack respectively adapt to different working environments, so that the hybrid battery system can adapt to different working environments and has higher adaptability.

Description

Technical Field

[0001] The present invention relates to the technical field of storage batteries, and particularly to a hybrid battery system. Background Art

[0002] Lithium-ion batteries have significant advantages as power batteries in terms of high energy density, but they are relatively sensitive to temperature. The temperature of the battery itself and the internal temperature uniformity have a great impact on the reliability and life of the battery. Whether the working temperature of the battery pack is too high or too low will affect the performance of the battery. High temperature will cause thermal runaway of the battery, leading to safety problems, while unreasonable temperature distribution will result in reduced battery capacity utilization and accelerated capacity attenuation. Therefore, during the charging and discharging process, the battery needs to be maintained within a suitable temperature range, and its environmental adaptability is relatively low.

[0003] Sodium-ion batteries have the advantages of high power and good low-temperature performance, and can operate stably in extremely cold environments, but they have the disadvantage of low energy density.

[0004] Existing storage batteries, especially power batteries, usually adopt lithium-ion batteries or sodium-ion batteries. However, both of these batteries have corresponding disadvantages. For example, lithium-ion batteries have unstable discharge in low-temperature environments, while sodium-ion batteries have low energy density.

[0005] Therefore, the storage batteries in the prior art have technical problems such as poor environmental adaptability or low energy density. Summary of the Invention

[0006] A hybrid battery system provided by the present invention solves the technical problems of poor environmental adaptability or low energy density of the storage batteries in the prior art.

[0007] Some embodiments for solving the above technical problems include: A hybrid battery system, including a first battery pack; A second battery pack, where the first battery pack and the second battery pack are respectively adapted to different working environments; And a control unit, and the working states of the first battery pack and the second battery pack are both controlled by the control unit; Wherein, when the environmental conditions meet the working environments of both the first battery pack and the second battery pack at the same time, the control unit controls the first battery pack or / and the second battery pack to work normally; When the environmental conditions do not meet the working environment of the first battery pack and do not meet the working environment of the second battery pack, the control unit controls the first battery pack and the second battery pack to stop working; When the environmental conditions meet the operating environment of the second battery pack and do not meet the operating environment of the first battery pack, the control unit controls the second battery pack to operate and controls the first battery pack to enter the environmental adaptation state until the first battery pack meets the operating conditions, and then the control unit controls the first battery pack to operate and the second battery pack stops operating.

[0008] Preferably, the first battery pack is a lithium-ion battery pack and the second battery pack is a sodium-ion battery pack.

[0009] Preferably, when the environmental temperature meets the operating environment of the second battery pack and is lower than the operating environment of the first battery pack, the control unit controls the second battery pack to operate and controls the first battery pack to enter the environmental adaptation state.

[0010] Preferably, when the first battery pack enters the environmental adaptation state, the first battery pack is repeatedly charged and discharged.

[0011] Preferably, when the first battery pack enters the environmental adaptation state, the first battery pack is repeatedly charged and discharged in a high-rate and short-time pulse manner.

[0012] Preferably, the control unit includes a first switching device connected in series with the first battery pack, a second switching device connected in series with the second battery pack, a battery management unit, a discharge switching device, and a power conversion device. The first switching device, the second switching device, the discharge switching device, and the power conversion device are all controlled by the battery management unit. The power conversion device is connected in series between the first battery pack and the second battery pack. The discharge switching device is connected in series between the first battery pack and the first switching device. The first battery pack and the second battery pack are arranged in parallel.

[0013] Preferably, both the first switching device and the second switching device are relays or MOSFETs.

[0014] Preferably, the battery management unit is a single-chip microcomputer, and the battery management unit collects the battery voltage, loop current, and temperature of the first battery pack and the second battery pack.

[0015] Preferably, the power conversion device includes a circuit connecting the first battery pack and the second battery pack, a capacitor, a first switch drive circuit output, a second switch drive circuit output, a first alternating switch, and a second alternating switch. The circuit includes a first circuit connecting the positive electrode of the first battery pack to the positive electrode of the second battery pack, a second circuit connecting the negative electrode of the first battery pack to the negative electrode of the second battery pack, and a third circuit connecting the first circuit and the second circuit. Among them, the capacitor and the second alternating switch are both connected in series to the first circuit, and the second alternating switch is connected to the third circuit through the second switch drive circuit output. The first alternating switch is connected in series to the third circuit, and one end of the first switch drive circuit output is connected to the first alternating switch, and the other end of the first switch drive circuit output is connected to the second circuit.

[0016] Preferably, both the first alternating switch and the second alternating switch are MOSFETs.

[0017] Compared with the prior art, the present invention has the following advantages: By providing the first battery pack, the first battery pack, and the control unit, the control unit controls the operation of the first battery pack and the second battery pack. The first battery pack and the second battery pack respectively adapt to different working environments, so that the hybrid battery system can adapt to different working environments and has higher adaptability.

[0018] For example, in a low-temperature state, the second battery pack can be made to adapt to the low-temperature environment, and the second battery pack discharges first. During the discharge process of the second battery pack, the first battery pack enters the environment adaptation state. When the first battery pack meets the working conditions, the first battery pack or / and the second battery pack discharges. The hybrid battery system can output at any time in low temperature without waiting, and the user will not feel any jerks. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] For purposes of explanation, several embodiments of the technology of the present invention are illustrated in the following drawings. The following drawings are incorporated herein and form a part of the specific embodiments. In some cases, well-known structures and components are shown in block diagram form to avoid obscuring the concepts of the subject technology of the present invention.

[0020] Figure 1 is the circuit diagram of the present invention.

[0021] Figure 2 is the circuit diagram of the power conversion device.

[0022] Figure 3 is the first schematic diagram of the current flow direction when the first battery pack enters the environment adaptation state.

[0023] Figure 4 It is a schematic diagram of the second current flow direction when the first battery pack enters the environmental adaptation state. Figure 3 、 Figure 4 The double-dashed line in [[ ]] indicates the direction of the current.

[0024] As shown in the figure: 1. First battery pack, 2. Second battery pack, 3. First switching device, 4. Second switching device, 5. Battery management unit, 6. Discharge switching device, 7. Power conversion device.

[0025] 71. Capacitor, 72. First alternating switch, 73. Second alternating switch, 74. Output of the first switch drive circuit, 75. Output of the second switch drive circuit. Detailed implementation manners

[0026] The following detailed implementation manners shown are intended to be descriptions of various configurations of the subject technology of the present invention, and are not intended to represent the only configuration in which the subject technology of the present invention can be practiced. The detailed implementation manners include specific details intended to provide a thorough understanding of the subject technology of the present invention. However, it will be clear and obvious to those skilled in the art that the subject technology of the present invention is not limited to the specific details shown herein, and can be practiced without these specific details.

[0027] It can be understood that, herein, relational terms such as "first" and "second" are intended to distinguish one entity or operation from another entity or operation, and are not intended to explicitly or implicitly imply any actual relationship or order between these entities or operations.

[0028] The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device including a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0029] Referring to Figures 1 to 4 As shown, a hybrid battery system includes a first battery pack 1; A second battery pack 2, where the first battery pack 1 and the second battery pack 2 are adapted to different working environments respectively; And a control unit, and the working states of both the first battery pack 1 and the second battery pack 2 are controlled by the control unit; Among them, when the environmental conditions meet the working environments of the first battery pack 1 and the second battery pack 2 at the same time, the control unit controls the first battery pack 1 or / and the second battery pack 2 to work normally; When the environmental conditions do not meet the working environment of the first battery pack 1 and do not meet the working environment of the second battery pack 2, the control unit controls the first battery pack 1 and the second battery pack 2 to stop working; When the environmental conditions meet the working environment of the second battery pack 2 and do not meet the working environment of the first battery pack 1, the control unit controls the second battery pack 2 to work and controls the first battery pack 1 to enter the environmental adaptation state until the first battery pack 1 meets the working conditions, and then the control unit controls the first battery pack 1 to work and the second battery pack 2 to stop working.

[0030] It can be understood that this solution uses two or more batteries with different electrochemical systems, as well as necessary electronic control devices and control software to form an overall battery pack. By using batteries with two different electrochemical systems, the advantages of two or more batteries are complementary and the disadvantages are reduced, so that the overall battery pack shows stronger technical advantages and a wider range of applications.

[0031] In some embodiments, the first battery pack 1 is a lithium-ion battery pack, and the second battery pack 2 is a sodium-ion battery pack.

[0032] Refer to Figure 1 As shown, in this embodiment, the batteries of the two chemical systems respectively use lithium-ion batteries and sodium-ion batteries. It can be understood that this embodiment is only for further introducing the technical solution of the present invention and is not a limitation on the technical solution of the present invention. For example, the lithium-ion battery pack and sodium-ion battery pack used in this embodiment are not limitations on the first battery pack 1 and the second battery pack 2. The first battery pack 1 and the second battery pack 2 can be replaced by any two batteries with different electrochemical systems. For example, it can be a combination of a battery and a supercapacitor, etc. As long as it is a combination of two different electrical energy storage devices, it can be applied to the technical solution described in the present invention.

[0033] In some embodiments, when the environmental temperature meets the working environment of the second battery pack 2 and is lower than the working environment of the first battery pack 1, the control unit controls the second battery pack 2 to work and controls the first battery pack 1 to enter the environmental adaptation state.

[0034] In some embodiments, when the first battery pack 1 enters the environmental adaptation state, the first battery pack 1 is repeatedly charged and discharged. For example, when the first battery pack 1 enters the environmental adaptation state, the first battery pack 1 is repeatedly charged and discharged in a high-rate, short-time pulse manner.

[0035] Refer to Figure 1As shown, in some embodiments, the control unit includes a first switching device 3 connected in series with the first battery pack 1, a second switching device 4 connected in series with the second battery pack 2, a battery management unit 5, a discharge switching device 6, and a power conversion device 7. The first switching device 3, the second switching device 4, the discharge switching device 6, and the power conversion device 7 are all controlled by the battery management unit 5. The power conversion device 7 is connected in series between the first battery pack 1 and the second battery pack 2. The discharge switching device 6 is connected in series between the first battery pack 1 and the first switching device 3. The first battery pack 1 and the second battery pack 2 are arranged in parallel.

[0036] In some embodiments, both the first switching device 3 and the second switching device 4 are relays or MOSFETs.

[0037] In some embodiments, the battery management unit 5 is a single-chip microcomputer, and the battery management unit 5 collects the battery voltages, loop currents, and temperatures of the first battery pack 1 and the second battery pack 2.

[0038] The technical solution of the present invention will be specifically introduced below with a practical application example: The first switching device 3 and the second switching device 4 are two different controllable switches, which can be relays, MOSFETs, or any other controllable circuit switching devices, and are respectively used to unidirectionally cut off the loop current in the charging and discharging directions to achieve the purpose of independently controlling charging and discharging. The battery management unit 5 is any unit that can collect data and can be any electronic device with relevant functions, such as a single-board computer. Its function is to collect the battery physical states of the first battery pack 1 and the second battery pack 2, including battery voltage, loop current, and temperature information, and can run software. The software realizes the control of the hybrid battery according to the collected physical quantities and corresponding control strategies.

[0039] Specifically, the working principle of the hybrid battery system of the present invention is that one of the electrochemical system batteries is used as a primary energy storage component to directly output or receive charging; the other system battery is used as a secondary energy storage component, and is elastically loaded into the hybrid battery system according to the power consumption demand and working conditions, or works in parallel with the primary energy storage component, or is completely separated from the primary energy storage component, or is in an elastic connection state.

[0040] Refer to Figures 2 to 4As shown, the power conversion device 7 is the core unit of the present invention. In some embodiments, the power conversion device 7 may include a loop connecting the first battery pack 1 and the second battery pack 2, a capacitor 71, a first switch drive circuit output 74, a second switch drive circuit output 75, a first alternating switch 72, and a second alternating switch 73. The loop includes a first circuit connecting the positive electrode of the first battery pack 1 to the positive electrode of the second battery pack 2, a second circuit connecting the negative electrode of the first battery pack 1 to the negative electrode of the second battery pack 2, and a third circuit connecting the first circuit and the second circuit. Among them, the capacitor 71 and the second alternating switch 73 are both connected in series to the first circuit, and the second alternating switch 73 is connected to the third circuit through the second switch drive circuit output 75. The first alternating switch 72 is connected in series to the third circuit, and one end of the first switch drive circuit output 74 is connected to the first alternating switch 72, and the other end of the first switch drive circuit output 74 is connected to the second circuit.

[0041] In some embodiments, both the first alternating switch 72 and the second alternating switch 73 are MOSFETs.

[0042] The following specifically introduces the working process of the hybrid battery system: Under the condition of reasonable temperature, that is, the temperature is not lower than the lithium battery discharge cut-off temperature and not higher than the zero-above discharge temperature, the first switch device 3, the second switch device 4, and the discharge switch device 6 are all turned on, the power conversion device 7 stops working, and the hybrid battery system can be charged and discharged; on this premise, if the hybrid battery system is fully charged or charging protection is triggered for other reasons, the first switch device 3 is turned off, the first switch device 3 remains turned on, and the power conversion device 7 stops working; if the hybrid battery system discharges to over-discharge protection or discharge protection is triggered, the second switch device 4 and the discharge switch device 6 are turned off, the first switch device 3 remains turned on, and the power conversion device 7 stops working.

[0043] When the temperature is too low or too high, exceeding the working range of the overall hybrid battery system, the first switch device 3, the second switch device 4, and the discharge switch device 6 are all turned off, the power conversion device 7 stops working, and the overall product is in a protected state.

[0044] When the temperature is relatively low and it is not suitable for the lithium-ion battery pack to discharge, but the sodium-ion battery pack can still discharge, the first switching device 3 and the second switching device 4 are turned on, the discharge switching device 6 is turned off, and the power conversion device 7 operates. During the operation of the power conversion device 7, the lithium-ion battery pack will be repeatedly charged and discharged at an extremely high rate and in a short-time pulse manner, rather than charging or discharging in a single direction: the continuous high-rate charging and discharging, combined with the relatively high polarization internal resistance of the lithium-ion battery pack in the low-temperature state, will generate a large amount of Joule heat inside the battery, directly heating the lithium-ion battery pack, and moreover, directly heating from the inside, which can quickly raise the temperature of the lithium-ion battery pack. When the temperature rise is completed, the first switching device 3 and the second switching device 4 are turned on, the discharge switching device 6 is turned on, and the power conversion device 7 stops operating. Through this device, the low-temperature experience of the overall hybrid battery system can be greatly improved.

[0045] First, in the low-temperature state, due to the presence of the sodium-ion battery pack and the first switching device 3 being always turned on, that is to say, the hybrid battery system can output at any time in the low temperature without waiting. At this time, the sodium-ion battery pack maintains the output first, and at the same time, the power conversion device 7 operates to ensure that almost all the electrical energy consumption for heating generates Joule heat, and it directly acts on the inside of the lithium-ion battery pack. Therefore, the temperature of the lithium-ion battery pack rises very quickly. When the temperature of the lithium battery rises to completion, the discharge switching device 6 is turned on, and the lithium battery also starts to supply power, and the user will not feel any jerks. In other words, this method can be equipped with a small number of sodium-ion battery packs and a large number of lithium-ion batteries, enabling the hybrid battery system to have both the low-temperature advantages of the sodium-ion battery pack and the energy density advantages of the lithium-ion battery pack.

[0046] Refer to Figures 3 to 4 As shown in the figure, the working principle of the power conversion device 7 will be introduced below in conjunction with the attached drawings. Here, Lpack represents the lithium-ion battery pack, Npack represents the sodium-ion battery pack, C1 represents the capacitor 71, M1 represents the first alternating switch 72, M2 represents the second alternating switch 73, M1 and M2 are two MOSFETs, and can also be any device of a controllable circuit switch. Vp represents the output of the first switch drive circuit 74, and Vn represents the output of the second switch drive circuit 75. Among them, when in the off state, neither Vp nor Vn outputs voltage, and when in the working state, Vp and Vn alternately output PWM waveforms with dead zones.

[0047] When working, first M1 is turned on, and the current flows from the positive electrode of the lithium-ion battery pack through C1 and M1 back to the negative electrode, generating a discharge current. Constrained by the physical characteristics of the capacitor, the instantaneous current generated is huge but the duration is very short. After the process is over, C1 is fully charged and the voltage is equal to the Lpack voltage. Then M1 is closed and M2 is opened, and the Npack voltage is superimposed on the C1 voltage to generate a voltage that must be greater than Lpack, so the current flows from the positive electrode of the sodium-ion battery pack through M2, C1, and the lithium-ion battery pack back to the negative electrode of the sodium-ion battery pack. The above cycle is repeated continuously, and pulse charging and pulse discharging continue to alternate. The continuous pulse current continuously generates Joule heat and continuously heats the lithium-ion battery pack. The Joule heat generated in this way directly acts on the inside of the lithium-ion battery pack, so the lithium-ion battery pack will heat up faster than external heating. Moreover, this alternating pulse charge and discharge method can minimize the lithium precipitation phenomenon of the lithium-ion battery pack working at low temperature and large current compared to the pulse current heating method in a single charging or single discharging direction, and rarely damages the battery life. The capacitor-based circuit topology used in the present invention does not require an inductor, is small in size, low in complexity and cost, and even if any single MOSFET (M1 or M2) is turned on for a long time, since the lithium-ion battery pack and the sodium-ion battery pack are connected by a capacitor and DC is electrically isolated, it will not cause overcurrent in the circuit or the lithium-ion battery pack or the sodium-ion battery pack. This approach also greatly simplifies the control logic and improves reliability.

[0048] The above describes the subject technical solution and corresponding details of the present invention. It can be understood that the above description is only some implementation plans of the subject technical solution of the present invention, and some details may be omitted during the specific implementation.

[0049] In addition, in some embodiments of the above invention, multiple embodiments may be implemented in combination, and various combinations are not listed one by one due to space limitations. Those skilled in the art can freely combine and implement the above embodiments as needed in specific implementation to obtain a better application experience.

[0050] When implementing the subject technical solution of the present invention, those skilled in the art can obtain other detailed configurations or drawings based on the subject technical solution of the present invention and the drawings. Obviously, these details still fall within the scope covered by the subject technical solution of the present invention without departing from the subject technical solution of the present invention.

Claims

1. A hybrid battery system, characterized in that: The invention comprises a first battery group (1); a second battery group (2), wherein the first battery group (1) and the second battery group (2) are adapted to different working environments respectively; and a control unit, wherein the working states of the first battery group (1) and the second battery group (2) are both controlled by the control unit; wherein when the environmental conditions meet the working environments of the first battery group (1) and the second battery group (2) at the same time, the control unit controls the first battery group (1) and / or the second battery group (2) to work normally; when the environmental conditions do not meet the working environment of the first battery group (1) and do not meet the working environment of the second battery group (2), the control unit controls the first battery group (1) and the second battery group (2) to stop working; when the environmental conditions meet the working environment of the second battery group (2) and do not meet the working environment of the first battery group (1), the control unit controls the second battery group (2) to work and controls the first battery group (1) to enter an environmental adaptation state, until the first battery group (1) meets the working conditions, the control unit controls the first battery group (1) to work and the second battery group (2) to stop working.

2. The hybrid battery system according to claim 1, characterized in that: The first battery pack (1) is a lithium-ion battery pack, and the second battery pack (2) is a sodium-ion battery pack.

3. The hybrid battery system according to claim 2, characterized in that: When the ambient temperature meets the working environment of the second battery pack (2) and is lower than the working environment of the first battery pack (1), the control unit controls the second battery pack (2) to operate and controls the first battery pack (1) to enter an environmental adaptation state.

4. The hybrid battery system according to claim 3, characterized in that: When the first battery pack (1) enters an environmental adaptation state, the first battery pack (1) is repeatedly charged and discharged.

5. The hybrid battery system according to claim 4, characterized in that: When the first battery pack (1) enters the environmental adaptation state, the first battery pack (1) is repeatedly charged and discharged in a high-rate, short-time pulse manner.

6. The hybrid battery system according to claim 1, characterized in that: The control unit comprises a first switch device (3) connected in series with the first battery group (1), a second switch device (4) connected in series with the second battery group (2), a battery management unit (5), a discharge switch device (6) and a power conversion device (7); the first switch device (3), the second switch device (4), the discharge switch device (6) and the power conversion device (7) are all controlled by the battery management unit (5); the power conversion device (7) is connected in series between the first battery group (1) and the second battery group (2); the discharge switch device (6) is connected in series between the first battery group (1) and the first switch device (3); and the first battery group (1) and the second battery group (2) are arranged in parallel.

7. The hybrid battery system according to claim 5, characterized in that: The first switch device (3) and the second switch device (4) are both relays or MOSFETs.

8. The hybrid battery system according to claim 5, characterized in that: The battery management unit (5) is a single chip microcomputer, and the battery management unit (5) collects the battery voltage, loop current and temperature of the first battery group (1) and the second battery group (2).

9. The hybrid battery system according to claim 6, characterized in that: The power conversion device (7) comprises a circuit connecting a first battery group (1) and a second battery group (2), a capacitor (71), a first switch drive circuit output (74), a second switch drive circuit output (75), a first alternating switch (72) and a second alternating switch (73), wherein the circuit comprises a first circuit connecting the positive electrode of the first battery group (1) with the positive electrode of the second battery group (2), a second circuit connecting the negative electrode of the first battery group (1) with the negative electrode of the second battery group (2), and a third circuit connecting the first circuit with the second circuit, wherein the capacitor (71) and the second alternating switch (73) are both connected in series to the first circuit, and the second alternating switch (73) is connected to the third circuit via the second switch drive circuit output (75), the first alternating switch (72) is connected in series to the third circuit, and one end of the first switch drive circuit output (74) is connected to the first alternating switch (72), and the other end of the first switch drive circuit output (74) is connected to the second circuit.

10. The hybrid battery system according to claim 9, characterized in that: The first alternating switch (72) and the second alternating switch (73) are both MOSFETs.

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