All-solid-state battery system and method of manufacturing the same
An all-solid-state battery system comprising an all-solid-state battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, and a control device configured to control a charge-discharge voltage during use of the all-solid-state battery. The negative electrode active material layer includes alloy negative electrode active material particles. The amorphization degree of the alloy negative electrode active material particles is in the range of 27.8% to 82.8% and a ratio Z/W is in the range of 0.32 to 0.60, where Z is a controlled discharge capacity of the all-solid-state battery, and W is a theoretical capacity of the alloy negative electrode active material particles × a total weight of the alloy negative electrode active material particles × the amorphization degree.
1. A method of manufacturing an all-solid-state battery system, the all-solid-state battery system comprising an all-solid-state battery and a control device, the all-solid-state battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer including alloy negative electrode active material particles, the control device being configured to control a charge-discharge voltage during use of the all-solid-state battery, the method comprising:
laminating the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer including the alloy negative electrode active material particles; and
performing initial charging of the all-solid-state battery to an initial charge voltage that is higher than the charge-discharge voltage applied to the all-solid-state battery by the control device during use of the all-solid-state battery.
2. The method according to claim 1 , wherein the alloy negative electrode active material particles are silicon particles.
3. The method according to claim 1 , wherein the charge-discharge voltage is in the range of 2.50 V to 4.40 V, and
the initial charge voltage is in the range of higher than 4.45 V and 5.00 V or lower.
4. The method according to claim 3 , wherein the initial charge voltage is in the range of 4.60 V to 4.70 V.
5. The method according to claim 1 , wherein the positive electrode active material layer includes a positive electrode active material coated with a lithium-containing metal oxide protective coating.
6. The method according to claim 5 , wherein the lithium-containing metal oxide is lithium niobate.
7. The method according to claim 5 , wherein the initial charging is performed so that a value (a)/(b) is more than 1.3, where (a) is a change ratio of a charge amount to an upper limit charge voltage during the initial charging, and (b) is an average change ratio of a charge amount to a charge voltage in the range of 4.00 V to 4.40 V.