Charging system

Abstract

To provide a charging system capable of suppressing a lithium deposition.SOLUTION: A charging system comprises a processor. The processor limits quick charge in a case where a potential of a cathode of a battery cell achieves a predetermined threshold, and allows quick charge in a case where the potential of the cathode falls below the predetermined threshold.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a charging system. [Background technology]

[0002] Patent Document 1 discloses a system that suppresses the charging current when the potential of the negative electrode, calculated based on an estimated voltage drop associated with charging, falls below the lithium deposition potential. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-077464 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 is not designed for rapid charging, and therefore repeated rapid charging may result in localized resistance increase due to metal elution from the positive electrode, leading to the precipitation of lithium.

[0005] The present disclosure has been made in view of the above, and has an object to provide a charging system capable of suppressing lithium deposition. [Means for solving the problem]

[0006] The charging system according to the present disclosure includes a processor that limits rapid charging when the potential of the positive electrode of a battery cell reaches a predetermined threshold, and allows rapid charging when the potential of the positive electrode falls below the predetermined threshold. Effect of the Invention

[0007] According to the present disclosure, lithium deposition can be suppressed by controlling the potential of the positive electrode within a reversible range. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a charging system according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing an example of the configuration of a battery cell included in the battery of the charging system according to the embodiment. [Diagram 3] FIG. 3 is a flowchart showing an example of a charge control method executed by the charging system according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A charging system according to an embodiment of the present disclosure will be described with reference to the drawings. Note that components in the following embodiments include those that are easily replaceable by a person skilled in the art, or those that are substantially the same.

[0010] (Charging system) The charging system according to the embodiment is mounted on a vehicle such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV).

[0011] The charging system 1 according to the embodiment includes a control unit 10 and a battery 20, as shown in FIG.

[0012] Specifically, the control unit 10 includes a processor and a memory (main storage unit) including a RAM (Random Access Memory), a ROM (Read Only Memory), etc. The processor includes, for example, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), a GPU (Graphics Processing Unit), etc.

[0013] The control unit 10 controls charging of the battery 20. That is, the control unit 10 limits rapid charging of the battery 20 when the potential of the positive electrode 215 of the battery cell 21 described later reaches a predetermined threshold. Also, the control unit 10 allows rapid charging of the battery 20 when the potential of the positive electrode 215 falls below the predetermined threshold. In this way, the control unit 10 performs rapid charging within a reversible range of the potential of the positive electrode 215, and limits rapid charging and provides a relaxation time when the potential of the positive electrode 215 rises. The above-mentioned "predetermined threshold" can be experimentally obtained by simulation or the like based on the relationship between the increase in the potential of the positive electrode 215 and lithium deposition, for example.

[0014] Here, for example, if the potential of the positive electrode 215 exceeds the reversible range due to repeated rapid charging, metal elution occurs, which may lead to a local increase in resistance, causing lithium deposition on the negative electrode 216. On the other hand, in the charging system 1 according to the embodiment, charging is controlled within the reversible range of the potential of the positive electrode 215, thereby making it possible to suppress lithium deposition.

[0015] The battery 20 includes a plurality of battery cells 21, for example, as shown in Fig. 2. The battery cells 21 are, for example, lithium ion secondary batteries. The battery cells 21 include a lid 211a, a case 211b, a positive electrode terminal 212, a negative electrode terminal 213, an electrode body 214, a positive electrode 215, a negative electrode 216, and a separator 217.

[0016] The lid 211a is for sealing the upper surface of the case 211b. The lid 211a is provided with a positive electrode terminal 212 and a negative electrode terminal 213. One end (upper side) of the positive electrode terminal 212 and the negative electrode terminal 213 protrudes from the lid 211a to the outside. The other end (lower side) of the positive electrode terminal 212 and the negative electrode terminal 213 is electrically connected to an internal positive electrode terminal and an internal negative electrode terminal (not shown) inside the case 211b, respectively.

[0017] The electrode body 214 is housed inside the case 211b. The electrode body 214 is formed, for example, by winding a positive electrode (positive electrode sheet) 215 and a negative electrode (negative electrode sheet) 216, which are laminated with a separator 217 interposed therebetween, into a cylindrical shape. The electrode body 214 is impregnated with an electrolyte.

[0018] Various known materials can be used as the materials for the positive electrode 215, the negative electrode 216, the separator 217, and the electrolyte. For example, the positive electrode 215 can be made of lithium cobalt oxide or lithium manganese oxide. The current collector foil of the positive electrode 215 can be made of aluminum or the like. The negative electrode 216 can be made of carbon (graphite) or the like. The current collector foil of the negative electrode 216 can be made of copper or the like. The separator 217 can be made of polyolefin or the like. The electrolyte contains, for example, an organic solvent, lithium ions, and additives.

[0019] In this embodiment, the battery cell 21 is a typical lithium ion secondary battery. However, this lithium ion secondary battery also includes, for example, a lithium polymer battery that uses a polymer gel as an electrolyte.

[0020] (Charging control method) The flow of a charge control method executed by the charging system according to the embodiment will be described with reference to FIG.

[0021] First, the control unit 10 integrates the increase in the potential of the positive electrode 215 (step S1). Next, the control unit 10 determines whether the integrated value of the increase in the potential of the positive electrode 215 is equal to or greater than a predetermined threshold value (step S2).

[0022] In step S2, when it is determined that the integrated value of the increase in the potential of the positive electrode 215 is equal to or greater than the predetermined threshold value (Yes in step S2), the control unit 10 limits the rapid charging of the battery 20 (step S3). Next, the control unit 10 determines whether or not the integrated value of the increase in the potential of the positive electrode 215 is less than the predetermined threshold value (step S4).

[0023] In step S4, when it is determined that the integrated value of the increase in the potential of the positive electrode 215 is less than the predetermined threshold value (Yes in step S4), the control unit 10 performs (allows) rapid charging of the battery 20 (step S5) and completes this process.

[0024] Here, in step S2, if the control unit 10 determines that the integrated value of the increase in the potential of the positive electrode 215 is not equal to or greater than the predetermined threshold value (No in step S2), the control unit 10 proceeds to step S5. In addition, in step S4, if the control unit 10 determines that the integrated value of the increase in the potential of the positive electrode 215 is not less than the predetermined threshold value (No in step S4), the control unit 10 proceeds to step S3.

[0025] According to the charging system according to the embodiment described above, the potential of the positive electrode 215 is controlled within a reversible range, thereby making it possible to suppress lithium deposition.

[0026] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0027] 1 Charging System 10 Control section 20 Battery 21 Battery Cell 211a Lid body 211b Case 212 Positive terminal 213 Negative terminal 214 Electrode body 215 Positive electrode 216 negative electrode 217 Separator

Claims

[Claim 1] A processor is provided. The processor, When the potential of the positive electrode of the battery cell reaches a predetermined threshold, the fast charging is limited. When the potential of the positive electrode falls below the predetermined threshold, rapid charging is permitted. Charging system.

Images